Parallel processing of internal and external feedback in the spinocerebellar system of primates
Cerebellar control of voluntary movements is achieved by the integration of external and internal feedback information to adjust and correct properly ongoing actions. In the forelimb of primates, rostral-spinocerebellar tract (RSCT) neurons are thought to integrate segmental, descending, and afferent sources and relay upstream a compound signal that contains both an efference copy of the spinal-level motor command and the state of the periphery. We tested this hypothesis by implanting stimulating electrodes in the superior cerebellar peduncle and recording the activity of cervical spinal neurons in primates. To dissociate ...
Source: Journal of Neurophysiology - July 5, 2017 Category: Neurology Authors: Cohen, O., Harel, R., Aumann, T. D., Israel, Z., Prut, Y. Tags: Research Articles Source Type: research
Frequency tagging to track the neural processing of contrast in fast, continuous sound sequences
The human auditory system presents a remarkable ability to detect rapid changes in fast, continuous acoustic sequences, as best illustrated in speech and music. However, the neural processing of rapid auditory contrast remains largely unclear, probably due to the lack of methods to objectively dissociate the response components specifically related to the contrast from the other components in response to the sequence of fast continuous sounds. To overcome this issue, we tested a novel use of the frequency-tagging approach allowing contrast-specific neural responses to be tracked based on their expected frequencies. The EEG...
Source: Journal of Neurophysiology - July 5, 2017 Category: Neurology Authors: Nozaradan, S., Mouraux, A., Cousineau, M. Tags: Research Articles Source Type: research
Musculoskeletal geometry accounts for apparent extrinsic representation of paw position in dorsal spinocerebellar tract
We examined the contribution of musculoskeletal geometry to this apparent extrinsic representation by simulating a three-joint hindlimb with mono- and biarticular muscles, each providing a muscle spindlelike signal, modulated by the muscle length. We simulated neurons driven by randomly weighted combinations of these signals and moved the paw to different positions under two joint-covariance conditions similar to the original experiments. Our results paralleled those experiments in a number of respects: 1) Many neurons were tuned to paw position relative to the hip under both conditions. 2) The distribution of tuning was s...
Source: Journal of Neurophysiology - July 5, 2017 Category: Neurology Authors: Chowdhury, R. H., Tresch, M. C., Miller, L. E. Tags: Research Articles Source Type: research
Transfer of dynamic motor skills acquired during isometric training to free motion
This study provided early evidence supporting that training movement skills without moving is possible. In contrast to previous studies, our study involves 1) exploiting cross-modal sensory interactions between vision and proprioception in a motionless setting to teach motor skills that could be transferable to a corresponding physical task, and 2) evaluates the movement skill of controlling muscle-generated forces to execute arm movements in the presence of external forces that were only virtually present during training. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - July 5, 2017 Category: Neurology Authors: Melendez-Calderon, A., Tan, M., Bittmann, M. F., Burdet, E., Patton, J. L. Tags: Research Articles Source Type: research
Dynamic population codes of multiplexed stimulus features in primate area MT
The middle-temporal area (MT) of primate visual cortex is critical in the analysis of visual motion. Single-unit studies suggest that the response dynamics of neurons within area MT depend on stimulus features, but how these dynamics emerge at the population level, and how feature representations interact, is not clear. Here, we used multivariate classification analysis to study how stimulus features are represented in the spiking activity of populations of neurons in area MT of marmoset monkey. Using representational similarity analysis we distinguished the emerging representations of moving grating and dot field stimuli....
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Goddard, E., Solomon, S. G., Carlson, T. A. Tags: Research Articles Source Type: research
Functional remodeling of subtype-specific markers surrounding implanted neuroprostheses
In this study, we investigated whether or not device insertion causes alterations in specific subtypes of these cells. We assessed the expression of both excitatory and inhibitory markers of neurotransmission (vesicular glutamate and GABA transporters, VGLUT1 and VGAT, respectively) surrounding single-shank Michigan-style microelectrode arrays implanted in the motor cortex of adult rats by use of quantitative immunohistochemistry. We found a pronounced shift from significantly elevated VGLUT1 within the initial days following implantation to relatively heightened VGAT by the end of the 4-wk observation period. Unexpectedly...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Salatino, J. W., Winter, B. M., Drazin, M. H., Purcell, E. K. Tags: Research Articles Source Type: research
Afferent motor feedback determines the perceived location of tactile stimuli in the external space presented to the moving arm
In this study, we tested the contributions of afferent proprioceptive feedback and predictive arm position signals by comparing localization errors during passive vs. active arm movements. In the active trials, participants were instructed to localize a tactile stimulus in the external space that was presented to the index finger near the time of a self-generated arm movement. In the passive trials, each of the active trials was passively replayed in randomized order, using a robotic device. Our results provide evidence that the localization error patterns of the passive trials are similar to the active trials and, moreove...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Maij, F., Wing, A. M., Medendorp, W. P. Tags: Research Articles Source Type: research
Dynamical signatures of isometric force control as a function of age, expertise, and task constraints
