Insular cortex#Interoceptive awareness

The insula is divided into an anterior and a posterior part by the central sulcus of the insula.{{cite web |last1=Kortz |first1=Michael W. |last2=Lillehei |first2=Kevin O. |title=Insular Cortex |url=https://www.ncbi.nlm.nih.gov/books/NBK570606/ |website=StatPearls |publisher=StatPearls Publishing |date=2024}}

The anterior part of the insula is subdivided by shallow sulci into three or four short gyri.

The anterior insula receives a direct projection from the basal part of the ventral medial nucleus of the thalamus and a particularly large input from the central nucleus of the amygdala. In addition, the anterior insula itself projects to the amygdala.

One study on rhesus monkeys revealed widespread reciprocal connections between the insular cortex and almost all subnuclei of the amygdaloid complex. The posterior insula projects predominantly to the dorsal aspect of the lateral and to the central amygdaloid nuclei. In contrast, the anterior insula projects to the anterior amygdaloid area as well as the medial, the cortical, the accessory basal magnocellular, the medial basal, and the lateral amygdaloid nuclei.{{cite journal|last=MUFSON|first=E|author2=MESULAM, M |author3=PANDYA, D |title=Insular interconnections with the amygdala in the rhesus monkey|journal=Neuroscience|date=1 July 1981|volume=6|issue=7|pages=1231–1248|doi=10.1016/0306-4522(81)90184-6|pmid=6167896|s2cid=46366616}}

The posterior part of the insula is formed by a long gyrus.

The posterior insula connects reciprocally with the secondary somatosensory cortex and receives input from spinothalamically activated ventral posterior inferior thalamic nuclei. It has also been shown that this region receives inputs from the ventromedial nucleus (posterior part) of the thalamus that are highly specialized to convey homeostatic information such as pain, temperature, itch, local oxygen status, and sensual touch.{{cite journal |vauthors=Craig AD, Chen K, Bandy D, Reiman EM | year = 2000 | title = Thermosensory activation of insular cortex | journal = Nat. Neurosci. | volume = 3 | issue = 2| pages = 184–90 | doi = 10.1038/72131 | pmid = 10649575 | s2cid = 7077496 }}

A human neuroimaging study using diffusion tensor imaging revealed that the anterior insula is interconnected to regions in the temporal and occipital lobe, opercular and orbitofrontal cortex, triangular and opercular parts of the inferior frontal gyrus. The same study revealed differences in the anatomical connection patterns between the left and right hemisphere.{{cite journal|last=JAKAB|first=A|author2=MOLNAR, P |author3=BOGNER, P |author4=BERES, M |author5=BERENYI, E |title= Connectivity-based parcellation reveals interhemispheric differences in the insula|journal=Brain Topography|date=1 Oct 2011| doi= 10.1007/s10548-011-0205-y|pmid=22002490|volume=25 |issue=3 |pages=264–271|s2cid=12293575}}

The circular sulcus of insula (or sulcus of Reil{{cite web | url=http://babel.hathitrust.org/cgi/pt?q1=circular%20sulcus;id=ien.35558004773517;view=plaintext;seq=243;start=1;size=100;page=root;num=145;orient=0 | title=Sobotta's Atlas and Text-book of human anatomy 1909 | access-date=November 10, 2013 | author= Johannes Sobotta | pages=145}}) is a semicircular sulcus or fissure that separates the insula from the neighboring gyri of the operculum{{cite web| publisher=MediLexicon| title=Definition: 'Circular Sulcus Of Insula'| access-date=2012-03-30| url=http://www.medilexicon.com/medicaldictionary.php?t=86332| archive-date=2013-06-04| archive-url=https://web.archive.org/web/20130604181646/http://www.medilexicon.com/medicaldictionary.php?t=86332| url-status=dead}} in the front, above, and

behind.

The insular cortex has regions of variable cell structure or cytoarchitecture, changing from granular in the posterior portion to agranular in the anterior portion. The insula also receives differential cortical and thalamic input along its length. The anterior insular cortex contains a population of spindle neurons (also called von Economo neurons), identified as characterising a distinctive subregion as the agranular frontal insula.{{cite journal|last1=Bauernfeind A|title =A volumetric comparison of the insular cortex and its subregions in primates|journal=Human Evolution|date=April 2013|volume=64 | issue = 4 |pages=263–279|doi=10.1016/j.jhevol.2012.12.003|pmc=3756831|display-authors=etal|pmid=23466178|bibcode =2013JHumE..64..263B}}

The insular cortex is considered a separate lobe of the telencephalon by some authorities.[http://encarta.msn.com/encyclopedia_761555359/Brain.html Brain], MSN Encarta. [https://web.archive.org/web/20091028015600/http://encarta.msn.com/encyclopedia_761555359/Brain.html Archived] 2009-10-31. Other sources see the insula as a part of the temporal lobe.{{cite book |author1=Kolb, Bryan |author2=Whishaw, Ian Q. |title=Fundamentals of human neuropsychology |publisher=Worth |location=[New York] |year=2003 |isbn=978-0-7167-5300-1 |edition=5th}} It is also sometimes grouped with limbic structures deep in the brain into a limbic lobe.{{Citation needed|date=March 2008}} As a paralimbic cortex, the insular cortex is considered to be a relatively old structure.

Functional imaging studies show activation of the insula during audio-visual integration tasks.{{cite journal|last1=Bushara|first1=KO|last2=Grafman|first2=J|last3=Hallett|first3=M|title=Neural correlates of auditory-visual stimulus onset asynchrony detection.|journal=The Journal of Neuroscience|date=1 January 2001|volume=21|issue=1|pages=300–4|pmid=11150347|pmc=6762435|doi=10.1523/JNEUROSCI.21-01-00300.2001}}{{cite journal|last1=Bushara|first1=KO|last2=Hanakawa|first2=T|last3=Immisch|first3=I|last4=Toma|first4=K|last5=Kansaku|first5=K|last6=Hallett|first6=M|title=Neural correlates of cross-modal binding.|journal=Nature Neuroscience|date=February 2003|volume=6|issue=2|pages=190–5|pmid=12496761|doi=10.1038/nn993|s2cid=1098979}}{{Cite journal |last=Kostanyan |first=Daria |last2=Vartanov |first2=Alexander |last3=Kiselnikov |first3=Andrey |last4=Kozlovskiy |first4=Stanislav |author-link4=Stanislav Kozlovsky |date=2018 |title=The role of insula in processes of audio- visual integration |url=https://istina.msu.ru/publications/article/144166858/ |journal=Psychophysiology |publisher=Blackwell Publishing Inc. |volume=55 |issue=1 |pages=133-134}}

The anterior insula is part of the primary gustatory cortex.{{Cite book | last1 = Marieb | first1 = Elaine N. | first2 = Katja | last2 = Hoehn | title = Anatomy & Physiology, Third Edition | location = Boston | publisher = Benjamin Cummings/Pearson | year= 2008 | pages = 391–395 | isbn = 978-0-8053-0094-9 }}{{cite journal|last=Pritchard|first=TC|author2=Macaluso, DA |author3=Eslinger, PJ |title=Taste perception in patients with insular cortex lesions.|journal=Behavioral Neuroscience|date=August 1999|volume=113|issue=4|pages=663–71|pmid=10495075|doi=10.1037/0735-7044.113.4.663}} Research in rhesus monkeys has also reported that apart from numerous taste-sensitive neurons, the insular cortex also responds to non-taste properties of oral stimuli related to the texture (viscosity, grittiness) or temperature of food.{{Cite journal |last1=Verhagen |first1=Justus V. |last2=Kadohisa |first2=Mikiko |last3=Rolls |first3=Edmund T. |date=September 2004 |title=Primate Insular/Opercular Taste Cortex: Neuronal Representations of the Viscosity, Fat Texture, Grittiness, Temperature, and Taste of Foods |url=https://www.physiology.org/doi/10.1152/jn.00321.2004 |journal=Journal of Neurophysiology |language=en |volume=92 |issue=3 |pages=1685–1699 |doi=10.1152/jn.00321.2004 |pmid=15331650 |issn=0022-3077}}

