Significant Differences In Peak Amplitude Research Articles

The influence of cerebellum on visual selective attention in patients with multiple lacunar cerebral infarction and its neuromodulatory mechanisms.

This study aims to investigate the influence of the cerebellum on visual selective attention function and its neuromodulatory mechanism in patients with multiple lacunar cerebral infarction (MLCI). A retrospective analysis was conducted on 210 patients admitted with MLCI from January 2016 to May 2022. Analyzed the electrophysiological characteristics of the P3a and P3b components of vision in both groups, as well as source reconstruction simulations of dipole activation in the brains of the two groups, and analyzed the brain regions with differences in activation strength between the two groups. This study found that there was no significant difference in peak amplitude between the two groups, but compared with the control group, the peak latency of the case group was significantly prolonged. Specifically, the P3a peak latency induced by the novel stimulus was longer than that induced by the target stimulus P3b peak latency. Source reconstruction results showed decreased and increased activation in several brain regions in the case group compared to the control group. The study suggests that the impairment of distracted attention capture is more pronounced in patients with MLCI. The cerebellum indirectly influences the ventral and dorsal frontoparietal attention networks by modulating the levels of excitation and inhibition within the cerebral cortex of the attention network. This may represent a potential mechanism through which the cerebellum regulates visual selective attention information in MLCI patients.

КОГНІТИВНІ ПОТЕНЦІАЛИ ГОЛОВНОГО МОЗКУ ЧОЛОВІКІВ, ВИКЛИКАНІ СПРИЙНЯТТЯМ ОБЛИЧ ОСІБ РІЗНОЇ СТАТІ З РІЗНОЮ ЕМОЦІЙНОЮ МОДАЛЬНІСТЮ

The calculation of the difference in peaks of the event-related potential in men during exposure to different-sex faces with differential emotional modality using the MATLAB and EEGLAB software packages. The electrical activity of the brain of 20 male students of Taras Shevchenko Kyiv National University was recorded to identify the difference in the activation of brain structures during the demonstration of portraits of different sexes with positive and negative emotional modalities. Statistically significant differences in peak amplitude were recorded for components N250, N400, and P300 when subjects were presented with male and female portraits with a positive emotional modality, while when exposed to a series of images with a negative emotional modality, no statistical differences were registered in any of the componenStatistically significant differences in the peak amplitude were recorded for the N250, N400, and P300 components when subjects were presented with male and female portraits with a positive emotional modality, while when exposed to a series of images with a negative emotional modality, no statistical differences were registered in any of the components.

Informational Masking Effects on Neural Encoding of Stimulus Onset and Acoustic Change.

Recent investigations using cortical auditory evoked potentials have shown masker-dependent effects on sensory cortical processing of speech information. Background noise maskers consisting of other people talking are particularly difficult for speech recognition. Behavioral studies have related this to perceptual masking, or informational masking, beyond just the overlap of the masker and target at the auditory periphery. The aim of the present study was to use cortical auditory evoked potentials, to examine how maskers (i.e., continuous speech-shaped noise [SSN] and multi-talker babble) affect the cortical sensory encoding of speech information at an obligatory level of processing. Specifically, cortical responses to vowel onset and formant change were recorded under different background noise conditions presumed to represent varying amounts of energetic or informational masking. The hypothesis was, that even at this obligatory cortical level of sensory processing, we would observe larger effects on the amplitude and latency of the onset and change components as the amount of informational masking increased across background noise conditions. Onset and change responses were recorded to a vowel change from /u-i/ in young adults under four conditions: quiet, continuous SSN, eight-talker (8T) babble, and two-talker (2T) babble. Repeated measures analyses by noise condition were conducted on amplitude, latency, and response area measurements to determine the differential effects of these noise conditions, designed to represent increasing and varying levels of informational and energetic masking, on cortical neural representation of a vowel onset and acoustic change response waveforms. All noise conditions significantly reduced onset N1 and P2 amplitudes, onset N1-P2 peak to peak amplitudes, as well as both onset and change response area compared with quiet conditions. Further, all amplitude and area measures were significantly reduced for the two babble conditions compared with continuous SSN. However, there were no significant differences in peak amplitude or area for either onset or change responses between the two different babble conditions (eight versus two talkers). Mean latencies for all onset peaks were delayed for noise conditions compared with quiet. However, in contrast to the amplitude and area results, differences in peak latency between SSN and the babble conditions did not reach statistical significance. These results support the idea that while background noise maskers generally reduce amplitude and increase latency of speech-sound evoked cortical responses, the type of masking has a significant influence. Speech babble maskers (eight talkers and two talkers) have a larger effect on the obligatory cortical response to speech sound onset and change compared with purely energetic continuous SSN maskers, which may be attributed to informational masking effects. Neither the neural responses to the onset nor the vowel change, however, were sensitive to the hypothesized increase in the amount of informational masking between speech babble maskers with two talkers compared with eight talkers.

