Electrophysiological Characteristics of Inhibitive Control for Adults with Different Physiological or Psychological Obesity.

Individuals exhibiting high scores on the fatness subscale of the negative-physical-self scale (NPSS-F) are characterized by heightened preoccupation with body fat accompanied by negative body image perceptions, often leading to excessive dieting behaviors. This demographic constitutes a considerable segment of the populace in China, even among those who are not obese. Nonetheless, scant empirical inquiries have delved into the behavioral and neurophysiological profiles of individuals possessing a healthy body mass index (BMI) alongside elevated NPSS-F scores. This study employed an experimental paradigm integrating go/no-go and one-back tasks to assess inhibitory control and working memory capacities concerning food-related stimuli across three adult cohorts: those with normal weight and low NPSS-F scores, those with normal weight and high NPSS-F scores, and individuals classified as obese. Experimental stimuli comprised high- and low-caloric-food pictures with concurrent electroencephalogram (EEG) and photoplethysmogram (PPG) recordings. Individuals characterized by high NPSS-F scores and normal weight exhibited distinctive electrophysiological responses compared to the other two cohorts, evident in event-related potential (ERP) components, theta and alpha band oscillations, and heart rate variability (HRV) patterns. In essence, the findings underscore alterations in electrophysiological reactivity among individuals possessing high NPSS-F scores and a healthy BMI in the context of food-related stimuli, underscoring the necessity for increased attention to this demographic alongside individuals affected by obesity.

Morpho-electric diversity of human hippocampal CA1 pyramidal neurons.

Hippocampal pyramidal neuron activity underlies episodic memory and spatial navigation. Although extensively studied in rodents, extremely little is known about human hippocampal pyramidal neurons, even though the human hippocampus underwent strong evolutionary reorganization and shows lower theta rhythm frequencies. To test whether biophysical properties of human Cornu Amonis subfield 1 (CA1) pyramidal neurons can explain observed rhythms, we map the morpho-electric properties of individual CA1 pyramidal neurons in human, non-pathological hippocampal slices from neurosurgery. Human CA1 pyramidal neurons have much larger dendritic trees than mouse CA1 pyramidal neurons, have a large number of oblique dendrites, and resonate at 2.9 Hz, optimally tuned to human theta frequencies. Morphological and biophysical properties suggest cellular diversity along a multidimensional gradient rather than discrete clustering. Across the population, dendritic architecture and a large number of oblique dendrites consistently boost memory capacity in human CA1 pyramidal neurons by an order of magnitude compared to mouse CA1 pyramidal neurons.

Different responses of mice and rats hippocampus CA1 pyramidal neurons to in vitro and in vivo-like inputs.

The fundamental role of any neuron within a network is to transform complex spatiotemporal synaptic input patterns into individual output spikes. These spikes, in turn, act as inputs for other neurons in the network. Neurons must execute this function across a diverse range of physiological conditions, often based on species-specific traits. Therefore, it is crucial to determine the extent to which findings can be extrapolated between species and, ultimately, to humans. In this study, we employed a multidisciplinary approach to pinpoint the factors accounting for the observed electrophysiological differences between mice and rats, the two species most used in experimental and computational research. After analyzing the morphological properties of their hippocampal CA1 pyramidal cells, we conducted a statistical comparison of rat and mouse electrophysiological features in response to somatic current injections. This analysis aimed to uncover the parameters underlying these distinctions. Using a well-established computational workflow, we created ten distinct single-cell computational models of mouse CA1 pyramidal neurons, ready to be used in a full-scale hippocampal circuit. By comparing their responses to a variety of somatic and synaptic inputs with those of rat models, we generated experimentally testable hypotheses regarding species-specific differences in ion channel distribution, kinetics, and the electrophysiological mechanisms underlying their distinct responses to synaptic inputs during the behaviorally relevant Gamma and Sharp-Wave rhythms.

Analysis of Age-Dependent Alterations in Excitability Properties of CA1 Pyramidal Neurons in an APPPS1 Model of Alzheimer's Disease.

Age-dependent accumulation of amyloid-ß, provoking increasing brain amyloidopathy, triggers abnormal patterns of neuron activity and circuit synchronization in Alzheimer's disease (AD) as observed in human AD patients and AD mouse models. Recent studies on AD mouse models, mimicking this age-dependent amyloidopathy, identified alterations in CA1 neuron excitability. However, these models generally also overexpress mutated amyloid precursor protein (APP) and presenilin 1 (PS1) and there is a lack of a clear correlation of neuronal excitability alterations with progressive amyloidopathy. The active development of computational models of AD points out the need of collecting such experimental data to build a reliable disease model exhibiting AD-like disease progression. We therefore used the feature extraction tool of the Human Brain Project (HBP) Brain Simulation Platform to systematically analyze the excitability profile of CA1 pyramidal neuron in the APPPS1 mouse model. We identified specific features of neuron excitability that best correlate either with over-expression of mutated APP and PS1 or increasing Aß amyloidopathy. Notably, we report strong alterations in membrane time constant and action potential width and weak alterations in firing behavior. Also, using a CA1 pyramidal neuron model, we evidence amyloidopathy-dependent alterations in I h . Finally, cluster analysis of these recordings showed that we could reliably assign a trace to its correct group, opening the door to a more refined, less variable analysis of AD-affected neurons. This inter-disciplinary analysis, bringing together experimentalists and modelers, helps to further unravel the neuronal mechanisms most affected by AD and to build a biologically plausible computational model of the AD brain.

