opto-1:Photostimulation of SEPs

Experiment: In situ validation of glutamatergic and GABAergic populations expressing ChR2 with whisker-related sensory evoked potentials (SEPs) and photostimulationDescription:This experiment was designed to validate the selective activation of either glutamatergic or GABAergic neurons through optogenetic stimulation. To this end, a simple sensory protocol was used to evoke whisker-related sensory-evoked potentials (SEPs) in the primary somatosensory cortex (S1). Electrical stimulation of the left whisker pad was delivered (0.2 ms pulses, sub-maximal intensity) every 10 ± 2 seconds to evoke SEPs. The protocol was first performed in the absence of light (Whisker only) and then repeated with simultaneous photostimulation (Light + Whisker), consisting of 20 ms light pulses at 20 mA. Comparing the SEP amplitudes between conditions allowed in situ confirmation of neuron type-specific activation (e.g., excitatory vs inhibitory modulation). The choice of a 20 ms light pulse (as opposed to 10 ms in prior experiments) was intended to ensure overlap between the light stimulation and the peak of the evoked potential, which typically occurs around 15 ms after whisker stimulation. Access before the embargo ends: the files are under embargo until 30 June 2027. To request access before then, email Ricardo Salvador ([e-mail]) with a short description of the intended use.