Submental Muscle Activation During Lingual Tasks in Healthy Adults.

Lingual strengthening exercises are established to improve lingual function, thereby oral swallowing. This study measured submental muscle activation during maximum isometric pressure (MIP) lingual tasks in healthy adults, tasks that are or can be adopted in lingual strengthening exercises. In addition, the effects of age and gender on submental muscle activation are examined. Forty-nine participants between the ages of 18 to 35 years and greater than 60 years were included in the study. Participants completed trials of intraoral MIP lingual elevation, protrusion, and depression, during which submental muscle activation was measured using surface electromyography (sEMG). Peak amplitude measures were normalized and log transformed, following which a three-way ANOVA was performed. Peak amplitudes of submental muscle activation were highest during lingual MIP protrusion, followed by lingual depression, and were least during lingual elevation. No significant differences in peak amplitudes were observed between older and younger adults, but higher peak amplitudes were recorded in women. The differential effects of lingual task, age, and gender on peak submental muscle activation are examined. The potential impact of incorporating tasks adopted in this study in lingual strengthening exercises to improve oral and pharyngeal swallowing is discussed.

Effects of neck flexion on discriminative and cognitive processing in anticipatory postural control during bilateral arm movement

We investigated the effect of neck flexion on discriminative and cognitive processing in postural control during bilateral arm movement while standing, using event-related potential (ERP) and electromyogram. Fourteen healthy subjects flexed their arms to the target stimuli with a 20% probability in neck resting and flexion positions. Amplitude and latency of N2 and P3, anterior deltoid (AD) reaction time, onset time of postural muscles with respect to AD activation, and peak amplitude and latency of all muscles were measured. With neck flexion, N2 and P3 amplitudes increased, N2 and P3 latencies and AD reaction time shortened, and onset times of all postural muscles became earlier. No significant differences in peak amplitude and latency of each muscle were found between neck positions. Significant positive correlations were found in changes with neck flexion between P3 latency and AD reaction time, and between N2 latency and onset time of erector spinae. These suggest that with neck flexion, attention allocation to discriminative and cognitive processing increased, and the processing speed increased with shortening of reaction time in focal muscles. In addition, the onset time of postural muscles became earlier without changing the activation pattern, which was associated with the hastened discriminative processing.

Overexpression of sarcolipin decreases myocyte contractility and calcium transient

Sarcolipin (SLN) is a novel 31-amino-acid protein associated with the sarcoplasmic reticulum (SR) whose function in cardiac muscle is poorly defined. In this study, we tested the hypothesis that SLN is a regulator of SR Ca(2+) transport function by overexpressing SLN in adult rat ventricular myocytes which express low levels of SLN. Expression of SLN mRNA in rat tissues was analyzed by Northern blot as well by RT-PCR analysis. To define the role of SLN in cardiac muscle contractility, we overexpressed SLN in adult rat ventricular myocytes using adenoviral gene transfer techniques. Localization of SLN in the adult rat ventricular myocytes was determined using confocal microscopy. Myocyte contractility and calcium transients were measured using edge detection and Fura 2AM. Our results demonstrate that overexpression of SLN decreased the cell shortening significantly when compared to control myocytes, whereas the time to peak contraction was not altered. In addition, SLN overexpression prolonged the time of 50% relaxation. Calcium transient analysis shows that time to 50% decay of [Ca(2+) ]i was markedly prolonged in SLN-overexpressing myocytes (control -245.0+/-3.78 vs. SLN -199.0+/-3.25 ms, p<0.001). However, there were no significant differences in peak amplitudes of [Ca(2+)](i) between SLN-overexpressing and control myocytes. We further demonstrate that SLN is localized within the SR membrane similar to PLB and SR Ca(2+) ATPase. Co-immunoprecipitation studies indicate that SLN can physically interact with phospholamban. We conclude that SLN may play an important role in regulating the SR calcium ATPase pump, possibly by interacting with phospholamban.

Intramammary pressure in the lactating sow in response to oxytocin and during natural milk ejections throughout lactation.

