PET STUDIES OF ENCODING AND RETRIEVAL - THE HERA MODEL

We review positron emission tomography (PET) studies whose results con verge on the hemispheric encoding/retrieval asymmetry (HERA) model of the involvement of prefrontal cortical regions in the processes of hum an memory. The model holds that the left prefrontal cortex is differen tially more involved in retrieval of information from semantic memory, and in simultaneously encoding novel aspects of the retrieved informa tion into episodic memory, than is the right prefrontal cortex. The ri ght prefrontal cortex, on the other hand, is differentially more invol ved in episodic memory retrieval than is the left prefrontal cortex. T his general pattern holds for different kinds of information (e.g., ve rbal materials, pictures, faces) and a variety of conditions of encodi ng and retrieval.