REGION-SPECIFIC THALAMIC RETICULAR CIRCUITS REGULATING SENSORY AND NON-SENSORY THALAMOCORTICAL DYNAMICS

Recent advances in neuroscience highlighted that higher-order cortical functions cannot be meaningfully discussed without acknowledging the essential role of the thalamus. Despite this progress, our understanding remains largely grounded in sensory systems, and the extent to which sensory and higher-order cognitive thalamocortical circuits are structurally and functionally specialized remains poorly understood. Recent work has focused on the thalamic reticular nucleus (TRN), which is the main source of intrathalamic inhibition and plays a key role in regulating information transfer within corticothalamic networks. Importantly, TRN dysfunction has been implicated in a wide range of neurological disorders.
Our previous work has shown that TRN sectors associated with sensory versus frontal cortical areas differ fundamentally in their cortical innervation. Notably, TRN sectors associated with frontal—but not sensory—cortical areas receive strong excitatory input from cortical pyramidal tract neurons. Here, we investigate the functional consequences of this dichotomous innervation in freely moving animals using silicon probe recordings. In addition, we show that these TRN sectors also receive anatomically and functionally distinct, sector-specific input from the external segment of the globus pallidus.
In conclusion, TRN regions associated with sensory versus frontal cortical areas exhibit pronounced differences in their cortical and subcortical inputs. This functional dichotomy may lead to significant differences in the dynamics of thalamocortical networks and suggests that these networks may respond differently to pharmacological interventions, underscoring their distinct therapeutic potential.