Increased cortisol and decreased right ear advantage (REA) in dichotic listening following a negative mood induction

The influence of stress on the neural underpinnings of disinhibited eating: a systematic review and future directions for research

Disinhibited eating involves overconsumption and loss of control over food intake, and underpins many health conditions, including obesity and binge-eating related disorders. Stress has been implicated in the development and maintenance of disinhibited eating behaviours, but the mechanisms underlying this relationship are unclear. In this systematic review, we examined how the impact of stress on the neurobiological substrates of food-related reward sensitivity, interoception and cognitive control explains its role in disinhibited eating behaviours. We synthesised the findings of functional magnetic resonance imaging studies including acute and/or chronic stress exposures in participants with disinhibited eating. A systematic search of existing literature conducted in alignment with the PRISMA guidelines identified seven studies investigating neural impacts of stress in people with disinhibited eating. Five studies used food-cue reactivity tasks, one study used a social evaluation task, and one used an instrumental learning task to probe reward, interoception and control circuitry. Acute stress was associated with deactivation of regions in the prefrontal cortex implicated in cognitive control and the hippocampus. However, there were mixed findings regarding differences in reward-related circuitry. In the study using a social task, acute stress associated with deactivation of prefrontal cognitive control regions in response to negative social evaluation. In contrast, chronic stress was associated with both deactivation of reward and prefrontal regions when viewing palatable food-cues. Given the small number of identified publications and notable heterogeneity in study designs, we propose several recommendations to strengthen future research in this emerging field.

Modulation of Auditory Perception Laterality under Anxiety and Depression Conditions

The objective of this work is to confirm the asymmetry in non-linguistic auditory perception, as well as the influence of anxiety-depressive disorders on it. Eighty-six people were recruited in the emotional well-being group, fifty-six in the anxiety group, fourteen in the depression group, and seventy-seven in the mixed group. In each group, audiograms were obtained from both ears and the differences were statistically analyzed. Differences in hearing sensitivity were found between both ears in the general population, such differences increased in people with anxiety-depressive disorders. When faced with anxiety-depressive disorders, the right ear suffered greater hearing loss than the left, showing peaks of hyper-hearing at the frequency of 4000 Hz in the anxiety subgroup, and hearing loss in the depression subgroup. In relation to anxiety, the appearance of the 4:8 pattern was observed in the right ear when the person had suffered acute stress in the 2 days prior to the audiometry, and in both ears if they had suffered stress in the 3–30 days before said stress. In conclusion, the advantage of the left ear in auditory perception was increased with these disorders, showing a hyperaudition peak in anxiety and a hearing loss in depression.

Does non-invasive brain stimulation modulate emotional stress reactivity?

Excessive emotional responses to stressful events can detrimentally affect psychological functioning and mental health. Recent studies have provided evidence that non-invasive brain stimulation (NBS) targeting the prefrontal cortex (PFC) can affect the regulation of stress-related emotional responses. However, the reliability and effect sizes have not been systematically analyzed. In the present study, we reviewed and meta-analyzed the effects of repetitive transcranial magnetic (rTMS) and transcranial direct current stimulation (tDCS) over the PFC on acute emotional stress reactivity in healthy individuals. Forty sham-controlled single-session rTMS and tDCS studies were included. Separate random effects models were performed to estimate the mean effect sizes of emotional reactivity. Twelve rTMS studies together showed no evidence that rTMS over the PFC influenced emotional reactivity. Twenty-six anodal tDCS studies yielded a weak beneficial effect on stress-related emotional reactivity (Hedges’ g = −0.16, CI_95% = [−0.33, 0.00]). These findings suggest that a single session of NBS is insufficient to induce reliable, clinically significant effects but also provide preliminary evidence that specific NBS methods can affect emotional reactivity. This may motivate further research into augmenting the efficacy of NBS protocols on stress-related processes.