The sensory speech region, Wernicke’s area, and the motor speech region, Broca’s area, are interconnected by a large axonal fiber system known as the arcuate fasciculus which passes directly beneath the insular cortex. On account of this anatomical architecture, ischemic strokes in the insular region can disrupt the arcuate fasciculus.{{Cite journal |url=https://academic.oup.com/brain/article-abstract/103/2/337/378338 |access-date=2023-12-11 |doi=10.1093/brain/103.2.337 |title=The Anatomical Basis of Conduction Aphasia |date=1980 |last1=Damasio |first1=Hanna |last2=Damasio |first2=Antonio R. |journal=Brain |volume=103 |issue=2 |pages=337–350 |pmid=7397481 }} Functional imaging studies on the cerebral correlates of language production also suggest that the anterior insula forms part of the brain network of speech motor control.{{Cite journal |last1=Bohland |first1=Jason W. |last2=Guenther |first2=Frank H. |date=2006-08-15 |title=An fMRI investigation of syllable sequence production |url=https://www.sciencedirect.com/science/article/pii/S1053811906004472 |journal=NeuroImage |volume=32 |issue=2 |pages=821–841 |doi=10.1016/j.neuroimage.2006.04.173 |pmid=16730195 |s2cid=9909543 |issn=1053-8119}} Moreover, electrical stimulation of the posterior insular can evoke speech disturbances such as speech arrest and reduced voice intensity.{{Cite journal |last1=Afif |first1=Afif |last2=Minotti |first2=Lorella |last3=Kahane |first3=Philippe |last4=Hoffmann |first4=Dominique |date=November 2010 |title=Anatomofunctional organization of the insular cortex: A study using intracerebral electrical stimulation in epileptic patients |journal=Epilepsia |language=en |volume=51 |issue=11 |pages=2305–2315 |doi=10.1111/j.1528-1167.2010.02755.x |pmid=20946128 |issn=0013-9580|doi-access=free }}

Lesion of the pre-central gyrus of the insula can also cause “pure speech apraxia” (i.e. the inability to speak with no apparent aphasic or orofacial motor impairments).{{Cite journal |url=https://academic.oup.com/cercor/article/31/8/3723/6213947 |access-date=2023-12-11 |doi=10.1093/cercor/bhab043 |title=The Precentral Insular Cortical Network for Speech Articulation |date=2021 |last1=Tomaiuolo |first1=Francesco |last2=Campana |first2=Serena |last3=Voci |first3=Loredana |last4=Lasaponara |first4=Stefano |last5=Doricchi |first5=Fabrizio |last6=Petrides |first6=Michael |journal=Cerebral Cortex |volume=31 |issue=8 |pages=3723–3731 |pmid=33825880 }} This demonstrates that the insular cortex forms part of a critical circuit for the coordination of complex articulatory movements prior to and during the execution of the motor speech plans. Importantly, this specific cortical circuit is different from those that relate to the cognitive aspects of language production (e.g., Broca’s area on the inferior frontal gyrus). Subvocal, or silent, speech has also been shown to activate right insular cortex, further supporting the theory that the motor control of speech proceeds from the insula.{{Cite journal |last1=Kato |first1=Yutaka |last2=Muramatsu |first2=Taro |last3=Kato |first3=Motoichiro |last4=Shintani |first4=Masuro |last5=Kashima |first5=Haruo |date=2007-03-26 |title=Activation of right insular cortex during imaginary speech articulation |url=https://journals.lww.com/neuroreport/abstract/2007/03260/activation_of_right_insular_cortex_during.21.aspx |journal=NeuroReport |language=en-US |volume=18 |issue=5 |pages=505–509 |doi=10.1097/WNR.0b013e3280586862 |pmid=17496812 |s2cid=2040545 |issn=0959-4965}}

{{Further |Interoception}}

There is evidence that, in addition to its base functions, the insula may play a role in certain higher-level functions that operate only in humans and other great apes. The spindle neurons found at a higher density in the right frontal insular cortex are also found in the anterior cingulate cortex, which is another region that has reached a high level of specialization in great apes. It has been speculated that these neurons are involved in cognitive-emotional processes that are specific to primates including great apes, such as empathy and metacognitive emotional feelings. This is supported by functional imaging results showing that the structure and function of the right frontal insula is correlated with the ability to feel one's own heartbeat, or to empathize with the pain of others. It is thought that these functions are not distinct from the lower-level functions of the insula but rather arise as a consequence of the role of the insula in conveying homeostatic information to consciousness.{{cite journal |author1=Benedetto De Martino |author2=Dharshan Kumaran |author3=Ben Seymour |author4=Raymond J. Dolan |title=Frames, Biases, and Rational Decision-Making in the Human Brain |journal=Science |volume=313 |issue=6|date=August 2006 |pages= 684–687 |doi=10.1126/science.1128356 |pmid=16888142 |pmc=2631940|bibcode=2006Sci...313..684D }}{{cite journal |author1=Gui Xue |author2=Zhonglin Lu |author3=Irwin P. Levin d |author4=Antoine Bechara |title=The impact of prior risk experiences on subsequent risky decision-making: The role of the insula|journal=NeuroImage|volume=50 |year=2010 |pages= 709–716 |doi=10.1016/j.neuroimage.2009.12.097 |pmid=20045470 |issue=2 |pmc=2828040}} The right anterior insula is engaged in interoceptive awareness of homeostatic emotions such as thirst, pain and fatigue,{{cite journal|title=Gut feelings: the emerging biology of gut–brain communication|author=Emeran A. Mayer|journal=Nature Reviews Neuroscience|volume=12|issue=8|pages=453–466|date=August 2011|doi=10.1038/nrn3071|url= |pmid=21750565|pmc=3845678}} and the ability to time one's own heartbeat. Moreover, greater right anterior insular gray matter volume correlates with increased accuracy in this subjective sense of the inner body, and with negative emotional experience.{{cite journal |vauthors=Critchley HD, Wiens S, Rotshtein P, Ohman A, Dolan RJ |title=Neural systems supporting interoceptive awareness |journal=Nat. Neurosci. |volume=7 |issue=2 |pages=189–95 |date=February 2004 |pmid=14730305 |doi=10.1038/nn1176|hdl=21.11116/0000-0001-A2FB-D |s2cid=13344271 |hdl-access=free }} It is also involved in the control of blood pressure,{{cite journal |vauthors=Lamb K, Gallagher K, McColl R, Mathews D, Querry R, Williamson JW |title=Exercise-induced decrease in insular cortex rCBF during postexercise hypotension |journal=Med Sci Sports Exerc |volume=39 |issue=4 |pages=672–9 |date=April 2007 |pmid=17414805 |doi=10.1249/mss.0b013e31802f04e0 |doi-access=free }} in particular during and after exercise, and its activity varies with the amount of effort a person believes he/she is exerting.{{cite journal |vauthors=Williamson JW, McColl R, Mathews D, Mitchell JH, Raven PB, Morgan WP |title=Hypnotic manipulation of effort sense during dynamic exercise: cardiovascular responses and brain activation |journal=J. Appl. Physiol. |volume=90 |issue=4 |pages=1392–9 |date=April 2001 |pmid=11247939 |doi=10.1152/jappl.2001.90.4.1392 |s2cid=8653997 }}{{cite journal |vauthors=Williamson JW, McColl R, Mathews D, Ginsburg M, Mitchell JH |title=Activation of the insular cortex is affected by the intensity of exercise |journal=J. Appl. Physiol. |volume=87 |issue=3 |pages=1213–9 |date=September 1999 |pmid=10484598 |doi=10.1152/jappl.1999.87.3.1213|citeseerx=10.1.1.492.2730 |s2cid=1078691 }}

