Lastly, a special thank you to all participants and their families and also to Pediatric Epilepsy Surgery Alliance for their continued support and assistance with our research!

Don't hesitate to reach out with any questions!

@cmu.edu @pittophathalmology.bsky.social @nyu.edu

This work is the collective efforts of co-first author
Tina Liu and co-authors Marge Maallo, Sophia Robert, Jason Fu, Christina Patterson, David Plaut, and Marlene Behrmann!

A special thank you too to @amepilepsysoc.bsky.social and
@ampsychfdn.bsky.social for providing funding for this work.

And a key clinical implication is that we see the rapid but atypical emergence of word representations in right OTC just months after left OTC resection, suggesting that surgical treatment itself may promote plasticity, but more work needs to be done with a larger sample.

In summary, our study highlights a striking case of plasticity: we show that when faces and words are constrained to develop in a single hemisphere, there is a dynamic competition such that after left surgery, word representations out-compete face representations, and vice versa.

We see a similar pattern in patient UD. UD had a RIGHT OTC resection, and we observe face representations emerging in LEFT OTC, with voxels in his left OTC also "switching allegiance" from words to faces, an extension of Tina Liu's prior work: www.cell.com/cell-reports...

Notably, we see that over time & pre- to post-surgery, voxels in TC's right OTC "switch allegiance" from representing faces to representing words. That is, word representations emerge in RIGHT OTC after LEFT OTC resection, a complete deviation from the standard topography.

For one patient (TC), we imaged her pre-surgery (at age 13y3m) and twice post-surgery (months and then years after surgery). While we cannot map word representations in superior temporal gyrus (light orange) or inferior frontal gyrus (yellow) PRE-surgery, we can POST-surgery.

With the above in mind, here are a few highlights from our study:

First, we show in several cases of LEFT pediatric OTC resection that word representations are in fact lateralized to the RIGHT hemisphere, both in right OTC and right language cortex (shaded yellow/orange here).

Additionally, attributing deviations from the standard topography to plasticity necessitates tracking changes in preserved cortex, longitudinally. There is also the question of whether we may see pre- to post-surgical changes, i.e., can disease treatment enhance plasticity.

Word representations typically emerge in left OTC, presumably as language regions are also left-lateralized. However, we have not before demonstrated whether following left OTC resection, word representations lateralize in both right OTC and right language regions.

More recently, we showed with fMRI data from pediatric OTC resection patients that there are intact representations for both faces and words in patients' preserved OTC, including for exemplar individuation.
www.cell.com/iscience/ful...

Our previous work supports the idea of such plasticity. In one study, we saw that patients developing with only a left or right hemisphere could perform face and word recognition tasks at ~85% accuracy independent of which hemisphere had been resected.
www.pnas.org/doi/10.1073/...

Pediatric patients with unilateral resection develop with only a single OTC. If the topographic emergence of visual stimulus representations is truly malleable, face and word representations may come to emerge in preserved OTC, contralateral to the site of resection.

Over typical development, representations for face and word stimuli become largely segregated across the two hemispheres, with representations for faces and words predominantly lateralizing to right and left OTC, respectively. The question is how malleable is this organization?

And hope to connect with clinicians and researchers on this app working in pediatric epilepsy surgery! #AES2024