Our lab’s long-term goal is to uncover 'general principles that govern how information is processed by neural circuits' in the cerebral cortex.
What does it take to understand a neural circuit?
1.) We need an understanding of the circuit components and their connections that has explanatory power. We are working with circuit diagrams at the level of genetically defined cell types in mice.
2.) The circuit has to have an identified function. That is, it has to perform a defined computation in the context of the kinds of behaviors for which the circuit has evolved.
3.) The computation has to play roles in animal behavior. Does information represented at a particular circuit node actually influence behavior? Only when precise synthetic spike trains, imposed on specific neurons, elicit predictable behavior can we claim to understand the neural code.
4.) The circuit mechanisms shaping spike trains have to be delineated so that a detailed biophysical model can reproduce the key features of the computation.
With these levels of analysis in mind, we probe the cortical circuits underlying active tactile decision making. Whisker-based haptic tasks for head-fixed mice developed in our lab provide outstanding stimulus control and facilitate applications of powerful biophysical methods, such as whole cell recordings and two-photon microscopy.
We currently focus on the primary somatosensory (‘barel’) cortex and the motor cortex, as well as related thalamic structures. Barrel cortex is a paradigmatic sensory cortex which processes tactile information from the whiskers. A great deal is known about barrel cortex circuits. Barrel cortex is an ideal place where to decipher the synaptic basis of neural computation.
Using a delayed movement task in mice we recently discovered that an anterior-lateral part of the motor cortex (ALM) controls planning and execution of directional movements. ALM neurons show persistent activity and ramping activity predicting specific future movements. We are studying the roles of ALM in decision making, motor planning and movement initiation. We are also interested in the mechanisms underlying persistent activity related to short-term memory in cortical circuits.