We developed a simple, non-invasive method to measure the intramammary pressure (IMP) response in sows during natural milk ejection and after i.v. injections of oxytocin. The teats of sows were cannulated and the amplitude and duration of IMP changes were measured via a pressure transducer linked to a computer. During natural milk ejections, the amplitude of the response was 5.5+/-1.8 kPa (mean +/- SD) and the duration of response at half the peak amplitude was 6.8+/-1.6 s. In response to oxytocin a threshold response occurred at 60 mIU oxytocin with no further change up to 200 mIU. The amplitude of the response to an i.v. dose of 60-200 mIU oxytocin (5.5+/-2.2 kPa) and duration (6.4+/-1.7 s) were similar to that during a natural milk ejection. The responses of two galactophorous ducts of a teat measured simultaneously were similar in peak amplitude and duration. When the responses of four glands of a sow were measured simultaneously, there was a lag time in the onset of the IMP peak from the anterior to the posterior glands, and an increase in the peak amplitude from anterior to posterior. Both during natural milk ejections and in response to oxytocin injections, there were significant differences in peak amplitude between sows. We also aimed to determine whether the pressure or duration of milk flow during natural milk ejections was limiting piglet growth rates. IMP of nine sows and the growth rates of their piglets were measured. Both the peak amplitude of IMP response and the growth rate of piglets increased over the course of lactation, but the relationship was not causal. We found that the growth rate of piglets did not depend on IMP amplitude or duration, but we suggest that it may depend on the frequency of suckling and/or the ability of piglets to withdraw milk while it is available.

GABA B-activated gK + in thalamic neurons in the lethargic ( [formula omitted]) mouse model of generalized absence seizures

Whole-cell voltage-clamp recordings were made from thalamic ventrobasal (V13) neurons of age-matched lethargic ( lh lh ) and wildtype (+/+) mice. Hyperpolarizing voltage commands (40 mV) from a holding potential of −60 mV were delivered to the cell and the resulting K + conductance ( gK +) activated by the GABA B receptor agonist baclofen was measured and compared between the two groups. VB cells from +/+ and lh lh displayed no significant differences in resting conductance ( gIN) or gK + activated by baclofen. In addition to this, isolated, evoked GABA B-mediated currents were recorded in VB cells. There was no significant difference in peak amplitude or latency to peak noted between the two groups. These data suggest that postsynaptic GABA B receptor-mediated function is not altered in VB thalamic neurones in this model of absence seizures.

Cannabinoids selectively decrease paired-pulse facilitation of perforant path synaptic potentials in the dentate gyrus in vitro.

Perforant path synaptic potentials recorded from the outer molecular layer of the dentate gyrus were tested for paired-pulse potentiation and stimulus sensitivity in the presence and absence of the potent cannabinoid receptor ligand, WIN 55,212-2. Extracellular perforant path synaptic potential amplitudes were increased by 51% in 2 mM Ca2+ medium and 60% in 3 mM Ca2+ medium at a conditioning-test (C-T) interval of 10 ms, decreasing to 10-15% facilitation at an 80 ms C-T interval. Exposure to the potent cannabinoid receptor ligand WIN 55,212-2 produced a marked and dose-dependent reduction in the amplitude of the facilitated perforant path synaptic potentials. Maximum paired-pulse facilitation was reduced to 35% and 25% in 2.0 and 5.0 microM WIN 55,212-2 respectively. The effect was selective for potentials facilitated at C-T intervals of 10-60 ms. Input/output (I/O) curves of perforant path field potentials were shifted to the right in a dose-dependent (2.0 and 5.0 microM) manner by WIN 55,212-2. Significant differences in peak amplitudes of perforant path potentials were obtained at all suprathreshold stimulus intensities. A comparison of WIN 55,212-2 (5 microM) with the GABAB receptor agonist baclofen (200 microM) showed that when both drugs were administered independently each produced similar decreases in perforant path paired-pulse potentiation. However when administered together at these concentrations baclofen and WIN failed to potentiate each other, suggesting nonadditivity due to effects on a common process.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute stroke: detection of changes in cerebral perfusion with dynamic CT scanning.

Fifteen patients with acute cerebral infarct in the territory of the middle cerebral artery were examined with dynamic computed tomography (CT) to evaluate cerebral perfusion changes. Perfusion changes could be detected in 93% of the patients within a short period after the attack (the earliest instance was within 2 hours) and before any detectable morphologic change. The attenuation coefficient of the area of infarction showed a statistically significant difference in peak amplitude compared with that in the contralateral unaffected brain or with that in the control group (P less than .05). A delay in the time to peak in the affected side versus in the contralateral side was observed in six patients with stroke and ranged from 4.2 to 49.2 seconds with or without a change in peak amplitude. The clinical outcome in the patients correlated well with the initial perfusion change measured with dynamic CT scanning. The greater the difference in peak amplitude, the worse the residual neurologic defect. Patients with a prolonged time to peak (greater than 8 seconds) usually had poor clinical outcome. The whole dynamic study took 10-15 minutes more than a conventional CT study but provided more complete information as a basis for clinical treatment and an indication of clinical outcome.