The review surveys various aspects of the plasticity of nerve fibres, in particular the prolonged increase in their excitability evoked by polarization, focusing on a long-lasting increase in the excitability of myelinated afferent fibres traversing the dorsal columns of the spinal cord. We review the evidence that increased axonal excitability (i) follows epidurally applied direct current as well

Reaching movements performed from a crouched body posture require a shift of body weight from both arms to one arm. This situation has remained unexamined despite the analogous load requirements during step initiation and the many studies of reaching from a seated or standing posture. To determine whether the body weight shift involves anticipatory or exclusively reactive control we obtained force

Predominant expression of leak-type K+ channels provides astrocytes a high membrane permeability to K+ ions and a hyperpolarized membrane potential that are crucial for astrocyte function in brain homeostasis. In functionally mature astrocytes, the expression of leak K+ channels creates a unique membrane K+ conductance that lacks voltage-dependent rectification. Accordingly, the conductance is named

Motor skill learning involves improvement in feedforward control, the ability to execute a motor plan more reliably, and feedback control, the ability to adjust the motor plan on the fly. The dependence between these control components and the association between training conditions and their improvement have not been directly examined. This study characterizes the contribution of feedforward and feedback

Besides providing information on elementary properties of objects-like texture, roughness, and softness-the sense of touch is also important in building a representation of object movement, and the movement of our hands. Neural and behavioral studies shed light on the mechanisms and limits of our sense of touch in the perception of texture and motion, and of its role in the control of movement of our

During active object manipulation, the finger-object interactions give rise to complex fingertip skin deformations. These deformations are in turn encoded by the local tactile afferents and provide rich and behaviorally relevant information to the central nervous system. Most of the work studying the mechanical response of the finger to dynamic loading has been performed under a passive setup, thereby

Repeated short episodes of hypoxia produces a sustained increase in phrenic nerve output lasting well beyond AIH exposure (i.e., phrenic long term facilitation, pLTF). Pretreatment with ampakines, drugs which allosterically modulate AMPA receptors, enables a single brief episode of hypoxia to produce pLTF, lasting up to 90 min after hypoxia. Here we tested the hypothesis that ampakine pretreatment

Rett Syndrome (RTT) is a neurodevelopmental disorder characterized a spectrum of phenotypes affecting neuronal and glial populations. Recent work by Dong et al., 2020 suggests that augmented GABA uptake by astrocytes diminishes tonic inhibition in the hippocampus and contributes to increased seizure propensity in RTT. Here, I will review evidence supporting this possibility and critically evaluate

With effects of ageing, voluntary neural drive to the muscle, measured as motor unit (MU) firing rates, are lower in older adults during sustained isometric contractions as compared to young, but differences remain unknown during limb movements. Therefore, our purpose was to compare MU firing rates during both isometric and shortening contractions between two adult age groups. We analyzed intramuscular

During the non-invasive evaluation phase for refractory epilepsy, the localization of the epileptogenic zone (EZ) is essential for the surgical protocols. Confirmation of laterality is required when the preoperative evaluation limits the EZ into bilateral anterior temporal lobes or bilateral frontal lobes. High frequency oscillations (HFOs) are considered to be promising biological markers for the

Following vibration, Hoffmann reflex (H-reflex) amplitude is depressed; however, the mechanisms underlying these phenomena remain unknown. This study investigated the influence of frequency and duration of vibration on the H-reflex amplitude, heteronymous facilitation of the tendon jerk (T-wave) mediated by group Ia afferents, and cervicomedullary motor evoked potential (CMEP) amplitude in 18 healthy

Choline is an essential nutrient that is being explored as a nutritional treatment for many neurological disorders. Indeed, choline has already moved to being used in clinical trials for Fetal Alcohol Spectrum Disorders (FASD), and there is increased pressure to better understand its therapeutic mechanism(s) of action. This is particularly true given its potential to directly effect synaptic mechanisms

Echolocating big brown bats (Eptesicus fuscus) perceive their surroundings by broadcasting frequency-modulated (FM) ultrasonic pulses and processing returning echoes. Bats echolocate in acoustically-cluttered environments containing multiple objects, where each broadcast is followed by multiple echoes at varying time delays. The bat must decipher this complex echo cascade in order to form a coherent

Although the connection between heat shock protein 70 (HSP70) and vestibular migraine is not clear, HSP70 is neuroprotective in other scenarios. This study aimed to investigate the potential of exogenous HSP70 for treating migraine-like symptoms in a mouse model of nitroglycerin (NTG) induced migraine. HSP70 levels were assessed in patients with vestibular migraine and healthy individuals by ELISA

The electroencephalogram (EEG) provides an objective, neural correlate of consciousness. Opioid receptors modulate mammalian neuronal excitability, and this fact was used to characterize how opioids administered to mice alter EEG power and states of consciousness. The present study tested the hypothesis that antinociceptive doses of fentanyl, morphine, or buprenorphine differentially alter the EEG

