Electrophysiological Responses Research Articles

Electrophysiological and behavioral responses of elongated solifuge sensilla to mechanical stimuli.

A fundamental understanding of animal sensory systems is crucial for comprehending their interactions with the environment and with other conspecifics. However, knowledge gaps persist, particularly in arachnids like the order Solifugae. While certain solifuge setae and palpal papillae have been studied structurally and electrophysiologically, providing evidence of chemoreception and mechanoreception, the sensilla on their walking legs remain unexplored. Notably, elongated sensilla on the femur and tibia of the 4th walking legs resemble trichobothria in other arachnid orders yet their function remains unknown. Thus, this study investigates whether these sensilla serve a mechanosensory function. Using electrophysiological and behavioral assays on Eremobates pallipes (Eremobatidae), we assessed the response of the elongated 4th leg sensilla to- (i) air particle movement and- (ii) air pressure changes. Air particle movement stimuli were generated using a speaker placed in the near field of the elongated sensilla that emitted low-frequency pure tones (10-1000Hz). Air pressure stimuli involved forceful blowing on the sensilla. No response to air particle movement was observed, but a mechanosensory response to air pressure stimuli was detected. Electrophysiological data identified a fast-adapting and fast-recovering cell, and behavioral observations revealed a startle response. Our electrophysiology results suggest a mechanosensory role of elongated sensilla on the 4th walking legs of solifuge, indicating that although they are not sensitive enough to detect air particle movement stimuli, they can receive and respond to air pressure stimuli. Our behavioral experiments similarly show that these sensilla are not sensitive enough to detect air particle movement but respond to more forceful mechanosensory stimuli.

Fear-evoked stimuli in social and non-social domains: comparative effects on electrophysiological processes

Fear is a vital survival mechanism across species, triggering responses to threats and aiding in navigating dangerous environments. In humans, it plays a key role in risk assessment and decision-making, contributing to adaptive behaviour and survival. Emotional well-being and inform strategies can be enhanced for managing fear-related disorders by understanding fear's neural processing through fear-evoked stimuli. This study aimed to compare the effects of social (human mutilation) and non-social (wild animals) fear-evoked stimuli on the human brain using the event-related potential (ERP) technique. Thirty-eight participants of mixed gender and ethnicity underwent ERP assessments while being exposed to images of mutilation and wild animals alongside neutral geometric images. Brain activity was measured using a 128 HydroCel Geodesic Sensor Net, focusing on the N200 component, indicative of emotional processing. The analysis revealed that social fear-evoked stimuli (human mutilation images) elicited greater electrophysiological responses in most brain areas than non-social stimuli (wild animal images). This finding suggests that stimuli related to social fears have a greater impact on the brain than non-social fears, likely due to humans' inherent empathy for one another. The gender factor may interfere with this emotional fear processing. It highlights the critical role of social context in fear response. It suggests that understanding these dynamics can guide more effective treatments for anxiety and phobias, opening avenues for further exploration into how psychological interventions influence fear reactions.

Reward processing dominates the brain during feedback evaluation: Electrophysiological evidence.

During reinforcement learning, people learn based on both positive and negative feedback. Researchers have revealed the reward positivity (RewP) that reflects positive feedback evaluation, however, no electrophysiological indicator has been found to explain negative feedback processing. In reinforcement learning, people would like to expect the positive feedback after a choice, which might explain why previous studies usually found neural responses for reward processing, while the negative feedback processing seems absent. However, no study has designed a task to separate positive and negative feedback processing to measure the corresponding electrophysiological responses. Thus, the present study designed gain processing-advantaged (GA) and loss processing-advantaged (LA) contexts using a modified gambling task to measure specific neural responses to gain processing and loss processing. Electroencephalography (EEG) data were processed using time-domain and time-frequency analyses. The results revealed the RewP and delta oscillation following gain feedback in the GA context, while no negativity or other components specific to loss processing was found, even in the loss condition of LA context. The current results indicate that reward processing dominates the brain during feedback evaluation, whereas loss processing can't be captured by electrophysiological signal.

