Arousal State Research Articles

The effect of reward-induced arousal on the success and precision of episodic memory retrieval

Moment-to-moment fluctuations in arousal can have large effects on learning and memory. For example, when neutral items are predictive of a later reward, they are often remembered better than neutral items without a reward association. This reward anticipation manipulation is thought to induce a heightened state of arousal, resulting in stronger encoding. It is unclear, however, whether these arousal-induced effects on encoding are ‘all-or-none’, or whether encoding precision varies from trial to trial with degree of arousal. Here, we examined whether trial-to-trial variability in reward-related pupil-linked arousal might correspond to variability in participants’ long-term memory encoding precision. We tested this using a location memory paradigm in which half of the to-be-encoded neutral items were linked to later monetary reward, while the other half had no reward association. After the encoding phase, we measured immediate item location memory on a continuous scale, allowing us to assess both memory success and memory precision. We found that pre-item baseline pupil size and pupil size during item encoding were not related to subsequent memory performance. In contrast, the anticipation of instrumental reward increased pupil size, and a smaller anticipatory increase in pupil size was linked to greater subsequent memory success but not memory precision.

Arousal dysregulation and executive dysfunction in attention deficit hyperactivity disorder (ADHD).

Attention deficit/hyperactivity disorder (ADHD) is a heterogeneous neurodevelopmental condition, that continues to have an elusive etiological background. A number of extant models and theories have historically intended to explain the many factors contributing to ADHD behaviors. One of the most accepted hypotheses has been the executive dysfunction theory associating reduction in executive control to abnormalities in structure and operational dysfunction of dopaminergic signaling networks. Nevertheless, executive functions are not always impaired in ADHD, and the literature describes other symptoms commonly reported suggesting individuals with ADHD would appear to suffer from a more general deficit. Another existing line of research, that has gained much attention recently, establishes that ADHD would have dysregulated states of brain arousal that would account for its commonly observed cognitive deficits and behavioral symptoms, described as the state regulation theory, which has now included measures of autonomic function. This article describes some important aspects that compose and challenge these two most influential theoretical constructs, executive dysfunction and state-regulation, based on their empirical evidence, implying the need to reevaluate the norms used to classify individuals and establish ADHD diagnosis. Large number of controversial results continue to exist within the study of ADHD biological and/or performance markers, possibly due to such heterogeneity and variability within the same diagnosis. The need to resolve these issues and establish newly revised diagnostic criteria for ADHD is critical, as therapeutic success depends on having accurately identified underlying neurophysiological factors in order to appropriately address them in treatment.

Altered Sexual Response-Related Functional Connectivity and Morphometric Changes Influenced by Sex Hormones across Menopausal Status.

Our study retrospectively investigated differential patterns of the functional connectivity (FC) of core brain regions synchronous with morphometric changes associated with sexual dysfunction in menopausal women, and their correlations with sexual hormones. Twenty-three premenopausal women (mean age: 41.52 ± 7.38 years) and 21 menopausal women (mean age: 55.52 ± 2.80 years) underwent sex hormone level measurements with high-resolution T1 and functional magnetic resonance imaging (MRI) during rest, neutral, and sexual arousal conditions. Analysis of covariance adjusted for age was used to compare the FC and gray matter (GM) volume between the two groups. Menopausal women showed lower GM volumes in the superior frontal gyrus (SFG), superior temporal pole, parahippocampal gyrus (PHG), hippocampus (Hip), amygdala (Amg), and cerebellum (Cb) compared to premenopausal women (p < 0.05). In addition, compared to premenopausal women, menopausal women showed decreased FC of seed regions involved in the SFG, frontal eye fields, and Amg, as well as target regions involved in the PHG, Hip, inferior frontal gyrus, Cb, and vermis (p < 0.005). Furthermore, the FC between the right Amg and right Cb and between the left Amg and right Cb during sexual arousal in both groups was positively correlated with total estrogen and estradiol levels, respectively (p < 0.01). The GM volume values in the right Amg and right Cb were positively correlated with total estrogen and estradiol levels (p < 0.05). Our study demonstrated an association between menopause-related differential FC and GM volume variations and fluctuating sex hormones. Our findings highlight that overlapping brain regions with functional alterations and morphometric changes are closely linked with menopausal symptom-related decreases in sexual arousal and hormone levels.

