connectogram

File:ConnectogramExample.tif

File:Connectogram Key.jpg

The connectogram, as a graphical representation of brain connectomics, was proposed in 2012.

Circular representations of connections have been used in a number of disciplines; examples include representation of aspects of epidemics,{{cite journal|last=Guo|first=Zhenyang|title=National Borders Effectively Halt the Spread of Rabies: The Current Rabies Epidemic in China Is Dislocated from Cases in Neighboring Countries|journal=PLOS Neglected Tropical Diseases|date=January 2013|volume=7|issue=1|doi=10.1371/journal.pntd.0002039|pmid=23383359|pages=e2039|display-authors=etal|pmc=3561166 |doi-access=free }} geographical networks,{{cite journal|last=Hennemann|first=Stefan|title=Information-rich visualisation of dense geographical networks|journal=Journal of Maps|year=2013|volume=9|issue=1|pages=1–8|doi=10.1080/17445647.2012.753850|hdl=10.1080/17445647.2012.753850|s2cid=128952987|hdl-access=free}} musical beats,{{cite web|last=Lamere|first=Paul|title=The Infinite Jukebox|url=http://musicmachinery.com/2012/11/12/the-infinite-jukebox/|work=Music Machinery|date=2012-11-12}} diversity in bird populations,{{cite journal|last=Jetz|first=W. |author2=G. H. Thomas |author3=J. B. Joy |author4=K. Hartmann |author5=A. O. Mooers|title=The global diversity of birds in space and time.|journal=Nature|date=15 November 2012|volume=491|pages=444–448|doi=10.1038/nature11631|pmid=23123857|issue=7424|bibcode=2012Natur.491..444J |s2cid=590585 }} and genomic data.{{cite journal|last=Yip|first=Kevin|title=Classification of human genomic regions based on experimentally determined binding sites of more than 100 transcription-related factors|journal=Genome Biology|date=26 September 2012|volume=13|issue=9|doi=10.1186/gb-2012-13-9-r48|pmid=22950945|pages=R48|display-authors=etal|pmc=3491392 |doi-access=free }} Connectograms were also cited as a source of inspiration for the heads-up display style of Tony Stark's helmet in Iron Man 3.{{cite conference|url=http://helenabarbas.net/papers/2017_VR_AR_MR_Simulation_IronMan_H_Barbas.pdf|title=VR, AR, MR SIMULATIONS AND INSPIRATIONS FROM "IRON MAN 3"|first=Helen|last=Barbas|date=October 2017|conference=European Simulation and Modelling Conference|editor=Paulo J.S. Goncalves|access-date=6 November 2017}}

File:ParcellationBrains.jpg

Connectograms are circular, with the left half depicting the left hemisphere and the right half depicting the right hemisphere. The hemispheres are further broken down into frontal lobe, insular cortex, limbic lobe, temporal lobe, parietal lobe, occipital lobe, subcortical structures, and cerebellum. At the bottom the brain stem is also represented between the two hemispheres. Within these lobes, each cortical area is labeled with an abbreviation and assigned its own color, which can be used to designate these same cortical regions in other figures, such as the parcellated brain surfaces in the adjacent image, so that the reader can find the corresponding cortical areas on a geometrically accurate surface and see exactly how disparate the connected regions may be. Inside the cortical surface ring, the concentric circles each represent different attributes of the corresponding cortical regions. In order from outermost to innermost, these metric rings represent the grey matter volume, surface area, cortical thickness, curvature, and degree of connectivity (the relative proportion of fibers initiating or terminating in the region compared to the whole brain). Inside these circles, lines connect regions that are found to be structurally connected. The relative density (number of fibers) of these connections is reflected in the opacity of the lines, so that one can easily compare various connections and their structural importance. The fractional anisotropy of each connection is reflected in its color.{{cite journal|last=Irimia|first=Andrei |author2=Chambers, M.C. |author3=Torgerson, C.M. |author4=Van Horn, J.D. |title=Circular representation of human cortical networks for subject and population-level connectomic visualization|journal=NeuroImage|date=2 April 2012|doi=10.1016/j.neuroimage.2012.01.107|pmid=22305988|volume=60|issue=2|pages=1340–51|pmc=3594415}}

