Showing papers in "Journal of Neurophysiology in 1998"
TL;DR: Dopamine systems may have two functions, the phasic transmission of reward information and the tonic enabling of postsynaptic neurons.
Abstract: Schultz, Wolfram. Predictive reward signal of dopamine neurons. J. Neurophysiol. 80: 1–27, 1998. The effects of lesions, receptor blocking, electrical self-stimulation, and drugs of abuse suggest t...
3,962 citations
TL;DR: A relatively simple control scheme for regulation of upright posture that provides almost instantaneous corrective response and reduces the operating demands on the CNS is proposed.
Abstract: Winter, David A., Aftab E. Patla, Francois Prince, Milad Ishac, and Krystyna Gielo-Perczak. Stiffness control of balance in quiet standing. J. Neurophysiol. 80: 1211–1221, 1998. Our goal was to pro...
1,389 citations
TL;DR: Training rapidly, and transiently, established a change in the cortical network representing the thumb, which encoded kinematic details of the practiced movement, suggesting that this phenomenon may be regarded as a short-term memory for movement and be the first step of skill acquisition.
Abstract: Classen, Joseph, Joachim Liepert, Steven P. Wise, Mark Hallett, and Leonardo G. Cohen. Rapid plasticity of human cortical movement representation induced by practice. J. Neurophysiol. 79: 1117–1123...
1,161 citations
TL;DR: Differences in the time course of activation across the dorsal and ventral streams provide important temporal constraints on theories of visual processing.
Abstract: Schmolesky, Matthew T., Youngchang Wang, Doug P. Hanes, Kirk G. Thompson, Stefan Leutgeb, Jeffrey D. Schall, and Audie G. Leventhal. Signal timing across the macaque visual system. J. Neurophysiol....
982 citations
TL;DR: Results demonstrate that motor skill learning is associated with a reorganization of movement representations within the rodent motor cortex.
Abstract: Kleim, Jeffrey A., Scott Barbay, and Randolph J. Nudo. Functional reorganization of the rat motor cortex following motor skill learning. J. Neurophysiol. 80: 3321–3325, 1998. Adult rats were alloca...
812 citations
TL;DR: The large proportion of bimodal tactile and visual neurons with congruent response properties in area VIP indicates that there are important functional differences between area VIP and other dorsal stream areas involved in the analysis of motion.
Abstract: Duhamel, Jean-Rene, Carol L. Colby, and Michael E. Goldberg. Ventral intraparietal area of the macaque: congruent visual and somatic response properties. J. Neurophysiol. 79: 126–136, 1998. In a pr...
779 citations
TL;DR: The results support a "biased competition" model of attention, according to which objects in the visual field compete for representation in the cortex, and this competition is biased in favor of the behaviorally relevant object by virtue of "top-down" feedback from structures involved in working memory.
Abstract: Chelazzi, Leonardo, John Duncan, Earl K. Miller, and Robert Desimone. Responses of neurons in inferior temporal cortex during memory-guided visual search. J. Neurophysiol. 80: 2918–2940, 1998. A ty...
734 citations
TL;DR: Channel deactivation was fast and comparable among receptors obtained by cotransfecting five distinct spliced variants of the NR1 subunit, each with the NR2A subunits, and recovery from desensitization was slower for NR1/NR2B than for NR2/NR3 channels, suggesting mechanisms additional to subunit composition may also regulate deactivation time course.
