Multi-neuronal activity patterns are defined by the spike timing of one neuron relative to another. Because neurons do not spike synchronously during normal brain activity this results in a spatial temporal pattern of spike activity within the imaged population of neurons (see below). We have shown that one neuron can participate in multiple patterns and that it’s spike times are unique to each individual pattern. Thus the synaptic input a neuron receives, rather than it’s intrinsic properties, set that neuron’s spike time(s). This result indicates that the pattern is the result of synaptic connectivity providing us a means to explore structure function relationships.
To image quickly we jump from cell to cell, which speeds up frame rates by skipping over empty space. Read about our method here. We detect the fluorescence change that occurs whenever a neuron fires an action potential. Using our approach we are able to image between 200-300 neurons at 30-40Hz in vivo in an ambulating mouse.
To image motor cortical circuit activity in a freely moving mouse we are using a head mountable microscope.
Monitoring population activity in vivo
Recorded in mouse primary visual cortex using GCAMP6s