Nicotine and the hallucinating brain: Effects on mismatch negativity (MMN) in schizophrenia

Fisher DJ et al. – Nicotine did not affect mismatch negativity (MMN) amplitudes in schizophrenia patients with persistent auditory verbal hallucinations (AVH), however this study reports accelerated auditory change detection to intensity deviants with nicotine in this group. Additionally, nicotine appeared to induce a generalized activation of the auditory cortex in schizophrenia, resulting in a concurrent increase in intensity MMN amplitude and subjective clarity of AVHs.

Methods

• Using a modified multi–feature paradigm, MMNs to duration, frequency and intensity deviants were recorded in 12 schizophrenia outpatients (SZ) with persistent AVHs following nicotine (6mg) and placebo administration.
• Electrical activity was recorded from 32 scalp electrodes; MMN amplitudes and latencies for each deviant were compared between treatments and were correlated with trait (PSYRATS) and state measures of AVH severity and Positive and Negative Syndrome Scale (PANSS) ratings.

Results

• Nicotine administration resulted in a shortened latency for intensity MMN.
• Additionally, nicotine–related change in MMN amplitude was correlated with nicotine–related change in subjective measures of hallucinatory state.

[more...]