Abolition of CA1 population spike by sensory stimulation

The effect of sensory stimulation, such as stroking of the animals' fur, on activation of the hippocampal CA1 field was studied in paralyzed and locally anaesthetized rats. CA1 population responses evoked either monosynaptically (ipsilateral CA3 stimulation) or trisynaptically (perforant pathway stimulation) decreased markedly when sensory stimulation was applied, and CA1 population spikes were absent during most periods of sensory stimulation. These results demonstrate the strong modulatory role of sensory inputs on hippocampal circuits.