Response differences in monkey TE and perirhinal cortex: stimulus association related to reward schedules.
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Anatomic and behavioral evidence shows that TE and perirhinal cortices are two directly connected but distinct inferior temporal areas. Despite this distinctness, physiological properties of neurons in these two areas generally have been similar with neurons in both areas showing selectivity for complex visual patterns and showing response modulations related to behavioral context in the sequential delayed match-to-sample (DMS) trials, attention, and stimulus familiarity. Here we identify physiological differences in the neuronal activity of these two areas. We recorded single neurons from area TE and perirhinal cortex while the monkeys performed a simple behavioral task using randomly interleaved visually cued reward schedules of one, two, or three DMS trials. The monkeys used the cue's relation to the reward schedule (indicated by the brightness) to adjust their behavioral performance. They performed most quickly and most accurately in trials in which reward was immediately forthcoming and progressively less well as more intermediate trials remained. Thus the monkeys appeared more motivated as they progressed through the trial schedule. Neurons in both TE and perirhinal cortex responded to both the visual cues related to the reward schedules and the stimulus patterns used in the DMS trials. As expected, neurons in both areas showed response selectivity to the DMS patterns, and significant, but small, modulations related to the behavioral context in the DMS trial. However, TE and perirhinal neurons showed strikingly different response properties. The latency distribution of perirhinal responses was centered 66 ms later than the distribution of TE responses, a larger difference than the 10-15 ms usually found in sequentially connected visual cortical areas. In TE, cue-related responses were related to the cue's brightness. In perirhinal cortex, cue-related responses were related to the trial schedules independently of the cue's brightness. For example, some perirhinal neurons responded in the first trial of any reward schedule including the one trial schedule, whereas other neurons failed to respond in the first trial but respond in the last trial of any schedule. The majority of perirhinal neurons had more complicated relations to the schedule. The cue-related activity of TE neurons is interpreted most parsimoniously as a response to the stimulus brightness, whereas the cue-related activity of perirhinal neurons is interpreted most parsimoniously as carrying associative information about the animal's progress through the reward schedule. Perirhinal cortex may be part of a system gauging the relation between work schedules and rewards. (+info)
Attention to both space and feature modulates neuronal responses in macaque area V4.
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Attention is the mechanism with which we select specific aspects of our environment for processing. Psychological experiments have shown that attention can be directed to a spatial location or to a particular object. Electrophysiological studies in trained macaque monkeys have found that attention can strengthen the responses of neurons in cortical area V4. Some of these studies have attributed these effects to spatial attention, whereas others have suggested that feature-directed attention may modulate the neuronal response. Here we report that neuronal correlates for both spatial and feature-directed attention exist in individual neurons in area V4 of behaving rhesus monkeys. (+info)
Rostrocaudal distinction of the dorsal premotor area based on oculomotor involvement.
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To investigate functional differences between the rostral and caudal parts of the dorsal premotor cortex (PMd), we first examined the effects of intracortical microstimulation (ICMS) while monkeys were performing oculomotor and limb motor tasks or while they were at rest. We found that saccades were evoked from the rostral part (PMdr) whereas ICMS in the caudal part (PMdc) predominantly produced forelimb or body movements. Subsequently, we examined neuronal activity in relation to the performance of visually cued and memorized saccades while monkeys reached an arm toward a visual target. We found that roughly equal numbers of PMdr neurons were active during performance of the oculomotor and limb motor tasks. In contrast, the majority of PMdc neurons were related preferentially to arm movements and not to saccades. In the subsequent analysis, we found that the oculomotor effects evoked in the PMdr differ from the effects evoked in either the frontal eye field (FEF) or supplementary eye field (SEF). These findings suggest that the PMdr is involved in oculomotor as well as limb motor behavior. However, the oculomotor involvement of the PMdr seems to have a functional aspect different from that operating in the FEF and SEF. (+info)
Integrating basic and applied research and the utility of Lattal and Perone's Handbook of research methods in human operant behavior.
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Lattal and Perone's Handbook of methods used in human operant research on behavioral processes will be a valuable resource for researchers who want to bridge laboratory developments with applied study. As a supplemental resource, investigators are also encouraged to examine the series of papers in the Journal of Applied Behavior Analysis that discuss basic research and its potential for application. Increased knowledge of behavioral processes in laboratory research could lead to innovative solutions to practical problems addressed by applied behavior analysts in the home, classroom, clinic, and community. (+info)
Learning performance of normal and mutant Drosophila after repeated conditioning trials with discrete stimuli.