Acoustics versus linguistics? Context is Part and Parcel to lateralized processing of the parts and parcels of speech

The purpose of this review is to provide an accessible exploration of key considerations of lateralization in speech and non-speech perception using clear and defined language. From these considerations, the primary arguments for each side of the linguistics versus acoustics debate are outlined and explored in context of emerging integrative theories. This theoretical approach entails a perspective that linguistic and acoustic features differentially contribute to leftward bias, depending on the given context. Such contextual factors include stimulus parameters and variables of stimulus presentation (e.g., noise/silence and monaural/binaural) and variances in individuals (sex, handedness, age, and behavioural ability). Discussion of these factors and their interaction is also aimed towards providing an outline of variables that require consideration when developing and reviewing methodology of acoustic and linguistic processing laterality studies. Thus, there are three primary aims in the present paper: (1) to provide the reader with key theoretical perspectives from the acoustics/linguistics debate and a synthesis of the two viewpoints, (2) to highlight key caveats for generalizing findings regarding predominant models of speech laterality, and (3) to provide a practical guide for methodological control using predominant behavioural measures (i.e., gap detection and dichotic listening tasks) and/or neurophysiological measures (i.e., mismatch negativity) of speech laterality.

The Other End of the Line

Abstract. The two hemispheres of the human brain are asymmetrically involved in representing a person’s motivational orientation: Approach motivation is reflected in greater activation of the left hemisphere, whereas avoidance motivation more strongly activates the right hemisphere. Visuospatial bias, as assessed in the line-bisection task, is often used as a simple behavioral measure of relative hemispheric activation. In three experiments, we investigated whether affect-induced approach and avoidance motivation are associated with spatial biases in line-bisection performance. Happy or terrifying pictures (Experiment 1, N = 70), happy or sad music (Experiment 2, N = 50), and joyful or frightening videos (Experiment 3, N = 90) were used to induce negative and positive affect. Mood-induction procedures successfully changed emotional states in the intended direction. However, our analyses revealed no effect of mood on visuospatial biases in the line-bisection task. Additional Bayesian analyses also provided more evidence against the hypothesized effect than in favor of it. Thus, visuospatial bias in line bisection does not seem to be a sensitive measure of approach and avoidance motivation induced by positive and negative affect.

Seeing a Face in a Crowd of Emotional Voices: Changes in Perception and Cortisol in Response to Emotional Information across the Senses

One source of information we glean from everyday experience, which guides social interaction, is assessing the emotional state of others. Emotional state can be expressed through several modalities: body posture or movements, body odor, touch, facial expression, or the intonation in a voice. Much research has examined emotional processing within one sensory modality or the transfer of emotional processing from one modality to another. Yet, less is known regarding interactions across different modalities when perceiving emotions, despite our common experience of seeing emotion in a face while hearing the corresponding emotion in a voice. Our study examined if visual and auditory emotions of matched valence (congruent) conferred stronger perceptual and physiological effects compared to visual and auditory emotions of unmatched valence (incongruent). We quantified how exposure to emotional faces and/or voices altered perception using psychophysics and how it altered a physiological proxy for stress or arousal using salivary cortisol. While we found no significant advantage of congruent over incongruent emotions, we found that changes in cortisol were associated with perceptual changes. Following exposure to negative emotional content, larger decreases in cortisol, indicative of less stress, correlated with more positive perceptual after-effects, indicative of stronger biases to see neutral faces as happier.

