Search results for "POTENT"

Cl−uptake promoting depolarizing GABA actions in immature rat neocortical neurones is mediated by NKCC1

2004

GABA is the principal inhibitory neurotransmitter in the mature brain, but during early postnatal development the elevated [Cl−]i in immature neocortical neurones causes GABAA receptor activation to be depolarizing. The molecular mechanisms underlying this intracellular Cl− accumulation remain controversial. Therefore, the GABA reversal potential (EGABA) or [Cl−]i in early postnatal rat neocortical neurones was measured by the gramicidin-perforated patch-clamp method, and the relative expression levels of the cation−Cl− cotransporter mRNAs (in the same cells) were examined by semiquantitative single-cell multiplex RT-PCR to look for statistical correlations with [Cl−]i. The mRNA expression …

Vertigo and multiple sclerosis: aspects of differential diagnosis.

2002

Equilibrium disorders caused by involvement of brainstem and cerebellar structures are common in patients with multiple sclerosis (MS), but peripheral conditions such as benign paroxysmal positional vertigo (BPPV) can be sometimes confused with those of a central origin. Therefore, an accurate otoneurologic investigation paying attention to differential diagnosis aspects should be performed in these subjects. Among available diagnostic tools, electro-oculography, posturography and vestibular evoked myogenic potentials (VEMPs) are especially suited to assess vestibulo-oculomotor and vestibulospinal systems. This paper briefly describes the most recent otoneurologic diagnostic strategies for …

Study and modulation of human cortical excitability with transcranial magnetic stimulation.

1998

Transcranial magnetic stimulation (TMS) can be applied in different paradigms to obtain a measure of various aspects of cortical excitability. These different TMS paradigms provide information about different neurotransmitter systems, enhance our understanding about the pathophysiology of neuropsychiatric conditions, and in the future may be helpful as a guide for pharmacological interventions. In addition, repetitive TMS (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. These effects can be demonstrated neurophysiologically or by combining rTMS…

2001

Little is known about somatosensory evoked potentials (SEPs) from muscle stimulation compared to that from skin stimulation. The current study examined this issue in the full SEP spectrum (0 - 440 ms). The aims of the study were to (1) establish the dynamics of early to late latency SEPs from intramuscular stimulation in contrast to surface stimulation, (2) compare the effect of non-painful and painful stimuli on SEP latencies and amplitudes of the two methods, and (3) investigate to which extent these results can be shared between the median nerve innervated thenar site and ulnar nerve innervated hypothenar site. Stimuli were delivered (2 Hz) at a non-painful and a painful intensity above …

Presence of muscarinic inhibitory and absence of nicotinic excitatory receptors at the terminal sympathetic nerves of chicken hearts.

1976

Nicotine (2 X 10(-4) M) or acetylcholine (5.5 X 10(-4) M) in the presence of 3 X 10(-6) M atropine did not increase the rate or amplitude of contraction in isolated atria or ventricular strips of the chicken heart; both drugs also did not cause an output of noradrenaline or adrenaline and did not evoke antidromic discharges in the right sympathetic nerves of isolated perfused chicken hearts. In contrast, "high K+-solutions" evoked an output of noradrenaline and adrenaline and caused a burst of antidromic discharges. Dimethylphenylpiperazine (DMPP; 3.1 X 10(-4) M), by a tyramine-like action, elicited a small output of noradrenaline and increased rate and amplitude of contraction" but did not…

Advanced technologies for detecting tremor in Parkinson's disease.

2019

Objective Accurate and reliable detection of tremor onset in Parkinson’s disease (PD) is critical to the success of adaptive deep brain stimulation (aDBS) therapy. Here, we investigated the potential use of feature engineering and machine learning methods for more accurate detection of rest tremor in PD. Methods We analyzed the local field potential (LFP) recordings from the subthalamic nucleus region in 12 patients with PD (16 recordings). To explore the optimal biomarkers and the best performing classifier, the performance of state-of-the-art machine learning (ML) algorithms and various features of the subthalamic LFPs were compared. We further used a Kalman filtering technique in feature…

Neurophysiological evaluation of visual function in iRBD: potential role in stratifying RBD conversion risk.

2021

Abstract Study objectives To evaluate neurophysiological alterations of visual function in idiopathic REM sleep Behavior Disorder (iRBD) both as markers and predictors of neurodegenerative disorders. Methods In a longitudinal follow-up study of 46 consecutive iRBD patients (follow-up duration 8.4 ± 3.4 years), the baseline parameters in luminance-contrast pattern (VEPp), red-green color (VEPc) and motion-onset (VEPm) Visual Evoked Potentials in iRBD were compared to early (ePD) and advanced (aPD) Parkinson's Disease subjects. Parameters of latency and amplitude of iRBD converters to neurodegenerative disease were compared with those of the non-converters. Results The VEP P100 mean latency v…

IRS-2 deficiency impairs NMDA receptor-dependent long-term potentiation

2011

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License.-- et al.

Proton conductance of human transient receptor potential-vanilloid type-1 expressed in oocytes of Xenopus laevis and in Chinese hamster ovary cells.

2004

Transient receptor potential-vanilloid type-1 (TRPV1) is a ligand-gated cation channel with preference for divalent cations, especially Ca(2+) (sequence of conductances: Ca(2+)Mg(2+)Na(+) approximately/= K(+) approximately/= Cs(+)). In the present study, the two-electrode voltage-clamp technique was used on oocytes of Xenopus laevis expressing TRPV1 to evaluate whether human TRPV1 also conducts protons. In medium devoid of K(+), Na(+), Mg(2+), and Ca(2+), capsaicin 1 microM induced a significant inward current (62% of the current in physiological medium). The effects of capsaicin were abolished in the presence of capsazepine 3 microM. The capsaicin-induced currents in medium devoid of Na(+)…

Oxygen and glucose deprivation induces major dysfunction in the somatosensory cortex of the newborn rat

2005

The mechanisms and functional consequences of ischemia-induced injury during perinatal development are poorly understood. Subplate neurons (SPn) play a central role in early cortical development and a pathophysiological impairment of these neurons may have long-term detrimental effects on cortical function. The acute and long-term consequences of combined oxygen and glucose deprivation (OGD) were investigated in SPn and compared with OGD-induced dysfunction of immature layer V pyramidal cortical neurons (PCn) in somatosensory cortical slices from postnatal day (P)0-4 rats. OGD for 50 min followed by a 10-24-h period of normal oxygenation and glucose supply in vitro or in culture led to pron…