Cryogenic blockade of cortical activity induced via implanted cooling loops. Cartoon A shows a schematic of the brain and cooling loop placement. The cooling loop was inserted into the AES during surgery (denoted by the arrow). Detachable tubes were used to circulate refrigerated water through the previously implanted loop (normally closed/sealed) to deactivate adjacent cortical tissue during the course of a recording session. Raster plots B and C show 2 neurons’ visual responses recorded before (bottom row), during (intermediate), and after (top) cortical deactivation. In each raster panel, each dot represents one spike, and each line of dots represents the neuron's response to 1 trial exposure. Note that all visual responsiveness and spontaneous activity in the AES neuron (B) were extinguished during active cooling and visual responses in the SC neuron were diminished during cortical deactivation.