Didhiti Mukherjee, University of Iowa
ABSTRACT: Sensory feedback from myoclonic twitching during active (or REM) sleep is thought to facilitate sensorimotor integration in the developing nervous system. The inferior olive (IO) is a precerebellar nucleus that plays an important role in sensorimotor integration in mammalian species. However, little is known about the functional development of the IO. Here, using extracellular electrophysiology, we characterized the spontaneous activity of the IO during sleep and wake and found that the activity of the IO is uniquely and precisely correlated with twitches. Adjacent to the IO, another associated structure is the lateral reticular nucleus (LRN), also implicated in sensorimotor integration. We interestingly found a similar pattern of twitch-related activity in the LRN. The activity pattern suggests that, unlike other sensory structures that receive feedback from twitches, the IO and LRN receive twitch-related motor information from areas involved in the production of twitches. Next, we identified non-overlapping areas in the midbrain that are likely to be involved in twitch-production and likely send that information to the IO and LRN. By recording from those midbrain nuclei, we found a significant increase in neural firing before twitching of different muscles. Finally, using a pharmacological approach, we aim to understand the neural mechanism underlying processing of twitch-related information in the IO and LRN. These results, together, shed light on how self-generated twitches during early infancy could facilitate activity-dependent development of brain structures, critically important for sensorimotor integration.