The insular cortex also is where the sensation of pain is judged as to its degree.{{cite journal |vauthors=Baliki MN, Geha PY, Apkarian AV |title=Parsing pain perception between nociceptive representation and magnitude estimation |journal=J. Neurophysiol. |volume=101 |issue=2 |pages=875–87 |date=February 2009 |pmid=19073802 |pmc=3815214 |doi=10.1152/jn.91100.2008 }} Lesion of the insula is associated with dramatic loss of pain perception and isolated insular infarction can lead to contralateral elimination of pinprick perception.{{Cite journal |last1=Birklein |first1=Frank |last2=Rolke |first2=Roman |last3=Müller-Forell |first3=Wibke |date=2005-11-08 |title=Isolated insular infarction eliminates contralateral cold, cold pain, and pinprick perception |journal=Neurology |language=en |volume=65 |issue=9 |pages=1381 |doi=10.1212/01.wnl.0000181351.82772.b3 |pmid=16275823 |issn=0028-3878|doi-access=free }} Further, the insula is where a person imagines pain when looking at images of painful events while thinking about their happening to one's own body.{{cite journal |vauthors=Ogino Y, Nemoto H, Inui K, Saito S, Kakigi R, Goto F |title=Inner experience of pain: imagination of pain while viewing images showing painful events forms subjective pain representation in human brain |journal=Cereb. Cortex |volume=17 |issue=5 |pages=1139–46 |date=May 2007 |pmid=16855007 |doi=10.1093/cercor/bhl023 |doi-access=free }} Those with irritable bowel syndrome have abnormal processing of visceral pain in the insular cortex related to dysfunctional inhibition of pain within the brain.{{cite journal |vauthors=Song GH, Venkatraman V, Ho KY, Chee MW, Yeoh KG, Wilder-Smith CH |title=Cortical effects of anticipation and endogenous modulation of visceral pain assessed by functional brain MRI in irritable bowel syndrome patients and healthy controls |journal=Pain |volume=126 |issue=1–3 |pages=79–90 |date=December 2006 |pmid=16846694 |doi=10.1016/j.pain.2006.06.017 |s2cid=21437784 }}

Physiological studies in rhesus monkeys have shown that neurons in the insula respond to skin stimulation.{{Cite journal |last1=Schneider |first1=Richard J. |last2=Friedman |first2=David P. |last3=Mishkin |first3=Mortimer |date=1993-09-03 |title=A modality-specific somatosensory area within the insula of the rhesus monkey |url=https://dx.doi.org/10.1016/0006-8993%2893%2990305-7 |journal=Brain Research |volume=621 |issue=1 |pages=116–120 |doi=10.1016/0006-8993(93)90305-7 |pmid=8221062 |s2cid=20207990 |issn=0006-8993}} PET studies have also revealed that the human insula can also be activated by vibrational stimulation to the skin.{{Cite journal |last1=Burton |first1=H. |last2=Videen |first2=T. O. |last3=Raichle |first3=M. E. |date=January 1993 |title=Tactile-Vibration-Activated Foci in Insular and Parietal-Opercular Cortex Studied with Positron Emission Tomography: Mapping the Second Somatosensory Area in Humans |url=http://www.tandfonline.com/doi/full/10.3109/08990229309028839 |journal=Somatosensory & Motor Research |language=en |volume=10 |issue=3 |pages=297–308 |doi=10.3109/08990229309028839 |pmid=8237217 |issn=0899-0220}}

Another perception of the right anterior insula is the degree of nonpainful warmth{{cite journal |vauthors=Olausson H, Charron J, Marchand S, Villemure C, Strigo IA, Bushnell MC |title=Feelings of warmth correlate with neural activity in right anterior insular cortex |journal=Neurosci. Lett. |volume=389 |issue=1 |pages=1–5 |date=November 2005 |pmid=16051437 |doi=10.1016/j.neulet.2005.06.065 |s2cid=20068852 }} or nonpainful coldness{{cite journal |vauthors=Craig AD, Chen K, Bandy D, Reiman EM |title=Thermosensory activation of insular cortex |journal=Nat. Neurosci. |volume=3 |issue=2 |pages=184–90 |date=February 2000 |pmid=10649575 |doi=10.1038/72131|s2cid=7077496 }} of a skin sensation. Other internal sensations processed by the insula include stomach or abdominal distension.{{cite journal |vauthors=Ladabaum U, Minoshima S, Hasler WL, Cross D, Chey WD, Owyang C |title=Gastric distention correlates with activation of multiple cortical and subcortical regions |journal=Gastroenterology |volume=120 |issue=2 |pages=369–76 |date=February 2001 |pmid=11159877 |doi=10.1053/gast.2001.21201|doi-access=free }}{{cite journal |vauthors=Hamaguchi T, Kano M, Rikimaru H, etal |title=Brain activity during distention of the descending colon in humans |journal=Neurogastroenterol. Motil. |volume=16 |issue=3 |pages=299–309 |date=June 2004 |pmid=15198652 |doi=10.1111/j.1365-2982.2004.00498.x |s2cid=20437580 }}{{dead link|date=February 2019|bot=medic}}{{cbignore|bot=medic}} A full bladder also activates the insular cortex.{{cite journal |vauthors=Matsuura S, Kakizaki H, Mitsui T, Shiga T, Tamaki N, Koyanagi T |title=Human brain region response to distention or cold stimulation of the bladder: a positron emission tomography study |journal=J. Urol. |volume=168 |issue=5 |pages=2035–9 |date=November 2002 |pmid=12394703 |doi=10.1016/s0022-5347(05)64290-5}}

One brain imaging study suggests that the unpleasantness of subjectively perceived dyspnea is processed in the right human anterior insula and amygdala.{{cite journal|last=von Leupoldt|first=A.|author2=Sommer, T.|author3=Kegat, S.|author4=Baumann, H. J.|author5=Klose, H.|author6=Dahme, B.|author7=Buchel, C.|title=The Unpleasantness of Perceived Dyspnea Is Processed in the Anterior Insula and Amygdala|journal=American Journal of Respiratory and Critical Care Medicine|date=24 January 2008|volume=177|issue=9|pages=1026–1032|doi=10.1164/rccm.200712-1821OC|pmid=18263796|url=http://171.66.122.149/content/177/9/1026.full.pdf+html}}{{Dead link|date=April 2019 |bot=InternetArchiveBot |fix-attempted=yes }}

The cerebral cortex processing vestibular sensations extends into the insula,{{cite journal |vauthors=Kikuchi M, Naito Y, Senda M, etal |title=Cortical activation during optokinetic stimulation — an fMRI study |journal=Acta Otolaryngol. |volume=129 |issue=4 |pages=440–3 |date=April 2009 |pmid=19116795 |doi=10.1080/00016480802610226 |s2cid=42990194 }}

with small lesions in the anterior insular cortex being able to cause loss of balance and vertigo.{{cite journal |vauthors=Papathanasiou ES, Papacostas SS, Charalambous M, Eracleous E, Thodi C, Pantzaris M |title=Vertigo and imbalance caused by a small lesion in the anterior insula |journal=Electromyogr Clin Neurophysiol |volume=46 |issue=3 |pages=185–92 |year=2006 |pmid=16918202 }}