Abstract: N-methyl-D-aspartic acid (NMDA) receptors transiently transfected into mammalian HEK-293 cells were characterized with subunit-specific antibodies and electrophysiological recordings. Deactivation time course recorded in response to fast-glutamate pulses were studied in isolated and lifted cells, as well as in outside-out membrane patches excised from cells expressing recombinant NR1 subunits in combination with the NR2A, NR2B, NR2C, or NR2D NMDA receptor subunits. Transfected cells were preidentified by the fluorescence emitted from the coexpressed Aequorea victoria jellyfish Green Lantern protein. Currents generated by NR1/NR2A channels displayed double exponential deactivation time course being faster than that in NR1/NR2B or NR1/NR2C channels. However, a large decay variability was observed within each cotransfection, suggesting that mechanisms additional to subunit composition may also regulate deactivation time course. NR1/NR2D channels displayed slowly deactivating currents. Channel deactivation was fast and comparable among receptors obtained by cotransfecting five distinct spliced variants of the NR1 subunit, each with the NR2A subunit. Additionally, recovery from desensitization was slower for NR1/NR2B than for NR1/NR2A channels. The average deactivation time course of responses to brief L-glutamate applications in cells where NR1/NR2A/NR2B cDNAs were cotransfected at variable ratio was intermediate between those of the NR1/NR2A and NR1/NR2B channels. Although immunocytochemical evidence indicates that the majority of cells are cotransfected by all plasmids in triple transfection, our experimental condition did not allow for a tight control of the expression of NMDA receptor subunits. This produced the result that many cells were characterized by deactivation time course and haloperidol sensitivities of separate NR1/NR2A and NR1/NR2B subunit heteromers. We also speculate on the possible formation of channels resulting from the coassembly in the same receptor of NR1/NR2A/NR2B subunits from a minority of cells that gave responses to brief application of L-glutamate characterized by slow deactivation time course and decreased haloperidol sensitivity.
689 citations
TL;DR: Evidence is provided for a faithful duplication of receptive field properties and virtually every other dimension of task-related activity observed when parietal and prefrontal cortex are recruited to a common task.
Abstract: Chafee, Matthew V. and Patricia S. Goldman-Rakic. Matching patterns of activity in primate prefrontal area 8a and parietal area 7ip neurons during a spatial working memory task. J. Neurophysiol. 79...
666 citations
TL;DR: All the reconstruction methods considered in this paper can be implemented by a unified neural network architecture, which the brain feasibly could use to solve related problems.
Abstract: Physical variables such as the orientation of a line in the visual field or the location of the body in space are coded as activity levels in populations of neurons. Reconstruction or decoding is an inverse problem in which the physical variables are estimated from observed neural activity. Reconstruction is useful first in quantifying how much information about the physical variables is present in the population and, second, in providing insight into how the brain might use distributed representations in solving related computational problems such as visual object recognition and spatial navigation. Two classes of reconstruction methods, namely, probabilistic or Bayesian methods and basis function methods, are discussed. They include important existing methods as special cases, such as population vector coding, optimal linear estimation, and template matching. As a representative example for the reconstruction problem, different methods were applied to multi-electrode spike train data from hippocampal place cells in freely moving rats. The reconstruction accuracy of the trajectories of the rats was compared for the different methods. Bayesian methods were especially accurate when a continuity constraint was enforced, and the best errors were within a factor of two of the information-theoretic limit on how accurate any reconstruction can be and were comparable with the intrinsic experimental errors in position tracking. In addition, the reconstruction analysis uncovered some interesting aspects of place cell activity, such as the tendency for erratic jumps of the reconstructed trajectory when the animal stopped running. In general, the theoretical values of the minimal achievable reconstruction errors quantify how accurately a physical variable is encoded in the neuronal population in the sense of mean square error, regardless of the method used for reading out the information. One related result is that the theoretical accuracy is independent of the width of the Gaussian tuning function only in two dimensions. Finally, all the reconstruction methods considered in this paper can be implemented by a unified neural network architecture, which the brain feasibly could use to solve related problems.
632 citations
TL;DR: Widespread coupling of oscillatory signals is consistent with the concept that temporal coding processes operate in motor cortex, but because the relationship between neuronal discharge and the appearance of fast oscillations may be altered by behavioral condition, they must reflect a global process active in conjunction with motor planning or preparatory functions.
Abstract: Donoghue, John P., Jerome N. Sanes, Nicholas G. Hatsopoulos, and Gyongyi Gaal. Neural discharge and local field potential oscillations in primate motor cortex during voluntary movements. J. Neuroph...
TL;DR: It is suggested that chemical activation and sensitization of dura-sensitive peripheral nociceptors could lead to enhanced responses in central neurons and that this central sensitization therefore could result in extracranial tenderness (mechanical and thermal allodynia) in the absence of extacranial pathology.
