Generation of end-inhibition in striate neurons in rabbits.

Eighty-six rabbit striate neurons were tested with lateral microinjection of lidocaine, GABA or bicuculline. Seven of the neurons expressed different levels of end-inhibition. We examined these end-stopping units by injection of lidocaine or bicuculline in adjacent areas in order to determine if a lateral cortical mechanism is underlying end-inhibition in rabbits as it has been proposed in cats. Microinjection of lidocaine resulted in an attenuation of the end-inhibition strength. Application of bicuculline had the opposite effect; the end-inhibition was reinforced. We suggest that as observed in cats, in rabbits end-inhibition is mediated through horizontal cortical connections which implies a postsynaptic inhibitory input to the end-stopping cell.