Comparison of electrophysiological features in peripheral vertigo and central vertigo / 临床神经病学杂志

Objective To compared the electrophysiological features in peripheral vertigo and central vertigo. Methods The electronystagmograph ( ENG ) and brainstem auditory evoked potentials ( BAEP ) were applied in peripheral vertigo group(85 cases) and central vertigo group(61 cases).Result ENG abnomal was in 67 cases (78.8%) in peripheral vertigo group.Overshoot or undershoot of dysmetria test was in 6 cases ( 7.1%);spontaneous nystagmus was in 5 cases(5.9%);abnormal of gaze test was in 16 cases(18.8%); eye tracking test typeⅠwas in 42 case(49.4%), typeⅡwas in 17 cases(20.0%), and typeⅢwas in 8 cases(9.4%); bilateral asymmetry of optokinetic nystagmus test was in 19 cases(22.4%);positioning nystagmus was in 51 cases(60.0%);abnormal of cold and hot test was in 31 cases(36.5%).ENG abnomal was 42 cases(49.4%) in central vertigo group.Overshoot or undershoot of dysmetria test was in 19 case(31.1%);spontaneous nystagmus was in 13 cases (21.3%);abnormal of gaze test was in 23 cases(37.7%);eye tracking test typeⅠwas in 35 cases(57.4%), typeⅡwas in 13 cases(21.3%), and typeⅢwas in 8 cases(13.1%);bilateral asymmetry of optokinetic nystagmus test was in 33 cases(54.1%); positioning nystagmus was in 2 cases(3.3%); abnormal of cold and hot test was in 6 cases(9.8%).Compared with peripheral vertigo group, the abnormal rates of optokinetic nystagmus test, gaze test, eye tracking test, optokinetic nystagmus test in central vertigo group were significantly increased, and the abnormal rates of positioning nystagmus, cold and hot test in central vertigo group were significantly decreased (all P<0.05). There were 32 cases(37.6%) in peripheral vertigo group with BAEP abnormal, and 31 cases(50.8%) were in central vertigo group with BAED abnormal.Compared with central vertigo group, the latency ofⅠwave andⅠ-Ⅲwave latency delayed in peripheral vertigo group were significantly increased, the latency ofⅤwave andⅠ-Ⅴwave latency delayed were significantly decreased ( all P<0.05 ) .Conclusions There are high sensitivity of optokinetic nystagmus test, gaze test, eye tracking test, optokinetic nystagmus test of ENG to the diagnosis of central vertigo. There are high sensitivity of positioning nystagmus, cold and hot test to the diagnosis of peripheral vertigo.The positive rate of BAEP is relatively lower, but it can provide objective foundation for location of vertigo patients.

Features of accessory pathways in adult Ebstein's anomaly.

AIMS: The aim of the study was to describe the complex electrophysiological features of accessory pathways (APs) in adult Ebstein's anomaly (EA). METHODS AND RESULTS: We performed a retrospective study of 17 consecutive adult EA cases with APs who underwent electrophysiological study and radiofrequency catheter ablation (RFCA) from November 2011 to May 2013. There were a total of 24 atrioventricular reentrant tachycardias (AVRTs) due to 23 APs, including 20 (87.0%) non-decremental conducting, 2 (8.7%) decremental conducting, and 1 (4.3%) nodofascicular bundle. Six (6/17 = 35.3%) patients had two APs while others had only one. Twenty-one APs (91.3%) in 15 patients were manifested and 2 APs (8.7%) in 2 patients were concealed. Six APs (26.1%) were broad, while 17 APs (73.9%) were narrow in width. Two patients suffered from duodromic tachycardias mediated by two APs. Accessory pathways were mainly located on the posterior, posteroseptal, and posterolateral tricuspid annulus (TA). Right ventriculography confirmed that all APs were located on the anatomic TA. All the patients remained free from tachycardias during 11.9 ± 6.8 months of follow-up after RFCA. For the 15 patients with manifest APs, 10 patients' electrocardiograms (ECGs) after RFCA demonstrated morphologies of right bundle branch block, while 5 patients' ECGs were normal. CONCLUSIONS: Accessory pathways in EA are predominantly right-sided, manifest and localize to the lower half of the anatomic TA. A number of APs in EA have broad widths. The incidence of multiple APs is high in these patients and RFCA is effective.