Language Lateralization and Cognitive Reorganization in Epilepsy
I demonstrated that when language skills reorganize to the right hemisphere they show substantial independence, suggesting that component language skills do not shift in a monolithic fashion. I argued that the status of the healthy hippocampus plays a role in determining whether language reorganizes ipsilaterally or contralaterally. I published the first work demonstrating that resting state functional connectivity (rsFC) can be used to predict hemispheric language lateralization. I showed that the pathophysiology of seizures and epileptogenesis are neuroplastic processes, causing epilepsy patients to be highly prone to reorganization, showing that cognitive network change is a dynamic not static process.
Structural and Functional Connectivity in Epilepsy
I provided evidence for a “pruning” hypothesis to model the relation between task fMRI and functional connectivity. I presented evidence for considering focal epilepsies a network disorder. I have used rsFC to demonstrate that the build-up of seizure networks is not random and may, in some cases, be adaptive, generating an inhibitory surround to keep seizures focal.
Memory Functioning in Epilepsy
I demonstrated that temporal lobe epilepsy demonstrates a dissociation between implicit (intact) and explicit (impaired) memory. Using rsFC, I was the first to show that the dorsal (not ventral) DMN bears the impact of TLE, interacting with the side of pathology. I demonstrated that the side of epilepsy pathology produces distinct FC effects, implying different capacities for cognitive reorganization and recovery.
Prediction of Outcomes Following Epilepsy Surgery
In the first article using rsFC to predict outcome, I demonstrated that cognitive outcome was successfully predicted with 68% of the variance explained, with connections to the healthy hippocampus the most common predictor. I demonstrated that genuine reorganization of white matter tracks after ATL can implement inter-hemispheric shifts in language, with this associated with better surgical outcomes. I presented a conceptual framework for identifying and interpreting multi-modal neuroimaging studies of cognitive reorganization and recovery.
Cognitive Reorganization from Learning
I reported that throughout different stages of learning and a form of adaptation occurs, or a new functional circuit is formed with some structures dropping off and others joining. I argued that strong learning of a complex motor task generates an anterior to posterior shift in activation, reflecting a shift toward “non-executive” cognitive control.