With the recent concerted push to map all of the human brain and its connections,{{cite web|title=Human Connectome Project|url=http://www.humanconnectomeproject.org/|publisher=NIH}}{{cite news|title=Hard Cell|url=https://www.economist.com/news/science-and-technology/21573089-ambitious-project-map-brain-works-possibly-too-ambitious-hard|accessdate=11 March 2013|newspaper=The Economist|date=9 March 2013}} it has become increasingly important to find ways to graphically represent the large amounts of data involved in connectomics. Most other representations of the connectome use 3 dimensions, and therefore require an interactive graphical user interface. The connectogram can display 83 cortical regions within each hemisphere, and visually display which areas are structurally connected, all on a flat surface. It is therefore conveniently filed in patient records, or to display in print. The graphs were originally developed using the visualization tool called Circos.{{cite web|url=http://circos.ca|title=Introduction to Circos, Features and Uses // CIRCOS Circular Genome Data Visualization}}{{cite journal|title=Circos: an information aesthetic for comparative genomics|journal=Genome Research|date=28 May 2009|volume=19|issue=9|pages=1639–1645|doi=10.1101/gr.092759.109|pmc=2752132|pmid=19541911 | last1 = Krzywinski | first1 = M | last2 = Schein | first2 = J | last3 = Birol | first3 = I | last4 = Connors | first4 = J | last5 = Gascoyne | first5 = R | last6 = Horsman | first6 = D | last7 = Jones | first7 = SJ | last8 = Marra | first8 = MA}}

File:Connections One-by-One.ogv

File:Phineas Gage's Damage.jpeg, who in 1848 survived a large iron bar being propelled through his skull and brain. The connectogram shows only the connections that were estimated to be damaged.]]

On an individual level, connectograms can be used to inform the treatment of patients with neuroanatomical abnormalities. Connectograms have been used to monitor the progression of neurological recovery of patients who suffered a traumatic brain injury (TBI).{{cite journal|last=Irimia|first=Andrei |author2=Chambers, M.C. |author3=Torgerson, C.M. |author4=Filippou, M. |author5=Hovda, D.A. |author6=Alger, J.R. |author7=Gerig, G. |author8=Toga, A.W. |author9=Vespa, P.M. |author10=Kikinis, R. |author11=Van Horn, J.D. |title=Patient-tailored connectomics visualization for the assessment of white matter atrophy in traumatic brain injury|journal=Frontiers in Neurology|date=6 February 2012|doi=10.3389/fneur.2012.00010|pmid=22363313|volume=3|pages=10|pmc=3275792|doi-access=free }} They have also been applied to famous patient Phineas Gage, to estimate damage to his neural network (as well as the damage at the cortical level—the primary focus of earlier studies on Gage).{{cite journal|last=Van Horn|first=John D.|author2=Irimia, A. |author3=Torgerson, C.M. |author4=Chambers, M.C. |author5=Kikinis, R. |author6=Toga, A.W. |title=Mapping connectivity damage in the case of Phineas Gage|journal=PLOS ONE|date=16 May 2012|volume=7|issue=5|doi=10.1371/journal.pone.0037454|pmid=22616011|editor1-last=Sporns|editor1-first=Olaf|pages=e37454|pmc=3353935 |bibcode=2012PLoSO...737454V|doi-access=free}}

