Search results for "Potentials"

Identification of Synaptic Integration Mode in CA3 Pyramidal Neuron Model

2019

International audience; A morphologically realistic and anisotropic model of CA3 pyramidal neuron was developed to determine the synaptic integration modes the neuron is able to perform. Linearity and nonlinearity were identified in different synaptic locations with varying active mechanisms such as the presence of ionic channels in the dendritic arbor and the types of receptors in the synapse. Quantification of synaptic integration was performed using paired-pulse stimulation protocol and subthreshold input/output (sI/O) transformation. Results show that the mode of synaptic integration is location-dependent while the linearity or nonlinearity in the integration is mainly influenced by the…

Putative excitatory and putative inhibitory inputs are localised in different dendritic domains in aDrosophilaflight motoneuron

2012

Input-output computations of individual neurons may be affected by the three-dimensional structure of their dendrites and by the targeting of input synapses to specific parts of their dendrites. However, only few examples exist where dendritic architecture can be related to behaviorally relevant computations of a neuron. By combining genetic, immunohistochemical, and confocal laser scanning methods this study estimates the location of the spike initiating zone and the dendritic distribution patterns of putative synaptic inputs on an individually identified Drosophila flight motorneuron, MN5. MN5 is a monopolar neuron with more than 4000 dendritic branches. The site of spike initiation was e…

Behavioral and hippocampal evoked responses in an auditory oddball situation when an unconditioned stimulus is paired with deviant tones in the cat: …

1995

Event-related potentials (ERP) in the areas CA1, CA3 and dentate fascia (Df) of the hippocampal formation were recorded during an oddball situation in the cat. A rewarding electrical stimulation of the lateral hypothalamus (US) was paired with deviant tones (2500 Hz) that occurred randomly in a series of the standard tones (2000 Hz) given to the left ear. In addition to developing orienting head movements to the side of the deviant tones, an increase in the amplitude of parallel hippocampal ERPs was observed. Both the behavioral and neural responses appeared not until a 50 ms latency range. Furthermore, time-amplitude characteristics of the ERPs corresponded to time-acceleration characteris…

Dissecting task-specific plasticity capacity in patients with multiple sclerosis with transcranial magnetic stimulation.

2020

Electrophysiological brain stem investigations in idiopathic narcolepsy.

1998

Narcolepsy is associated with various rapid eye movement (REM) sleep abnormalities. Distinct brain stem areas seem to play a prominent role in REM sleep regulation. Recent magnetic resonance imaging (MRI) studies have led to conflicting findings concerning the presence of structural brain stem lesions in patients with idiopathic narcoleptic syndrome. However, multimodal electrophysiological brain stem investigations may reveal functional brain stem abnormalities even in the absence of MRI abnormality. Therefore we investigated brain stem function in 12 idiopathic narcoleptic patients by systematically studying tegmental brain stem pathways. All of the patients met the diagnostic criteria of…

The effect of experimental and clinical musculoskeletal pain on spinal and supraspinal projections to motoneurons and motor unit properties in humans…

2021

Background and Objective Numerous studies have examined the influence of pain on spinal reflex excitability, motor unit behaviour and corticospinal excitability. Nevertheless, there are inconsistencies in the conclusions made. This systematic review sought to understand the effect of pain on spinal and supraspinal projections to motoneurons and motor unit properties by examining the influence of clinical or experimental pain on the following three domains: H-reflex, corticospinal excitability and motor unit properties. Databases and Data Treatment MeSH terms and preselected keywords relating to the H-reflex, motor evoked potentials and motor unit decomposition in chronic and experimental pa…

New fast mismatch negativity paradigm for determining the neural prerequisites for musical ability.

2011

Studies have consistently shown that the mismatch negativity (MMN) for different auditory features correlates with musical skills, and that this effect is more pronounced for stimuli integrated in complex musical contexts. Hence, the MMN can potentially be used for determining the development of auditory skills and musical expertise. MMN paradigms, however, are typically very long in duration, and far from sounding musical. Therefore, we developed a novel multi-feature MMN paradigm with 6 different deviant types integrated in a complex musical context of no more than 20 min in duration. We found significant MMNs for all 6 deviant types. Hence, this short objective measure can putatively be …

Informal musical activities are linked to auditory discrimination and attention in 2-3-year-old children: an event-related potential study

2012

The relation between informal musical activities at home and electrophysiological indices of neural auditory change detection was investigated in 2-3-year-old children. Auditory event-related potentials were recorded in a multi-feature paradigm that included frequency, duration, intensity, direction, gap deviants and attention-catching novel sounds. Correlations were calculated between these responses and the amount of musical activity at home (i.e. musical play by the child and parental singing) reported by the parents. A higher overall amount of informal musical activity was associated with larger P3as elicited by the gap and duration deviants, and smaller late discriminative negativity r…

Dendritic Ih selectively blocks temporal summation of unsynchronized distal inputs in CA1 pyramidal neurons.

2004

The active dendritic conductances shape the input-output properties of many principal neurons in different brain regions, and the various ways in which they regulate neuronal excitability need to be investigated to better understand their functional consequences. Using a realistic model of a hippocampal CA1 pyramidal neuron, we show a major role for the hyperpolarization-activated current, I-h, in regulating the spike probability of a neuron when independent synaptic inputs are activated with different degrees of synchronization and at different distances from the soma. The results allowed us to make the experimentally testable prediction that the I-h in these neurons is needed to reduce ne…

Relaxant effects of flavonoids on the mouse isolated stomach: structure-activity relationships.

2008

Flavonoids are a large heterogeneous group of benzo-gamma-pyrone derivatives, which are abundantly present in our diet. In this study we investigated the effects of six flavonoids (apigenin, genistein, quercetin, rutin, naringenin and catechin) on the gastric tone in mouse isolated stomach. The mechanical activity was recorded as changes of intraluminal pressure. All flavonoids tested produced a concentration-dependent relaxation, which was reversible after washout. The relative order of potency of the flavonoids was apigenin> or =genistein>quercetin>naringenin> or =rutin>catechin. Analysis of the chemical structure showed that the relaxant activity was progressively diminished by the prese…