ECG-based emotion recognition using random convolutional kernel method

The recognition of human emotions based on physiological signals has garnered significant attention from various fields such as human–computer interaction, cognitive-behavioral science, and the treatment of emotion-related diseases. Using the easily accessible ECG signal for emotion recognition presents a viable approach. However, method relying on hand-crafted features necessitate task-specific domain knowledge and consume substantial time to design suitable features, and studies employing deep learning technologies incur greater computational complexity and extended training durations. To address these problems, we proposed an emotion recognition method that employs random convolutional kernels on ECG signals. Following ECG signal preprocessing, a large number of random convolutional kernels were used to transform the signals, and the resulting features are utilized to classify the various emotion states. In addition to accurately and automatically extracting the multi-scale features from ECG signals, combining the random convolutional kernels with ECG signal alone also reduces the computational complexity and training time compared to methods using multiple physiological signals or deep neural networks. Validation on three publicly available datasets revealed that the proposed method achieved recognition accuracies of 91.5%, 96% and 92.5% for valence, arousal and dominance in AMIGOS dataset, and 95.1%, 98.8% and 90.2% for same labels in DREAMER dataset. The accuracy for valence, arousal and affective states in WESAD dataset are 94.5%, 91.8% and 91.8%. The results show that the proposed method outperforms previous researches in multi-class emotion recognition, thus offering a new and promising approach for swift and precise emotion recognition.

Brainstem astrocytes regulate breathing and may affect arousal state in rats

Variations in arousal levels can impact respiratory patterns. The mechanisms by which breathing behaviors can influence arousal state is not fully understood. In this study, we investigated the role of astrocytes in the preBötzinger complex (preBötC) in modulating arousal states via breathing in adult conscious rats. Using viral vector tools, we selectively interfered with astrocytic signaling in the preBötC. Rats with inhibited astrocytic signaling exhibited slower breathing rates and behaviors indicative of a calmer state, whereas enhanced purinergic signaling in preBötC astrocytes led to faster breathing and heightened arousal. Our findings reveal a key role for an astrocyte-mediated mechanism in the preBötC that influences both respiratory behaviors and higher-order brain functions like arousal, suggesting a bidirectional link between breathing behaviors and mental states.

Bayesian Inference of Hidden Cognitive Performance and Arousal States in Presence of Music.

Goal: Poor arousal management may lead to reduced cognitive performance. Specifying a model and decoder to infer the cognitive arousal and performance contributes to arousal regulation via non-invasive actuators such as music. Methods: We employ a Bayesian filtering approach within an expectation-maximization framework to track the hidden states during the [Formula: see text]-back task in the presence of calming and exciting music. We decode the arousal and performance states from the skin conductance and behavioral signals, respectively. We derive an arousal-performance model based on the Yerkes-Dodson law. We design a performance-based arousal decoder by considering the corresponding performance and skin conductance as the observation. Results: The quantified arousal and performance are presented. The existence of Yerkes-Dodson law can be interpreted from the arousal-performance relationship. Findings display higher matrices of performance within the exciting music. Conclusions: The performance-based arousal decoder has a better agreement with the Yerkes-Dodson law. Our study can be implemented in designing non-invasive closed-loop systems.

Interactive effects of pain and arousal state on heart rate and cortical activity in the mouse anterior cingulate and somatosensory cortices

Sensory disconnection is a hallmark of sleep, yet the cortex retains some ability to process sensory information. Acute noxious stimulation during sleep increases the heart rate and the likelihood of awakening, indicating that certain mechanisms for pain sensing and processing remain active. However, processing of somatosensory information, including pain, during sleep remains underexplored. To assess somatosensation in natural sleep, we simultaneously recorded heart rate and local field potentials in the anterior cingulate (ACC) and somatosensory (S1) cortices of naïve, adult male mice, while applying noxious and non-noxious stimuli to their hind paws throughout their sleep-wake cycle. Noxious stimuli evoked stronger heart rate increases in both wake and non-rapid eye movement sleep (NREMS), and resulted in larger awakening probability in NREMS, as compared to non-noxious stimulation, suggesting differential processing of noxious and non-noxious information during sleep. Somatosensory information differentially reached S1 and ACC in sleep, eliciting complex transient and sustained responses in the delta, alpha, and gamma frequency bands as well as somatosensory evoked potentials. These dynamics depended on sleep state, the behavioral response to the stimulation and stimulation intensity (non-noxious vs. noxious). Furthermore, we found a correlation of the heart rate with the gamma band in S1 in the absence of a reaction in wake and sleep for noxious stimulation. These findings confirm that somatosensory information, including nociception, is sensed and processed during sleep even in the absence of a behavioral response.

