David C. Riccio

Riccio's research focuses upon memory processes and learning in animals with interest in behavioral aspects of anterograde and retrograde amnesia, ontogenetic changes in memory, memory for stimulus attributes, and extinction of fear. He has generated substantial evidence that memorial deficits long believed to be due to trace disruption are most likely due to retrieval difficulties. Trauma induced forgetting is not due to loss of the engram, but are the result of dissociation. During recall, the absence of critical contextual/state cues can result in total amnesia. This contradicts the hypothesis that the trauma erases the memory, leaving no trace to access.

Evidence for his interpretation includes the observation that the development of retrograde amnesia (RA) is quite slow, leading to high test scores for up to 12 hours after treatment before declining rapidly. He has also shown that RA for an old memory can be established if the memory is briefly cued prior to administration of the amnestic treatment.

The degree of treatment used to induce amnesia was also found to influence memory. The severity of hypothermia used to induce amnesia interacted with the age of the memory, whether it was old or new. Old memory, when reactivated by cue exposure, becomes vulnerable to both mild and severe amnestic treatment, whereas newly acquired memory was only susceptible to severe treatment. However, the severity of amnesia diminished as a function of the delay between reactivation and hypothermia. If RA is due to the failure to maintain the engram, how can a old (consolidated) memory be more readily disrupted by trauma? Clearly, the trauma does not erase the memory. It must affect retrieval.

Repeatedly, Riccio has shown that the thermal gradient is influential in the formation and retention of amnestic memory. It is relatively close to the changes seen in stimulus generalization and supports the contention that realigning the stimulus context at testing to something closer to that present at training can have a profoundly beneficial effect on memory retrieval (Riccio and Richardson, 1984).

Memory and memory retrieval have been important areas of research for many researchers in the field of psychology. The way in which amnesia effects memory retrieval has also become important in understanding memory failure in relation to human patients afflicted with such illnesses as Alzheimer's disease. Riccio has been instrumental in a contemporary movement to examine cognitive issues with animal models. Although long viewed as the exclusive realm of human research, animal studies of cognition show great potential for increasing understanding. Spear & Riccio (1994) have demonstrated the utility of such approach in their remarkable text, Memory: Phenomena and Principles.

Riccio, D. C. and Richardson, R. 1984. The Status of memory following experimentally induced amnesias: Gone, but not forgotten. Physiological Psychology, 12(2):59-72.
Spear, N. E. and Riccio, D. C. 1994. Memory: Phenomena and Priciples. Needham Heights, MA: Allyon & Bacon.