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Positive reinforcement helps to control the acquisition of learned behaviours. Here we report a cellular mechanism in the brain that may underlie the behavioural effects of positive reinforcement. We used intracranial self-stimulation (ICSS) as a model of reinforcement learning, in which each rat learns to press a lever that applies reinforcing electrical(More)
Knowledge of the effect of dopamine on corticostriatal synaptic plasticity has advanced rapidly over the last 5 years. We consider this new knowledge in relation to three factors proposed earlier to describe the rules for synaptic plasticity in the corticostriatal pathway. These factors are a phasic increase in dopamine release, presynaptic activity and(More)
The spiny projection neurons are by far the most numerous type of striatal neuron. In addition to being the principal projection neurons of the striatum, the spiny projection neurons also have an extensive network of local axon collaterals by which they make synaptic connections with other striatal projection neurons. However, up to now there has been no(More)
Behavioral conditioning of cue-reward pairing results in a shift of midbrain dopamine (DA) cell activity from responding to the reward to responding to the predictive cue. However, the precise time course and mechanism underlying this shift remain unclear. Here, we report a combined single-unit recording and temporal difference (TD) modeling approach to(More)
Learning deficits resulting from dopamine depletion suggest that striatal dopamine release is crucial for reinforcement. Recently described firing patterns of dopamine neurons in behaving monkeys show that transient increases in dopamine release are brought about by reinforcement. We describe an enduring change in the strength of synaptic transmission(More)
Dopamine and glutamate are key neurotransmitters involved in learning and memory mechanisms of the brain. These two neurotransmitter systems converge on nerve cells in the neostriatum. Dopamine modulation of activity-dependent plasticity at glutamatergic corticostriatal synapses has been proposed as a cellular mechanism for learning in the neostriatum. The(More)
The spiny projection neurons of the neostriatum are a site at which dopamine inputs from the substantia nigra converge with excitatory inputs from the cerebral cortex. These two systems interact in certain learning and motor control mechanisms of the brain. We investigated these interactions using intracellular recording from spiny striatal neurons in(More)
Attention-deficit hyperactivity disorder (ADHD) is a prevalent and debilitating disorder diagnosed on the basis of persistent and developmentally-inappropriate levels of overactivity, inattention and impulsivity. The etiology and pathophysiology of ADHD is incompletely understood. There is evidence of a genetic basis for ADHD but it is likely to involve(More)
A neural network model based on the anatomy and physiology of the matrix compartment of the striatum is described. The model consists of a network of neurons which are mutually inhibitory within a defined domain. A membrane potassium conductance (GK) under dopaminergic-cholinergic control is included in the model. Computer simulation results show that(More)
The striatum is the major input nucleus of the basal ganglia. It is thought to play a key role in learning on the basis of positive reinforcement and in action selection. One view of the striatum conceives it as comprising a reiterated matrix of processing units that perform common operations in different striatal regions, namely synaptic plasticity(More)