Other noninteroceptive perceptions include passive listening to music,{{cite journal |vauthors=Brown S, Martinez MJ, Parsons LM |title=Passive music listening spontaneously engages limbic and paralimbic systems |journal=NeuroReport |volume=15 |issue=13 |pages=2033–7 |date=September 2004 |pmid=15486477 |doi=10.1097/00001756-200409150-00008|s2cid=12308683 }} laughter and crying,{{cite journal |vauthors=Sander K, Scheich H |title=Left auditory cortex and amygdala, but right insula dominance for human laughing and crying |journal=J Cogn Neurosci |volume=17 |issue=10 |pages=1519–31 |date=October 2005 |pmid=16269094 |doi=10.1162/089892905774597227 |s2cid=9509954 }} empathy and compassion,{{Cite web |url=http://ccare.stanford.edu/node/89 |title=Interview with Tania Singer | the Center for Compassion and Altruism Research and Education |access-date=2010-07-04 |archive-url=https://web.archive.org/web/20100714152432/http://ccare.stanford.edu/node/89 |archive-date=2010-07-14 |url-status=dead }} and language.{{cite journal |vauthors=Bamiou DE, Musiek FE, Luxon LM |title=The insula (Island of Reil) and its role in auditory processing. Literature review |journal=Brain Res. Brain Res. Rev. |volume=42 |issue=2 |pages=143–54 |date=May 2003 |pmid=12738055 |doi=10.1016/S0165-0173(03)00172-3|s2cid=22339177 }}

In motor control, it contributes to hand-and-eye motor movement,{{cite journal |vauthors=Anderson TJ, Jenkins IH, Brooks DJ, Hawken MB, Frackowiak RS, Kennard C |title=Cortical control of saccades and fixation in man. A PET study |journal=Brain |volume=117 |issue=Pt 5 |pages=1073–84 |date=October 1994 |pmid=7953589 |doi=10.1093/brain/117.5.1073}}{{cite journal |vauthors=Fink GR, Frackowiak RS, Pietrzyk U, Passingham RE |title=Multiple nonprimary motor areas in the human cortex |journal=J. Neurophysiol. |volume=77 |issue=4 |pages=2164–74 |date=April 1997 |pmid=9114263 |doi=10.1152/jn.1997.77.4.2164 |s2cid=15881491 }} swallowing,{{cite journal |vauthors=Sörös P, Inamoto Y, Martin RE |title=Functional brain imaging of swallowing: an activation likelihood estimation meta-analysis |journal=Hum Brain Mapp |volume=30 |issue=8 |pages=2426–39 |date=August 2009 |pmid=19107749 |doi=10.1002/hbm.20680 |pmc=6871071 |s2cid=15438676 }} gastric motility,{{cite journal |vauthors=Penfield W, Faulk ME |title=The insula; further observations on its function |journal=Brain |volume=78 |issue=4 |pages=445–70 |year=1955 |pmid=13293263 |doi=10.1093/brain/78.4.445}} and speech articulation.{{cite journal |author=Dronkers NF |title=A new brain region for coordinating speech articulation |journal=Nature |volume=384 |issue=6605 |pages=159–61 |date=November 1996 |pmid=8906789 |doi=10.1038/384159a0|bibcode=1996Natur.384..159D |s2cid=4305696 }}{{cite journal |vauthors=Ackermann H, Riecker A |title=The contribution of the insula to motor aspects of speech production: a review and a hypothesis |journal=Brain Lang |volume=89 |issue=2 |pages=320–8 |date=May 2004 |pmid=15068914 |doi=10.1016/S0093-934X(03)00347-X |s2cid=36867434 }} It has been identified as a "central command” centre that ensures that heart rate and blood pressure increase at the onset of exercise.{{cite journal |vauthors=Nowak M, Holm S, Biering-Sørensen F, Secher NH, Friberg L |title="Central command" and insular activation during attempted foot lifting in paraplegic humans |journal=Hum Brain Mapp |volume=25 |issue=2 |pages=259–65 |date=June 2005 |pmid=15849712 |doi=10.1002/hbm.20097|pmc=6871668 }} Research upon conversation links it to the capacity for long and complex spoken sentences.{{cite journal |vauthors=Borovsky A, Saygin AP, Bates E, Dronkers N |title=Lesion correlates of conversational speech production deficits |journal=Neuropsychologia |volume=45 |issue=11 |pages=2525–33 |date=June 2007 |pmid=17499317 |pmc=5610916 |doi=10.1016/j.neuropsychologia.2007.03.023 }} It is also involved in motor learning{{cite journal |vauthors=Mutschler I, Schulze-Bonhage A, Glauche V, Demandt E, Speck O, Ball T |editor1-last=Fitch |editor1-first=Tecumseh |title=A rapid sound-action association effect in human insular cortex |journal=PLOS ONE |volume=2 |issue=2 |pages=e259 |year=2007 |pmid=17327919 |pmc=1800344 |doi=10.1371/journal.pone.0000259 |bibcode=2007PLoSO...2..259M |doi-access=free }} and has been identified as playing a role in the motor recovery from stroke.{{cite journal |vauthors=Weiller C, Ramsay SC, Wise RJ, Friston KJ, Frackowiak RS |title=Individual patterns of functional reorganization in the human cerebral cortex after capsular infarction |journal=Annals of Neurology |volume=33 |issue=2 |pages=181–9 |date=February 1993 |pmid=8434880 |doi=10.1002/ana.410330208 |s2cid=25131597 }}

It plays a role in a variety of homeostatic functions related to basic survival needs, such as taste, visceral sensation, and autonomic control. The insula controls autonomic functions through the regulation of the sympathetic and parasympathetic systems.{{cite journal |vauthors=Oppenheimer SM, Gelb A, Girvin JP, Hachinski VC |title=Cardiovascular effects of human insular cortex stimulation |journal=Neurology |volume=42 |issue=9 |pages=1727–32 |date=September 1992 |pmid=1513461 |doi=10.1212/wnl.42.9.1727|s2cid=32371468 }}{{cite journal |author=Critchley HD |title=Neural mechanisms of autonomic, affective, and cognitive integration |journal=J. Comp. Neurol. |volume=493 |issue=1 |pages=154–66 |date=December 2005 |pmid=16254997 |doi=10.1002/cne.20749|s2cid=32616395 }} It has a role in regulating the immune system.{{cite journal |vauthors=Pacheco-López G, Niemi MB, Kou W, Härting M, Fandrey J, Schedlowski M |title=Neural substrates for behaviorally conditioned immunosuppression in the rat |journal=J. Neurosci. |volume=25 |issue=9 |pages=2330–7 |date=March 2005 |pmid=15745959 |pmc=6726099 |doi=10.1523/JNEUROSCI.4230-04.2005 }}{{cite journal |vauthors=Ramírez-Amaya V, Alvarez-Borda B, Ormsby CE, Martínez RD, Pérez-Montfort R, Bermúdez-Rattoni F |title=Insular cortex lesions impair the acquisition of conditioned immunosuppression |journal=Brain Behav. Immun. |volume=10 |issue=2 |pages=103–14 |date=June 1996 |pmid=8811934 |doi=10.1006/brbi.1996.0011|s2cid=24813018 }}{{cite journal |vauthors=Ramírez-Amaya V, Bermúdez-Rattoni F |title=Conditioned enhancement of antibody production is disrupted by insular cortex and amygdala but not hippocampal lesions |journal=Brain Behav. Immun. |volume=13 |issue=1 |pages=46–60 |date=March 1999 |pmid=10371677 |doi=10.1006/brbi.1998.0547 |s2cid=20527835 }}

The insula has been identified as playing a role in the experience of bodily self-awareness,{{cite journal |vauthors=Karnath HO, Baier B, Nägele T |title=Awareness of the functioning of one's own limbs mediated by the insular cortex? |journal=J. Neurosci. |volume=25 |issue=31 |pages=7134–8 |date=August 2005 |pmid=16079395 |pmc=6725240 |doi=10.1523/JNEUROSCI.1590-05.2005 }}{{cite journal |author=Craig AD |title=How do you feel—now? The anterior insula and human awareness |journal=Nature Reviews Neuroscience |volume=10 |issue=1 |pages=59–70 |date=January 2009 |pmid=19096369 |doi=10.1038/nrn2555|s2cid=2340032 }} sense of agency,{{cite journal |vauthors=Farrer C, Frith CD |title=Experiencing oneself vs another person as being the cause of an action: the neural correlates of the experience of agency |journal=NeuroImage |volume=15 |issue=3 |pages=596–603 |date=March 2002 |pmid=11848702 |doi=10.1006/nimg.2001.1009 |s2cid=768408 }} and sense of body ownership.{{cite journal |vauthors=Tsakiris M, Hesse MD, Boy C, Haggard P, Fink GR |title=Neural signatures of body ownership: a sensory network for bodily self-consciousness |journal=Cereb. Cortex |volume=17 |issue=10 |pages=2235–44 |date=October 2007 |pmid=17138596 |doi=10.1093/cercor/bhl131 |doi-access=free }}