Cortisol and trait anxiety as relevant factors involved in memory performance in people with drug-resistant epilepsy

People with drug-resistant epilepsy are exposed to unpredictable and uncontrollable seizures, which can be considered as a chronic stress condition. Additionally, these patients present memory deficits and a high prevalence of depression and anxiety. Cortisol, the main stress hormone, has a modulatory role on memory in healthy individuals and patients with emotional disorders, but its role in memory and emotional processes remains unclear in people with epilepsy. This study analyzes the differences in cortisol levels in people with epilepsy with high and low memory performance, and the relationships among cortisol levels, epilepsy-related factors, memory, anxiety, and depression. Fifty-two adults with drug-resistant epilepsy underwent a neuropsychological evaluation, in which nine saliva samples were collected to analyze the ability of the hypothalamic-pituitary-adrenal axis to descend in accordance with the circadian rhythm. Cortisol area under the curve (AUC) was computed to study the global cortisol changes. Patients with low immediate and delayed memory performance and left-hemisphere focus showed higher cortisol levels. Additionally, patients with low memory scores had higher cortisol AUC, and therefore slower declining levels in the afternoon. Memory performance was negatively related to the cortisol AUC and trait anxiety, being both reliable predictors of memory performance, especially in patients with left-hemisphere focus. These results suggest that memory deficits in people with drug-resistant epilepsy may be influenced by exposure to cortisol derived from chronic stress. Additionally, trait anxiety could contribute to increasing the vulnerability to stress.

Psychobiological response to an anger induction task in schizophrenia: The key role of anxiety

In this study an anger induction laboratory task was applied to men with schizophrenia, and resulted in significant changes in different psychophysiological parameters that were measured in a pre-post design. We observed a significantly greater self-reported anger mood and negative affection, lower self-reported positive affection, an increase in cardiovascular reactivity (with blood pressure in deeper affection compared to controls), higher salivary testosterone levels, lower salivary cortisol levels, and an increase in right ear items reported in dichotic listening. Furthermore, clinical risk factors related to anger in our patients were analyzed by Stepwise Regression analyses. Trait anger was significantly associated with a higher level of delusional pathology and impulsivity. Regarding the resulted state of anger as an output of the induction, the most relevant finding was that anxiety consistently and significantly predicted the increasing in anger feelings, and, remarkably, it predicted also the increasing in T levels and the cardiovascular reactivity of the patients.

Negative urgency, mood induction, and alcohol seeking behaviors

BACKGROUND

Negative urgency, defined as impulsive risk-taking during extreme negative emotional states, is the most important impulsivity-related trait for alcohol-related problems and alcohol dependence. However, how negative urgency imparts risk for alcohol-related problems is not yet well understood. Therefore, the goal of the current study was to examine how negative urgency relates to separable aspects of the emotional experience and alcohol-seeking behaviors.

METHODS

A total of 34 (19 women) community-dwelling, alcohol-using adults aged 21-32 (mean age=24.86, SD=3.40, 74.3% Caucasian) completed two counterbalanced intravenous alcohol self-administration sessions: one during a neutral mood condition and one during a negative mood condition.

RESULTS

Negative urgency was associated with 1) greater mood change following negative mood induction (F=4.38, df=15, p=0.002, η2=0.87), but was unrelated to changes in craving or cortisol release in response to mood induction; 2) greater alcohol craving prior to and after an alcohol prime (F=3.27, p=0.02, η2=0.86), but only in the negative and not the neutral mood condition; and 3) higher peak BrAC (F=2.13, df=42, p=0.02, η2=0.48), continuing to increase intoxication level over a longer period (F=3.77, df=42, p<0.001, η2=0.62), and more alcohol seeking (F=21.73, df=22, p<0.001, η2=0.94) throughout the negative session. Negative urgency was associated with overall lower cortisol release.

CONCLUSIONS

These results highlight the importance of assessing behavioral indicators of negative urgency under mood condition, and suggest that negative urgency may amplify alcohol self-administration through increased negative emotional reactivity to mood events and increased alcohol craving after initial alcohol exposure, leading to maintenance of alcohol related behavior.

