Anesthesia and the Thalamocortical System

Alkire, Michael T.

doi:10.1007/978-1-60761-462-3_6

Cited by 1 publication

(2 citation statements)

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“…6,8,11,25–27 The rich and reciprocal nature of thalamocortical interconnectivity involving differential thalamic divisions establishes oscillatory circuits across multiple cortical layers. Such organizational structures put the thalamocortical networks in a unique and crucial position for implementing integrative functionalities necessary for the development of conscious experience.…”

Section: Discussionmentioning

confidence: 99%

“…6–8 In particular, the two major divisions of the thalamus, the specific relay nuclei and the more diffusely projecting “nonspecific” nuclei, may collaborate to accomplish this task; 9–11 with the specific system responsible for the transmission and encoding of sensory and motor information and the nonspecific system engaged in the control of cortical arousal and temporal conjunction of information across distributed cortical areas. 11 These considerations emphasize the importance of the nonspecific thalamocortical system in information integration, and raise the possibility that its dysfunction may be a primary, and possibly unitary, mechanism of anesthetic-induced unconsciousness.…”

Section: Introductionmentioning

confidence: 99%

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Differential Effects of Deep Sedation with Propofol on the Specific and Nonspecific Thalamocortical Systems

Liu

Lauer

Ward³

et al. 2013

Anesthesiology

139

108

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Background Current state of knowledge suggests that disruption of neuronal information integration may be a unitary mechanism of anesthetic-induced unconsciousness. A neural system central for information integration is the thalamocortical system whose specific and nonspecific divisions may play the roles for representing and integrating information; respectively. How anesthetics affect the function of these systems individually is not completely understood. We studied the effect of propofol on thalamocortical functional connectivity in the specific and nonspecific systems using functional magnetic resonance imaging. Methods Eight healthy volunteers were instructed to listen to and encode 40 English words during wakeful baseline, light sedation, deep sedation, and recovery in the scanner. Functional connectivity was determined as the temporal correlation of blood oxygen level-dependent signals with seed regions defined within the specific and nonspecific thalamic nuclei. Results Thalamocortical connectivity at baseline was dominantly medial and bilateral frontal and temporal for the specific system and medial frontal and medial parietal for the nonspecific system. During deep sedation, propofol reduced functional connectivity by 43% (specific) and 79% (nonspecific), a significantly greater reduction of connections in the nonspecific than in the specific system and in the left hemisphere than in the right. Upon regaining consciousness, functional connectivity increased by 58% (specific) and 123% (nonspecific) during recovery, exceeding their values at baseline. Conclusions Propofol conferred differential changes in functional connectivity of the specific and nonspecific thalamocortical systems. The changes in nonspecific thalamocortical connectivity may correlate with loss and return of consciousness.

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