The central medial (CMT) and paraventricular (PVT) thalamic nuclei project strongly to the basolateral amygdala (BL). Similarities between the responsiveness of CMT, PVT, and BL neurons suggest that these nuclei strongly influence BL activity. Supporting this possibility, an electron microscopic study reported that in contrast with other extrinsic afferents, CMT and PVT axon terminals form very few

This study explored the role of the p38 mitogen-activated protein kinase (MAPK) signaling pathway in hippocampal neuron autophagy in rats with chronic intermittent hypoxia (CIH). Sixty-four male Sprague-Dawley rats were randomly divided to normoxic control (CON), CIH (subdivided into groups A, B, and C undergoing intermittent hypoxia for 2, 4, and 6 weeks, respectively), solvent (CIH+Veh), or p38MAPK

Postural instability marks one of the most disabling features of Parkinson's disease (PD), but only reveals itself after affected brain areas have already been significantly damaged. Thus, there is a need to detect deviations in balance and postural control before visible symptoms occur. In this study, we visually perturbed balance in the anterior-posterior direction using sinusoidal oscillations of

Huntington's disease (HD) is a fatal, hereditary neurodegenerative disorder that predominantly affects striatal medium-sized spiny neurons and cortical pyramidal neurons (CPNs). It has been proposed that perturbations in Ca2+ homeostasis could play a role in CPN alterations. To test this hypothesis, we used the R6/2 mouse model of juvenile HD at different stages of disease progression; presymptomatic

Frontal-midline theta (FMT) oscillations are increased in amplitude during cognitive control tasks. Since these tasks often conflate cognitive control and cognitive effort, it remains unknown if FMT amplitude maps onto cognitive control or effort. To address this gap, we utilized the glucose facilitation effect to manipulate cognitive effort without changing cognitive control demands. We performed

Blast-induced hearing difficulties affect thousands of veterans and civilians. The long-term impact of even a mild blast exposure on the central auditory system is hypothesized to contribute to lasting behavioral complaints associated with mild blast traumatic brain injury (bTBI). Although recovery from mild blast has been studied separately over brief or long time windows, few, if any, studies have

How does the brain coordinate concurrent adaptation of arm movements and standing posture? From previous studies, the postural control system can use information about previously adapted arm movement dynamics to plan appropriate postural control; however, it is unclear whether postural control can be adapted and controlled independently of arm control. The present study addresses that question. Subjects

A considerable amount of energy is expended following presynaptic activity to regenerate electrical polarization and maintain efficient release and recycling of neurotransmitter. Mitochondria are the major suppliers of neuronal energy, generating ATP via oxidative phosphorylation. However, the specific utilization of energy from cytosolic glycolysis rather than mitochondrial respiration at the presynaptic

Animal studies have shown that high-frequency electrical stimulation (HFS) of peripheral C-fiber nociceptors induces both homo- and heterosynaptic long-term potentiation (LTP) within spinal nociceptive pathways. In humans, when HFS is applied onto the skin to activate nociceptors, single electrical stimuli are perceived more intense at the HFS site compared to a control site, a finding that was interpreted

Diplopia (double vision) in strabismus is prevented by suppression of the image emanating from one eye. In a recent study conducted in two macaques raised with exotropia (an outwards ocular deviation), simultaneous display of stimuli to each eye did not induce suppression in V1 neurons. Puzzled by this negative result, we have modified our protocol to display stimuli in a staggered sequence, rather

The prepositus hypoglossi nucleus (PHN) and the interstitial nucleus of Cajal (INC) are oculomotor neural integrators involved in the control of horizontal and vertical gaze, respectively. We previously reported that local application of adenosine 5'-trisphosphate (ATP) to PHN neurons induced P2X receptor-mediated fast inward currents, P2Y receptor-mediated slow inward currents, and/or adenosine P1

Analysis of electrophysiological data from Purkinje cells (P-cells) of the cerebellum presents unique challenges to spike sorting. Complex spikes have waveforms that vary significantly from one event to the next, raising the problem of misidentification. Even when complex spikes are detected correctly, the simple spikes may belong to a different P-cell, raising the danger of misattribution. To address

Motorized assessment of the stretch reflex is instrumental to gain understanding of the stretch reflex, its physiological origin and to differentiate effects of neurological disorders, like spasticity. Both short-latency (M1) and medium-latency (M2) stretch reflexes have been reported to depend on the velocity and acceleration of an applied ramp-and-hold perturbation. In the upper limb, M2 has also

Electrical spinal cord stimulation enables paraplegic patients to regain voluntary leg movement. This treatment was only intended to engage local spinal networks to facilitate basic standing and postural stabilization without supraspinal input. Therefore the mechanism(s) enabling voluntary movement are unknown. Here we developed the first conditioned behavioral paradigm in rats for studying the recovery

Journal of Neurophysiology, Ahead of Print.