Attraction of Lygus lineolaris (Hemiptera: Miridae) to a ubiquitous floral volatile in the field.

Herbivorous insects utilize olfactory and visual cues to orient on suitable host plants, and such cues can be employed to facilitate insect monitoring. Lygus lineolaris Palisot de Beauvois is a polyphagous pest throughout North America. Monitoring this pest as it moves between crop and non-crop hosts remains challenging, and a lack of effective monitoring tools complicates management of this insect. In this study, we examined the electrophysiological and behavioral responses of L. lineolaris to the volatile emissions of 2 crop hosts: alfalfa and strawberry. Gas chromatography with electroantennographic detection was applied to identify antennally active compounds in headspace extracts of flowering host plants, before responses to individual compounds were examined in the field. Five compounds consistently elicited antennal depolarizations in adults of L. lineolaris and, of these, (±)-linalool increased the capture rate of L. lineolaris females in the field. Subsequent experiments examined the influence of visual cues and stereochemistry on capture rate, revealing that lures containing (±)-linalool and (S)-(+)-linalool significantly increased the capture rate of L. lineolaris females compared with traps baited with (R)-(-)-linalool and controls, indicating that L. lineolaris is attracted to (S)-(+)-linalool. While lures increased capture on red traps, this was not the case for white traps, emphasizing the importance of visual cues in the movements and monitoring of L. lineolaris. This study demonstrates that L. lineolaris is attracted to (S)-(+)-linalool in the field, and that attraction depends on trap color. This knowledge is expected to improve monitoring strategies for L. lineolaris in agricultural systems.

Be ready to manage stress "Before" and "After" a critical event. What the EEG and autonomic correlates tell us.

This study examined behavioral, electrophysiological (EEG), and autonomic responses to stress during the preparation and speech stages of five discourses among 26 adults. Participants underwent an increasingly stressful job-interview based on a modified Trier Social Stress Test, receiving feedback from an evaluative board. Findings showed increased RTs, higher cardiovascular responses [Pulse Volume Amplitude (PVA), and Heart Rate Variability (HRV)] and generalized increases in EEG frequency bands (delta, theta, alpha, beta, gamma) during the speech compared to the preparation stage. The rising emotional salience of the discourses induced a negativity bias and extensive low-frequency band activation (delta and theta) across the scalp in response to emotional demands. High-frequency bands exhibited a plateau effect, indicating less cognitive involvement as the discourses progressed. In our opinion, a possible interpretation is that this effect could be due to habituation mechanisms or coping strategies. Autonomic results revealed significant variations in PVA, with higher levels during the first discourse preparation, indicating substantial cognitive effort. Despite increased emotional arousal, participants managed stress effectively, as evidenced by increased HRV during the speech stage. Overall, during progressively increasing ecological psychosocial stress, individuals displayed marked emotional reactions in terms of low-frequency bands and cardiovascular indices, particularly during the first speeches rather than the preparation stages of an interview.

Beyond the Score: Exploring the Associations Between Adverse Childhood Experiences and Electrophysiological Responses to Errors.

Adverse childhood experiences (ACEs) have diverse effects on physical development and mental health. This study aimed to clarify the relationship between the quantity of ACE exposure, type of ACE exposure, and subjective level of stress felt, correlated with event-related potential activity across the scalp, while controlling for relevant confounding variables. Fifty-three participants aged 18-32years completed questionnaires assessing their current mental health, self-regulation, childhood socioeconomic status, and history of traumatic events. Electroencephalographic activity was recorded while participants completed the Combined Attention Systems Task, a modified flanker task. Using cluster-corrected robust statistical approaches, significant relationships existed between the total number of ACEs, ACE type, the subjective impact of trauma, and amplitudes during the error-related negativity (ERN) and error positivity (Pe) at various scalp locations. In the ERN time window, greater error-correct differences were associated with greater total ACEs, abuse, and other ACEs at C5, P9, and TP10/C1 clusters, respectively. In addition, reduced error-correct differences at cluster-maximal C2 during the timing of the Pe were related to experiencing greater numbers of total ACEs while increased error-correct differences at cluster-maximal FPz during the timing of the Pe were associated with greater numbers of other ACEs. The subjective impact of total number of ACEs was not associated with error-correct differences, however, the subjective impact of household dysfunction, abuse, and 'other' ACE types were linked to error-correct differences at various scalp locations and timings. Notably, increased, rather than decreased, subjective impact of household dysfunction was related to greater error-correct differentiation during the timing of the ERN, maximal at Cz. These results suggest that both ACE type and subjective rating are relevant to future outcomes. The effects extended beyond the ERN-affecting error-related positivity and later event-related potentials-indicating associations with the number, type, and subjective impact of ACEs across a larger time window and scalp topography.

