Pairwise maximum entropy model explains the role of white matter structure in shaping emergent co-activation states

Abstract

A major challenge in neuroscience is determining a quantitative relationship between the brain’s white matter structural connectivity and emergent activity. We seek to uncover the intrinsic relationship among brain regions fundamental to their functional activity by constructing a pairwise maximum entropy model (MEM) of the inter-ictal activation patterns of five patients with medically refractory epilepsy over an average of ~14 hours of band-passed intracranial EEG (iEEG) recordings per patient. We find that the pairwise MEM accurately predicts iEEG electrodes’ activation patterns’ probability and their pairwise correlations. We demonstrate that the estimated pairwise MEM’s interaction weights predict structural connectivity and its strength over several frequencies significantly beyond what is expected based solely on sampled regions’ distance in most patients. Together, the pairwise MEM offers a framework for explaining iEEG functional connectivity and provides insight into how the brain’s structural connectome gives rise to large-scale activation patterns by promoting co-activation between connected structures.

A Framework for Brain Atlases: Lessons from Seizure Dynamics

“…The change from preictal to ictal SFC is denoted ΔSFC. This finding supports the hypothesis that seizure activity harnesses the underlying structural connectivity of the brain 23,24 . SFC was similarly calculated for random whole-brain atlases.…”

“…We show that SFC increases during the ictal state for many atlases (CerebrA, AAL2, Craddock 400), but not all atlases (Hammersmith). The increase in SFC during seizures follows previous SFC publications with ECoG 23,24 . Similarly, SFC increases for a subset of random whole-brain atlases.…”

“…SFC increases during seizure state for some standard atlases (Craddock 400,AAL2,and CerebrA atlases). This result follows previous SFC publications with ECoG 13,14 . However, SFC does not increase for the Hammersmith atlas.…”

“…(Hammersmith). The increase in SFC during seizures follows previous SFC studies using ECoG 13,14 . Similarly, SFC increases for a subset of random whole-brain atlases.…”

“…Another limitation is that we assume a change in SFC supports the hypothesis that seizures harness the underlying structural connectome of the brain (along with support from prior literature 23,24,51 ). We may be biasing our results to select an atlas that maximizes ΔSFC.…”