Neuronal Properties (neuronal + property)

Distribution by Scientific Domains


Selected Abstracts


Mapping responses to frequency sweeps and tones in the inferior colliculus of house mice

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2003
Steffen R. Hage
Abstract In auditory maps of the primary auditory cortex, neural response properties are arranged in a systematic way over the cortical surface. As in the visual system, such maps may play a critical role in the representation of sounds for perception and cognition. By recording from single neurons in the central nucleus of the inferior colliculus (ICC) of the mouse, we present the first evidence for spatial organizations of parameters of frequency sweeps (sweep speed, upward/downward sweep direction) and of whole-field tone response patterns together with a map of frequency tuning curve shape. The maps of sweep speed, tone response patterns and tuning curve shape are concentrically arranged on frequency band laminae of the ICC with the representation of slow speeds, build up response types and sharp tuning mainly in the centre of a lamina, and all (including high) speeds, phasic response types and broad tuning mainly in the periphery. Representation of sweep direction shows preferences for upward sweeps medially and laterally and downward sweeps mainly centrally in the ICC (either striped or concentric map). These maps are compatible with the idea of a gradient of decreasing inhibition from the centre to the periphery of the ICC and by gradients of intrinsic neuronal properties (onset or sustained responding). The maps in the inferior colliculus compare favourably with corresponding maps in the primary auditory cortex, and we show how the maps of sweep speed and direction selectivity of the primary auditory cortex could be derived from the here-found maps of the inferior colliculus. [source]


Long-term modifications in intrinsic neuronal properties and rule learning in rats

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2003
Drorit Saar
No abstract is available for this article. [source]


The generation of rhythmic activity in dissociated cultures of rat spinal cord

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2001
Jürg Streit
Abstract Locomotion in vertebrates is controlled by central pattern generators in the spinal cord. The roles of specific network architecture and neuronal properties in rhythm generation by such spinal networks are not fully understood. We have used multisite recording from dissociated cultures of embryonic rat spinal cord grown on multielectrode arrays to investigate the patterns of spontaneous activity in randomised spinal networks. We were able to induce similar patterns of rhythmic activity in dissociated cultures as in slice cultures, although not with the same reliability and not always with the same protocols. The most reliable rhythmic activity was induced when a partial disinhibition of the network was combined with an increase in neuronal excitability, suggesting that both recurrent synaptic excitation and neuronal excitability contribute to rhythmogenesis. During rhythmic activity, bursts started at several sites and propagated in variable ways. However, the predominant propagation patterns were independent of the protocol used to induce rhythmic activity. When synaptic transmission was blocked by CNQX, APV, strychnine and bicuculline, asynchronous low-rate activity persisted at ,,50% of the electrodes and ,,70% of the sites of burst initiation. Following the bursts, the activity in the interval was transiently suppressed below the level of intrinsic activity. The degree of suppression was proportional to the amount of activity in the preceding burst. From these findings we conclude that rhythmic activity in spinal cultures is controlled by the interplay of intrinsic neuronal activity and recurrent excitation in neuronal networks without the need for a specific architecture. [source]


Chronic hypoxia-induced morphological and neurochemical changes in the carotid body

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2002
Zun-Yi Wang
Abstract The carotid body (CB) plays an important role in the control of ventilation. Type I cells in CB are considered to be the chemoreceptive element which detects the levels of PO2, PCO2, and [H+] in the arterial blood. These cells originate from the neural crest and appear to retain some neuronal properties. They are excitable and produce a number of neurochemicals. Some of these neurochemicals, such as dopamine and norepinephrine, are considered to be primarily inhibitory to CB function and others, such as adenosine triphosphate, acetylcholine, and endothelin, are thought to be primarily excitatory. Chronic hypoxia (CH) induces profound morphological as well as neurochemical changes in the CB. CH enlarges the size of CB and causes hypertrophy and mitosis of type I cells. Also, CH changes the vascular structure of CB, including inducing marked vasodilation and the growth of new blood vessels. Moreover, CH upregulates certain neurochemical systems within the CB, e.g., tyrosine hydroxylase and dopaminergic activity in type I cells. There is also evidence that CH induces neurochemical changes within the innervation of the CB, e.g., nitric oxide synthase. During CH the sensitivity of the CB chemoreceptors to hypoxia is increased but the mechanisms by which the many CH-induced structural and neurochemical changes affect the sensitivity of CB to hypoxia remains to be established. Microsc. Res. Tech. 59:168,177, 2002. © 2002 Wiley-Liss, Inc. [source]


