Catching the voltage gradient—asymmetric boost of cortical spread generates motion signals across visual cortex: a brief review with special thanks to Amiram Grinvald

Abstract

Abstract. Wide-field voltage imaging is unique in its capability to capture snapshots of activity-across the full gradient of average changes in membrane potentials from subthreshold to suprathreshold levels-of hundreds of thousands of superficial cortical neurons that are simultaneously active. Here, I highlight two examples where voltage-sensitive dye imaging (VSDI) was exploited to track gradual space-time changes of activity within milliseconds across several millimeters of cortex at submillimeter resolution: the line-motion condition, measured in Amiram Grinvald's Laboratory more than 10 years ago and-coming full circle running VSDI in my laboratoryanother motion-inducing condition, in which two neighboring stimuli counterchange luminance simultaneously. In both examples, cortical spread is asymmetrically boosted, creating suprathreshold activity drawn out over primary visual cortex. These rapidly propagating waves may integrate brain signals that encode motion independent of direction-selective circuits.

High-resolution VSDI retinotopic mapping via a DLP-based projection system

“…Recording the population response of the visual cortex is of great importance for studying basic visual processing, plasticity processes, and various pathologies. Of particular interest to this study is the generation of retinotopic maps, which can shed light on many retina-visual cortex processes, as well as plasticity, and circuitry [1][2][3][4]. Various techniques are available, enabling the investigation of the cortical population response; one such technique is Voltage-sensitive dye imaging (VSDI).…”