The general anesthetic etomidate, which acts through GABAA receptors, impairs the formation of new memories under anesthesia. This study addresses the molecular and cellular mechanisms by which this occurs. Here, using a new line of genetically engineered mice carrying the GABAAR β2-N265M mutation, we tested the roles of receptors that incorporate GABAA receptor β2 vs. β3 subunits to suppression of

The cause for the increased sensitivity of fibromyalgia (FM) patients to painful stimuli is unclear but sensitization of dorsal horn spinal cord neurons has been suggested. There, critical changes of sensory information occur which depend on the plasticity of second-order neurons and descending pain modulation, including facilitation and inhibition. This study used repetitive stimuli that produce

Presympathetic neurons in the paraventricular nucleus of the hypothalamus (PVN) play a key role in cardiovascular regulation. We have previously shown that brain-derived neurotrophic factor (BDNF), acting in the PVN, increases sympathetic activity and blood pressure and serves as a key regulator of stress-induced hypertensive responses. BDNF is known to alter glutamatergic and GABA-ergic signaling

Non-sinusoidal waveform is emerging as an important feature of neuronal oscillations. However, the role of single cycle shape dynamics in rapidly unfolding brain activity remains unclear. Here, we develop an analytical framework that isolates oscillatory signals from time-series using masked Empirical Mode Decomposition to quantify dynamical changes in the shape of individual cycles (along with amplitude

A previous study using traditional paired-pulse TMS methods (amplitude-tracking) has reported differences in resting motor threshold (RMT) and short-interval intracortical inhibition (SICI) between healthy subjects of Caucasian and Han Chinese backgrounds, probably due to differences in the skull shape. The amplitude-tracking method delivers stimuli with constant intensity, and causes substantial variabilities

Parkinsonian motor deficits are associated with elevated inhibitory output from the basal ganglia (BG). However, several features of Parkinson's disease (PD) have not been accounted for by this simple "classical rate model" framework, including the observation in PD patients that movements guided by external stimuli are less impaired than otherwise-identical movements generated based on internal goals

Journal of Neurophysiology, Volume 126, Issue 2, Page 707-707, August 2021.

Supraspinal signals play a significant role in compensatory responses to postural perturbations. While the cortex is not necessary for basic postural tasks in intact animals, its role in responding to unexpected postural perturbations after spinal cord injury (SCI) has not been studied. To better understand how SCI impacts cortical encoding of postural perturbations, the activity of single neurons

The neural processing of others' observed actions recruits a large network of brain regions (the action observation network, AON), in which frontal motor areas are thought to play a crucial role. Since the discovery of mirror neurons (MNs) in the ventral premotor cortex, it has been assumed that their activation was conditional upon the presentation of biological rather than nonbiological motion stimuli

It has been suggested that sensorimotor adaptation involves at least two processes (i.e., fast and slow) that differ in retention and error sensitivity. Previous work has shown that repeated exposure to an abrupt force field perturbation results in greater error sensitivity for both the fast and slow processes. While this implies that the faster relearning is associated with increased error sensitivity

The wide diversity of inhibitory cells across the brain makes them suitable to contribute to network dynamics in specialized fashions. However, the contributions of a particular inhibitory cell type in a behaving animal are challenging to untangle as one needs to both record cellular activities and identify the cell type being recorded. Thus, using computational modeling and theory to predict and hypothesize

Space coding affects perception of stimuli associated to negative valence: threatening stimuli presented within the peripersonal space (PPS) speed up behavioral responses compared to non-threatening events. However, it remains unclear whether the association between stimuli and their negative valence is acquired in a body-part centered reference system, a main feature of the PPS coding. Here we test

The connectivity among architectonically defined areas of the frontal, parietal, and temporal cortex of the macaque has been extensively mapped through tract tracing methods. To investigate the statistical organization underlying this connectivity, and identify its underlying architecture, we performed a hierarchical cluster analysis on 69 cortical areas based on their anatomically defined inputs.