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A new olfactory conditioning procedure is described using short training trials with discrete presentation of conditioned stimuli (CS) and unconditioned stimuli (US). A short odor presentation along with a single-shock stimulus produced modest but reliable and reproducible learning. Multiple trials presented sequentially improved performance with increasing trial number. Trial spacing had a significant impact on performance. Two trials presented with a short intertrial interval (ITI) produced no improvement over a single trial; two trials with a 15 min ITI significantly boosted performance. This effect required two associative trials, because substituting one of the trials with the CS alone, US alone, or an unpaired CS-US failed to boost performance. The increase in initial performance with two trials decayed within 15 min after training. Thus, the effect is short-lived. The utility of using a battery of tests, including a single short trial, two massed trials, and two spaced trials, to investigate parameters of memory formation in several mutants was demonstrated. (+info)
The operant and the classical in conditioned orientation of Drosophila melanogaster at the flight simulator.
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Ever since learning and memory have been studied experimentally, the relationship between operant and classical conditioning has been controversial. Operant conditioning is any form of conditioning that essentially depends on the animal's behavior. It relies on operant behavior. A motor output is called operant if it controls a sensory variable. The Drosophila flight simulator, in which the relevant behavior is a single motor variable (yaw torque), fully separates the operant and classical components of a complex conditioning task. In this paradigm a tethered fly learns, operantly or classically, to prefer and avoid certain flight orientations in relation to the surrounding panorama. Yaw torque is recorded and, in the operant mode, controls the panorama. Using a yoked control, we show that classical pattern learning necessitates more extensive training than operant pattern learning. We compare in detail the microstructure of yaw torque after classical and operant training but find no evidence for acquired behavioral traits after operant conditioning that might explain this difference. We therefore conclude that the operant behavior has a facilitating effect on the classical training. In addition, we show that an operantly learned stimulus is successfully transferred from the behavior of the training to a different behavior. This result unequivocally demonstrates that during operant conditioning classical associations can be formed. (+info)
Control of cocaine-seeking behavior by drug-associated stimuli in rats: effects on recovery of extinguished operant-responding and extracellular dopamine levels in amygdala and nucleus accumbens.
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The conditioning of the pharmacological actions of cocaine with environmental stimuli is thought to be a critical factor in the long-term addictive potential of this drug. Cocaine-related stimuli may increase the likelihood of relapse by evoking drug craving, and brain-imaging studies have identified the amygdala and nucleus accumbens (NAcc) as putative neuroanatomical substrates for these effects of cocaine cues. To study the significance of environmental stimuli in the recovery of extinguished cocaine-seeking behavior, male Wistar rats were trained to associate discriminative stimuli (SDeltas) with response-contingent availability of intravenous cocaine vs. saline. The rats then were subjected to repeated extinction sessions during which cocaine, saline, and the respective SDeltas were withheld until the animals reached an extinction criterion of +info)
Effects of ethanol on working memory and attention in pigeons.
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To determine whether the effects of ethanol on working memory are mediated by a secondary effect on attention, dose-response curves for ethanol were determined in eight pigeons trained under a titrating matching-to-sample (TMTS) procedure, in eight pigeons trained under a discrete-trial measure of attention, and in eight pigeons trained under a continuous-trial measure of attention. Ethanol decreased accuracy under the TMTS procedure following the three highest doses (1, 1.8, and 3 g/kg). Only the highest dose (3 mg/kg) decreased rates of responding. Attention, as measured under the discrete-trial procedure, was affected only by the two highest doses (1.8 and 3 g/kg). The 3-g/kg dose caused significant decreases in the probability of a hit and probability of a correct rejection, as well as significant increases in the probability of an error of omission and response latencies. Sensitivity to the signal decreased following 1.8 and 3 g/kg ethanol. Under the continuous-trial procedure, ethanol caused a peak in false alarms after the 1.8-g/kg dose, decreased the probability of a hit following the 1.8- and 3-g/kg doses, and increased probability of a miss at all doses. Sensitivity to the signal was not affected. A comparison of the dose-response curves for the TMTS procedure and the two measures of attention revealed that working memory (TMTS) was decreased by a lower dose than that affecting attention. This suggests that the effects of ethanol on working memory are not mediated by the subject's ability to pay attention to stimulus changes in the environment. (+info)