The anterior insula processes a person's sense of disgust both to smells{{cite journal |vauthors=Wicker B, Keysers C, Plailly J, Royet JP, Gallese V, Rizzolatti G |title=Both of us disgusted in My insula: the common neural basis of seeing and feeling disgust |journal=Neuron |volume=40 |issue=3 |pages=655–64 |date=October 2003 |pmid=14642287 |doi=10.1016/S0896-6273(03)00679-2|s2cid=766157 |doi-access=free }} and to the sight of contamination and mutilation{{cite journal |vauthors=Wright P, He G, Shapira NA, Goodman WK, Liu Y |title=Disgust and the insula: fMRI responses to pictures of mutilation and contamination |journal=NeuroReport |volume=15 |issue=15 |pages=2347–51 |date=October 2004 |pmid=15640753 |doi=10.1097/00001756-200410250-00009|s2cid=6864309 }} — even when just imagining the experience.{{cite journal |vauthors=Jabbi M, Bastiaansen J, Keysers C |editor1-last=Lauwereyns |editor1-first=Jan |title=A common anterior insula representation of disgust observation, experience and imagination shows divergent functional connectivity pathways |journal=PLOS ONE |volume=3 |issue=8 |pages=e2939 |year=2008 |pmid=18698355 |pmc=2491556 |doi=10.1371/journal.pone.0002939 |bibcode=2008PLoSO...3.2939J |doi-access=free }} This associates with a mirror neuron-like link between external and internal experiences.

In social experience, it is involved in the processing of norm violations,{{cite journal |vauthors=Sanfey AG, Rilling JK, Aronson JA, Nystrom LE, Cohen JD |title=The neural basis of economic decision-making in the Ultimatum Game |journal=Science |volume=300 |issue=5626 |pages=1755–8 |date=June 2003 |pmid=12805551 |doi=10.1126/science.1082976 |bibcode=2003Sci...300.1755S |s2cid=7111382 }} emotional processing,{{cite journal |vauthors=Phan KL, Wager T, Taylor SF, Liberzon I |title=Functional neuroanatomy of emotion: a meta-analysis of emotion activation studies in PET and fMRI |journal=NeuroImage |volume=16 |issue=2 |pages=331–48 |date=June 2002 |pmid=12030820 |doi=10.1006/nimg.2002.1087 |s2cid=7150871 }} empathy,{{cite journal |author=Singer T |title=The neuronal basis and ontogeny of empathy and mind reading: review of literature and implications for future research |journal=Neurosci Biobehav Rev |volume=30 |issue=6 |pages=855–63 |year=2006 |pmid=16904182 |doi=10.1016/j.neubiorev.2006.06.011 |s2cid=15411628 }} and orgasms.{{cite journal |vauthors=Ortigue S, Grafton ST, Bianchi-Demicheli F |title=Correlation between insula activation and self-reported quality of orgasm in women |journal=NeuroImage |volume=37 |issue=2 |pages=551–60 |date=August 2007 |pmid=17601749 |doi=10.1016/j.neuroimage.2007.05.026 |s2cid=3377994 |url=https://archive-ouverte.unige.ch/unige:29406 }}

The insula is active during social decision making. Tiziana Quarto et al. measured emotional intelligence (EI) (the ability to identify, regulate, and process emotions of themselves and of others) of sixty-three healthy subjects. Using fMRI EI was measured in correlation with left insular activity. The subjects were shown various pictures of facial expressions and tasked with deciding to approach or avoid the person in the picture. The results of the social decision task yielded that individuals with high EI scores had left insular activation when processing fearful faces. Individuals with low EI scores had left insular activation when processing angry faces.{{Cite journal|last1=Quarto|first1=Tiziana|last2=Blasi|first2=Giuseppe|last3=Maddalena|first3=Chiara|last4=Viscanti|first4=Giovanna|last5=Lanciano|first5=Tiziana|last6=Soleti|first6=Emanuela|last7=Mangiulli|first7=Ivan|last8=Taurisano|first8=Paolo|last9=Fazio|first9=Leonardo|date=2016-02-09|title=Association between Ability Emotional Intelligence and Left Insula during Social Judgment of Facial Emotions|journal=PLOS ONE|volume=11|issue=2|pages=e0148621|doi=10.1371/journal.pone.0148621|issn=1932-6203|pmc=4747486|pmid=26859495|bibcode=2016PLoSO..1148621Q|doi-access=free}}

The insular cortex, in particular its most anterior portion, is considered a limbic-related cortex. The insula has increasingly become the focus of attention for its role in body representation and subjective emotional experience. In particular, Antonio Damasio has proposed that this region plays a role in mapping visceral states that are associated with emotional experience, giving rise to conscious feelings. This is in essence a neurobiological formulation of the ideas of William James, who first proposed that subjective emotional experience (i.e., feelings) arise from our brain's interpretation of bodily states that are elicited by emotional events. This is an example of embodied cognition.{{Citation needed|date=February 2025}}

In terms of function, the insula is believed to process convergent information to produce an emotionally relevant context for sensory experience. To be specific, the anterior insula is related more to olfactory, gustatory, viscero-autonomic, and limbic function, whereas the posterior insula is related more to auditory-somesthetic-skeletomotor function. Functional imaging experiments have revealed that the insula has an important role in pain experience and the experience of a number of basic emotions, including anger, fear, disgust, happiness, and sadness.{{cite journal|last=Wager|first=Tor|title=Functional Neuroanatomy of Emotion: A Meta-Analysis of Emotion Activation Studies in PET and fMRI|doi=10.1006/nimg.2002.1087|pmid=12030820|volume=16|issue=2|date=June 2002|journal=NeuroImage|pages=331–48|s2cid=7150871}}

The anterior insular cortex (AIC) is believed to be correlated to emotional sensations, including maternal and romantic love, anger, fear, sadness, happiness, sexual arousal, disgust, aversion, unfairness, inequity, indignation, uncertainty,{{cite journal |vauthors=Vilares I, Howard JD, Fernandes HL, Gottfried JA, Kording KP |title=Differential Representations of Prior and Likelihood Uncertainty in the Human Brain |journal=Current Biology |volume=22 |issue=18 |pages=1641–1648 |date=2012 |doi=10.1016/j.cub.2012.07.010 |pmid=22840519 |pmc=3461114 |bibcode=2012CBio...22.1641V }}{{Dubious|date=February 2025}} disbelief, social exclusion, trust, empathy, sculptural beauty, a ‘state of union with God’, and hallucinogenic states.{{cite journal |last=Craig |first=A. D. (Bud) |year=2009 |title=How do you feel — now? The anterior insula and human awareness |journal=Nature Reviews Neuroscience |volume=10 |pages=59–70 |url=http://www.allmanlab.caltech.edu/biCNS217/PDFs/Craig2009.pdf |archive-url=https://wayback.archive-it.org/all/20130107223506/http://www.allmanlab.caltech.edu/biCNS217/PDFs/Craig2009.pdf |url-status=dead |archive-date=2013-01-07 |doi=10.1038/nrn2555 |issue=1 |pmid=19096369 |s2cid=2340032 }}

