Korean J Psychopharmacol.  2001 Dec;12(4):322-327.

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

• Youn T
• Ahn KH
• Pae JS
• Kim MS
• Kim JJ
• Kwon JS

Abstract

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.

Keyword

Schizophrenia; Information process; NMDA receptor; Mismatch negativity; Echoic memory

MeSH Terms

Brain
Brief Psychiatric Rating Scale
Electroencephalography
Glutamic Acid*
Humans
Ketamine*
Memory*
N-Methylaspartate
Psychophysiology
Receptors, Glutamate*
Receptors, N-Methyl-D-Aspartate
Schizophrenia*
Glutamic Acid
Ketamine
N-Methylaspartate
Receptors, Glutamate
Receptors, N-Methyl-D-Aspartate