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An Intracranial Electrophysiology Study of Visual Language Encoding: The Contribution of the Precentral Gyrus to Silent Reading. J Cogn Neurosci 2021 10 01;33(11):2197-2214

Date

08/05/2021

Pubmed ID

34347873

Pubmed Central ID

PMC8497063

DOI

10.1162/jocn_a_01764

Scopus ID

2-s2.0-85116941162

Abstract

Models of reading emphasize that visual (orthographic) processing provides input to phonological as well as lexical-semantic processing. Neurobiological models of reading have mapped these processes to distributed regions across occipital-temporal, temporal-parietal, and frontal cortices. However, the role of the precentral gyrus in these models is ambiguous. Articulatory phonemic representations in the precentral gyrus are obviously involved in reading aloud, but it is unclear if the precentral gyrus is recruited during reading silently in a time window consistent with participation in phonological processing contributions. Here, we recorded intracranial electrophysiology during a speeded semantic decision task from 24 patients to map the spatio-temporal flow of information across the cortex during silent reading. Patients selected animate nouns from a stream of nonanimate words, letter strings, and false-font stimuli. We characterized the distribution and timing of evoked high-gamma power (70-170 Hz) as well as phase-locking between electrodes. The precentral gyrus showed a proportion of electrodes responsive to linguistic stimuli (27%) that was at least as high as those of surrounding peri-sylvian regions. These precentral gyrus electrodes had significantly greater high-gamma power for words compared to both false-font and letter-string stimuli. In a patient with word-selective effects in the fusiform, superior temporal, and precentral gyri, there was significant phase-locking between the fusiform and precentral gyri starting at a??180 msec and between the precentral and superior temporal gyri starting at a??220 msec. Finally, our large patient cohort allowed exploratory analyses of the spatio-temporal reading network underlying silent reading. The distribution, timing, and connectivity results place the precentral gyrus as an important hub in the silent reading network.

Author List

Kaestner E, Thesen T, Devinsky O, Doyle W, Carlson C, Halgren E

Author

Chad Carlson MD Professor in the Neurology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Brain Mapping
Electrophysiology
Humans
Language
Magnetic Resonance Imaging
Motor Cortex
Reading