Functional imaging studies have also implicated the insula in conscious desires, such as food craving and drug craving. What is common to all of these emotional states is that they each change the body in some way and are associated with highly salient subjective qualities. The insula is well-situated for the integration of information relating to bodily states into higher-order cognitive and emotional processes. The insula receives information from "homeostatic afferent" sensory pathways via the thalamus and sends output to a number of other limbic-related structures, such as the amygdala, the ventral striatum, and the orbitofrontal cortex, as well as to motor cortices.{{cite journal |last=Craig |first=A. D. (Bud) |year=2002 |title=A new view of pain as a homeostatic emotion |journal=Trends in Neurosciences |volume=26 |issue=6 |pages=303–307 |url=http://meagherlab.tamu.edu/M-Meagher/%20Health%20Psyc%20630/Readings%20630/Pain%20mech%20read/Craig%2003%20pain%20emotion.pdf |doi=10.1016/s0166-2236(03)00123-1 |pmid=12798599 |s2cid=19794544 |access-date=2009-09-03 |archive-url=https://web.archive.org/web/20100622001631/http://meagherlab.tamu.edu/M-Meagher/%20Health%20Psyc%20630/Readings%20630/Pain%20mech%20read/Craig%2003%20pain%20emotion.pdf |archive-date=2010-06-22 |url-status=dead }}

A study using magnetic resonance imaging found that the right anterior insula is significantly thicker in people that meditate.{{cite journal |vauthors=Lazar SW, Kerr CE, Wasserman RH, Gray JR, Greve DN, Treadway MT, McGarvey M, Quinn BT, Dusek JA, Benson H, Rauch SL, Moore CI, Fischl B |title=Meditation experience is associated with increased cortical thickness |journal=NeuroReport |volume=16 |issue=17 |pages=1893–7 |year=2005 |pmid=16272874 |pmc=1361002 |doi=10.1097/01.wnr.0000186598.66243.19}} Other research into brain activity and meditation has shown an increase in grey matter in areas of the brain including the insular cortex.{{cite journal|last=Fox|first=Kieran C.R.|author2=Nijeboer, Savannah |author3=Dixon, Matthew L. |author4=Floman, James L. |author5=Ellamil, Melissa |author6=Rumak, Samuel P. |author7=Sedlmeier, Peter |author8= Christoff, Kalina |title=Is meditation associated with altered brain structure? A systematic review and meta-analysis of morphometric neuroimaging in meditation practitioners|journal=Neuroscience & Biobehavioral Reviews|date=June 2014|volume=43|pages=48–73|doi=10.1016/j.neubiorev.2014.03.016 |pmid=24705269|s2cid=207090878}}

Another study using voxel-based morphometry and MRI on experienced Vipassana meditators was done to extend the findings of Lazar et al., which found increased grey matter concentrations in this and other areas of the brain in experienced meditators.{{Cite journal | url= | doi=10.1093/scan/nsm038| pmid=19015095| title=Investigation of mindfulness meditation practitioners with voxel-based morphometry| journal=Social Cognitive and Affective Neuroscience| volume=3| issue=1| pages=55–61| year=2008| last1=Hölzel| first1=Britta K.| last2=Ott| first2=Ulrich| last3=Gard| first3=Tim| last4=Hempel| first4=Hannes| last5=Weygandt| first5=Martin| last6=Morgen| first6=Katrin| last7=Vaitl| first7=Dieter| pmc=2569815}}

The strongest evidence against a causative role for the insula cortex in emotion comes from Damasio et al. (2012) {{Cite journal | doi=10.1093/cercor/bhs077| pmid=22473895| title=Persistence of Feelings and Sentience after Bilateral Damage of the Insula| journal=Cerebral Cortex| volume=23| issue=4| pages=833–846| year=2013| last1=Damasio| first1=A.| last2=Damasio| first2=H.| last3=Tranel| first3=D.| pmc=3657385}} which showed that a patient who suffered bilateral lesions of the insula cortex expressed the full complement of human emotions, and was fully capable of emotional learning.

Functional neuroimaging research suggests the insula is involved in two types of salience. Interoceptive information processing that links interoception with emotional salience to generate a subjective representation of the body. This involves, first, the anterior insular cortex with the pregenual anterior cingulate cortex (Brodmann area 33) and the anterior and posterior mid-cingulate cortices, and, second, a general salience network concerned with environmental monitoring, response selection, and skeletomotor body orientation that involves all of the insular cortex and the mid-cingulate cortex.{{cite journal |vauthors=Taylor KS, Seminowicz DA, Davis KD |title=Two systems of resting state connectivity between the insula and cingulate cortex |journal=Hum Brain Mapp |volume=30 |issue=9 |pages=2731–45 |date=September 2009 |pmid=19072897 |doi=10.1002/hbm.20705|pmc=6871122 |s2cid=12917288 }} A related idea is that the anterior insula, as part of the salience network, interacts with the mid-posterior insula to combine salient stimuli with autonomic information, leading to a high state of physiological awareness of salient stimuli.{{Cite journal|last1=Menon|first1=Vinod|last2=Uddin|first2=Lucina Q.|date=2010-05-29|title=Saliency, switching, attention and control: a network model of insula function|url=http://dx.doi.org/10.1007/s00429-010-0262-0|journal=Brain Structure and Function|volume=214|issue=5–6|pages=655–667|doi=10.1007/s00429-010-0262-0|pmid=20512370 |pmc=2899886 |issn=1863-2653}}

An alternative or perhaps complementary proposal is that the right anterior insular regulates the interaction between the salience of the selective attention created to achieve a task (the dorsal attention system) and the salience of arousal created to keep focused upon the relevant part of the environment (ventral attention system).{{cite journal |vauthors=Eckert MA, Menon V, Walczak A, Ahlstrom J, Denslow S, Horwitz A, Dubno JR | year = 2009 | title = At the heart of the ventral attention system: the right anterior insula | journal = Hum. Brain Mapp. | volume = 30 | issue = 8| pages = 2530–41 | doi = 10.1002/hbm.20688 | pmid = 19072895 | pmc=2712290}} This regulation of salience might be particularly important during challenging tasks where attention might fatigue and so cause careless mistakes but if there is too much arousal it risks creating poor performance by turning into anxiety.

Studies have shown that damage or dysfunction in the insular cortex can impair decision-making, emotional regulation, and social behavior. The insula is considered a key brain structure in the neural circuitry underlying complex decision-making processes.{{cite journal |last1=Billeke |first1=Pablo |last2=Ossandon |first2=Tomas |last3=Perrone-Bertolotti |first3=Marcela |last4=Kahane |first4=Philippe |last5=Bastin |first5=Julien |last6=Jerbi |first6=Karim |last7=Lachaux |first7=Jean-Philippe |last8=Fuentealba |first8=Pablo |title=Human Anterior Insula Encodes Performance Feedback and Relays Prediction Error to the Medial Prefrontal Cortex |journal=Cerebral Cortex |date=1 June 2020 |volume=30 |issue=7 |pages=4011–4025 |doi=10.1093/cercor/bhaa017|pmid=32108230 }} It plays a significant role in integrating internal and external cues to facilitate adaptive choices.