Vibration prolongs the cortical silent period in an antagonistic muscle

MUSCLE AND NERVE, Issue 6 2009
Christian Binder MD
Abstract We tested whether the silent period, an indicator of inhibitory neuronal activity, is modulated by muscle vibration. Vibration was applied to the right extensor carpi radialis (ECR) muscle in 17 healthy subjects and, as a control experiment, to the dorsal terminal phalanges in 5 subjects. Data before vibration were compared with those during vibration. The cortical silent period (CSP) was evoked by transcranial magnetic stimuli (TMS) during voluntary wrist flexion or during voluntary wrist extension. TMS-evoked motor potentials (MEPs) of the flexor carpi radialis (FCR) muscle were recorded during muscle relaxation. The mixed nerve silent period (MNSP) was obtained by electrical stimulation of the median nerve during wrist flexion. ECR vibration induced a significant prolongation of the CSP in FCR. CSP increases induced by vibration of the dorsal terminal phalanges were significantly less pronounced. In ECR, the CSP tended to be shortened. MEPs and MNSP remained unchanged. We conclude that vibration enhances inhibitory neuronal properties in a non-vibrated antagonistic muscle, presumably at a supraspinal level. These results may be relevant for the treatment of spasticity of the upper extremity. Muscle Nerve, 2009 [source]


Serotonin 5-HT2 receptor activation induces a long-lasting amplification of spinal reflex actions in the rat

THE JOURNAL OF PHYSIOLOGY, Issue 1 2001
D. W. Machacek
1C-fibre activation induces a long-term potentiation (LTP) in the spinal flexion reflex in mammals, presumably to provide enhanced reflexive protection of damaged tissue from further injury. Descending monoaminergic pathways are thought to depress sensory input but may also amplify spinal reflexes; the mechanisms of this modulation within the spinal cord remain to be elucidated. 2We used electrical stimulation of primary afferents and recordings of motor output, in the rat lumbar spinal cord maintained in vitro, to demonstrate that serotonin is capable of inducing a long-lasting increase in reflex strength at all ages examined (postnatal days 2,12). 3Pharmacological analyses indicated an essential requirement for activation of 5-HT2C receptors while 5-HT1A/1B, 5-HT7 and 5-HT2A receptor activation was not required. In addition, primary afferent-evoked synaptic potentials recorded in a subpopulation of laminae III-VI spinal neurons were similarly facilitated by 5-HT. Thus, serotonin receptor-evoked facilitatory actions are complex, and may involve alterations in neuronal properties at both motoneuronal and pre-motoneuronal levels. 4This study provides the first demonstration of a descending transmitter producing a long-lasting amplification in reflex strength, accomplished by activating a specific serotonin receptor subtype. It is suggested that brain modulatory systems regulate reflex pathways to function within an appropriate range of sensori-motor gain, facilitating reflexes in behavioural situations requiring increased sensory responsiveness. [source]


Gene expression profiling of cranial sensory ganglia that transmit food intake stimuli

BIOFACTORS, Issue 1-4 2004
Ichiro Matsumoto
Abstract Peripheral cranial sensory nerves projecting into the oral cavity receive food intake stimuli and transmit sensory signals to the central nervous system. They are derived from four cranial sensory ganglia, trigeminal, geniculate, petrosal, and nodose ganglia, each of which contains multiple kinds of sensory neurons with different cell morphologies and neuronal properties. We investigated the complex properties of these neurons from the viewpoint of gene expression using DNA microarrays. The 498 genes were selected from a total of 8,740 genes as showing tissue-dependent expression on the microarray by hierarchical cluster analysis, in which several genes known to be differentially expressed in cranial sensory ganglia are included. This suggests that DNA microarray cluster analysis revealed a number of characteristic genes for sensory neurons in these ganglia. Among the selected 498 genes, 44 genes are associated with neurotransmission, such as neuropeptides, their receptors, and vesicle transport, and 26 are ion channels regulating membrane potentials. The identification of a number of genes related directly to neural properties indicates that these sensory ganglia contain heterogeneous types of neurons with different neural properties. [source]


EXPRESSION OF P2X PURINOCEPTORS IN PC12 PHAEOCHROMOCYTOMA CELLS

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2007
Ji-Hu Sun
SUMMARY 1The PC12 cell line, which was cloned from a rat adrenal phaeochromocytoma, is a useful model system. It expresses neuronal properties after treatment with nerve growth factor (NGF). The nervous system-specific P2X receptor subtype P2X2 was initially cloned from PC12 cells, but little is known about the expression of other subtypes of P2X receptors in PC12 cells. The aim of the present study was to investigate whether PC12 cells express the other P2X receptors when exposed to NGF. 2Reverse transcription,polymerase chain reaction at the mRNA level and immunocytochemisty at the protein level showed that, among the seven P2X purinoceptor subtypes, only P2X2 was found to be expressed in undifferentiated PC12 phaeochromocytoma cells, but all seven P2X purinoceptor subtypes were expressed in differentiated PC12 cells treated with 50 µg/mL NGF. 3Electrophysiological recordings indicated that ATP (30 µmol/L) but not ,,,-methylene ATP (,,,-meATP; 30 µmol/L) evoked an inward current in undifferentiated PC12 cells, but both ,,,-meATP and ATP evoked inward currents in differentiated PC12 cells. The results indicate that the NGF-induced P2X receptors expressed in PC12 cells are functional channels. 4The present study suggests that the NGF-induced neuronal phenotype of PC12 cells may be a model for the study of P2X heteromeric receptors. [source]