Microinjections of flupenthixol into the caudate-putamen but not the nucleus accumbens, amygdala or frontal cortex of rats produce intra-session declines in food-rewarded operant responding. 1993

R J Beninger, and R Ranaldi
Department of Psychology, Queen's University, Kingston, Ont., Canada.

Results of recent studies suggest that dopamine (DA) transmission in the caudate-putamen may be involved in food reward-related learning. The purpose of the present study was to evaluate this hypothesis by injecting the DA antagonist cis-flupenthixol (25 micrograms in 0.5 microliters) into the dorsal caudate-putamen of rats (n = 19) trained to lever press for food presented according to a variable interval 30-s schedule. Additional groups received non-reward (n = 8), systemic cis-flupenthixol (0.01, 0.1 mg/kg i.p.; ns = 8), dorsal caudate-putamen injections of the inactive isomer trans-flupenthixol (n = 10), frontal cortical (dorsal to the caudate-putamen site) injections of cis-flupenthixol (n = 6), or cis- or trans-flupenthixol injected into the nucleus accumbens (ns = 9, 8) or amygdala (ns = 6, 5). Rats were tested in 30-min sessions and response rates were recorded every 5 min. As expected, non-reward produced a gradual decline in responding. A similar pattern was seen in the groups receiving systemic (0.1 mg/kg) or dorsal caudate-putamen injections of cis-flupenthixol. No significant effect was seen following systemic (0.01 mg/kg), cortical or amygdala cis-flupenthixol or dorsal caudate-putamen or amygdala trans-flupenthixol. Accumbens cis-flupenthixol reduced rates but did not produce a gradual decline in responding; however, accumbens trans-flupenthixol led to a time-dependent elevation in response rates making interpretation of the accumbens results difficult. It was concluded that dopaminergic projections to the dorsal caudate-putamen may play a critical role in mediating the effects of food-reward on operant responding.

UI MeSH Term Description Entries
D007267 Injections Introduction of substances into the body using a needle and syringe. Injectables,Injectable,Injection
D008297 Male Males
D009042 Motivation Those factors which cause an organism to behave or act in either a goal-seeking or satisfying manner. They may be influenced by physiological drives or by external stimuli. Incentives,Disincentives,Expectations,Disincentive,Expectation,Incentive,Motivations
D009435 Synaptic Transmission The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES. Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D009714 Nucleus Accumbens Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA. Accumbens Nucleus,Nucleus Accumbens Septi,Accumbens Septi, Nucleus,Accumbens Septus, Nucleus,Accumbens, Nucleus,Nucleus Accumbens Septus,Nucleus, Accumbens,Septi, Nucleus Accumbens,Septus, Nucleus Accumbens
D011699 Putamen The largest and most lateral of the BASAL GANGLIA lying between the lateral medullary lamina of the GLOBUS PALLIDUS and the EXTERNAL CAPSULE. It is part of the neostriatum and forms part of the LENTIFORM NUCLEUS along with the GLOBUS PALLIDUS. Nucleus Putamen,Nucleus Putamens,Putamen, Nucleus,Putamens,Putamens, Nucleus
D012055 Reinforcement Schedule A schedule prescribing when the subject is to be reinforced or rewarded in terms of temporal interval in psychological experiments. The schedule may be continuous or intermittent. Reinforcement Schedules,Schedule, Reinforcement,Schedules, Reinforcement
D001931 Brain Mapping Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures. Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D002421 Caudate Nucleus Elongated gray mass of the neostriatum located adjacent to the lateral ventricle of the brain. Caudatus,Nucleus Caudatus,Caudatus, Nucleus,Nucleus, Caudate
D003216 Conditioning, Operant Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced. Instrumental Learning,Learning, Instrumental,Operant Conditioning,Conditionings, Operant,Instrumental Learnings,Learnings, Instrumental,Operant Conditionings

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