All spectral frequencies of neural activity reveal semantic representation in the human anterior ventral temporal cortex.

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 ventral anterior temporal lobe (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".