Exploring the role of sex, sex steroids, menstrual cycle, and hormonal contraception use in visual working memory: Insights from behavioral and EEG analyses.

Sex hormones have been shown to influence cognitive and emotional processes, yet their effects on visual working memory (VWM) are poorly understood. This study aimed to investigate the relationship between VWM, sex, and female hormonal status in participants aged 18-35 years. We recruited 32 males (M) and 133 females, categorized into four groups: naturally cycling females in the early follicular (NCF, n = 33) and mid-luteal (NCL, n = 35) phases of the menstrual cycle, oral contraceptive (OC, n = 37), and intrauterine device users (IUD, n = 28). Participants completed a bilateral change detection task while behavioral and EEG data were recorded. We evaluated VWM performance and associated brain electrophysiological responses, specifically Contralateral Delay Activity (CDA). Salivary levels of testosterone, progesterone, and estradiol were assessed. We found no systematic differences in VWM task performance or CDA between groups, nor any correlations with hormone levels. However, an exception to this was that NCF females performed worse than OC users when recalling four items. Age emerged as a significant covariate, with greater age being linked to poorer performance. An interaction between age and group in memory capacity highlighted differential patterns of age-related cognitive decline across sexes and female hormonal status groups. These findings provide valuable insights into the broader relationship between sex, sex hormones, and cognition. They suggest that in studies employing a between-subject design, hormone-dependent differences in more complex processes, such as visuospatial performance, are unlikely to stem from the role of sex hormones in VWM and may instead arise from other factors.

Sources of Microstructure in Mammalian Cochlear Responses.

Quasiperiodic fluctuations with frequency are observed in a variety of responses that either originate from or strongly depend on the cochlea's active mechanics. These spectral microstructures are unique and stable features of individual ears and have been most thoroughly studied in behavioral hearing thresholds and otoacoustic emissions (OAEs). While the exact morphology of the microstructure patterns may differ across measurement types, the patterns are interrelated and are thought to depend on common mechanisms. This review summarizes the characteristics and proposed origins of the microstructures observed in behavioral and OAE responses, as well as other mechanical and electrophysiological responses of the mammalian cochlea. Throughout, the work of Glenis Long and colleagues is highlighted. Long contributed greatly to our understanding of microstructure and its perceptual consequences, as well as to the development of techniques for reducing the impact of microstructure on OAE-based assays of cochlear function.

Error-related potentials during multitasking involving sensorimotor control: an ERP and offline decoding study for brain-computer interface