Connectograms can represent the averages of cortical metrics (grey matter volume, surface area, cortical thickness, curvature, and degree of connectivity), as well as tractography data, such as the average densities and fractional anisotropy of the connections, across populations of any size. This allows for visual and statistical comparison between groups such as males and females,{{cite journal |last=Ingalhalikar |first=Madhura |author2=Smith |first2=Alex |author3=Parker |first3=Drew |author4=Satterthwaite |first4=Theodore |author5=Elliott |first5=Mark |author6=Ruparel |first6=Kosha |author7=Hakonarson |first7=Hakon |author8=Gur |first8=Raquel |author-link8=Raquel Gur |author9=Verma |first9=Ragini |date=December 2013 |title=Sex differences in the structural connectome of the human brain |journal=Proceedings of the National Academy of Sciences |volume=111 |issue=2 |pages=823–8 |bibcode=2014PNAS..111..823I |doi=10.1073/pnas.1316909110 |pmc=3896179 |pmid=24297904 |doi-access=free}} differing age cohorts, or healthy controls and patients. Some versions have been used to analyze how partitioned networks are in patient populations{{cite journal|last=Messé|first=Arnaud|author2=Sophie Caplain |author3=Mélanie Pélégrini-Issac |author4=Sophie Blancho |author5=Richard Lévy |author6=Nozar Aghakhani |author7=Michèle Montreuil |author8=Habib Benali |author9=Stéphane Lehéricy |title=Specific and Evolving Resting-State Network Alterations in Post-Concussion Syndrome Following Mild Traumatic Brain Injury|journal=PLOS ONE|date=6 June 2013|pmid=23755237|doi=10.1371/journal.pone.0065470|volume=8|issue=6|pages=e65470 |pmc=3675039|bibcode=2013PLoSO...865470M|doi-access=free}} or the relative balance between inter- and intra-hemispheric connections.{{cite journal|last=Wee|first=Chong-Yaw |author2=Pew-Thian Yap |author3=Daoqiang Zhang |author4=Lihong Wang |author5=Dinggang Shen|title=Group-constrained sparse fMRI connectivity modeling for mild cognitive impairment identification|journal=Brain Structure & Function|date=7 March 2013|doi=10.1007/s00429-013-0524-8|pmid=23468090|volume=219|issue=2 |pages=641–656 |pmc=3710527}}

There are many possibilities for which measures are included in the rings of a connectogram. Irimia and Van Horn (2012) have published connectograms which examine the correlative relationships between regions and uses the figures to compare the approaches of graph theory and connectomics.{{cite journal|last=Irimia|first=Andrei|author2=Jack Van Horn|title=The structural, connectomic, and network covariance of the human brain|journal=NeuroImage|date=29 October 2012|doi=10.1016/j.neuroimage.2012.10.066|pmid=23116816|volume=66|pages=489–499|pmc=3586751}}

Some have been published without the inner circles of cortical metrics.{{cite journal|last=Pandit|first=A.S. |author2=Robinson E |author3=Aljabar P |author4=Ball G |author5=Gousias IS |author6=Wang Z |author7=Hajnal JV |author8=Rueckert D |author9=Counsell SJ |author10=Montana G |author11=Edwards AD|title=Whole-Brain Mapping of Structural Connectivity in Infants Reveals Altered Connection Strength Associated with Growth and Preterm Birth|journal=Cerebral Cortex|date=31 March 2013|pmid=23547135|doi=10.1093/cercor/bht086|volume=24|issue=9 |pages=2324–2333|doi-access=free }} Others include additional measures relating to neural networks,{{cite book|last=Sporns|first=Olaf|title=Networks of the Brain|year=2011|publisher=MIT Press|isbn=978-0-262-01469-4}} which can be added as additional rings to the inside to show metrics of graph theory, as in the extended connectogram here:

File:Double Connectogram.png

• {{annotated link|Connectome}}
• {{annotated link|Connectomics}}
• {{annotated link|Human Connectome Project}}
• {{annotated link|Brain mapping}}
• {{annotated link|Tractography}}
• {{annotated link|Chord diagram (information visualization)}}

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Category:Neuroimaging

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