Abstract:
:Previous research has described kinetic characteristics of treadmill steps in very stable steppers, in cross-sectional designs. In this study we examined, longitudinally, muscle activation patterns during treadmill stepping, without practice, in 12 healthy infants at 1, 6, and 12 mo of age. We assessed lateral gastrocnemius, tibialis anterior, rectus femoris, and biceps femoris as infants stepped on a treadmill during twelve 20-s trials. Infants showed clear changes in kinematics, such as increased step frequency, increased heel contact at touch down, and more flat-footed contact at midstance. Electromyographic data showed high variability in muscle states (combinations), with high prevalence of all muscles active initially, reducing with age. Agonist-antagonist muscle coactivation also decreased as age increased. Probability analyses showed that across step cycles, the likelihood a muscle was on at any point tended to be <50%; lateral gastrocnemius was the exception, showing an adultlike pattern of probability across ages. In summary, over time, healthy infants produce a wide variety of muscle activation combinations and timings when generating stepping patterns on a treadmill, even if some levels of muscle control arose with time. However, the kinematic stability improved much more clearly than the underlying kinetic strategies. We conclude that although innate control of limb movement improves as infants grow, explore, and acquire functional movement, stepping on a treadmill is a novel and unpracticed one. Hence, developing stable underlying neural activations will only arise as functional practice ensues, similarly to that observed for other functional movements in infancy.
journal_name
J Neurophysioljournal_title
Journal of neurophysiologyauthors
Teulier C,Sansom JK,Muraszko K,Ulrich BDdoi
10.1152/jn.01037.2011subject
Has Abstractpub_date
2012-08-01 00:00:00pages
853-62issue
3eissn
0022-3077issn
1522-1598pii
jn.01037.2011journal_volume
108pub_type
杂志文章abstract::We constantly make eye movements to bring objects of interest onto the fovea for more detailed processing. Activity in area V4, a prestriate visual area, is enhanced at the location corresponding to the target of an eye movement. However, the precise role of activity in V4 in relation to these saccades and the modulat...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00898.2009
更新日期:2010-10-01 00:00:00
abstract::Nitric oxide (NO) has been recognized as an atypical neuronal messenger affecting synaptic transmission, but its cellular source has remained unresolved as the neuronal NO synthase isoform (nNOS) in brain areas such as the neocortex is expressed only by a small subset of inhibitory neurons. The involvement of the glia...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00676.2009
更新日期:2010-03-01 00:00:00
abstract::The extracellular pH of living tissue in the retina and elsewhere in the brain is lower than the pH of the surrounding milieu. We have shown that the pH gradient between the in vitro retina and the superfusion solution is regulated by a circadian (24-h) clock so that it is smaller in the subjective day than in the sub...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00881.2003
更新日期:2004-06-01 00:00:00
abstract::Current and voltage-clamp recordings were made at room temperature from cultured mouse spinal neurons using conventional two-electrode voltage-clamp techniques and electrodes filled with either 3 M KCl, 3 M CsCl, or 3 M Cs2SO4. In the presence of tetraethylammonium and tetrodotoxin, "fast" (rapidly rising and falling)...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1986.55.6.1115
更新日期:1986-06-01 00:00:00
abstract::The motor pathway responsible for the complex vocalizations of songbirds has been extensively characterized, both in terms of intrinsic and synaptic physiology in vitro and in terms of the spatiotemporal patterns of neural activity in vivo. However, the relationship between the neural architecture of the song motor pa...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.01146.2003
更新日期:2004-07-01 00:00:00
abstract::An initial overload of intracellular Ca2+ plays a critical role in the delayed death of hippocampal CA1 neurons that die a few days after transient ischemia. Without direct evidence, the prevailing hypothesis has been that Ca2+ overload may recur until cell death. Here, we report the first measurements of intracellula...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1999.81.1.299
更新日期:1999-01-01 00:00:00
abstract::Depolarization-induced suppression of inhibition (DSI) is a form of retrograde signaling at GABAergic synapses that is initiated by the calcium- and depolarization-dependent release of endocannabinoids from postsynaptic neurons. In the neocortex, pyramidal neurons (PNs) appear to use DSI as a mechanism for regulating ...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00351.2004