Humans achieve efficient behaviors by perceiving and responding to errors. Error-related potentials (ErrPs) are electrophysiological responses that occur upon perceiving errors. Leveraging ErrPs to improve the accuracy of brain-computer interfaces (BCIs), utilizing the brain's natural error-detection processes to enhance system performance, has been proposed. However, the influence of external and contextual factors on the detectability of ErrPs remains poorly understood, especially in multitasking scenarios involving both BCI operations and sensorimotor control. Herein, we hypothesized that the difficulty in sensorimotor control would lead to the dispersion of neural resources in multitasking, resulting in a reduction in ErrP features. To examine this, we conducted an experiment in which participants were instructed to keep a ball within a designated area on a board, while simultaneously attempting to control a cursor on a display through motor imagery. The BCI provided error feedback with a random probability of 30%. Three scenarios–without a ball (single-task), lightweight ball (easy-task), and heavyweight ball (hard-task)–were used for the characterization of ErrPs based on the difficulty of sensorimotor control. In addition, to examine the impact of multitasking on ErrP-BCI performance, we analyzed single-trial classification accuracy offline. Contrary to our hypothesis, varying the difficulty of sensorimotor control did not result in significant changes in ErrP features. However, multitasking significantly affected ErrP classification accuracy. Post-hoc analyses revealed that the classifier trained on single-task ErrPs exhibited reduced accuracy under hard-task scenarios. To our knowledge, this study is the first to investigate how ErrPs are modulated in a multitasking environment involving both sensorimotor control and BCI operation in an offline framework. Although the ErrP features remained unchanged, the observed variation in accuracy suggests the need to design classifiers that account for task load even before implementing a real-time ErrP-based BCI.

Longitudinal assessment of retinal and visual pathway electrophysiology and structure after high altitude exposure.

High altitude (HA) exposure induces impairments in visual function. This study was designed to dynamically observe visual function after returning to lowland and elucidate the underlying mechanism by examining the structure and function of retina and visual pathway. Twenty-three subjects were recruited before (Test 1), and one week (Test 2) and three months (Test 3) after their return from HA (4300m) where they resided for 30 days. The clock task was used to assess visual cognition; and pattern-reversal visual evoked potential (p-VEP) and full-field electroretinogram (ff-ERG) were employed to record electrophysiological responses of retinal cells; optical coherence tomography (OCT), color doppler imaging (CDI) and magnetic resonance imaging(MRI) were used to measure structures of retina and visual pathway. In Test 2 vs. Test 1, there was increased reaction time during angle task; the amplitudes of scotopic 3.0cd·s/m2 and scotopic 10.0cd·s/m2 ERG a-wave and scotopic 3.0cd·s/m2 oscillatory potential in the right eye were significantly decreased, all of which were negatively correlated with the increased reaction time during the angle task. In Test 3 vs. Test 1, there were decreased amplitude of scotopic 10.0cd·s/m2 a-wave in the right eye and increased velocity of ophthalmic artery and ocular perfusion pressure in bilateral eyes. The VEP and visual pathway structures remained normal throughout the entire test. HA exposure caused damage to rod and cone responses in both outer and inner retina. After returning to sea level, the damaged visual cell functions gradually recovered over time, coinciding with an increase in the ocular perfusion.

To err is human: Differences in performance monitoring ERPs during interactions with human co-actors and machines.

In interactive tasks, agents often aim at eliciting a certain response from their partner. Not accomplishing this goal calls for adjusting behavior on the fly. Previous research suggests that such adjustments differ when interacting with a machine or with a fellow human agent. In this study, we investigated whether such differences are also reflected in event-related potentials induced by observing human and machine errors in an interactive setting. In a four-choice reaction time task, participants performed actions that were followed by regular and irregular visual effects. In different conditions, participants were led to believe that they were interacting with another human agent or with a machine so that the irregular effects were attributed either to human errors or to machine malfunctions. We compared observed-error-related negativity (oERN) and observed-error positivity (oPE) for these two error types. The oPE was not affected by the experimental manipulation, whereas the oERN amplitude was more pronounced for machine malfunctions than for human errors. This contradicts previous findings that reported behavioral and electrophysiological responses to errors being larger when they are committed by a human agent than if they are caused by machine malfunctions. Our results might suggest that automated systems are expected to operate predictably and, as a consequence, in interactive settings, errors committed by such systems are more salient and elicit a larger prediction error signal than if the same mistake is made by a human agent.

