Cortico-striatal-thalamocortical feedback loop
202308161359
Vollenweider2001b The limbic cortico-striato-thalamic-cortical (CSTC) feedback loops are involved in memory, learning, and self–nonself discrimination by linkage of cortically categorized exteroceptive perception with internal stimuli of the value system. The filter function of the thalamus, which is under the control of the CSTC feedback/reentry loops, is postulated to protect the cortex from exteroceptive sensory information overload, as well as from internal overarousal. The model predicts that sensory overload of the cortex and psychosis may result from thalamic gating deficits, which may be caused by ketamine by blockade of N-methyl-D-aspartate (NMDA)–mediated glutamatergic (Glu) corticostriatal and/or by increasing mesolimbic dopaminergic (DA) neurotransmission. Excessive stimulation of serotonin 5-HT2 receptors (for example, by psilocybin) may lead to a similar neurotransmitter imbalance in the CSTC loops, which again results in an opening of the thalamic filter, sensory overload of the cortex, and psychosis. VTA, ventral tegmental area; SNc, substantia nigra pars compacta; GABA, γ-aminobutyric acid; , NMDA receptor.
Summary
The thalamus plays a key role within CSTC feedback loops for gating external and internal information to the cortex, crucially involved in regulation of the level of awareness and attention Vollenweider2007 Geyer2008.
This view is consistent with integrated information theory Tononi2004
(Review: Nichols2016)
Thalamic filter model of psychedelic action
Thalamocortical system is essential for conscious activity Edelman2003 (Review: Nichols2016)
Thalamocortical interactions play a special role in integration of distributed neural activity across wide cortical regions and in generation of conscious experience Edelman1998 (Review: Nichols2016)
psychedelics disrupt information processing in CSTC loops
Psychedelics impair sensorimotor gating