Abstract: Burstein, Rami, Hiroyoshi Yamamura, Amy Malick, and Andrew M. Strassman. Chemical stimulation of the intracranial dura induces enhanced responses to facial stimulation in brain stem trigeminal neur...
TL;DR: FMRI results suggest that attentive tracking is mediated by a network of areas that includes parietal and frontal regions responsible for attention shifts and eye movements and the MT complex, thought to be responsible for motion perception.
Abstract: Culham, Jody C., Stephan A. Brandt, Patrick Cavanagh, Nancy G. Kanwisher, Anders M. Dale, and Roger B. H. Tootell. Cortical fMRI activation produced by attentive tracking of moving targets. J. Neur...
TL;DR: Clear evidence is obtained that FEF neurons with eye movement-related activity generate signals sufficient to control the production of gaze shifts, and a fraction of tonic visual cells exhibited a reduction of activity once a saccade command had been cancelled even though the visual target was still present in the receptive field.
Abstract: Hanes, Doug P., Warren F. Patterson II, and Jeffrey D. Schall. Role of frontal eye fields in countermanding saccades: visual, movement, and fixation activity. J. Neurophysiol. 79: 817–834, 1998. A ...
TL;DR: Results show that face-specific fusiform activity is reduced when stimuli appear outside (vs. inside) the focus of attention, despite the modular nature of the FFA, which depends on voluntary attention.
Abstract: Wojciulik, Ewa, Nancy Kanwisher, and Jon Driver. Covert visual attention modulates face-specific activity in the human fusiform gyrus: an fMRI study. J. Neurophysiol. 79: 1574–1578, 1998. Several l...
TL;DR: The findings suggest that the intracortical mechanisms for inhibition and facilitation in different motor representations are not related to the strength of corticospinal projections.
Abstract: Chen, Robert, Alda Tam, Cathrin Butefisch, Brian Corwell, Ulf Ziemann, John C. Rothwell, and Leonardo G. Cohen. Intracortical inhibition and facilitation in different representations of the human m...
TL;DR: Functional magnetic resonance imaging is used to locate discrete regions of the thalamus, insula, and second somatosensory cortex modulated during innocuous and noxious thermal stimulation and provides support for a role of the anterior insula and S2 in the perception of pain; whereas the posterior insula appears to be involved in tactile and innocuous temperature perception.
Abstract: Davis, Karen D., Chun L. Kwan, Adrian P. Crawley, and David J. Mikulis. Functional MRI study of thalamic and cortical activations evoked by cutaneous heat, cold, and tactile stimuli. J. Neurophysio...
TL;DR: The background synaptic activity present in intact networks dramatically reduces the electrical compactness of cortical neurons and modifies their integrative properties and should be taken into account when extrapolating in vitro findings to the intact brain.
Abstract: Pare, Denis, Eric Shink, Helene Gaudreau, Alain Destexhe, and Eric J. Lang. Impact of spontaneous synaptic activity on the resting properties of cat neocortical pyramidal neurons in vivo. J. Neurop...
TL;DR: It is suggested that a local network of inhibitory interneurons may help shape not only the reciprocal discharge pattern of fixation and saccade neurons but also permit lateral interactions between all regions of the ipsilateral and contralateral SC.
Abstract: Munoz, Douglas P. and Peter J. Istvan. Lateral inhibitory interactions in the intermediate layers of the monkey superior colliculus. J. Neurophysiol. 79: 1193–1209, 1998. The intermediate layers of...
TL;DR: The capacity of the adult lumbar spinal cord to generate full weight-bearing stepping over a range of speeds is defined, in large part, by the functional experience of the spinal cord after supraspinal connectivity has been eliminated.
Abstract: de Leon, R. D., J. A. Hodgson, R. R. Roy, and V. R. Edgerton. Locomotor capacity attributable to step training versus spontaneous recovery after spinalization in adult cats. J. Neurophysiol. 79: 13...
TL;DR: Many of the behavior-related neurons investigated in the anterior striatum were influenced by an upcoming primary liquid reward and did not appear to code behavioral acts in a motivationally neutral manner.
Abstract: Hollerman, Jeffrey R., Leon Tremblay, and Wolfram Schultz. Influence of reward expectation on behavior-related neuronal activity in primate striatum. J. Neurophysiol. 80: 947–963, 1998. Rewards con...