Olfactory and electrophysiological response of cucumber moth Diaphania indica (Saunders)n(Lepidoptera, Crambidae) to different plants

The behavioural response of adults and larvae of cucumber moth, Diaphania indica (Saunders) (Lepidoptera, Crambidae), a serious pest of cucurbitaceous crops was evaluated on different cucurbitaceous and non-cucurbitaceous plants through olfactometer bioassay. The volatile organic compounds (VOCs) present in these plants were identified by gas chromatography-mass spectrometry. Further, electrophysiological response of D. indica to plant extracts and synthetic volatiles were recorded by electroantennographic detection. Larvae had the highest olfactory response to wild coccinia followed by bitter gourd, coccinia and cucumber. In GC-MS analysis, á-linolenic acid, palmitic acid and dotriacontane were identified as common components in leaf extracts, whereas, benzaldehyde was the major component in headspace of dried leaves. The antennae of gravid female moths were more sensitive to plant odours than unmated females and males. Gravid females showed highest response to extracts of bitter gourd and unmated females to cucumber extract. A synthetic volatile mixture of 10?L of benzaldehyde and 30?L of benzyl alcohol were found responsible for high antennal response. Significant orientation and landing response were shown by D. indica moths to a mixture of 10?L benzaldehyde (10%) and 20?L benzyl alcohol (10%). These findings suggest the above blend could be employed for the development of plant volatile based management strategies.

Phlebotomus perniciosus response to volatile organic compounds of dogs and humans.

The olfactory response of insect vectors such as phlebotomine sand flies is a key facet for investigating their interactions with vertebrate hosts and associated vector-borne pathogens. Such studies are mainly performed by assessing the electrophysiological response and the olfactory behaviour of these arthropods towards volatile organic compounds (VOCs) produced by hosts. Nonetheless, few studies are available for species of the subgenera Lutzomyia and Nyssomyia in South America, leaving a void for Old World sand fly species of the genus Phlebotomus. In this study, we evaluated the olfactory responses of Phlebotomus perniciosus, one of the most important vectors of Leishmania infantum in the Old World. To test the P. perniciosus behavioural response to VOCs, 28 compounds isolated from humans and dogs were assessed using electrophysiological (i.e., electroantennogram, EAG) and behavioural assays (i.e., Y-tube olfactometer). In the EAG trials, 14 compounds (i.e., acetic acid, nonanoic acid, 2-propanol, 2-butanol, pentanal, hexanal, nonanal, trans-2-nonenal, decanal, myrcene, p-cymene, verbenone, 2-ethyl-1-hexanol, and acetonitrile) elicited high antennal responses (i.e., ≥ 0.30 mV) in female sand flies, being those VOCs selected for the behavioural assays. From the 14 compounds tested in the Y-tube olfactometer, nonanal was significantly attractive for P. perniciosus females, whereas myrcene and p-cymene were significantly repellents (p < 0.05). The attraction indexes varied from 0.53 for nonanal (i.e., most attractive) to -0.47 to p-cymene (i.e., most repellent). Overall, our results shed light on the role of olfactory cues routing host seeking behaviour in P. perniciosus, with implications to develop sustainable sand fly monitoring as well as control in leishmaniasis endemic areas.

Two chemosensory proteins in Aleurocanthus spiniferus are involved in the recognition of host VOCs

BackgroundCSPs are known for their complex and arguably obscure function(s), particularly in chemical olfaction. It is unclear which CSPs in Aleurocanthus spiniferus are involved in the identification of host VOCs. This study on A. spiniferus utilized gene expression, ligand binding, RNAi and molecular docking to determine the CSPs involved in the binding and transport of six host VOCs.ResultsFour (AspiCSP7, 9, 12 and 16) of the 12 CSPs underwent transcriptional up- or down-regulation after induction by host VOCs. AspiCSP16 can bind to six VOCs, and AspiCSP7 can bind to five except linalool. dsAspiCSP7-treated adults showed significantly lower tendency to 3-carene, hexanol, (E)-2-hexenal, and lost avoidance of (Z)-3-hexenol; the preference for 3-carene, hexanol, and the avoidance of nonanal and (Z)-3-hexenol were reduced when AspiCSP16 was knocked down. Although it is difficult to convince the results on EAG after silencing 63% of AspiCSP7 and AspiCSP16. dsAspiCSP7 and dsAspiCSP16 treatments reduced the electrophysiological (EAG) response to attractive (3-carene and hexanol), and repellent chemicals [nonanal and (Z)-3-hexenol], which demonstrated the behavioral results. Molecular docking indicated that critical hydrophobic residues, LYS-95 and ILE-59, might be involved in the binding of AspiCSP7 and AspiCSP16 to six host VOCs, respectively.ConclusionsAspiCSP7 and AspiCSP16 are involved in the recognition of host VOCs, including four attractants [(E)-2-hexenal, linalool, 3-carene, hexanol] and two repellents [nonanal and (Z)-3-hexenol]. This study will deepen the understanding of the olfactory mechanisms of host VOCs recognition by A. spiniferus and will support the development of novel compounds and RNA pesticides for controlling pests.Graphical abstract

