Effects of acute nicotine on auditory change-related cortical responses.
OBJECTIVE
Nicotine is known to have enhancing effects on some aspects of attention and cognition. The purpose of the present study was to elucidate the effects of nicotine on pre-attentive change-related cortical activity.


METHODS
Change-related cortical activity in response to an abrupt increase (3 dB) and decrease (6 dB) in sound pressure in a continuous sound was recorded by using magnetoencephalography. Nicotine was administered with a nicotine gum (4 mg of nicotine). Eleven healthy nonsmokers were tested with a double-blind and placebo-controlled design. Effects of nicotine on the main component of the onset response peaking at around 50 ms (P50m) and the main component of the change-related response at around 120 ms (Change-N1m) were investigated.


RESULTS
Nicotine failed to affect P50m, while it significantly increased the amplitude of Change-N1m evoked by both auditory changes. The magnitude of the amplitude increase was similar among subjects regardless of the magnitude of the baseline response, which resulted in the percent increase of Change-N1m being greater for subjects with Change-N1m of smaller amplitude.


CONCLUSIONS
Since Change-N1m represents a pre-attentive automatic process to encode new auditory events, the present results suggest that nicotine can exert beneficial cognitive effects without a direct impact on attention.
Department of Integrative Physiology, National Institute for Physiological Sciences, Myodaiji, Okazaki 444-8585, Japan. ootsuru@nips.ac.jp
Naofumi
N
Otsuru
Aki
A
Tsuruhara
Eishi
E
Motomura
Hisashi
H
Tanii
Makoto
M
Nishihara
Koji
K
Inui
Ryusuke
R
Kakigi
D000328:Adult; D001288:Attention / Q000187:drug effects*; D001303:Auditory Cortex / Q000378:metabolism*; D001307:Auditory Perception / Q000187:drug effects; D003071:Cognition / Q000187:drug effects; D004311:Double-Blind Method; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D013016:Sound
D009538:Nicotine