Authors:

FRISBY, S.L., HALAI, A.D., Cox, C.R., Clark, A., Shimotake, A., Kikuchie, T., Kuneida, T., Arakawa, Y., Takahashi, R., Ikeda, A., Matsumoto, R., Rogers, T.T. & LAMBON RALPH, M.

Reference:

Year of publication:

In Press

CBU number:

9259

Abstract:

Intracranial electrophysiology offers a unique insight into the nature of information representation in the brain – it can be used to disentangle information encoded in gamma and high gamma frequencies from information encoded in lower frequencies. We used regularised logistic regression to decode animacy from time-frequency power and phase extracted from electrocorticography (ECoG) grid electrode data recorded on the surface of human vATL. Power in gamma (30 – 60 Hz) and high gamma (60 – 200 Hz) produced reliable decoding, indicating that semantic information is indeed expressed by local populations in vATL. However, power from a wide range of frequencies (4 – 200 Hz) produced significantly higher decoding accuracy and also exhibited the same rapidly-changing dynamic code previously observed when decoding voltage. These findings support the theory that semantic information is encoded by a local vATL “hub” that interacts with distributed cortical “spokes”. We are unable to share raw data for this study because patients did not provide informed consent for us to do so. However, matrices containing power, phase, and voltage features (columns) for each stimulus (rows) are available at https://osf.io/m5v42/ . Code is available at https://github.com/slfrisby/ECoG_LASSO .

Data for this project is available at: https://osf.io/m5v42/