Sensory-driven behaviors engage a cascade of cortical regions to process sensory input and generate motor output. To investigate the temporal dynamics of neural activity at this global scale, we have developed methods to perform functional imaging across large areas of cortex using a transgenic mouse expressing GCaMP6s, integrated with a head-fixed visual discrimination behavior. This technique allows imaging of activity across the dorsal surface of cortex at a spatial resolution of approximately 50μm and temporal resolution of approximately 100 msec. Imaging during an orientation discrimination task reveals a progression of activity in different cortical regions associated with different phases of the task. After cortex-wide patterns of activity are determined, we demonstrate the ability to select a region that displayed conspicuous responses for two-photon microscopy, and find that activity in populations of individual neurons there correlates with locomotion in trained mice. We expect that this paradigm will be a useful probe of information flow and network processing in brain-wide circuits involved in many sensory and cognitive processes.
- functional imaging
- visual cortex
- orientation selectivity
- Copyright © 2015, Journal of Neurophysiology