Dopaminergic modulation of receptive fields in rat sensorimotor cortex.
Dopaminergic projections to primary sensorimotor cortex (SMC) have been described anatomically, but their functional role is unknown. The objective here was to characterize how dopamine modulates the somatosensory evoked potential (SEP) and its receptive field in SMC. SEPs were evoked by median and tibial nerve stimulation and recorded using thin-film multielectrode arrays implanted epidurally over the caudal sensorimotor cortex of rats. SEP amplitudes and receptive fields were measured before and after intracortical injection of a D1- (SCH 23390) or a D2-receptor antagonist (raclopride). Both increased maximum SEP amplitudes by 107.5% and 82.1%, respectively (p<0.01), while vehicle application had no effect (5.9% change). SEP latencies and receptive fields remained unchanged. Dopamine antagonists increase the excitability of sensorimotor cortex to afferent signals. Dopamine, therefore, expectedly reduces SMC excitability thereby improving sensory signal-to-noise ratio. Dopaminergic modulation may render SMC circuitry more effective in processing sensory information from different sources.
Hosp
Jonas A
JA
RITZ-Rehabilitation Institute and Technology Center of Zurich, Department of Neurology, University of Zurich, Zurich, Switzerland.
Hertler
Benjamin
B
Atiemo
Clement Osei
CO
Luft
Andreas R
AR
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D001930:Brain Injuries / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000502:physiology*; D003399:Craniotomy / Q000379:methods; D004298:Dopamine / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008475:Median Nerve / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013003:Somatosensory Cortex / Q000187:drug effects / Q000502:physiology; D013979:Tibial Nerve / Q000502:physiology; D014738:Vibrissae / Q000502:physiology
D001552:Benzazepines; C534628:SCH 23390; D004298:Dopamine