From the conceptual and methodological framework of the dynamical systems approach, force control results from complex interactions of various subsystems yielding observable behavioral fluctuations, which comprise both deterministic (predictable) and stochastic (noise-like) dynamical components. Here, we investigated these components contributing to the observed variability in force control in groups of participants differing in age and expertise level. To this aim, young (18–25 yr) as well as late middle-aged (55–65 yr) novices and experts (precision mechanics) performed a force maintenance and a force modulat...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Vieluf, S., Sleimen-Malkoun, R., Voelcker-Rehage, C., Jirsa, V., Reuter, E.-M., Godde, B., Temprado, J.-J., Huys, R. Tags: Research Articles Source Type: research
SK channel inhibition mediates the initiation and amplitude modulation of synchronized burst firing in the spinal cord
This study demonstrates that cholinergic inhibition or direct blockade of small conductance Ca2+-activated potassium (SK) channels facilitates burst firing in spinal motoneurons. The data provide a novel mechanistic explanation for synchronized bursting initiation and amplitude modulation through SK channel inhibition. Evidence also shows that synchronized bursting is driven by NMDA (N-methyl-d-aspartate) and AMPA (α-amino-3-hydroxy-5-methylisoxazole-4-propionate) receptors and that gap junctions do not mediate motoneuron synchronization in this behavior. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Mahrous, A. A., Elbasiouny, S. M. Tags: Research Articles Source Type: research
Spatial attention during saccade decisions
Behavioral measures of decision making are usually limited to observations of decision outcomes. In the present study, we made use of the fact that oculomotor and sensory selection are closely linked to track oculomotor decision making before oculomotor responses are made. We asked participants to make a saccadic eye movement to one of two memorized target locations and observed that visual sensitivity increased at both the chosen and the nonchosen saccade target locations, with a clear bias toward the chosen target. The time course of changes in visual sensitivity was related to saccadic latency, with the competition betw...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Jonikaitis, D., Klapetek, A., Deubel, H. Tags: Research Articles Source Type: research
Developmental profile of motor cortex transcallosal inhibition in children and adolescents
The objective of this study was to examine the developmental profile of transcallosal inhibition in healthy children and adolescents. Nineteen typically developing right-handed participants were recruited. Two transcranial magnetic stimulation (TMS) paradigms assessed transcallosal inhibition: ipsilateral silent periods (iSP) and paired-pulse interhemispheric inhibition (IHI). TMS was applied to the motor hotspot of the first dorsal interosseous muscle. Resting motor threshold (RMT), iSP latency, duration and suppression strength, and paired-pulse IHI were measured from both hemispheres. The Purdue Pegboard Test assessed u...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Ciechanski, P., Zewdie, E., Kirton, A. Tags: Research Articles Source Type: research
Development and long-term integration of MGE-lineage cortical interneurons in the heterochronic environment
Interneuron precursors transplanted into visual cortex induce network plasticity during their heterochronic maturation. Such plasticity can have a significant impact on the function of the animal and is normally present only during a brief critical period in early postnatal development. Elucidating the synaptic and physiological properties of interneuron precursors as they mature is key to understanding how long-term circuit changes are induced by transplants. We studied the development of transplant-derived interneurons and compared it to endogenously developing interneurons (those that are born and develop in the same an...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Larimer, P., Spatazza, J., Stryker, M. P., Alvarez-Buylla, A., Hasenstaub, A. R. Tags: Rapid Reports Source Type: research
The modulation of two motor behaviors by persistent sodium currents in Xenopus laevis tadpoles
In this study we have characterized INaP and investigated its role in the swimming and struggling behavior of Xenopus tadpoles. INaP was identified in three groups of neurons, namely, sensory Rohon-Beard neurons (RB neurons), descending interneurons (dINs), and non-dINs (neurons rhythmically active in swimming). All groups of neurons expressed INaP, but the currents differed in decay time constants, amplitudes, and the membrane potential at which INaP peaked. Low concentrations (1 µM) of the INaP blocker riluzole blocked INaP ~30% and decreased the excitability of the three neuron groups without affecting spike ampli...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Svensson, E., Jeffreys, H., Li, W.-C. Tags: Research Articles Source Type: research
Ion diffusion may introduce spurious current sources in current-source density (CSD) analysis
Current-source density (CSD) analysis is a well-established method for analyzing recorded local field potentials (LFPs), that is, the low-frequency part of extracellular potentials. Standard CSD theory is based on the assumption that all extracellular currents are purely ohmic, and thus neglects the possible impact from ionic diffusion on recorded potentials. However, it has previously been shown that in physiological conditions with large ion-concentration gradients, diffusive currents can evoke slow shifts in extracellular potentials. Using computer simulations, we here show that diffusion-evoked potential shifts can int...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Halnes, G., Mäki-Marttunen, T., Pettersen, K. H., Andreassen, O. A., Einevoll, G. T. Tags: Rapid Reports Source Type: research
Glycolytic inhibition by 2-deoxy-D-glucose abolishes both neuronal and network bursts in an in vitro seizure model
In this study, we investigated the effects of glycolytic inhibition with 2-deoxy-d-glucose (2-DG) on basal membrane properties, spontaneous neuronal firing, and epileptiform network bursts in hippocampal slices. The effect of glycolytic inhibition on basal membrane properties was examined in hippocampal CA1 neurons, which are not ordinarily active spontaneously. Intracellular application of 2-DG did not significantly alter the membrane input resistance, action-potential threshold, firing pattern, or input-output relationship of these neurons compared with simultaneously recorded neighboring neurons without intracellular 2-...
Source: Journal of Neurophysiology - July 1, 2017 Category: Neurology Authors: Shao, L.-R., Stafstrom, C. E. Tags: Research Articles Source Type: research
