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In a previous modeling study, Leblois et al. (2006) demonstrated an action selection mechanism in cortico-basal ganglia loops based on competition between the positive feedback, direct pathway through the striatum and the negative feedback, hyperdirect pathway through the subthalamic nucleus. The present study investigates how multiple level action(More)
The striatal dopamine signal has multiple facets; tonic level, phasic rise and fall, and variation of the phasic rise/fall depending on the expectation of reward/punishment. We have developed a network model of the striatal direct pathway using an ionic current level model of the medium spiny neuron that incorporates currents sensitive to changes in the(More)
L-DOPA is the gold standard medication of Parkinson's disease, a neurological disorder consequent upon the degeneration of mesencephalic dopaminergic neurons. The therapeutic efficacy of L-DOPA has been related to its ability to restore dopamine (DA) extracellular levels in the Parkinsonian brain. The origin of the L-DOPA-induced rise in DA has been the(More)
Decision is a self-generated phenomenon, which is hard to track with standard time averaging methods, such as peri-event time histograms (PETHs), used in behaving animals. Reasons include variability in duration of events within a task and uneven reaction time of animals. We have developed a temporal normalization method where PETHs were juxtaposed all(More)
Serotonin2c (5-HT2c) receptors are widely expressed in the central nervous system where they play a pivotal role in the regulation of neuronal network excitability. Along with this fundamental physiological function, 5-HT2c receptors are thought to be implicated in the pathophysiology of several neuropsychiatric disorders and have become a major(More)
Data from many experiments has shown that serotonin2C (5-HT2C) receptor plays a role in the control of orofacial activity in rodents. Purposeless oral movements can be elicited either by agonists or inverse agonists implying a tight control exerted by the receptor upon oral activity. The effects of agonists has been related to an action of these drugs in(More)
Spatial learning has been recognized over the years to be under the control of the hippocampus and related temporal lobe structures. Hippocampal damage often causes severe impairments in the ability to learn and remember a location in space defined by distal visual cues. Recent experimental evidence in rodents demonstrates, however, that other brain areas(More)
The neurological bases of spatial navigation are mainly investigated in rodents and seldom in primates. The few studies led on spatial navigation in both human and non-human primates are performed in virtual, not in real environments. This is mostly because of methodological difficulties inherent in conducting research on freely-moving monkeys in real world(More)
The mechanisms of decision-making and action selection are generally thought to be under the control of parallel cortico-subcortical loops connecting back to distinct areas of cortex through the basal ganglia and processing motor, cognitive and limbic modalities of decision-making. We have used these properties to develop and extend a connectionist model at(More)