IN a series of papers by Gellhorn and collaborators1 it was shown that insulin hypoglycemia, especially in the form of insulin coma, and chemically or electrically induced convulsions lead to a restoration of inhibited conditioned reactions. In this work, conditioning of the escape reaction resulting from subjection of the experimental animal (rat) to a slight electric shock was accomplished by the simultaneous presentation of various sensory stimuli. After the conditioned reaction had been fully established, it was gradually inhibited by lack of reenforcement (Pavlov's internal inhibition). Spontaneous recovery of such inhibited reactions did not occur, but a restoration could be induced with great regularity if the animals were subjected to insulin coma and related forms of "shock treatment."
Furthermore, it was observed2 that if two or more conditioned reactions were studied in the same animal insulin coma and related forms of "shock treatment" acted only on the inhibited
GELLHORN E. IS RESTORATION OF INHIBITED CONDITIONED REACTIONS BY INSULIN COMA SPECIFIC FOR PAVLOVIAN INHIBITIONS?Contribution to the Theory of Shock Treatment. Arch NeurPsych. 1946;56(2):216-221. doi:10.1001/archneurpsyc.1946.02300190086007