更新日期:2004-10-01 00:00:00
abstract::Histamine is a known secretagogue in adrenal chromaffin cells. Activation of G-protein linked H(1) receptors stimulates phospholipase C, which generates inositol trisphosphate leading to release of intracellular calcium stores and stimulation of calcium influx through store operated and other channels. This calcium le...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.2000.83.3.1435
更新日期:2000-03-01 00:00:00
abstract::Glycinergic and GABAergic inhibition are juxtaposed at one retinal synaptic layer yet likely perform different functions. These functions have usually been evaluated using receptor antagonists. In examining retinal glycine receptors, we were surprised to find that commonly used concentrations of GABA antagonists block...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.01228.2004
更新日期:2005-06-01 00:00:00
abstract::Particular types of amacrine cells of the vertebrate retina show oscillatory membrane potentials (OMPs) in response to light stimulation. Historically it has been thought the oscillations arose as a result of circuit properties. In a previous study we found that in some amacrine cells, the ability to oscillate was an ...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00092.2003
更新日期:2003-07-01 00:00:00
abstract::The present study was undertaken to explore the neuronal mechanisms responsible for muscle atonia that occurs after the microinjection of bicuculline into the nucleus pontis oralis (NPO). Specifically, we wished to test the hypothesis that motoneurons are postsynaptically inhibited after the microinjection of bicucull...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.2001.86.4.1908
更新日期:2001-10-01 00:00:00
abstract::1. We examined the role of gamma-aminobutyric acid (GABA)-mediated inhibition in shaping excitatory tuning curves and creating selectivity for frequency-modulated (FM) sweeps in 29 neurons in the central nucleus of the inferior colliculus (ICC) of the pallid bat, with the use of single-unit recording coupled with the ...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1996.76.2.1059
更新日期:1996-08-01 00:00:00
abstract::1. The modulation of the voltage-activated Ca2+ current by the neuropeptide Phe-Met-Arg-Phe-NH2 (FMRFa) was investigated in dissociated central neurons from Helix aspersa using whole-cell voltage-clamp recording techniques. External Ba2+ was always used as the charge carrier in this study, and the intracellular Ca2+ c...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1991.65.6.1517
更新日期:1991-06-01 00:00:00
abstract::There is a great need to develop new approaches for rehabilitation of the upper limb after stroke. Robotic therapy is a promising form of neurorehabilitation that can be delivered in higher doses than conventional therapy. Here we sought to determine whether the reported effects of robotic therapy, which have been bas...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00336.2015
更新日期:2015-09-01 00:00:00
abstract::1. The responses of a total of 70 single neurons were recorded from the parabrachial nuclei (PBN) in awake rats. In 59 neurons, sapid stimuli (0.5 ml) elicited significant taste responses. Of these 59 neurons, 10 also had significant responses to water. The mean spontaneous rate of the taste neurons was 13.4 +/- 6.9 (...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1990.63.4.707
更新日期:1990-04-01 00:00:00
abstract::To investigate the specificity of fusimotor (gamma) drive during locomotion, gamma-efferents were recorded from the flexor digitorum longus (FDL) and flexor hallucis longus (FHL) nerves in a decerebrate cat preparation. These nerves innervate hindlimb muscles that differ in some aspects of their mechanical action. For...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00917.2000
更新日期:2002-01-01 00:00:00
abstract::Skeletal muscle force can be transmitted to the skeleton, not only via its tendons of origin and insertion but also through connective tissues linking the muscle belly to surrounding structures. Through such epimuscular myofascial connections, length changes of a muscle may cause length changes within an adjacent musc...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00937.2015
更新日期:2016-06-01 00:00:00
abstract::The receptive field organization of nociceptive neurons suggests that noxious information may be encoded by population-based mechanisms. Electrophysiological evidence of population coding mechanisms has remained limited. However, psychophysical studies examining interactions between multiple noxious stimuli can provid...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.91350.2008
更新日期:2009-12-01 00:00:00
