The visual evoked potential is a sensitive and powerful measure of experience-dependent visual cortical plasticity in...

Despite the explosion of high-tech methods to measure activity in the mouse visual cortex, the venerable visually evoked potential (VEP) continues to prove its worth as a sensitive measure of experience-dependent cortical plasticity. The VEP recorded in layer 4 is a good estimate of the strength of feedforward synaptic excitation, and changes in amplitude correspond closely to changes in the peak firing rate of principal cells. Chronic recording of VEPs in awake mice have enabled longitudinal study of modifications induced by selective visual experience or deprivation, and these have revealed several novel forms of plasticity. The VEP provides a good estimate of spatial acuity that compares well with values obtained by behavioral approaches. Furthermore, recordings of the local field potential through the same electrodes reveal changes in oscillatory activity that reflect differential recruitment of inhibitory networks. Thus, the VEP remains a powerful tool for the study of visual cortical plasticity.