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In this article we develop the concept that the hippocampus and the midbrain dopaminergic neurons of the ventral tegmental area (VTA) form a functional loop. Activation of the loop begins when the hippocampus detects newly arrived information that is not already stored in its long-term memory. The resulting novelty signal is conveyed through the subiculum,(More)
Intracellular recordings were obtained from directly identified rat nigral dopamine cells in vivo. This identification was based on an increase in glyoxylic acid-induced catecholamine fluorescence in the impaled dopamine neurons. One of three compounds was injected intracellularly into each cell to produce the heightened fluorescence: (1) L-DOPA, to(More)
In addition to firing in a single spiking mode, dopamine (DA) cells have been observed to fire in a bursting pattern with consecutive spikes in a burst displaying progressively decreasing amplitude and increasing duration. In vivo intracellular recording demonstrated the bursts to typically ride on a depolarizing wave (5 to 15 mV amplitude). Although the(More)
Dopamine (DA) neurons have been recorded in vivo in four states of activity: hyperpolarized, nonfiring; single spike firing; burst firing; and depolarization inactivation. Nonfiring DA neurons can be made to fire by iontophoretic application of the excitatory substances glutamate and cholecystokinin, or by depolarizing current injection. Spontaneously(More)
A novel mechanism for regulating dopamine activity in subcortical sites and its possible relevance to schizophrenia is proposed. This hypothesis is based on the regulation of dopamine release into subcortical regions occurring via two independent mechanisms: (1) transient or phasic dopamine release caused by dopamine neuron firing, and (2) sustained,(More)
In vitro intracellular recordings were made from neurons in the rat midbrain slice. Two neuronal types could be distinguished in dopamine-containing (DA) midbrain regions based on electrophysiological criteria. One neuron type exhibited short duration action potentials (less than 1.5 msec), could fire at high frequencies (greater than 10 Hz), and exhibited(More)
BACKGROUND Studies in experimental animals have implicated the mesolimbic dopaminergic projections into the ventral striatum in the neural processes underlying behavioral reinforcement and motivated behavior; however, understanding the relationship between subjective emotional experience and ventral striatal dopamine (DA) release has awaited human studies.(More)
The dopamine system is involved in motivation, reward and learning, and dysfunction in this system has been implicated in several disorders, including Parkinson's disease (PD) and schizophrenia. Key progress in our understanding of its functions has come from extracellular in vivo electrophysiological recordings from midbrain dopamine neurons. Numerous(More)
The mesolimbic dopamine system is centrally involved in reward and goal-directed behavior, and it has been implicated in multiple psychiatric disorders. Understanding the mechanism by which dopamine participates in these activities requires comprehension of the dynamics of dopamine release. Here we report dissociable regulation of dopamine neuron discharge(More)
There are several brain regions that have been implicated in the control of motivated behavior and whose disruption leads to the pathophysiology observed in major psychiatric disorders. These systems include the ventral hippocampus, which is involved in context and focus on tasks, the amygdala, which mediates emotional behavior, and the prefrontal cortex,(More)