Cognitive deficits are central to schizophrenia, but the underlying mechanisms still remain unclear. Imaging studies performed in patients point to decreased activity in the mediodorsal thalamus (MD) and reduced functional connectivity between the MD and prefrontal cortex (PFC) as candidate mechanisms. However, a causal link is still missing. We used a pharmacogenetic approach in mice to diminish MD neuron activity and examined the behavioral and physiological consequences. We found that a subtle decrease in MD activity is sufficient to trigger selective impairments in prefrontal-dependent cognitive tasks. In vivo recordings in behaving animals revealed that MD-PFC beta-range synchrony is enhanced during acquisition and performance of a working memory task. Decreasing MD activity interfered with this task-dependent modulation of MD-PFC synchrony, which correlated with impaired working memory. These findings suggest that altered MD activity is sufficient to disrupt prefrontal-dependent cognitive behaviors and could contribute to the cognitive symptoms observed in schizophrenia.
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http://dx.doi.org/10.1016/j.neuron.2013.01.038 | DOI Listing |
Cortex
December 2024
Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.
The role of the medial part of the thalamus, and in particular the mediodorsal nucleus (MD) and the mammillothalamic tract (MTT), in memory has long been studied, but their contribution remains unclear. While the main functional hypothesis regarding the MTT focuses on memory, some authors postulate that the MD plays a supervisory executive role (indirectly affecting memory retrieval) due to its dense structural connectivity with the prefrontal cortex (PFC). Recently, it has been proposed that the MD, MTT and PFC form part of the DMN the default mode network (DMN).
View Article and Find Full Text PDFNetw Neurosci
December 2024
Department of Psychology, The University of Western Ontario, London, Canada.
We examined how thalamocortical connectivity structure reflects children's reading performance. Diffusion-weighted MRI at 3 T and a series of reading measures were collected from 64 children (33 girls) ages 8-14 years with and without dyslexia. The topological properties of the left and right thalamus were computed based on the whole-brain white matter network and a hub-attached reading network, and were correlated with scores on several tests of children's reading and reading-related abilities.
View Article and Find Full Text PDFBrain Neurosci Adv
December 2024
Department of Psychology, University of Cambridge, Cambridge, UK.
Although a role of the thalamus in different arousal and awareness states is well established, there is a surprising lack of knowledge on subregional specificity within this complex, multinucleated structure of the diencephalon. In their recent paper 'Extrasynaptic GABA-A receptors in central medial thalamus mediate anaesthesia in rats', Muheyati et al. evaluated whether GABA receptors expressed in the central medial (CM), paraventricular (PV) or lateral mediodorsal (MD) nuclei of the thalamus contribute to the loss of the righting reflex (LORR) in rats.
View Article and Find Full Text PDFTransl Neurosci
January 2024
Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
Functional magnetic resonance imaging (fMRI) stands as a pivotal tool in advancing our comprehension of Schizophrenia, offering insights into functional segregations and integrations. Previous investigations employing either task-based or resting-state fMRI primarily focused on large main regions of interest (ROI), revealing the thalamus and superior temporal gyrus (STG) as prominently affected areas. Recent studies, however, unveiled the cytoarchitectural intricacies within these regions, prompting a more nuanced exploration.
View Article and Find Full Text PDFCereb Cortex
December 2024
Institute of Biomedical Innovation, Nanchang University, Nanchang 330031, China.
Value-based decision-making involves weighing costs and benefits. The activity of the medial prefrontal cortex reflects cost-benefit assessments, and the mediodorsal thalamus, reciprocally connected with the medial prefrontal cortex, has increasingly been recognized as an active partner in decision-making. However, the specific role of the interaction between the mediodorsal thalamus and the medial prefrontal cortex in regulating the neuronal activity underlying how costs and benefits influence decision-making remains largely unexplored.
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