Timing during transitions in Bengalese finch song: implications for motor sequencing
To investigate mechanisms of action sequencing, we examined the relationship between timing and sequencing of syllables in Bengalese finch song. An individual’s song comprises acoustically distinct syllables organized into probabilistic sequences: a given syllable potentially can transition to several different syllables (divergence points), and several different syllables can transition to a given syllable (convergence points). In agreement with previous studies, we found that more probable transitions at divergence points occur with shorter intersyllable gaps. One intuition for this relationship is that selection b...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Troyer, T. W., Brainard, M. S., Bouchard, K. E. Tags: Research Articles Source Type: research
Task-specific, dimension-based attentional shaping of motion processing in monkey area MT
Nonspatially selective attention is based on the notion that specific features or objects in the visual environment are effectively prioritized in cortical visual processing. Feature-based attention (FBA), in particular, is a well-studied process that dynamically and selectively addresses neurons preferentially processing the attended feature attribute (e.g., leftward motion). In everyday life, however, behavior may require high sensitivity for an entire feature dimension (e.g., motion), but experimental evidence for a feature dimension-specific attentional modulation on a cellular level is lacking. Therefore, we investiga...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Schledde, B., Galashan, F. O., Przybyla, M., Kreiter, A. K., Wegener, D. Tags: Research Articles Source Type: research
The proinflammatory cytokine tumor necrosis factor-{alpha} excites subfornical organ neurons
Tumor necrosis factor-α (TNF-α) is a proinflammatory cytokine implicated in cardiovascular and autonomic regulation via actions in the central nervous system. TNF-α–/– mice do not develop angiotensin II (ANG II)-induced hypertension, and administration of TNF-α into the bloodstream of rats increases blood pressure and sympathetic tone. Recent studies have shown that lesion of the subfornical organ (SFO) attenuates the hypertensive and autonomic effects of TNF-α, while direct administration of TNF-α into the SFO increases blood pressure, suggesting the SFO to be a key site for...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Simpson, N. J., Ferguson, A. V. Tags: Research Articles Source Type: research
Dynamic mechanisms of visually guided 3D motion tracking
The continuous perception of motion-through-depth is critical for both navigation and interacting with objects in a dynamic three-dimensional (3D) world. Here we used 3D tracking to simultaneously assess the perception of motion in all directions, facilitating comparisons of responses to motion-through-depth to frontoparallel motion. Observers manually tracked a stereoscopic target as it moved in a 3D Brownian random walk. We found that continuous tracking of motion-through-depth was selectively impaired, showing different spatiotemporal properties compared with frontoparallel motion tracking. Two separate factors were fou...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Bonnen, K., Huk, A. C., Cormack, L. K. Tags: Research Articles Source Type: research
Comparison of the VTA and LC response to methylphenidate: a concomitant behavioral and neuronal study of adolescent male rats
The objective of this study was to compare the neuronal responses of the VTA and LC to MPD in normal adolescent rats. Animals were implanted with permanent electrodes in the VTA and LC, and neuronal units were recorded following acute and repetitive (chronic) saline or 0.6, 2.5, or 10.0 mg/kg MPD exposure. Animals displayed either behavioral sensitization or tolerance to all three doses of MPD. Acute MPD exposure elicited excitation in the majority of all VTA and LC units. Chronic MPD exposure elicited a further increase in VTA and LC neuronal activity in animals exhibiting behavioral sensitization and an attenuation in VT...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Karim, T. J., Reyes-Vazquez, C., Dafny, N. Tags: Research Articles Source Type: research
Interhemispheric interactions between trunk muscle representations of the primary motor cortex
Unilateral arm movements require trunk stabilization through bilateral contraction of axial muscles. Interhemispheric interactions between primary motor cortices (M1) could enable such coordinated contractions, but these mechanisms are largely unknown. Using transcranial magnetic stimulation (TMS), we characterized interhemispheric interactions between M1 representations of the trunk-stabilizing muscles erector spinae at the first lumbar vertebra (ES L1) during a right isometric shoulder flexion. These interactions were compared with those of the anterior deltoid (AD), the main agonist in this task, and the first dorsal in...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Jean-Charles, L., Nepveu, J.-F., Deffeyes, J. E., Elgbeili, G., Dancause, N., Barthelemy, D. Tags: Research Articles Source Type: research
Dynamics of human subthalamic neuron phase-locking to motor and sensory cortical oscillations during movement
Coupled oscillatory activity recorded between sensorimotor regions of the basal ganglia-thalamocortical loop is thought to reflect information transfer relevant to movement. A neuronal firing-rate model of basal ganglia-thalamocortical circuitry, however, has dominated thinking about basal ganglia function for the past three decades, without knowledge of the relationship between basal ganglia single neuron firing and cortical population activity during movement itself. We recorded activity from 34 subthalamic nucleus (STN) neurons, simultaneously with cortical local field potentials and motor output, in 11 subjects with Pa...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Lipski, W. J., Wozny, T. A., Alhourani, A., Kondylis, E. D., Turner, R. S., Crammond, D. J., Richardson, R. M. Tags: Research Articles Source Type: research
Activation of ganglion cells and axon bundles using epiretinal electrical stimulation
