Previous references showed that the histamine injected peripherically produced a deterioration of the learning in experimental animals. The effects of 100 and 200 micrograms of histamine administered in the cerebral lateral ventricle, have been tested using an experimental paradigm which isolated attentional, motivational, and motor factor from the complex learned behavior. The obtained results showed to be similar to those produced by peripheric injection, and demonstrated a worsening in attentional, motivational, and motor parameters.