Research indicates that the insular cortex is involved in auditory perception. Responses to sound stimuli were obtained using intracranial EEG recordings acquired from patients with epilepsy. The posterior part of the insula showed auditory responses that resemble those observed in Heschl's gyrus, whereas the anterior part responded to the emotional contents of the auditory stimuli.{{Cite journal|last1=Zhang|first1=Yang|last2=Zhou|first2=Wenjing|last3=Wang|first3=Siyu|last4=Zhou|first4=Qin|last5=Wang|first5=Haixiang|last6=Zhang|first6=Bingqing|last7=Huang|first7=Juan|last8=Hong|first8=Bo|last9=Wang|first9=Xiaoqin|date=2019-02-01|title=The Roles of Subdivisions of Human Insula in Emotion Perception and Auditory Processing|url=https://academic.oup.com/cercor/article/29/2/517/4802217|journal=Cerebral Cortex|language=en|volume=29|issue=2|pages=517–528|doi=10.1093/cercor/bhx334|pmid=29342237|s2cid=36927038|issn=1047-3211}} Clinical data additionally shows that bilateral damage to the insula after ischemic injury or trauma can lead to auditory agnosia.{{Citation |last=Nieuwenhuys |first=Rudolf |title=Chapter 7 - The insular cortex: A review |date=2012-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780444538604000076 |journal=Progress in Brain Research |volume=195 |pages=123–163 |editor-last=Hofman |editor-first=Michel A. |access-date=2023-12-11 |series=Evolution of the Primate Brain |publisher=Elsevier |doi=10.1016/B978-0-444-53860-4.00007-6 |pmid=22230626 |isbn=978-0-444-53860-4 |editor2-last=Falk |editor2-first=Dean}} Functional magnetic resonance studies have also demonstrated that the insular cortex participates in many key auditory processes such as tuning into novel auditory stimuli and allocating auditory attention.{{Cite journal |last1=Bamiou |first1=Doris-Eva |last2=Musiek |first2=Frank E |last3=Luxon |first3=Linda M |date=2003-05-01 |title=The insula (Island of Reil) and its role in auditory processing: Literature review |url=https://www.sciencedirect.com/science/article/pii/S0165017303001723 |journal=Brain Research Reviews |volume=42 |issue=2 |pages=143–154 |doi=10.1016/S0165-0173(03)00172-3 |pmid=12738055 |s2cid=22339177 |issn=0165-0173}}

Direct recordings from the posterior part of the insula showed responses to unexpected sounds within regular auditory streams, a process known as auditory deviance detection. Researchers observed a mismatch negativity (MMN) potential, a well known event related potential, as well as the high frequency activity signals originating from local neurons.{{Cite journal|last1=Blenkmann|first1=Alejandro O.|last2=Collavini|first2=Santiago|last3=Lubell|first3=James|last4=Llorens|first4=Anaïs|last5=Funderud|first5=Ingrid|last6=Ivanovic|first6=Jugoslav|last7=Larsson|first7=Pål G.|last8=Meling|first8=Torstein R.|last9=Bekinschtein|first9=Tristan|last10=Kochen|first10=Silvia|last11=Endestad|first11=Tor|date=December 2019|title=Auditory deviance detection in the human insula: An intracranial EEG study|journal=Cortex|language=en|volume=121|pages=189–200|doi=10.1016/j.cortex.2019.09.002|pmid=31629197|s2cid=202749677|url=https://www.biorxiv.org/content/10.1101/487306v1|hdl=10852/75077|hdl-access=free}}

Simple auditory illusions and hallucinations were elicited by electrical functional mapping.{{Cite journal|last1=Afif|first1=Afif|last2=Minotti|first2=Lorella|last3=Kahane|first3=Philippe|last4=Hoffmann|first4=Dominique|date=November 2010|title=Anatomofunctional organization of the insular cortex: A study using intracerebral electrical stimulation in epileptic patients: Functional Organization of the Insula|journal=Epilepsia|language=en|volume=51|issue=11|pages=2305–2315|doi=10.1111/j.1528-1167.2010.02755.x|pmid=20946128|s2cid=2506125|doi-access=free}}

Progressive expressive aphasia is the deterioration of normal language function that causes individuals to lose the ability to communicate fluently while still being able to comprehend single words and intact other non-linguistic cognition. It is found in a variety of degenerative neurological conditions including Pick's disease, motor neuron disease, corticobasal degeneration, frontotemporal dementia, and Alzheimer's disease. It is associated with hypometabolism{{cite journal |vauthors=Nestor PJ, Graham NL, Fryer TD, Williams GB, Patterson K, Hodges JR |title=Progressive non-fluent aphasia is associated with hypometabolism centred on the left anterior insula |journal=Brain |volume=126 |issue=Pt 11 |pages=2406–18 |date=November 2003 |pmid=12902311 |doi=10.1093/brain/awg240 |doi-access=free }} and atrophy of the left anterior insular cortex.{{cite journal |vauthors=Gorno-Tempini ML, Dronkers NF, Rankin KP, etal |title=Cognition and anatomy in three variants of primary progressive aphasia |journal=Annals of Neurology |volume=55 |issue=3 |pages=335–46 |date=March 2004 |pmid=14991811 |pmc=2362399 |doi=10.1002/ana.10825}}

A number of functional brain imaging studies have shown that the insular cortex is activated when drug users are exposed to environmental cues that trigger cravings. This has been shown for a variety of drugs, including cocaine, alcohol, opiates, and nicotine. Despite these findings, the insula has been ignored within the drug addiction literature, perhaps because it is not known to be a direct target of the mesocortical dopamine system, which is central to current dopamine reward theories of addiction. Research published in 2007{{Cite journal

|author1=Nasir H. Naqvi |author2=David Rudrauf |author3=Hanna Damasio |author4=Antoine Bechara. | title = Damage to the Insula Disrupts Addiction to Cigarette Smoking

| journal = Science

| date = January 2007

| volume = 315

| issue = 5811

| pages = 531–4

| doi = 10.1126/science.1135926

| pmid = 17255515

| pmc = 3698854

|bibcode=2007Sci...315..531N }} has shown that cigarette smokers suffering damage to the insular cortex, from a stroke for instance, have their addiction to cigarettes practically eliminated. These individuals were found to be up to 136 times more likely to undergo a disruption of smoking addiction than smokers with damage in other areas. Disruption of addiction was evidenced by self-reported behavior changes such as quitting smoking less than one day after the brain injury, quitting smoking with great ease, not smoking again after quitting, and having no urge to resume smoking since quitting. The study was conducted on average eight years after the strokes, which opens up the possibility that recall bias could have affected the results.{{cite journal |vauthors=Vorel SR, Bisaga A, McKhann G, Kleber HD |title=Insula damage and quitting smoking |journal=Science |volume=317 |issue=5836 |pages=318–9; author reply 318–9 |date=July 2007 |pmid=17641181 |doi=10.1126/science.317.5836.318c |s2cid=8917168 }} More recent prospective studies, which overcome this limitation, have corroborated these findings{{cite journal|doi=10.1161/STROKEAHA.111.630004 | pmid=22052507 | title=Smoking Cessation 1 Year Poststroke and Damage to the Insular Cortex | journal=Stroke | date=2011 | volume=43 | issue=1 | pages=131–136 | first=R. | last=Suner-Soler| doi-access=free }}{{cite journal|doi=10.1093/ntr/ntt172 | pmid=24169814 | title=Basal Ganglia Plus Insula Damage Yields Stronger Disruption of Smoking Addiction Than Basal Ganglia Damage Alone | journal=Nicotine | date=2013 | volume=16 | issue=4 | pages=445–453 | first=N. | last=Gaznick| pmc=3954424 }} This suggests a significant role for the insular cortex in the neurological mechanisms underlying addiction to nicotine and other drugs, and would make this area of the brain a possible target for novel anti-addiction medication. In addition, this finding suggests that functions mediated by the insula, especially conscious feelings, may be particularly important for maintaining drug addiction, although this view is not represented in any modern research or reviews of the subject.{{Cite journal

| doi = 10.1176/appi.ajp.162.8.1414

| volume = 162

| issue = 8

| pages = 1414–22

| last = Hyman

| first = Steven E.

| title = Addiction: A Disease of Learning and Memory

| journal = Am J Psychiatry

| date = 2005-08-01

| pmid = 16055762

}}

A recent study in rats by Contreras et al.{{Cite journal

|author1=Marco Contreras |author2=Francisco Ceric |author3=Fernando Torrealba | title = Inactivation of the Interoceptive Insula Disrupts Drug Craving and Malaise Induced by Lithium

| journal = Science

| date = January 2007

| volume = 318

| issue = 5850

| pages = 655–8

| doi = 10.1126/science.1145590

| pmid = 17962567

|bibcode=2007Sci...318..655C |s2cid=23499558 | hdl= 10533/135157

| hdl-access= free

}} corroborates these findings by showing that reversible inactivation of the insula disrupts amphetamine conditioned place preference, an animal model of cue-induced drug craving. In this study, insula inactivation also disrupted "malaise" responses to lithium chloride injection, suggesting that the representation of negative interoceptive states by the insula plays a role in addiction. However, in this same study, the conditioned place preference took place immediately after the injection of amphetamine, suggesting that it is the immediate, pleasurable interoceptive effects of amphetamine administration, rather than the delayed, aversive effects of amphetamine withdrawal that are represented within the insula.

