Laminar profile of spontaneous and evoked theta: Rhythmic modulation of cortical processing during word integration

NEUROPSYCHOLOGIA

卷:76

Article

Halgren, Eric^1,2  Kaestner, Erik³  Marinkovic, Ksenija⁴  Cash, Sydney S.⁵  Wang, Chunmao^{1,2,3,4,5,6,7,8}  Schomer, Donald L.⁶  Madsen, Joseph R.⁷  Ulbert, Istvan⁸ 

[1] Univ Calif San Diego, Dept Radiol, La Jolla, CA 92069 USA

[2] Univ Calif San Diego, Dept Neurosci, La Jolla, CA 92069 USA

[3] Univ Calif San Diego, Interdepartmental Neurosci Program, La Jolla, CA 92069 USA

[4] San Diego State Univ, Dept Psychol, San Diego, CA 92182 USA

[5] Harvard Univ, Sch Med, Massachusetts Gen Hosp, Dept Neurol, Boston, MA 02129 USA

[6] Harvard Univ, Sch Med, Beth Israel Deaconess Med Ctr, Dept Neurol, Boston, MA 02115 USA

[7] Harvard Univ, Sch Med, Childrens Hosp, Dept Neurosurg, Boston, MA 02115 USA

[8] Hungarian Acad Sci, Res Ctr Nat Sci, Inst Cognit Neurosci & Psychol, H-1117 Budapest, Hungary

关键词: Entorhinal;    Inferotemporal;    Prefrontal;    Perirhinal;    Cingulate;    Feedforward;    Feedback;    Current-source density;    Gamma;    Delta;   

DOI  :  10.1016/j.neuropsychologia.2015.03.021

来源: Elsevier

【 摘 要 】

Theta may play a central role during language understanding and other extended cognitive processing, providing an envelope for widespread integration of participating cortical areas. We used linear microelectrode arrays in epileptics to define the circuits generating theta in inferotemporal, perirhinal, entorhinal, prefrontal and anterior cingulate cortices. In all locations, theta was generated by excitatory current sinks in middle layers which receive predominantly feedforward inputs, alternating with sinks in superficial layers which receive mainly feedback/associative inputs. Baseline and event-related theta were generated by indistinguishable laminar profiles of transmembrane currents and unit-firing. Word presentation could reset theta phase, permitting theta to contribute to late event-related potentials, even when theta power decreases relative to baseline. Limited recordings during sentence reading are consistent with rhythmic theta activity entrained by a given word modulating the neural background for the following word. These findings show that theta occurs spontaneously, and can be momentarily suppressed, reset and synchronized by words. Theta represents an alternation between feedforward/divergent and associative/convergent processing modes that may temporally organize sustained processing and optimize the timing of memory formation. We suggest that words are initially encoded via a ventral feedforward stream which is lexicosemantic in the anteroventral temporal lobe; its arrival may trigger a widespread theta rhythm which integrates the word within a larger context. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

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