MANAGEMENT OF A PATIENT PRESENTED WITH AMITRIPTILINE POISONING- A RARE CASE REPORT

Abstract Tricyclic Antidepressant overdose for suicidal poisoning purpose is not frequent but still possible in patient and his near relative due to its availability at home. On susception laboratory testing is required for many poisons but availability is limited and any delay in diagnosis and starting management may worsen the patient&amp;apos;s condition. Amongst all TCAs, Amitriptyline is classic having sedative and anticholinergic properties. Its self-poisoning is not that much common in general population. Here we are reporting a case of Amitriptyline poisoning in a healthy women aged 30 years brought by relatives with drowsiness and giddiness to our Emergency Medicine Department, LG Hospital, Narendra Modi Medical College, Ahmedabad. Her relatives had given history of self-ingestion of 30 Tab of Amitriptyline Hydrochloride. Each Tablet contained 25 mg of drug molecule. On examination in ED, patient was in drowsy but arousable state. Patient had tachycardia (130/min), high blood pressure (140/90 mm of Hg) and tachypnoea (RR 24/min). Except tachycardia her ECG did not show any significant findings. She was taking Tab. Amitriptyline for her psychiatric problems. Urine sample for toxicology was sent and the reports were normal. Other blood investigations were normal. In emergency room, Ryle&amp;apos;s tube inserted, gastric sample was collected and she was given activated charcoal lavage and force alkaline diuresis with Inj. Furosemide with saline. She was shifted to emergency ICU for further management. After 12 hours patient was conscious and oriented with stable hemodynamic. She was referred to psychiatry department and then transferred to Medicine department for further care. She remained stable there and discharged after 2 days.

Does movement preparation enhance attending to bodily sensations in the back in people with persistent low back pain?

Attention has been proposed to play an important role in persisting pain, with excessive attentional processes towards pain information leading to worse pain outcomes and maladaptive behaviors. Nevertheless, research on somatosensory attending during the anticipation of pain-related movements is still scarce. This study investigated if individuals with chronic and recurrent lower back pain compared to pain-free controls, show enhanced attending to somatosensory information in the back while anticipating back-recruiting movements. 43 healthy control, 33 recurrent (RLBP) and 33 chronic low back (CLBP) pain sufferers were asked to perform back-recruiting movements. Before the movement initiation cue, a task-irrelevant tactile stimulus was administered to participants' lower back to elicit somatosensory evoked potentials (SEPs), used as an index of somatosensory attending. In contrast to our hypothesis, most identified SEP components did not differ across groups. The only exception was the P175 amplitude which was larger for the CLBP group compared to individuals with RLBP and healthy controls. The current study did not find robust evidence of enhanced somatosensory attending to the back in people with persisting lower back pain. The finding that CLBP, but not RLBP individuals, had larger amplitudes to the P175 component, is discussed as possibly reflecting a higher state of emotional arousal in these patients when having to prepare the back-recruiting movements.

Pupil Dynamics, Salivary Alpha-Amylase, and Prefrontal Haemodynamics in Response to Very Light Exercise.

This study aimed to investigate the effects of exercise on pupil dynamics, prefrontal haemodynamic, and salivary alpha-amylase (sAA) responses in 45 healthy graduate students. These participants were divided into two groups: a resting control group (CTL) and a very-light-intensity exercise group (EX). Participants in the EX-group engaged in a 10-min exercise at 30% O2 peak on a cycle ergometer. Salivary samples and pupillometry assessments were collected before the exercise, at the end of the exercise, and 5 min after the completion to evaluate changes over time. Our analysis showed that exercise induced significant changes in the secretion of salivary alpha-amylase, with elevated levels suggesting increased neuroendocrine activity linked to the arousal state triggered by exercise. In addition, functional oxyHb signals indicated greater fluctuations in the mid-left prefrontal cortex among participants in the EX-group compared to those in the CTL group, pointing to altered prefrontal haemodynamic.