Effect of childhood epilepsy and antiepileptic drugs on visual evoked potential response and optical coherence tomography

BackgroundEpileptic seizures arise from an excessively synchronous and sustained discharge of a group of neurons. The single feature of all epileptic syndromes is a persistent increase of neuronal excitability. Visual affection in epileptic children could be attributed to the disease itself or the use of anti-epileptic drugs, these changes may involve abnormal electro-physiological response. This biphasic study, conducted at the neuro-pediatric clinic at neurology department, aimed to investigate effect of idiopathic childhood epilepsy per se on (1) visual evoked potential and (2) optical coherence tomography and effect of selected two antiepileptic medications on them. All subjects were exposed to visual evoked potential and only cooperative subjects exposed to ocular coherence tomography before and after anti-epileptic drugs and were followed up over 2 years.ResultsThe study included 50 newly diagnosed epileptic children and 50 healthy controls, the mean P100 latency in the right eyes of the control group was 110.4 ± 3.76ms, while in the patients group was 114.94 ± 12.81ms that showed significant difference between the two groups with p value (0.020). After 2 years of treatment by levetiracetam and valproate, the mean P100 latency of the right and left eyes in the valproate group was 112.34 ± 7.05 ms and 112.59 ± 5.2 ms, respectively, and it was 114.85 ± 10.39 ms and 116.14 ± 9.84 ms, respectively, in the valproate group, which showed insignificant difference between the two groups. The mean average of retinal nerve fiber layer thickness between patients and controls was significant in both right and left eyes with p value 0.002 and < 0.001, respectively. After 1 year of treatment by levetiracetam in the first group and valproate in the second group, there was no significant difference between the two groups neither regarding retinal nerve fiber layer thickness nor ganglion cell complex in both eyes.ConclusionsThere was prolonged latency in the epileptic children before starting anti-epileptic drugs more than the control group; also there was thinning of the retinal nerve fiber layer thickness and average part of the ganglion cell complex thickness more in the epileptic children than in the healthy controls.

Examining the Effects of Brief Mindfulness on Psychophysiological Responses and Performance in Self-Competitive Tasks

Mindfulness practice has been recognized as an effective method for reducing stress, enhancing self-awareness, and improving overall well-being, influencing various cognitive processes such as attention and self-control. While extensive research has focused on long-term mindfulness programs, recent years have seen the emergence of brief mindfulness practices. This study aims to investigate the effects of brief mindfulness on electrophysiological responses, and performance in a self-competitive context. A total of 52 participants were divided into two groups for the experiment. They were randomly assigned to one of two experimental conditions: a brief mindfulness practice (n = 29) or a control intervention (n = 23), each lasting 10 min. Initially, participants completed a cognitive task (Tower of Hanoi—ToH), followed by their respective intervention. Participants then performed the ToH task again, with encouragement to exceed their previous performance. Measures were taken for performance metrics and psychophysiological responses—including electrodermal response (EDA) and cardiovascular parameters. The results indicated that a brief mindfulness significantly enhanced performance (p &lt; 0.05), increased self-efficacy (including self-confidence and perceived task importance) prior to the ToH task, and reduced the perceived difficulty of the task upon completion. Moreover, an increase in EDA was found in the brief mindfulness group. However, no significant changes in the measured cardiovascular responses were observed. These findings suggest that brief mindfulness can effectively improve cognitive task performance by enhancing self-efficacy and reshaping task perception.

