AI Article Synopsis

  • The study investigates how phencyclidine (PCP), an NMDAr antagonist, affects neural responses to tone stimuli in rats, paralleling findings in schizophrenia where tone responses show diminished power and synchrony in EEG readings.
  • Two experiments measured the effects of PCP on EEG power and synchrony, revealing that acute PCP administration increased low-frequency power (10-30 Hz) while decreasing it at gamma frequencies (50-70 Hz).
  • The results indicate that acute PCP-induced disruptions of NMDAr function lead to varied effects on neural synchrony and power, suggesting potential biomarkers for understanding schizophrenia and related neuropsychiatric disorders.

Article Abstract

Background/aims: The onset response to a single tone as measured by electroencephalography (EEG) is diminished in power and synchrony in schizophrenia. Because neural synchrony, particularly at gamma frequencies (30-80 Hz), is hypothesized to be supported by the N-methyl-D-aspartate receptor (NMDAr) system, we tested whether phencyclidine (PCP), an NMDAr antagonist, produced similar deficits to tone stimuli in rats.

Methods: Experiment 1 tested the effect of a PCP dose (1.0, 2.5, and 4.5 mg/kg) on response to single tones on intracranial EEG recorded over the auditory cortex in rats. Experiment 2 evaluated the effect of PCP after acute administration of saline or PCP (5 mg/kg), after continuous subchronic administration of saline or PCP (5 mg/kg/day), and after a week of drug cessation. In both experiments, a time-frequency analysis quantified mean power (MP) and phase locking factor (PLF) between 1 and 80 Hz. Event-related potentials (ERPs) were also measured to tones, and EEG spectral power in the absence of auditory stimuli.

Results: Acute PCP increased PLF and MP between 10 and 30 Hz, while decreasing MP and PLF between approximately 50 and 70 Hz. Acute PCP produced a dose-dependent broad-band increase in EEG power that extended into gamma range frequencies. There were no consistent effects of subchronic administration on gamma range activity. Acute PCP increased ERP amplitudes for the P16 and N70 components.

Conclusions: Findings suggest that acute PCP-induced NMDAr hypofunction has differential effects on neural power and synchrony which vary with dose, time course of administration and EEG frequency. EEG synchrony and power appear to be sensitive translational biomarkers for disrupted NMDAr function, which may contribute to the pathophysiology of schizophrenia and other neuropsychiatric disorders.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752597PMC
http://dx.doi.org/10.1159/000480511DOI Listing

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