Molecular mapping of the human thalamus. Relationship with thalamocortical wiring and role in schizophrenia
Calzavara R, Akil H, Barchas JD, Bunney WE, Lee FS, Myers RM, Schatzberg AF, Watson SJ
Society for Neuroscience. 2017.
The thalamus is a key structure for relaying and integrating multi-functional information for perception, action and cognition within the cortex. Anatomical and functional data indicate that thalamo-cortical connectivity is impaired in schizophrenia. In particular, dysfunctional connectivity with frontal lobe areas, such as the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC), may represent a potential neural substrate for cognitive dysfunction. As a first step toward a cell type specific model of cortico-thalamic fine wiring in schizophrenia, we investigated the basic neurochemical and molecular mapping of the thalamus in control subjects. In particular, we focused on the nuclei connected to frontal cortex, such as the medial dorsal (MD) nucleus. We identified molecular markers of thalamic neurons and we used in situ hybridization to investigate the relative cell expression and distribution of these markers in the thalamus. Preliminary results indicate a complex neurochemical map in which some markers have complementary or similar distributions. In particular, some marker distributions seem to overlap in specific thalamic nuclei, such as observed for the cell clusters in the MD nucleus. This may indicate that thalamic cells can be identified by a unique set of molecular markers. The relative expression of these markers and their distributions in the thalamic relay nuclei is thought to be associated with cell development and neurotransmitter function, and therefore can be related to specific thalamo-cortical circuits. The major goal of our study is to test whether these thalamo-cortical circuits, and potential selective cell types, are particularly affected in schizophrenia. Thus, this gene-expression map of the human thalamus would guide our next steps in the investigation of thalamic gene-expression patterns in schizophrenia.