Sympathetic motor neuron dysfunction is a missing link in age-associated sympathetic overactivity

Overactivity of the sympathetic nervous system is a hallmark of aging. The cellular mechanisms behind this overactivity remain poorly understood, with most attention paid to likely central nervous system components. In this work, we hypothesized that aging also affects the function of motor neurons in the peripheral sympathetic ganglia. To test this hypothesis, we compared the electrophysiological responses and ion-channel activity of neurons isolated from the superior cervical ganglia of young (12 weeks), middle-aged (64 weeks), and old (115 weeks) mice. These approaches showed that aging does impact the intrinsic properties of sympathetic motor neurons, increasing spontaneous and evoked firing responses. A reduction of M current emerged as a major contributor to age-related hyperexcitability. Thus, it is essential to consider the effect of aging on motor components of the sympathetic reflex as a crucial part of the mechanism involved in sympathetic overactivity.

Sympathetic motor neuron dysfunction is a missing link in age-associated sympathetic overactivity.

Overactivity of the sympathetic nervous system is a hallmark of aging. The cellular mechanisms behind this overactivity remain poorly understood, with most attention paid to likely central nervous system components. In this work, we hypothesized that aging also affects the function of motor neurons in the peripheral sympathetic ganglia. To test this hypothesis, we compared the electrophysiological responses and ion-channel activity of neurons isolated from the superior cervical ganglia of young (12 weeks), middle-aged (64 weeks), and old (115 weeks) mice. These approaches showed that aging does impact the intrinsic properties of sympathetic motor neurons, increasing spontaneous and evoked firing responses. A reduction of M current emerged as a major contributor to age-related hyperexcitability. Thus, it is essential to consider the effect of aging on motor components of the sympathetic reflex as a crucial part of the mechanism involved in sympathetic overactivity.

Electrophysiology in ophthalmology

Electrophysiological examinations are used in ophthalmology to determine the functionality of the neurons of the visual pathway. As electrophysiological examinations are independent of the subjective perception and response of the patient, they are considered to be objective functional diagnostics of vision. Electroretinography (ERG) is used to examine the retina (especially the photoreceptors), electro-oculography (EOG) is used to examine the functionality of the retinal pigment epithelium and visually evoked potentials (VEP) are used to evaluate the integrity of the entire visual pathway. Abnormalities in electrophysiological responses should always be interpreted in the context of other functional and morphological findings.

Invitro high-content screening reveals miR-429 as a protective molecule in photoreceptor degeneration.

Inherited retinal diseases (IRDs) are clinically and genetically heterogeneous disorders characterized by progressive photoreceptor degeneration and irreversible vision loss. MicroRNAs (miRNAs), a class of endogenous non-coding RNAs with post-transcriptional regulatory properties, are known to play a major role in retinal function, both in physiological and pathological conditions. Given their ability to simultaneously modulate multiple molecular pathways, miRNAs represent promising therapeutic tools for disorders with high genetic heterogeneity, such as IRDs. In the present study, we performed high-content imaging (HCI) screening to assess the impact of miRNA overexpression on a photoreceptor cell line undergoing light-induced degeneration. More than 1,200 miRNAs were assayedfor putative protective effects in light-stressed 661W photoreceptor-like cells, and the top-performing miRNAs were further validated in independent invitro assays. miR-429 showed the strongest cell-protective effect invitro. Adeno-associated viral vector-mediated subretinal delivery of miR-429 in the Rho P23H/+ IRD mouse model preserved electrophysiological responses and was associated with reduced inflammatory processes in the retina. We demonstrate that the HCI invitro assay we devised is a reliable screening method to select candidate molecules for mutation-independent therapeutic approaches for retinal disorders. Moreover, our data indicate that miR-429 represents a potential therapeutic target against photoreceptor degeneration.