Effects of acute nicotine on prepulse inhibition of auditory change-related cortical responses.
Prepulse inhibition (PPI) of startle is a measure of inhibitory function in which a weak leading stimulus suppresses the startle response to an intense stimulus. Usually, startle blink reflexes to an intense sound are used for measuring PPI. A recent magnetoencephalographic study showed that a similar phenomenon is observed for auditory change-related cortical response (Change-N1m) to an abrupt change in sound features. It has been well established that nicotine enhances PPI of startle. Therefore, in the present magnetoencephalographic study, the effects of acute nicotine on PPI of the Change-N1m were studied in 12 healthy subjects (two females and 10 males) under a repeated measures and placebo-controlled design. Nicotine (4 mg) was given as nicotine gum. The test Change-N1m response was elicited with an abrupt increase in sound pressure by 6 dB in a continuous background sound of 65 dB. PPI was produced by an insertion of a prepulse with a 3-dB-louder or 6-dB-weaker sound pressure than the background 75 ms before the test stimulus. Results show that nicotine tended to enhance the test Change-N1m response and significantly enhanced PPI for both prepulses. Therefore, nicotine's enhancing effect on PPI of the Change-N1m was similar to that on PPI of the startle. The present results suggest that the two measures share at least some mechanisms.
Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan; Department of Medicine (Neurology and Rheumatology), Shinshu University School of Medicine, Matsumoto 390-8621, Japan. Electronic address: kodaira@nips.ac.jp.
Minori
M
Kodaira
Aki
A
Tsuruhara
Eishi
E
Motomura
Hisashi
H
Tanii
Koji
K
Inui
Ryusuke
R
Kakigi
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D001307:Auditory Perception / Q000187:drug effects* / Q000502:physiology; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D065808:Prepulse Inhibition / Q000187:drug effects* / Q000502:physiology; D013216:Reflex, Startle / Q000187:drug effects / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D055815:Young Adult
D018722:Nicotinic Agonists; D009538:Nicotine
ANOVA; Auditory change-related cortical response; BESA; Change-N1m; EEG; MEG; Magnetoencephalography; Nicotine; PPI; Post; Pre; Prepulse inhibition; SQUID; Startle; analysis of variance; brain electric source analysis; change-related auditory N1m; electroencephalography; fMRI; functional magnetic resonance imaging; mAChR; magnetoencephalography; muscarinic acetylcholine receptor; nAChR; nicotinic acetylcholine receptor; post-nicotine/placebo administration; pre-nicotine/placebo administration; prepulse inhibition; superconducting quantum interference device