Conflict versus consolidation of memory traces to explain "retrograde amnesia" produced by ECS.

Retroactive amnesia from electroconvulsive shock: Consolidation disruption or interference?

“…One hypothesis is that the shock disrupts neural activity necessary for the formation or consolidation of a memory trace (Duncan, 1949). Another view suggests that ECS is aversive and that the animal learns to avoid making responses which are followed by ECS in much the same manner that other aversive stimuli (e.g., peripheral shock) produce response elimination (Coons & Miller, 1960). A third hypothesis is that ECS elicits competing responses which interfere with the acquisition or retention of other responses.…”

Decreased resistance to extinction of a running response following electroconvulsive shock

“…Some investigators (Duncan, 1949;Glickman, 1961) propose that the ECS effect results from disruption of the neural memory trace of the learning situation before it can be consolidated into long term memory. Others (Coons & Miller, 1960) suggest that a learning deficit occurs because ECS possesses aversive properties that are remembered, become aSSOCiated with the learning situation, and result in suppression of the learned response.…”

“…Some investigators (Duncan, 1949;Glickman, 1961) propose that the ECS effect results from disruption of the neural memory trace of the learning situation before it can be consolidated into long term memory. Others (Coons & Miller, 1960) suggest that a learning deficit occurs because ECS possesses aversive properties that are remembered, become aSSOCiated with the learning situation, and result in suppression of the learned response.It is clear that either of these two proposed mechanisms can explain results involving a learning deficit due to administration of ECS. The present experiment was designed such that the data could most readily be explained either by the retrograde amnesia hypothesis, or by the aversive components hypothesiS, but not by both.…”

Dissociation of conditioned emotional and avoidance responses due to ECS

“…Maher & McIntyre (1960) have reported no differences in CER between frontal cortex lesioned and control rats, even though strong deficits in avoidance responding have been found as a result of frontal lesions (Thompson, 1964), There is also some reason to believe electroconvulsive shock (ECS) can produce a dissociation between avoidance responding and the CER. Although Coons & Miller (1960) report a greatly increased CER as a result of ECS treatments, Gerbrandt & Thomson (1964) and Hudspeth et al (1964) have found very little evidence for an avoidance of ECS as compared to footshock. The present study will directly compare the formation of a CER with the acquisition of an avoidance response when either footshock or ECS are used as punishment.…”