We have shown signs of behavioral depression after vibrissal deafferentation. Locomotor slowing, motor impairments and footshock thresholds increment were demonstrated after vibrissal afferent blockages. Here, we study the electrocortical (ECoG) effects of vibrissal pad anaesthesia, also replicated by bilateral brachial plexus blockage. We found in both cases, that this acute and massive deafferentation produces synchronization over the entire neocortex accompanied by an important loss of muscular electrical activity. Slow waves observed in this condition were similar to those recorded in the sleeping rat without any treatment, but in our case, there were no behavioral signs of sleep. Thus a clear behavioral electroencephalographic dissociation was obtained by acute deafferentation. These results would seem to support the sleep deafferentation hypothesis.