The climbing fiber input to the cerebellum conveys instructive signals that can induce synaptic plasticity and learning by triggering complex spikes accompanied by large calcium transients in Purkinje cells. In the cerebellar flocculus, which supports oculomotor learning, complex spikes are driven by image motion on the retina, which could indicate an oculomotor error. In the same neurons, complex

The ability to adjust movements to changes in the environment declines with aging. This age-related decline is caused by the decline of explicit adjustments. However, implicit adaptation remains intact and might even be increased with aging. Since proprioceptive information has been linked to implicit adaptation, it might well be that an age-related decline in proprioceptive acuity might be linked

Oculomotor target selection often requires discriminating visual features, but it remains unclear how oculomotor substrates encoding saccade vectors functionally contribute to this process. One possibility is that oculomotor vector representations (observed directly as physiological activation or inferred from behavioral interference) of potential targets are continuously re-weighted by task-relevance

Action potential waveforms generated at the axon initial segment (AIS) are specialized between and within neuronal classes. But is the fine structure of each electrical event retained when transmitted along myelinated axons or is it rapidly and uniformly transmitted to be modified again at the axon terminal? To address this issue action potential axonal transmission was evaluated in a class of primary

Cerebellar Purkinje neurons help compute absolute subsecond timing, but how their firing is affected during repetitive sensory stimulation with consistent subsecond intervals remains unaddressed. Here, we investigated how simple and complex spikes of Purkinje cells change during regular application of air puffs (3.3 Hz for ~4 min) to the whisker pad of awake, head-fixed female mice. Complex spike responses

Understanding the neural correlates of risk-sensitive skin conductance responses can provide insights into their connection to emotional and cognitive processes. To provide insights into this connection, we studied the cortical correlates of risk-sensitive skin conductance peaks using electroencephalography. Fluctuations in skin conductance responses were elicited while participants played a threa

Accurate perception of gravity and translation is fundamental for balance, navigation, motor control, etc.. Previous studies have reported that perceptual thresholds for earth-vertical (i.e. parallel to gravity) and earth-horizontal (i.e. perpendicular to gravity) translations are equivalent in healthy adults, suggesting that the nervous system compensates for the presence of gravity. However, past

Small fiber neuropathy (SFN) is a common condition affecting thinly myelinated Aδ and unmyelinated C fibers, often resulting in excruciating pain and dysautonomia. SFN has been associated with several conditions, but a significant number of cases have no discernible cause. Recent genetic studies have identified potentially pathogenic gain-of-function mutations in several the pore-forming voltage-gated

Limb dominance is evident in many daily activities leading to the prominent idea that each hemisphere of the brain specializes in controlling different aspects of movement. Past studies suggest the dominant arm is primarily controlled via an internal model of limb dynamics that enables the nervous system to produce efficient movements. In contrast, the non-dominant arm may be primarily controlled via

When reaching for an object with the hand, the gaze is usually directed at the target. In a laboratory setting, fixation is strongly maintained at the reach target until the reaching is completed, a phenomenon known as "gaze-anchoring". While conventional accounts of such tight eye-hand coordination have often emphasized the internal synergetic linkage between both motor systems, more recent optimal

The present study measured scalp potentials in response to low-frequency, narrowband noise bursts changing location in the front, azimuthal plane. At question was whether selective auditory attention has a modulatory effect on the cortical encoding of spatial change, and whether older listeners with normal-hearing thresholds would show depressed cortical representation for spatial changes relative

Intrapleural injection of cholera toxin B conjugated to saporin (CTB-SAP) mimics respiratory motor neuron death and respiratory deficits observed in rat models of neuromuscular diseases. 7d CTB-SAP rats elicit enhanced phrenic long-term facilitation (pLTF) primarily through TrkB and PI3K/Akt-dependent mechanisms (i.e., Gs-pathway, which can be initiated by adenosine 2A (A2A) receptors in naïve rats)

The technique of multi-fiber muscle velocity recovery cycle recordings was developed as a diagnostic tool to assess muscle membrane potential changes and ion channel function in vivo. This study was undertaken to assess the impact of intermittent high frequency stimulation on muscle velocity recovery cycle components, and to study whether the changes can be modified by endurance training. We recorded

Journal of Neurophysiology, Volume 126, Issue 1, Page 349-349, July 2021.

Synaptic and extrasynaptic GABAA receptor (GABAAR)-mediated neurotransmission is a critical component of the suprachiasmatic nucleus (SCN) neuronal network. However, the properties of the GABAA tonic current (Itonic) and its origin remain unexplored. Spontaneous GABAA postsynaptic currents (sGPSC) and Itonic were recorded from SCN neurons using the whole-cell voltage-clamp technique at different times

During a smooth pursuit eye movement of a target stimulus, a briefly flashed stationary background appears to move in the opposite direction as the eye's motion ― an effect known as the Filehne illusion. Similar illusions occur in audition, in the vestibular system, and in touch. Recently, we found that the movement of a surface perceived from tactile slip was biased if this surface was sensed with

Activation of renal sensory nerves by chemo- and mechano-sensitive stimuli produces changes in efferent sympathetic nerve activity (SNA) and arterial blood pressure (ABP). Anesthesia and sex influence autonomic function and cardiovascular hemodynamics, but it is unclear to what extent anesthesia and sex impact SNA and ABP responses to renal sensory stimuli. We measured renal, splanchnic, and lumbar