Behavioral detection of tactile stimuli during 7-12 Hz cortical oscillations in awake rats

Prominent 7-12 Hz oscillations in the primary somatosensory cortex (S1) of awake but immobile rats might represent a seizure-like state(1) in which neuronal burst firing renders animals unresponsive to incoming tactile stimuli; others have proposed(2-4) that these oscillations are analogous to human mu rhythm(5-7). To test whether rats can respond to tactile stimuli during(7-12) Hz oscillatory activity, we trained head-immobilized awake animals to indicate whether they could detect the occurrence of transient whisker deflections while we recorded local field potentials (LFPs) from microelectrode arrays implanted bilaterally in the S1 whisker representation area. They responded rapidly and reliably, suggesting that this brain rhythm represents normal physiological activity that does not preclude perception.