Effect of Ketamine on the Echoic Memory Process: The Mismatch Negativity and Glutamate Receptor System in Schizophrenia / 대한정신약물학회지

OBJECTIVE: The abnormality of mismatch negativity (MMN) in schizophrenia is thought to be associated with perceptional disturbance and cognitive dysfunction. And the antagonists of the N-methyl-D-aspartate (NMDA) receptors, ketamine, can induce anomalies of psychophysiology and cognitive function as those of schizophrenia. In order to explore the role of NMDA receptors on echoic memory system, MMN under ketamine administration was analyzed. METHODS: MMNs of Healthy 12 subjects under sub-anesthetic dose (0.65 mg/kg/hr) of ketamine administration in placebo-controlled design were recorded by 128 channel EEG. Brief Psychiatric Rating Scale (BPRS) change was also evaluated. RESULTS: BPRS score was significantly increased by ketamine administration (t=-6.655, p<0.001). Ketamine induced significant decrease in MMN amplitudes (Fz, t=-2.572, p=0.026). Neither MMN amplitude under placebo administration nor MMN latencies under ketamine administration and placebo was changed significantly. CONCLUSION: Ketamine induced echoic memory dysfunction in healthy subjects, which is usually found in schizophrenic patients. Consequently, reduced glutamatergic activity in brain could be involved some early processes of the memory dysfunction in schizophrenia.

A Neuropsychological Study of Frontal Lobe Function in Obsessive-compulsive Disorder / 신경정신의학

OBJECTIVES: Non-verbal memory deficits, impairments in executive function and deficits in visuospartial functions have been repeatedly reported in subjects with obsessive-compulsive disorder (OCD). The present study aimed to evaluate the frontal lobe function using neuro-psychological test in subjects with OCD and normal control. METHODS: A battery of neuropsychological tests (Wisconsin Card Sorting test, Rey-Osterrieth Complex Figure test, Controlled Oral Word Association test, Trail Making test, Verbal Learning test) reflecting frontal lobe function was administrated to 32 OCD patients and 28 healthy comparison subjects. RESULT: There were no significant differences in age, years of education, or estimated IQ between the groups. Scores in category fluency, immediate recall and delayed recall of Rey-Osterrieth Complex Figure test in OCD subjects were significantly lower than those of healthy comparison subjects (ANCOVA, F=15.07, df=58, p< .001; ANCOVA, F=6.33, df=57, p=0.015; ANCOVA, F=5.53, df=57, p=0.022, respectively). CONCLUSION: OCD patients had selective deficits in task involving non-verbal memory and categorical word fluency relative to healthy comparisons.