This study introduces a method to detect axon bundle activation on the basis of its electrical signature and uses the method to test whether epiretinal stimulation can directly elicit spikes in individual retinal ganglion cells without activating nearby axon bundles. Combined electrical stimulation and recording from isolated primate retina were performed using a custom multielectrode system (512 electrodes, 10-μm diameter, 60-μm pitch). Axon bundle signals were identified by their bidirectional propagation, speed, and increasing amplitude as a function of stimulation current. The threshold for bundle activation vari...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Grosberg, L. E., Ganesan, K., Goetz, G. A., Madugula, S. S., Bhaskhar, N., Fan, V., Li, P., Hottowy, P., Dabrowski, W., Sher, A., Litke, A. M., Mitra, S., Chichilnisky, E. J. Tags: Research Articles Source Type: research
Regulation of axonal regeneration following spinal cord injury in the lamprey
Following rostral spinal cord injury (SCI) in larval lampreys, injured descending brain neurons, particularly reticulospinal (RS) neurons, regenerate their axons, and locomotor behavior recovers in a few weeks. However, axonal regeneration of descending brain neurons is mostly limited to relatively short distances, but the mechanisms for incomplete axonal regeneration are unclear. First, lampreys with rostral SCI exhibited greater axonal regeneration of descending brain neurons, including RS neurons, as well as more rapid recovery of locomotor muscle activity right below the lesion site, compared with animals with caudal S...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Benes, J. A., House, K. N., Burks, F. N., Conaway, K. P., Julien, D. P., Donley, J. P., Iyamu, M. A., McClellan, A. D. Tags: Research Articles Source Type: research
Using theoretical models from adult stroke recovery to improve use of noninvasive brain stimulation for children with congenital hemiparesis
Noninvasive brain stimulation has been widely used for adults with stroke to improve upper limb motor function. A recent study by Kirton and colleagues (Kirton A, Ciechanski P, Zewdie E, Andersen J, Nettel-Aguirre A, Carlson H, Carsolio L, Herrero M, Quigley J, Mineyko A, Hodge J, Hill M. Neurology 88: 259–267, 2017) applied noninvasive brain stimulation to children with congenital hemiparesis but found no significant effect of noninvasive brain stimulation on motor function. Here, we explore theories about cortical reorganization in both adult and children with hemiparesis and discuss how to improve the approaches o...
Source: Journal of Neurophysiology - September 1, 2017 Category: Neurology Authors: Lin, Y.-L., Potter-Baker, K. A. Tags: Neuro Forum Source Type: research
Integration of visual and tactile information in reproduction of traveled distance
This study shows that tactile and visual information can be integrated to improve the estimates of the parameters of self-motion. This, however, happens only if the two sources of information are congruent—as they are in a natural environment. In contrast, an incongruent tactile stimulus is still used as a source of information about self-motion but it is not integrated with visual information. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - August 29, 2017 Category: Neurology Authors: Churan, J., Paul, J., Klingenhoefer, S., Bremmer, F. Tags: Research Articles Source Type: research
Effect of whisker geometry on contact force produced by vibrissae moving at different velocities
This study describes the geometry of facial whiskers distributed across the mystacial pad with emphasis on velocity encoding of object strikes. Findings indicate how the shapes, lengths, and thicknesses of individual hairs can contribute to sophisticated vibrissa-based tactile discrimination. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - August 29, 2017 Category: Neurology Authors: Carvell, G. E., Simons, D. J. Tags: Research Articles Source Type: research
Contribution of blood oxygen and carbon dioxide sensing to the energetic optimization of human walking
In this study we tested the hypothesis that an important source of energetic cost measurements arises from blood gas receptors that are sensitive to O2 and CO2 concentrations. These receptors are known to play a role in regulating other physiological processes related to energy consumption, such as ventilation rate. Given the role of O2 and CO2 in oxidative metabolism, sensing their levels can provide an accurate estimate of the body’s total energy use. To test our hypothesis, we simulated an added energetic cost for blood gas receptors that depended on a subject’s step frequency and determined if subjects chan...
Source: Journal of Neurophysiology - August 14, 2017 Category: Neurology Authors: Wong, J. D., OConnor, S. M., Selinger, J. C., Donelan, J. M. Tags: Research Articles Source Type: research
Validation of electrical stimulation models: intracellular calcium measurement in three-dimensional scaffolds
Peripheral nerve injury can be disabling. Regeneration is limited by the rate of axonal extension, and proximal injury to peripheral nerves can take over a year to reach target organs. Electrical stimulation (ES) has been shown to increase the rate of neurite growth, though the mechanism is not yet well understood. In our prior manuscript, we developed a computational model that demonstrates how ES can functionally elevate intracellular calcium concentration ([Ca2+]i) based on ES intensity and duration. In this article, we validate the computation model for the [Ca2+]i changes in neuron soma. Embryonic chicken dorsal root ...
Source: Journal of Neurophysiology - August 14, 2017 Category: Neurology Authors: Adams, R. D., Gupta, B., Harkins, A. B. Tags: Research Articles Source Type: research
The stochastic nature of action potential backpropagation in apical tuft dendrites
In cortical pyramidal neurons, backpropagating action potentials (bAPs) supply Ca2+ to synaptic contacts on dendrites. To determine whether the efficacy of AP backpropagation into apical tuft dendrites is stable over time, we performed dendritic Ca2+ and voltage imaging in rat brain slices. We found that the amplitude of bAP-Ca2+ in apical tuft branches was unstable, given that it varied from trial to trial (termed "bAP-Ca2+ flickering"). Small perturbations in dendritic physiology, such as spontaneous synaptic inputs, channel inactivation, or temperature-induced changes in channel kinetics, can cause bAP flickering. In th...
Source: Journal of Neurophysiology - August 14, 2017 Category: Neurology Authors: Short, S. M., Oikonomou, K. D., Zhou, W.-L., Acker, C. D., Popovic, M. A., Zecevic, D., Antic, S. D. Tags: Research Articles Source Type: research