A Unified Dynamic Model for the Decomposition of Skin Conductance and the Inference of Sudomotor Nerve Activities.

Electrodermal activity (EDA), commonly measured as skin conductance (SC), is a widely used physiological signal in psychological research and behavioral health applications. EDA is considered an indicator of arousal, a key aspect of emotion and stress. This work proposes a data-driven dynamic system model that characterizes the temporal dynamics of skin conductance and infers the latent arousal signal, utilizing techniques from system identification and sparse optimization. It introduces a fourth-order, linear time-invariant model for the overall skin conductance signal, including both the tonic and phasic components. The model was applied to a large dataset of over 200 participants to evaluate model fit. Furthermore, a three-component decomposition of skin conductance is introduced, based on mathematical definitions derived from the model, which provides key insights into the temporal dynamics of skin conductance. Comparative evaluation shows that the estimated latent neural signal effectively differentiates between high and low arousal states, while maintaining expected physiological properties. This work lays the foundation for numerous behavioral health applications and paves the road for designing physiology-based interventions aimed at regulating arousal.

Neuronal Hyperactivity in the Hippocampus during the Early Stage of Streptozotocin-Induced Type 1 Diabetes in Mice

Introduction: Cognitive dysfunction due to reduced neuronal transmission in the brain is a major emerging complication in diabetes. However, recent neuroimaging studies have demonstrated non-linear changes including hyperactivity in the hippocampus during the early stage of diabetes. This study aimed to determine the changes in neuronal activity at a single-cell level in hippocampal CA1 pyramidal neurons in the early stage of streptozotocin-induced type 1 diabetes in mice. Methods: Whole-cell patch-clamp recordings from acute brain slices were performed in mice over 4 consecutive weeks following the induction of hyperglycaemia using streptozotocin. In addition, microdialysate was collected from CA1 area while the mice were in an arousal state. The concentrations of glutamate and GABA in the microdialysate were then measured using ultra-performance liquid chromatography with mass spectrometry. Results: CA1 neurons in streptozotocin-induced diabetic mice exhibited higher membrane potentials (p = 0.0052), higher frequency of action potentials (p = 0.0052), and higher frequency of spontaneous excitatory post-synaptic currents (p = 0.037) compared with controls during the second week after hyperglycaemia was established. No changes in electrophysiological parameters were observed during the first, the third, and the fourth week. Moreover, the diabetic mice had higher extracellular glutamate concentration in CA1 area compared with controls (p = 0.021) during the second week after the initiation of diabetes. No change in the extracellular GABA concentration was observed. Conclusion: Our study demonstrated a temporary state of neuronal hyperactivity at the single-cell level in the hippocampal CA1 region during the early stage of diabetes. This neuronal hyperactivity might be related to altered glutamate metabolism and provide clues for future brain-target intervention.

The neural correlates of arousal: Ventral posterolateral nucleus-global transient co-activation

Arousal and awareness are two components of consciousness whose neural mechanisms remain unclear. Spontaneous peaks of global (brain-wide) blood-oxygenation-level-dependent (BOLD) signal have been found to be sensitive to changes in arousal. By contrasting BOLD signals at different arousal levels, we find decreased activation of the ventral posterolateral nucleus (VPL) during transient peaks in the global signal in low arousal and awareness states (non-rapid eye movement sleep and anesthesia) compared to wakefulness and in eyes-closed compared to eyes-open conditions in healthy awake individuals. Intriguingly, VPL-global co-activation remains high in patients with unresponsive wakefulness syndrome (UWS), who exhibit high arousal without awareness, while it reduces in rapid eye movement sleep, a state characterized by low arousal but high awareness. Furthermore, lower co-activation is found in individuals during N3 sleep compared to patients with UWS. These results demonstrate that co-activation of VPL and global activity is critical to arousal but not to awareness.

