Hyperpolarization-activated cyclic-nucleotide-gated channels potentially modulate axonal excitability at different thresholds
In conclusion, variation in the kinetics of HCN isoforms could account for the findings in motor and sensory axons. Importantly, assessing the function of HCN channels in sensory and motor axons of different thresholds may provide insights into the pathophysiological processes underlying peripheral neurological diseases in humans, particularly focusing on the role of HCN channels with the potential of identifying novel treatment targets.
NEW & NOTEWORTHY Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels, which underlie inward rectifying currents (Ih), appear to mediate differences in sensory and motor ...
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Weerasinghe, D., Menon, P., Vucic, S. Tags: Research Articles Source Type: research
Diversity in spatial scope of contrast adaptation among mouse retinal ganglion cells
Retinal ganglion cells adapt to changes in visual contrast by adjusting their response kinetics and sensitivity. While much work has focused on the time scales of these adaptation processes, less is known about the spatial scale of contrast adaptation. For example, do small, localized contrast changes affect a cell’s signal processing across its entire receptive field? Previous investigations have provided conflicting evidence, suggesting that contrast adaptation occurs either locally within subregions of a ganglion cell’s receptive field or globally over the receptive field in its entirety. Here, we investigat...
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Khani, M. H., Gollisch, T. Tags: Research Articles Source Type: research
Characterization of ion channels and O2 sensitivity in gill neuroepithelial cells of the anoxia-tolerant goldfish (Carassius auratus)
This study provides the first physiological characterization of oxygen chemoreceptors from an anoxia-tolerant vertebrate. Neuroepithelial cells (NECs) from the gills of goldfish displayed L-type Ca2+ channels and three types of K+ channels, one of which was dependent upon intracellular Ca2+. Although membrane currents were not inhibited by hypoxia during patch-clamp recording, this study is the first to show that NECs with an undisturbed cytosol responded to hypoxia with increased intracellular Ca2+ and synaptic vesicle activity. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Zachar, P. C., Pan, W., Jonz, M. G. Tags: Research Articles Source Type: research
Influence of biases in numerical magnitude allocation on human prosocial decision making
Over the past decade neuroscientific research has attempted to probe the neurobiological underpinnings of human prosocial decision making. Such research has almost ubiquitously employed tasks such as the dictator game or similar variations (i.e., ultimatum game). Considering the explicit numerical nature of such tasks, it is surprising that the influence of numerical cognition on decision making during task performance remains unknown. While performing these tasks, participants typically tend to anchor on a 50:50 split that necessitates an explicit numerical judgement (i.e., number-pair bisection). Accordingly, we hypothes...
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Arshad, Q., Nigmatullina, Y., Siddiqui, S., Franka, M., Mediratta, S., Ramachandaran, S., Lobo, R., Malhotra, P. A., Roberts, R. E., Bronstein, A. M. Tags: Research Articles Source Type: research
Effect of M-current modulation on mammalian vestibular responses to transient head motion
In this study we used the KCNQ antagonist XE991 and the KCNQ activator retigabine in anesthetized mice to evaluate the effects of M-current modulation on peripheral vestibular responses to transient head motion. At low doses of XE991, responses were modestly enhanced, becoming larger in amplitude and shorter in latency. Higher doses of XE991 produced transient response enhancement, followed by steady-state suppression where latencies and thresholds increased and amplitudes decreased. Retigabine produced opposite effects. Auditory function was also impacted, based on results of companion auditory brain stem response testing...
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Lee, C., Holt, J. C., Jones, T. A. Tags: Research Articles Source Type: research
Anatomy and physiology of phrenic afferent neurons
Large-diameter myelinated phrenic afferents discharge in phase with diaphragm contraction, and smaller diameter fibers discharge across the respiratory cycle. In this article, we review the phrenic afferent literature and highlight areas in need of further study. We conclude that 1) activation of both myelinated and nonmyelinated phrenic sensory afferents can influence respiratory motor output on a breath-by-breath basis; 2) the relative impact of phrenic afferents substantially increases with diaphragm work and fatigue; 3) activation of phrenic afferents has a powerful impact on sympathetic motor outflow, and 4) phrenic a...
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Nair, J., Streeter, K. A., Turner, S. M. F., Sunshine, M. D., Bolser, D. C., Fox, E. J., Davenport, P. W., Fuller, D. D. Tags: Reviews Source Type: research
Diversity of molecularly defined spinal interneurons engaged in mammalian locomotor pattern generation
Mapping the expression of transcription factors in the mouse spinal cord has identified ten progenitor domains, four of which are cardinal classes of molecularly defined, ventrally located interneurons that are integrated in the locomotor circuitry. This review focuses on the properties of these interneuronal populations and their contribution to hindlimb locomotor central pattern generation. Interneuronal populations are categorized based on their excitatory or inhibitory functions and their axonal projections as predictors of their role in locomotor rhythm generation and coordination. The synaptic connectivity and functi...
