Thalamokortikale

Thalamokortikale (thalamocortical) connectivity refers to the network of reciprocal projections between the thalamus and the cerebral cortex. This system supports sensory processing, motor coordination, and higher cognitive functions through dynamic communication across brain regions.

The thalamus contains first-order relay nuclei, such as the lateral geniculate nucleus for vision, the medial geniculate nucleus for audition, and the ventral posterior nucleus complex for somatosensation. These nuclei receive subcortical or peripheral input and project mainly to primary cortical areas, often targeting layer IV. In contrast, higher-order nuclei, including the pulvinar and the mediodorsal nucleus, integrate extensive cortical input and project to multiple cortical areas, enabling cortico-cortical integration through the thalamus.

Corticothalamic feedback is a key feature of thalamocortical circuits. Neurons in cortical layer VI send projections back to thalamic nuclei, modulating relay strength and timing. The thalamic reticular nucleus provides inhibitory control, shaping transmission and synchrony across networks, with particular relevance to attention and sleep rhythms.

Functional roles include the relay and integration of sensory information, motor planning, attention, and conscious perception. Thalamocortical loops participate in rhythms such as sleep spindles and oscillations linked to alertness, and they adapt through experience-dependent plasticity.

Clinical relevance includes thalamic lesions causing sensory loss or thalamic pain, as well as involvement in neuropsychiatric conditions and epilepsy, where altered thalamocortical connectivity contributes to symptoms.