Sensory neurons couple arousal and foraging decisions in Caenorhabditis elegans

Foraging animals optimize feeding decisions by adjusting both common and rare behavioral patterns. Here, we characterize the relationship between an animal’s arousal state and a rare decision to leave a patch of bacterial food. Using long-term tracking and behavioral state classification, we find that food leaving decisions in Caenorhabditis elegans are coupled to arousal states across multiple timescales. Leaving emerges probabilistically over minutes from the high arousal roaming state, but is suppressed during the low arousal dwelling state. Immediately before leaving, animals have a brief acceleration in speed that appears as a characteristic signature of this behavioral motif. Neuromodulatory mutants and optogenetic manipulations that increase roaming have a coupled increase in leaving rates, and similarly acute manipulations that inhibit feeding induce both roaming and leaving. By contrast, inactivating a set of chemosensory neurons that depend on the cGMP-gated transduction channel TAX-4 uncouples roaming and leaving dynamics. In addition, tax-4-expressing sensory neurons promote lawn-leaving behaviors that are elicited by feeding inhibition. Our results indicate that sensory neurons responsive to both internal and external cues play an integrative role in arousal and foraging decisions.

Sensory neurons couple arousal and foraging decisions in Caenorhabditis elegans.

Foraging animals optimize feeding decisions by adjusting both common and rare behavioral patterns. Here, we characterize the relationship between an animal's arousal state and a rare decision to leave a patch of bacterial food. Using long-term tracking and behavioral state classification, we find that food leaving decisions in Caenorhabditis elegans are coupled to arousal states across multiple timescales. Leaving emerges probabilistically over minutes from the high arousal roaming state, but is suppressed during the low arousal dwelling state. Immediately before leaving, animals have a brief acceleration in speed that appears as a characteristic signature of this behavioral motif. Neuromodulatory mutants and optogenetic manipulations that increase roaming have a coupled increase in leaving rates, and similarly acute manipulations that inhibit feeding induce both roaming and leaving. By contrast, inactivating a set of chemosensory neurons that depend on the cGMP-gated transduction channel TAX-4 uncouples roaming and leaving dynamics. In addition, tax-4-expressing sensory neurons promote lawn-leaving behaviors that are elicited by feeding inhibition. Our results indicate that sensory neurons responsive to both internal and external cues play an integrative role in arousal and foraging decisions.

Electrodermal activity: A continuous monitor of well-being

A smart society should not only support the efficiency and effectiveness of processes, they should also have the ability to comprehend and support its inhabitants well-being. To enable this, we need continuous information on individual’s well-being. As a first step, we suggest to evaluate people’s long term stress level, as it sheds light on their well-being. We propose using the biosignal Electrodermal Activity (EDA), a proven measure of people’s arousal or stress. Moreover, EDA can be measured continuously, in real-time, and unobtrusively via wearables. To assess this idea’s feasibility, the CASE, CEAP-360VR, and K-EmoCon datasets, including both continuous EDA recordings and continuous subjective self-reported arousal, were analyzed. With CASE and CEAP-360VR, a multilevel analysis unveiled that the frequency and amplitude of EDA’s non-specific skin conductance responses significantly correlated with the self-reported arousal. With K-EmoCon, this correlation was absent, which can be explained by the low arousal condition of this dataset. The latter also signals a main limitation: the lack of sensitivity of the proposed signal. Nevertheless, the results are promising as they show potential for EDA as a continuous stress monitor. Therefore, we are optimistic that a future smart society can be enabled to monitor and improve their inhabitant’s well-being.

Neural complexity and the spectral slope characterise auditory processing in wakefulness and sleep.

Auditory processing and the complexity of neural activity can both indicate residual consciousness levels and differentiate states of arousal. However, how measures of neural signal complexity manifest in neural activity following environmental stimulation and, more generally, how the electrophysiological characteristics of auditory responses change in states of reduced consciousness remain under-explored. Here, we tested the hypothesis that measures of neural complexity and the spectral slope would discriminate stages of sleep and wakefulness not only in baseline electroencephalography (EEG) activity but also in EEG signals following auditory stimulation. High-density EEG was recorded in 21 participants to determine the spatial relationship between these measures and between EEG recorded pre- and post-auditory stimulation. Results showed that the complexity and the spectral slope in the 2-20 Hz range discriminated between sleep stages and had a high correlation in sleep. In wakefulness, complexity was strongly correlated to the 20-40 Hz spectral slope. Auditory stimulation resulted in reduced complexity in sleep compared to the pre-stimulation EEG activity and modulated the spectral slope in wakefulness. These findings confirm our hypothesis that electrophysiological markers of arousal are sensitive to sleep/wake states in EEG activity during baseline and following auditory stimulation. Our results have direct applications to studies using auditory stimulation to probe neural functions in states of reduced consciousness.

