Synaptic mechanisms of sensory perception

A key goal of modern neuroscience is to understand the neural circuits and the synaptic mechanisms underlying simple forms of sensory perception and associative learning. Here, I will discuss our efforts to characterise sensory processing in the mouse barrel cortex, a brain region known to process tactile information relating to the whiskers on the snout. Each whisker is individually represented in the primary somatosensory neocortex by an anatomical unit termed a “barrel”. The barrels are arranged in a stereotypical map, which allows recordings and manipulations to be targeted with remarkable precision. In this cortical region it may therefore be feasible to gain a quantitative understanding of neocortical function. As a mouse explores its environment, the whiskers are actively moved backwards and forwards as if searching the space for tactile input. Indeed sensory information in this pathway is usually actively acquired. It is therefore crucial to measure and manipulate cortical function in awake behaving mice. We have begun this process using whole-cell recordings, voltage-sensitive dye imaging, viral manipulations and two-photon microscopy. Through combining these techniques with behavioural training, our experiments provide new insight into sensory perception at the level of individual neurons and their synaptic connections.