RT Journal Article
SR Electronic
T1 First-Pass Selectivity for Semantic Categories in Human Anteroventral Temporal Lobe
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 18119
OP 18129
DO 10.1523/JNEUROSCI.3122-11.2011
VO 31
IS 49
A1 Alexander M. Chan
A1 Janet M. Baker
A1 Emad Eskandar
A1 Donald Schomer
A1 Istvan Ulbert
A1 Ksenija Marinkovic
A1 Sydney S. Cash
A1 Eric Halgren
YR 2011
UL http://www.jneurosci.org/content/31/49/18119.abstract
AB How the brain encodes the semantic concepts represented by words is a fundamental question in cognitive neuroscience. Hemodynamic neuroimaging studies have robustly shown that different areas of posteroventral temporal lobe are selectively activated by images of animals versus manmade objects. Selective responses in these areas to words representing animals versus objects are sometimes also seen, but they are task-dependent, suggesting that posteroventral temporal cortex may encode visual categories, while more anterior areas encode semantic categories. Here, using the spatiotemporal resolution provided by intracranial macroelectrode and microelectrode arrays, we report category-selective responses to words representing animals and objects in human anteroventral temporal areas including inferotemporal, perirhinal, and entorhinal cortices. This selectivity generalizes across tasks and sensory modalities, suggesting that it represents abstract lexicosemantic categories. Significant category-specific responses are found in measures sensitive to synaptic activity (local field potentials, high gamma power, current sources and sinks) and unit-firing (multiunit and single-unit activity). Category-selective responses can occur at short latency (as early as 130 ms) in middle cortical layers and thus are extracted in the first pass of activity through the anteroventral temporal lobe. This activation may provide input to posterior areas for iconic representations when required by the task, as well as to the hippocampal formation for categorical encoding and retrieval of memories, and to the amygdala for emotional associations. More generally, these results support models in which the anteroventral temporal lobe plays a primary role in the semantic representation of words.