Effect of sleep deprivation and NREM sleep stage on physiological brain pulsations.

Sleep increases brain fluid transport and the power of pulsations driving the fluids. We investigated how sleep deprivation or electrophysiologically different stages of non-rapid-eye-movement (NREM) sleep affect the human brain pulsations. Fast functional magnetic resonance imaging (fMRI) was performed in healthy subjects (n = 23) with synchronous electroencephalography (EEG), that was used to verify arousal states (awake, N1 and N2 sleep). Cardiorespiratory rates were verified with physiological monitoring. Spectral power analysis assessed the strength, and spectral entropy assessed the stability of the pulsations. In N1 sleep, the power of vasomotor (VLF < 0.1 Hz), but not cardiorespiratory pulsations, intensified after sleep deprived vs. non-sleep deprived subjects. The power of all three pulsations increased as a function of arousal state (N2 > N1 > awake) encompassing brain tissue in both sleep stages, but extra-axial CSF spaces only in N2 sleep. Spectral entropy of full band and respiratory pulsations decreased most in N2 sleep stage, while cardiac spectral entropy increased in ventricles. In summary, the sleep deprivation and sleep depth, both increase the power and harmonize the spectral content of human brain pulsations.

P16: Report on a Dementia Prevention Workshop Organized through Multidiscipline Intervention: An Examination of Intervention Approach through the Evaluation of Group Reminiscence Method and Mental Aspect

Objective:This is a report of a workshop for local residents organized by university researchers in various fields with the aim to develop a dementia prevention method. The five academic fields involved in the project are Health &amp; Sports, Psychology, Food Nutrition, Music, and Nursing.Methods:Dementia Prevention Workshop took place once a week between October 2021 and July 2022 except for some intervals due to surges in Covid-19 infection cases. Dual task exercises were conducted at each session, followed by groupworks by researchers of Psychology, Nutrition, Music, and Nursing Science taking turns. Psychologists facilitated the understanding of assertion, nutritionists held lectures on food life designed for dementia prevention, musicians played instruments, and nurses intervened through the Group Reminiscence Method. The Nursing Science experts conducted evaluations at the beginning and the end of each session using SF-36 and CES-D and checked the participants’ mood before and after the reminiscence session with Japanese UWIST mood adjective checklist (JUMACL).Results:16 participants took the measurement after the workshop, and their average age (SD) was 72.9 (5.5). In the overall evaluation, the participants’ motor ability improved(p&lt;.05), and they retained cognitive functions. In SF-36, no statistically significant differences were observed before and after the classroom. Compared to the data from 2017, the scores in the social aspect were lower. In CES-D, the scores significantly worsened after the workshop, with some participants’ scores exceeding 16 points, which is the depression cutoff point. In JUMACL, the Tense Arousal (TA) related to the arousal state and the Energetic Arousal (EA), which is supposedly related to intellectual activities, both improved after the session.Conclusion:In a single evaluation before and after a group reminiscence session, the state of relaxed concentration with a suggested connection with intellectual activities, but the overall evaluation result throughout the workshop project suggested the need to reinforce the approach to the mental aspect because of some participants observed with decreased scores in the mental aspects with depressive tendency. We will establish an intervention plan by also incorporating the impact of Covid-19-related depression.

The world prefers a calm life, but not everyone gets to have one: global trends in valuing and experiencing calmness in the Gallup World Poll

ABSTRACT Psychology has paid relatively little attention to low arousal positive states like calmness. To remedy this lacuna, this study draws on the most globally comprehensive study to date on calmness (121,207 participants in 116 countries in the 2020 Gallup World Poll), featuring two items asking whether people: (a) prefer a calm life or an exciting life; and (b) experienced calmness yesterday. By intersecting these, we could categorise people in four categories of calmness: satisfied (both prefer and experience it); unwanted (experience calmness but prefer excitement); longed-for (prefer calmness but don’t experience it); and unmissed (neither prefer nor experience it). The results reveal a nuanced picture that challenges certain stereotypes (e.g. calmness had no particular association here with Eastern cultures), and shed new light on this overlooked topic (e.g. poorer people and countries are more likely to prefer calmness yet are less likely to actually experience it).