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Ziskind-Conhaim, L., Hochman, S. Tags: Reviews Source Type: research
Impact of prior errors on visuomotor adaptation and savings: experimental considerations and clinical implications
The motor system retains learning from visuomotor adaptation tasks in the form of "savings" to enable faster readaptation to similar perturbations in the future. Leow et al. (J Neurophysiol 116: 1603–1614, 2016) suggest that the experience of prior errors during relearning is necessary for savings while repetition of prior actions may not be sufficient. These findings provide novel insight into factors that contribute to visuomotor adaptation and can be applied to future experimental and clinical research. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - December 1, 2017 Category: Neurology Authors: Wright, M. Tags: Neuro Forum Source Type: research
Constitutive activity of 5-HT2C receptors is present after incomplete spinal cord injury but is not modified after chronic SSRI or baclofen treatment
After spinal cord injury (SCI), reflexes become hyperexcitable, leading to debilitating muscle spasms and compromised motor function. Previous work has described adaptations in spinal systems that might underlie this hyperexcitability, including an increase in constitutively active 5-HT2C receptors in spinal motoneurons. That work, however, examined adaptations following complete transection SCI, whereas SCI in humans is usually anatomically and functionally incomplete. We therefore evaluated whether constitutive activity of 5-HT2C receptors contributes to reflex hyperexcitability in an incomplete compression model of SCI ...
Source: Journal of Neurophysiology - November 14, 2017 Category: Neurology Authors: Tysseling, V. M., Klein, D. A., Imhoff-Manuel, R., Manuel, M., Heckman, C. J., Tresch, M. C. Tags: Research Articles Source Type: research
Role of digit placement control in sensorimotor transformations for dexterous manipulation
This study was designed to understand the sensorimotor mechanisms underlying digit force-to-position modulation required for manipulation. Surprisingly, estimation of relative digit position and force-to-position modulation was accurate regardless of whether the digits were passively or actively positioned. Therefore, accurate estimation of digit position does not require an efference copy of active digit positioning, and the hypothesized advantage of active over passive movement on estimation of end-point position appears to be task and effector dependent. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - November 14, 2017 Category: Neurology Authors: Shibata, D., Santello, M. Tags: Research Articles Source Type: research
Vowel generalization and its relation to adaptation during perturbations of auditory feedback
Repeated perturbations of auditory feedback during vowel production elicit changes not only in the production of the perturbed vowel (adaptation) but also in the production of nearby vowels that were not perturbed (generalization). The finding that adaptation generalizes to other, nonperturbed vowels suggests that sensorimotor representations for vowels are not independent; instead, the goals for producing any one vowel may depend in part on the goals for other vowels. The present study investigated the dependence or independence of vowel representations by evaluating adaptation and generalization in two groups of speakers...
Source: Journal of Neurophysiology - November 14, 2017 Category: Neurology Authors: Reilly, K. J., Pettibone, C. Tags: Research Articles Source Type: research
Ventilation inhibits sympathetic action potential recruitment even during severe chemoreflex stress
This study investigated the influence of ventilation on sympathetic action potential (AP) discharge patterns during varying levels of high chemoreflex stress. In seven trained breath-hold divers (age 33 ± 12 yr), we measured muscle sympathetic nerve activity (MSNA) at baseline, during preparatory rebreathing (RBR), and during 1) functional residual capacity apnea (FRCApnea) and 2) continued RBR. Data from RBR were analyzed at matched (i.e., to FRCApnea) hemoglobin saturation (HbSat) levels (RBRMatched) or more severe levels (RBREnd). A third protocol compared alternating periods (30 s) of FRC and RBR (FRC-RBRALT). S...
Source: Journal of Neurophysiology - November 14, 2017 Category: Neurology Authors: Badrov, M. B., Barak, O. F., Mijacika, T., Shoemaker, L. N., Borrell, L. J., Lojpur, M., Drvis, I., Dujic, Z., Shoemaker, J. K. Tags: Research Articles Source Type: research
Firing rate estimation using infinite mixture models and its application to neural decoding
Neural decoding is a framework for reconstructing external stimuli from spike trains recorded by various neural recordings. Kloosterman et al. proposed a new decoding method using marked point processes (Kloosterman F, Layton SP, Chen Z, Wilson MA. J Neurophysiol 111: 217–227, 2014). This method does not require spike sorting and thereby improves decoding accuracy dramatically. In this method, they used kernel density estimation to estimate intensity functions of marked point processes. However, the use of kernel density estimation causes problems such as low decoding accuracy and high computational costs. To overcom...
Source: Journal of Neurophysiology - November 14, 2017 Category: Neurology Authors: Shibue, R., Komaki, F. Tags: Research Articles Source Type: research
The superior colliculus and the steering of saccades toward a moving visual target
Following the suggestion that a command encoding current target location feeds the oculomotor system during interceptive saccades, we tested the involvement of the deep superior colliculus (dSC). Extracellular activity of 52 saccade-related neurons was recorded in three monkeys while they generated saccades to targets that were static or moving along the preferred axis, away from (outward) or toward (inward) a fixated target with a constant speed (20°/s). Vertical and horizontal motions were tested when possible. Movement field (MF) parameters (boundaries, preferred vector, and firing rate) were estimated after spline ...
Source: Journal of Neurophysiology - November 9, 2017 Category: Neurology Authors: Goffart, L., Cecala, A. L., Gandhi, N. J. Tags: Research Articles Source Type: research
Surface electrodes record and label brain neurons in insects
We used suction electrodes to reliably record the activity of identified ascending auditory interneurons from the anterior surface of the brain in crickets. Electrodes were gently attached to the sheath covering the projection area of the ascending interneurons and the ringlike auditory neuropil in the protocerebrum. The specificity and selectivity of the recordings were determined by the precise electrode location, which could easily be changed without causing damage to the tissue. Different nonauditory fibers were recorded at other spots of the brain surface; stable recordings lasted for several hours. The same electrode...
Source: Journal of Neurophysiology - November 9, 2017 Category: Neurology Authors: Kostarakos, K., Hedwig, B. Tags: Research Articles Source Type: research
