Deep brain imaging of neuronal activity in sensory thalamus during innate and learned avoidance behavior

Avoidance behaviors are critical for survival, enabling organisms to respond effectively to potential threats in their environment. While much is known about how cortical and limbic brain areas contribute to avoidance behavior, the role of the auditory thalamus (medial geniculate body - MGB) in mediating these active defensive responses has not been addressed to this date. Here I investigate how MGB neurons encode both innate and learned avoidance. Using a miniature microscope imaging approach, I monitor the activity of MGB neurons in freely moving mice across multiple days of exploratory tests and active avoidance task. I found that MGB neurons display a variety of plasticity profiles upon danger-predicting auditory stimuli. Furthermore, the population level encoding of auditory stimuli underwent prominent changes as learning progresses, resulting in a coherent neural representation in MGB. Besides the learned avoidance, the role of MGB in encoding innate avoidance behavior is explored. Notably, MGB exhibited distinctly opposing patterns of activity, dynamically encoding innate safety and danger during exploration of different environments. Moreover, the data shows MGB neurons modify their responses after avoidance training which has not been manifested in behavioral read-outs post-training. This research extends our understanding of sensory processing in the medial geniculate body and provides new insights into the neural mechanisms underlying avoidance behavior.