140 - Activity of the Non-overlapping Spinal Populations During the Formation of Fear Memories

Poster Board Number: 140
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Abstract Body : Pain is a very effective teacher. Memories that derive from single painful events (like fear conditioning or taste aversion protocols) usually show a remarkable strength: they are long-lasting, difficult to extinguish and have marked effects on behavior. However, not all pains matter the same: the strength of a memory formed by a painful event directly depends on the intensity of the aversive stimulus experienced. This direct relation has been used to examine how the nervous system differentially encodes memories of weak and strong nature. However, most studies in this specific topic are focused in supraspinal structures that receive direct or indirect inputs from nociceptive ascending pathways. How spinal and ganglionic nociceptive neural populations and circuits contribute to the formation of fear memories has been scarcely studied, although a considerable complexity exists in these bottom levels. During the last decades, several molecularly defined, non-overlapping neural populations have been identified in the spinal cord, but how these populations contribute to pain experience and its memory outcomes remains unclear. In the present work, we focused on the spinal level to describe which populations are involved in the processing of fear conditioning. Also, we examine if weak threats that produce weak memories engage different populations to the ones engaged by stronger threats that produce stronger memories. The goal is to better understand how this aversive learning experience is processed by the spinal cord and describe the changes in spinal activity that generates fear memories of different strengths.