abstract::Humans with spinal cord injury (SCI) modulate locomotor output in response to limb load. Understanding the neural control mechanisms responsible for locomotor adaptation could provide a framework for selecting effective interventions. We quantified feedback and feedforward locomotor adaptations to limb load modulation...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00604.2009
更新日期:2010-09-01 00:00:00
abstract::The century-old duplex theory of sound localization posits that low- and high-frequency sounds are localized with two different acoustical cues, interaural time and level differences (ITDs and ILDs), respectively. While behavioral studies in humans and behavioral and neurophysiological studies in a variety of animal m...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00062.2015
更新日期:2015-07-01 00:00:00
abstract::1. Semicircular-canal afferents in the squirrel monkey were characterized by their resting discharge, discharge regularity, sensitivity to galvanic currents delivered to the ear (beta *), the gain (g2Hz), and phase lead (phi 2Hz) of their response to 2-Hz sinusoidal head rotations, and their antidromic conduction velo...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1995.73.3.1270
更新日期:1995-03-01 00:00:00
abstract::Ion channel modulation by the peptide myomodulin (MM) has been demonstrated in a wide variety of organisms including Aplysia, Lymnaea, and Pleurobranchaea. This neural and muscular modulation has been shown to be important for shaping and modifying behavior. In this paper, we report that MM modulates several distinct ...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1999.82.1.216
更新日期:1999-07-01 00:00:00
abstract::We studied the responses of neurons in the inferior colliculus (IC) of cats to stimuli known to evoke the precedence effect (PE). This paper focuses on stimulus conditions that probe the neural mechanisms underlying the PE but that are not usually encountered in a natural situation. Experiments were conducted under bo...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1998.80.3.1302
更新日期:1998-09-01 00:00:00
abstract::The structural features of a synaptic connection between central neurons play an important role in determining the strength of the connection. In the present study, we have examined the relationship between the structural and functional properties of glycinergic synapses in the rat spinal cord. We have analyzed the st...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1999.82.1.312
更新日期:1999-07-01 00:00:00
abstract::The general objectives of our research, presented in this series of papers, were to develop a computational model of the brain stem respiratory neural network and to explore possible neural mechanisms that provide the genesis of respiratory oscillations and the specific firing patterns of respiratory neurons. The pres...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1997.77.4.1994
更新日期:1997-04-01 00:00:00
abstract::The human auditory system has an exceptional ability to separate competing sounds, but the neural mechanisms that underlie this ability are not understood. Responses of inferior colliculus (IC) neurons to "mistuned" complex tones were measured to investigate possible neural mechanisms for spectral segregation. A mistu...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.01194.2004
更新日期:2005-11-01 00:00:00
abstract::Neural correlates of gap detection in three auditory cortical fields in the cat. Mimimum detectable gaps in noise in humans are independent of the position of the gap, whereas in cat primary auditory cortex (AI) they are position dependent. The position dependence in other cortical areas is not known and may resolve t...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1999.81.5.2570
更新日期:1999-05-01 00:00:00
abstract::Prefrontal cortex (PFC) dopamine D1/5 receptors modulate long- and short-term neuronal plasticity that may contribute to cognitive functions. Synergistic to synaptic strength modulation, direct postsynaptic D1/5 receptor activation also modulates voltage-dependent ionic currents that regulate spike firing, thus alteri...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00317.2006
更新日期:2007-03-01 00:00:00
abstract::1. Mechanisms of depolarizing synaptic inhibition were investigated at the crayfish giant motor synapse with the use of two-electrode current- and voltage-clamp techniques. Depolarizing inhibitory postsynaptic potentials (d-IPSPs) of between 5 and 15 mV in amplitude are produced there in the motor giant motoneuron (Mo...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.1990.64.2.532
更新日期:1990-08-01 00:00:00
abstract::The ventromedial medulla is implicated in a variety of functions including nociceptive and cardiovascular modulation and the control of thermoregulation. To determine whether single microinjections into the ventromedial medulla elicit changes in one or multiple functional systems, the GABA(A) receptor antagonist bicuc...
journal_title:Journal of neurophysiology
pub_type: 杂志文章
doi:10.1152/jn.00089.2004
更新日期:2004-07-01 00:00:00