Thalamic bursting in rats during different awake behavioral states.

摘要: Thalamic neurons have two firing modes: tonic and bursting. It was originally suggested that bursting occurs only during states such as slow-wave sleep, when little or no information is relayed by the thalamus. However, wakefulness in visual somatosensory thalamus, could theoretically influence sensory processing. Here we used chronically implanted electrodes to record from ventroposterior medial thalamic nucleus (VPM) primary cortex (SI) of awake, freely moving rats different behaviors. These behaviors included quiet immobility, exploratory whisking (large-amplitude whisker movements), twitching (small-amplitude, 7- 12-Hz movements). We demonstrated appeared oscillatory activity occurring before movements, continued throughout twitching. Further, occurred substantially more often than other behaviors, a neuron most likely respond stimulus if burst ≈120 ms stimulation. In addition, amount cortical area activated similar whisking. SI inactivated muscimol infusion, never observed. Finally, statistical technique called partial directed coherence identify direction neural between VPM SI, observed there directional Based on these findings, propose twitching, descending signal triggers primes thalamocortical loop for enhanced detection behavior.