The Variability of Central Neural Activity in a Sensory System, and Its Implications for the Central Reflection of Sensory Events

Werner, Gerhard; Mountcastle, Vernon B.

doi:10.1152/jn.1963.26.6.958

Cited by 280 publications

(118 citation statements)

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“…The intervals were analyzed with regard to the number of bursts that occurred during a 100-spike sampling period along with the calculation of the percentage of spikes fired in bursts. Firing rate, percentage of spikes fired in bursts and variation coefficient (calculated as the ratio between the standard deviation and the mean interval of an ISH and used as a measure of the regularity of firing; Werner and Mountcastle, 1963), were expressed as the median of at least three consecutive ISHs.…”

Section: Discussionmentioning

confidence: 99%

Inhibitory Action of Clozapine on Rat Ventral Tegmental Area Dopamine Neurons Following Increased Levels of Endogenous Kynurenic Acid

Schwieler

Erhardt

2003

Neuropsychopharmacol

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The mode of action by which the atypical antipsychotic drug clozapine exerts its superior efficacy to ameliorate both positive and negative symptoms is still unknown. In the present in vivo electrophysiological study, we investigate the effects of haloperidol (a typical antipsychotic drug) and clozapine on ventral tegmental area (VTA) dopamine (DA) neurons in a situation of hyperdopaminergic activity in order to mimic tentatively a condition similar to that seen in schizophrenia. Increased DA transmission was induced by elevating endogenous levels of the N-methyl-D-aspartate receptor and a7* nicotinic receptor antagonist kynurenic acid (KYNA; by means of PNU 156561A, 40 mg /kg, i.v.). In control rats, i.v. administered haloperidol (0.05-0.8 mg/kg) or clozapine (1.25-10 mg/kg) was associated with increased firing rate and burst firing activity of VTA DA neurons. However, in rats displaying hyperdopaminergia (induced by elevated levels of KYNA), the effects of clozapine on VTA DA neurons were converted into pure inhibitory responses, including decrease in burst firing activity. In contrast, haloperidol still produced an excitatory action on VTA DA neurons in rats with elevated levels of endogenous brain KYNA. The results of the present study suggest that clozapine facilitates or inhibits VTA DA neurotransmission, depending on brain concentration of KYNA. Such an effect of clozapine may be related to its unique effect in also ameliorating negative symptoms of schizophrenia.

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Section: Discussionmentioning

confidence: 99%

Inhibitory Action of Clozapine on Rat Ventral Tegmental Area Dopamine Neurons Following Increased Levels of Endogenous Kynurenic Acid

Schwieler

Erhardt

2003

Neuropsychopharmacol

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“…The precision for neuronal activity to signal the reward magnitude was analyzed in four ways: (1) by evaluating the significance of the difference between the mean spike rates for large and small rewards ( p Ͻ 0.05, t test); (2) by receiver operating characteristic (ROC) analysis (significance level of p Ͻ 0.05) (Lusted, 1978) for discrimination between the small and large rewards; (3) by mutual information analysis to estimate the information contained in the spike discharges with respect to the magnitude of the reward (Werner and Mountcastle, 1963;Schreiner et al, 1978;Kitazawa et al, 1998);and (4) by regression analysis of the event parameters contributing to neuronal activities (shown below). The second and third analyses were conducted using a sliding time window of 200 ms moved in 1 ms steps.…”

Section: Methodsmentioning

confidence: 99%

Different Pedunculopontine Tegmental Neurons Signal Predicted and Actual Task Rewards

Okada

Toyama²,

Inoue³

et al. 2009

J. Neurosci.

103

145

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The dopamine system has been implicated in guiding behavior based on rewards. The pedunculopontine tegmental nucleus (PPTN) of the brainstem receives afferent inputs from reward-related structures, including the cerebral cortices and the basal ganglia, and in turn provides strong excitatory projections to dopamine neurons. This anatomical evidence predicts that PPTN neurons may carry reward information. To elucidate the functional role of the PPTN in reward-seeking behavior, we recorded single PPTN neurons while monkeys performed a visually guided saccade task in which the predicted reward value was informed by the shape of the fixation target. Two distinct groups of neurons, fixation target (FT) and reward delivery (RD) neurons, carried reward information. The activity of FT neurons persisted between FT onset and reward delivery, with the level of activity associated with the magnitude of the expected reward. RD neurons discharged phasically after reward delivery, with the levels of activity associated with the actual reward. These results suggest that separate populations of PPTN neurons signal predicted and actual reward values, both of which are necessary for the computation of reward prediction error as represented by dopamine neurons.

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“…In the second analysis, the ensemble activity was averaged across the time in which the monkey drew each segment, rather than in 25 ms bins. In both bin-and segment-based analyses, firing rates were first converted to fractional interspike intervals (31) and then log-transformed, because neuronal responses are commonly proportional to the baseline activity level (32)(33)(34); the log-transformation normalizes distributions of the measurements and stabilizes their variance. Transformed activity patterns were then classified to the segments as above.…”

Section: Methodsmentioning

confidence: 99%

Parallel processing of serial movements in prefrontal cortex

Averbeck

Chafee

Crowe

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

248

192

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A key idea in Lashley's formulation of the problem of serial order in behavior is the postulated neural representation of all serial elements before the action begins. We studied this question by recording the activity of individual neurons simultaneously in small ensembles in prefrontal cortex while monkeys copied geometrical shapes shown on a screen. Monkeys drew the shapes as sequences of movement segments, and these segments were associated with distinct patterns of neuronal ensemble activity. Here we show that these patterns were present during the time preceding the actual drawing. The rank of the strength of representation of a segment in the neuronal population during this time, as assessed by discriminant analysis, predicted the serial position of the segment in the motor sequence. An analysis of errors in copying and their neural correlates supplied additional evidence for this code and provided a neural basis for Lashley's hypothesis that errors in motor sequences would be most likely to occur when executing elements that had prior representations of nearly equal strength.

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The Variability of Central Neural Activity in a Sensory System, and Its Implications for the Central Reflection of Sensory Events

Cited by 280 publications

References 0 publications

Inhibitory Action of Clozapine on Rat Ventral Tegmental Area Dopamine Neurons Following Increased Levels of Endogenous Kynurenic Acid

Inhibitory Action of Clozapine on Rat Ventral Tegmental Area Dopamine Neurons Following Increased Levels of Endogenous Kynurenic Acid

Different Pedunculopontine Tegmental Neurons Signal Predicted and Actual Task Rewards

Parallel processing of serial movements in prefrontal cortex

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