TL;DR: The Piper rhythm in muscle may be driven by a comparable oscillatory activity in the contralateral motor cortex, which can be picked up in several types of movement and seems distinct from the 20- to 30-Hz rhythmicity recorded during weak sustained contractions.
Abstract: Brown, Peter, Stephan Salenius, John C. Rothwell, and Riitta Hari. Cortical correlate of the Piper rhythm in humans. J. Neurophysiol. 80: 2911–2917, 1998. The electromyogram (EMG) of healthy humans...
TL;DR: Overall, both in the early postlesion period and during recovery, changes in saccade amplitude and latency tended to vary together but not with changes inSaccade dynamics or adaptive capability, both of which behaved relatively independently.
Abstract: Takagi, Mineo, David S. Zee, and Rafael J. Tamargo. Effects of lesions of the oculomotor vermis on eye movements in primate: saccades. J. Neurophysiol. 80: 1911–1931, 1998. We studied the effects o...
TL;DR: The proposed cellular mechanism proposes that the large-scale synchrony of spindle oscillations in vivo is the result of thalamocortical interactions in which the corticothalamic feedback acts predominantly through the RE nucleus.
Abstract: Destexhe, Alain, Diego Contreras, and Mircea Steriade. Mechanisms underlying the synchronizing action of corticothalamic feedback through inhibition of thalamic relay cells. J. Neurophysiol. 79: 99...
TL;DR: Adult owl and squirrel monkeys were trained to master a small-object retrieval sensorimotor skill and revealed a postlesion reemergence of the representation of the fingertips engaged in the behavior in novel locations in two of five monkeys and a less substantial change in the representation in the hand in the intact parts of area 3b in three ofFive monkeys.
Abstract: Xerri, Christian, Michael M. Merzenich, Bret E. Peterson, and William Jenkins. Plasticity of primary somatosensory cortex paralleling sensorimotor skill recovery from stroke in adult monkeys. J. Ne...
TL;DR: Both contrasts between the conditions of sustained attention to color or to shape as compared with the fixation condition showed significant bilateral activation in occipital and inferior temporal regions.
Abstract: Le, Tuong Huu, Jose V. Pardo, and Xiaoping Hu. 4 T-fMRI study of nonspatial shifting of selective attention: cerebellar and parietal contributions. J. Neurophysiol. 79: 1535–1548, 1998. Regional bl...
TL;DR: It is argued that conservation of kinematic templates across gait reversal at the expense of a complete reorganization of muscle synergies does not arise from biomechanical constraints but may reflect a behavioral goal achieved by the central networks involved in the control of locomotion.
Abstract: Grasso, R., L. Bianchi, and F. Lacquaniti. Motor patterns for human gait: backward versus forward locomotion. J. Neurophysiol. 80: 1868–1885, 1998. Seven healthy subjects walked forward (FW) and ba...
TL;DR: The results indicate that the minimal substrate that is necessary for the production of seizures consisting of SW/PSW complexes and runs of fast activity is the neocortex.
Abstract: Steriade, Mircea and Diego Contreras. Spike-wave complexes and fast components of cortically generated seizures. I. Role of neocortex and thalamus. J. Neurophysiol. 80: 1439–1455, 1998. We explored...
TL;DR: Serodio, Paulo and Bernardo Rudy as mentioned in this paper showed that Kv4 K+ channel subunits mediating subthreshold transient K+(A)-type currents in rat brain were differentially expressed.
Abstract: Serodio, Paulo and Bernardo Rudy. Differential expression of Kv4 K+ channel subunits mediating subthreshold transient K+(A-type) currents in rat brain. J. Neurophysiol. 79: 1081–1091, 1998. The mam...
TL;DR: Results are consistent with a model in which visual expertise is acquired through the development of differential responses by inferotemporal cells to the images of relevant objects.
Abstract: Kobatake, Eucaly, Gang Wang, and Keiji Tanaka. Effects of shape-discrimination training on the selectivity of inferotemporal cells in adult monkeys. J. Neurophysiol. 80: 324–330, 1998. Through exte...