  Hepatic encephalopathy is a neurological complication that affects attention
and memory. Experimental animal models have been used to study hepatic
Encephalopathy, the most frequent being the portacaval shunt. In order to
determine learning impairment and brain functional alterations in this model,
we assessed reversal learning and neural metabolic activity in a PCS rat model.
Portacaval shunt and sham-operated rats were tested for reversal learning in
the Morris water maze. Brains were processed for cytochrome oxidase
histochemistry. The portacaval shunt group presents reversal learning
impairment and cytochrome oxidase activity reduction in prefrontal cortex,
ventral tegmental area and accumbens shell nucleus. These results suggest that
this model of portosystemic hepatic encephalopathy shows learning impairment
that could be linked to dysfunction in neural activity in the prefrontal cortex
and regions involved in motivated behavior.
