Good vibrations: cross-frequency coupling in the human nucleus accumbens during reward processing.
The nucleus accumbens is critical for reward-guided learning and decision-making. It is thought to "gate" the flow of a diverse range of information (e.g., rewarding, aversive, and novel events) from limbic afferents to basal ganglia outputs. Gating and information encoding may be achieved via cross-frequency coupling, in which bursts of high-frequency activity occur preferentially during specific phases of slower oscillations. We examined whether the human nucleus accumbens engages such a mechanism by recording electrophysiological activity directly from the accumbens of human patients undergoing deep brain stimulation surgery. Oscillatory activity in the gamma (40-80 Hz) frequency range was synchronized with the phase of simultaneous alpha (8-12 Hz) waves. Further, losing and winning small amounts of money elicited relatively increased gamma oscillation power prior to and following alpha troughs, respectively. Gamma-alpha synchronization may reflect an electrophysiological gating mechanism in the human nucleus accumbens, and the phase differences in gamma-alpha coupling may reflect a reward information coding scheme similar to phase coding.
Cohen
Michael X
MX
University of Bonn, Germany. mikexcohen@gmail.com
Axmacher
Nikolai
N
Lenartz
Doris
D
Elger
Christian E
CE
Sturm
Volker
V
Schlaepfer
Thomas E
TE
D000328:Adult; D003463:Cues; D046690:Deep Brain Stimulation / Q000379:methods; D003865:Major Depressive Disorder / Q000473:pathology; D004569:Electroencephalography / Q000145:classification; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D009714:Nucleus Accumbens / Q000503:physiopathology*; D010507:Periodicity; D012201:Reward; D013057:Spectrum Analysis; D013997:Time Factors