Ego Fails to Repress: The Role of Left Frontal Lobe Hypoactivation in Associative Memory Impairment in Schizophrenia

Abstract

Based on studies of the Word Association Task (WAT), C. G. Jung stated that the associative disturbances in schizophrenia are a result of decreased attention, leading to a failure in controlling intrusive egocentric associations. The ego of the patient seems to have failed in repressing egocentric memories. Today, associative disturbances are considered a symptom of left frontotemporal disconnection. The present study investigates whether the mode of monaural presentation of verbal stimuli in a WAT results in differential effects on associative memory. A total of 30 subjects with schizophrenia from the Psychiatry Clinics of the Marmara University Hospital and 30 control subjects were divided into two subgroups of 15 each to hear the WAT via either the right ear or the left ear. The WAT consisted of three tape-recorded lists each containing five target words with different emotional valences; positive, negative, and neutral. Each subject was presented with one target word at a time and was required to repeat the target word immediately and over the next 45 seconds to say the words that came to his/her mind. Word associations were evaluated in terms of total number of responses, semantic relatedness scores, perseverations, and egocentric responses. Compared to control groups, higher rates of intrusive egocentric associations, higher perseverations, and lower semantic relatedness of associations were observed in responses of schizophrenic subjects who took the WAT via the right ear. In line with the theory of left frontotemporal disconnection, associative memory impairment in schizophrenia seemed to be more marked within the left hemisphere. Underlying the memory impairment, the conclusion that failure of appropriate inhibition over intrusive associations—due to left frontal hypoactivation—seems reasonable. Using Jung’s perspective, the functional role of the left frontal lobe in the service of the repression of egocentric memories is discussed.