THALAMOCORTICAL BURSTS DURING SLEEP AND THEIR IMPACT ON SENSORY DISCRIMINATION LEARNING

Thalamocortical (TC) burst firing is known to support sensory processing, but burst firing is also very prominent during non-sensory states, like sleep. To better understand the function of TC bursts during sleep , we investigated the effects of transient pharmacological TC burst suppression during the resting periods of mice, after their daily training of a sensory discrimination learning task.

Freely moving mice were trained in a sensory go/no-go discrimination task, and learning speed was quantified using trials to expert criterion and d′ measures. Following training sessions, thalamocortical bursts were transiently inhibited by systemic administration of the T-type calcium channel blocker Z944, while control animals received vehicle injections. Task-related electrophysiological recordings confirmed robust burst activity during sensory engagement and effective pharmacological burst suppression. Post-session sleep was recorded and sleep stages were classified based on electrophysiological criteria.

Preliminary analyses indicate that Z944-treated mice are able to acquire the task at rates comparable to controls, suggesting that sensory discrimination learning remains normal despite post-session burst inhibition. This raises the possibility that compensatory mechanisms may support learning when thalamocortical bursting is attenuated. Ongoing analyses therefore focus on identifying learning-related alterations in sleep architecture and state-dependent thalamocortical activity that may mediate such compensation.

Together, this work establishes an experimental framework to test how thalamocortical burst dynamics interact with sleep to support learning and highlights sleep as a potential substrate for compensatory plasticity when canonical thalamic burst mechanisms are disrupted.