A model proposed by Naqvi et al. (see above) is that the insula stores a representation of the pleasurable interoceptive effects of drug use (e.g., the airway sensory effects of nicotine, the cardiovascular effects of amphetamine), and that this representation is activated by exposure to cues that have previously been associated with drug use. A number of functional imaging studies have shown the insula to be activated during the administration of addictive psychoactive drugs. Several functional imaging studies have also shown that the insula is activated when drug users are exposed to drug cues, and that this activity is correlated with subjective urges. In the cue-exposure studies, insula activity is elicited when there is no actual change in the level of drug in the body. Therefore, rather than merely representing the interoceptive effects of drug use as it occurs, the insula may play a role in memory for the pleasurable interoceptive effects of past drug use, anticipation of these effects in the future, or both. Such a representation may give rise to conscious urges that feel as if they arise from within the body. This may make addicts feel as if their bodies need to use a drug, and may result in persons with lesions in the insula reporting that their bodies have forgotten the urge to use, according to this study.

{{Main|Ecstatic seizures}}

A common quality in mystical experiences is a strong feeling of certainty which cannot be expressed in words. Fabienne Picard proposes a neurological explanation for this subjective certainty, based on clinical research of epilepsy.{{Citation | last =Picard | first =Fabienne |title =State of belief, subjective certainty and bliss as a product of cortical dysfuntion | journal =Cortex |volume=49 | issue =9 |year=2013 |pages=2494–2500| pmid =23415878 | doi =10.1016/j.cortex.2013.01.006 | s2cid =206984751 }}{{Citation | last1 =Gschwind | first1 =Markus | last2 =Picard | first2 =Fabienne | year =2016 | title =Ecstatic Epileptic Seizures: a glimpse into the multiple roles of the insula | journal =Frontiers in Behavioral Neuroscience | volume =10 | page =21 | doi=10.3389/fnbeh.2016.00021 | pmid=26924970 | pmc=4756129| doi-access =free }}

According to Picard, this feeling of certainty may be caused by a dysfunction of the anterior insula, a part of the brain which is involved in interoception, self-reflection, and in avoiding uncertainty about the internal representations of the world by "anticipation of resolution of uncertainty or risk". This avoidance of uncertainty functions through the comparison between predicted states and actual states, that is, "signaling that we do not understand, i.e., that there is ambiguity."Picard 2013, p.2496-2498 Picard notes that "the concept of insight is very close to that of certainty," and refers to Archimedes' "Eureka!"Picard 2013, p.2497-2498See also satori in Japanese Zen Picard hypothesizes that during ecstatic seizures the comparison between predicted states and actual states no longer functions, and that mismatches between predicted state and actual state are no longer processed, blocking "negative emotions and negative arousal arising from predictive uncertainty," which will be experienced as emotional confidence.Picard 2013, p.2498 Picard concludes that "[t]his could lead to a spiritual interpretation in some individuals."

The insular cortex has been suggested to have a role in anxiety disorders,{{cite journal |vauthors=Paulus MP, Stein MB |title=An insular view of anxiety |journal=Biol. Psychiatry |volume=60 |issue=4 |pages=383–7 |date=August 2006 |pmid=16780813 |doi=10.1016/j.biopsych.2006.03.042 |s2cid=17889111 }} emotion dysregulation,{{cite journal |vauthors=Thayer JF, Lane RD |title=A model of neurovisceral integration in emotion regulation and dysregulation |journal=J Affect Disord |volume=61 |issue=3 |pages=201–16 |date=December 2000 |pmid=11163422 |doi=10.1016/S0165-0327(00)00338-4|url=https://zenodo.org/record/1259859 }} and anorexia nervosa.{{cite journal |vauthors=Gaudio S, Wiemerslage L, Brooks SJ, Schiöth HB | title = A systematic review of resting-state functional-MRI studies in anorexia nervosa: Evidence for functional connectivity impairment in cognitive control and visuospatial and body-signal integration. | journal = Neurosci Biobehav Rev | year = 2016 | pmid = 27725172 | doi = 10.1016/j.neubiorev.2016.09.032 | volume=71 | pages=578–589| s2cid = 16526824 | url = http://researchonline.ljmu.ac.uk/9236/1/A%20systematic%20review%20of%20resting-state%20functional-MRI%20studies%20in%20anorexia%20nervosa%20Evidence%20for%20functional%20connectivity%20impairment%20in%20cognitive%20control%20and%20visuospatial%20and%20body-signal%20integration..pdf | doi-access = free }}

The insula was first described by Johann Christian Reil while describing cranial and spinal nerves and plexuses.{{cite journal |vauthors=Binder DK, Schaller K, Clusmann H |title=The seminal contributions of Johann-Christian Reil to anatomy, physiology, and psychiatry |journal=Neurosurgery |volume=61 |issue=5 |pages=1091–6; discussion 1096 |date=November 2007 |pmid=18091285 |doi=10.1227/01.neu.0000303205.15489.23 |s2cid=8152708 }} Henry Gray in Gray's Anatomy is responsible for it being known as the Island of Reil. John Allman and colleagues showed that anterior insular cortex contains spindle neurons.

File:Insula structure.png|Location and structure of the insular cortex

File:Gray717.png|Coronal section of brain immediately in front of pons (Insula labeled at upper right)

File:Telencephalon-Horiconatal.jpg|Horizontal section of left cerebral hemisphere

File:Insular cortex coronal sections.gif|Insular cortex highlighted in green on coronal T1 MRI images

File:Insular cortex sagittal sections.gif|Insular cortex highlighted in green on sagittal T1 MRI images

File:Insular cortex transversal sections.gif|Insular cortex highlighted in green on transversal T1 MRI images

{{Anatomy-terms}}

• List of regions in the human brain

{{Reflist|2}}

{{Commons category}}

• {{WOROI|67}}. Location and literature citations for the insula
• {{WhoNamedIt|synd|1212}}
• {{cite web|url=http://www.tk.de/rochelexikon/pics/s13048.000-1.html |title=Anatomy diagram: 13048.000-1 |work=Roche Lexicon - illustrated navigator |publisher=Elsevier |archive-url=https://web.archive.org/web/20141107120933/http://www.tk.de/rochelexikon/pics/s13048.000-1.html |archive-date=2014-11-07 |url-status=dead }}
• {{BrainMaps|insular%20cortex|insular cortex}}
• {{Cite journal

| title = The Insula: Anatomic Study and MR Imaging Display at 1.5 T

| author = Thomas P. Naidicha| journal = American Journal of Neuroradiology

| volume = 25

| pages = 222–32

| date = 1 February 2004

| url = http://www.ajnr.org/cgi/content/full/25/2/222

| pmid = 14970021

| issue = 2

| pmc = 7974606|display-authors=etal}}

• {{cite journal |vauthors=Kakigia R, Nakataa H, Inuia K, Hiroea N, etal | title = Intracerebral pain processing in a Yoga Master who claims not to feel pain during meditation |journal=Eur J Pain |volume=9 |issue=5 |pages=581–9 |date=October 2005 |doi=10.1016/j.ejpain.2004.12.006 |quote=As for fMRI recording, there were remarkable changes in levels of activity in the...SII-insula (mainly the insula) |pmid=16139187| s2cid = 17598717 }}

{{Prosencephalon}}

{{Authority control}}

{{DEFAULTSORT:Insular Cortex}}

Category:Homeostasis

Category:Human homeostasis

Category:Cerebral cortex