Music-induced changes in functional cerebral asymmetries

After decades of research, it remains unclear whether emotion lateralization occurs because one hemisphere is dominant for processing the emotional content of the stimuli, or whether emotional stimuli activate lateralised networks associated with the subjective emotional experience. By using emotion-induction procedures, we investigated the effect of listening to happy and sad music on three well-established lateralization tasks. In a prestudy, Mozart's piano sonata (K. 448) and Beethoven's Moonlight Sonata were rated as the most happy and sad excerpts, respectively. Participants listened to either one emotional excerpt, or sat in silence before completing an emotional chimeric faces task (Experiment 1), visual line bisection task (Experiment 2) and a dichotic listening task (Experiment 3 and 4). Listening to happy music resulted in a reduced right hemispheric bias in facial emotion recognition (Experiment 1) and visuospatial attention (Experiment 2) and increased left hemispheric bias in language lateralization (Experiments 3 and 4). Although Experiments 1-3 revealed an increased positive emotional state after listening to happy music, mediation analyses revealed that the effect on hemispheric asymmetries was not mediated by music-induced emotional changes. The direct effect of music listening on lateralization was investigated in Experiment 4 in which tempo of the happy excerpt was manipulated by controlling for other acoustic features. However, the results of Experiment 4 made it rather unlikely that tempo is the critical cue accounting for the effects. We conclude that listening to music can affect functional cerebral asymmetries in well-established emotional and cognitive laterality tasks, independent of music-induced changes in the emotion state.

Gender-Specific Effects of Mood on Alcohol-Seeking Behaviors: Preliminary Findings Using Intravenous Alcohol Self-Administration

BACKGROUND

Although negative mood has long been implicated in differences in alcohol seeking by men and women, little research has used precise, well-controlled laboratory experiments to examine how negative mood affects alcohol-seeking behaviors.

METHODS

A total of 34 (19 women) community-dwelling, alcohol-using adults aged 21 to 32 (mean age = 24.86, SD = 3.40, 74.3% Caucasian; Alcohol Use Disorders Identification Test [AUDIT] = 10.1, SD = 3.4) completed 2 counterbalanced intravenous alcohol self-administration sessions: one under negative mood and one under neutral mood. Fourteen individuals (9 women; mean age = 25.00, SD = 2.77) participated in an alcohol "liking" experiment (i.e., free access [FA] drinking) and 20 individuals (10 women; mean age = 24.77, SD = 3.73) participated in an alcohol "wanting" experiment, in which gaining access to alcohol required progressively effortful work. There was no significant difference between men and women on the AUDIT, t(32) = -0.38, p = 0.71.

RESULTS

Priming with negative mood induction caused a significant decrease in self-reported mood (mean change = -1.85, t(32) = -6.81, p < 0.001), as intended. In FA, negative mood was associated with a significantly increased peak breath alcohol concentration (BrAC; F = 9.41, p = 0.01), with a trend toward a greater effect in men than in women (F = 2.67, p = 0.13). Negative mood also had a significant effect on peak BrAC achieved in the progressive work paradigm (F = 5.28, p = 0.04), with a significantly stronger effect in men (F = 5.35, p = 0.03) than women; men also trended toward more consistent work for alcohol across both neutral and negative sessions.

CONCLUSIONS

These preliminary findings demonstrate a gender-specific response on how mood affects alcohol seeking and suggest gender-specific interventions to prevent mood-based alcohol consumption.

Mood modulates auditory laterality of hemodynamic mismatch responses during dichotic listening

Hemodynamic mismatch responses can be elicited by deviant stimuli in a sequence of standard stimuli even during cognitive demanding tasks. Emotional context is known to modulate lateralized processing. Right-hemispheric negative emotion processing may bias attention to the right and enhance processing of right-ear stimuli. The present study examined the influence of induced mood on lateralized pre-attentive auditory processing of dichotic stimuli using functional magnetic resonance imaging (fMRI). Faces expressing emotions (sad/happy/neutral) were presented in a blocked design while a dichotic oddball sequence with consonant-vowel (CV) syllables in an event-related design was simultaneously administered. Twenty healthy participants were instructed to feel the emotion perceived on the images and to ignore the syllables. Deviant sounds reliably activated bilateral auditory cortices and confirmed attention effects by modulation of visual activity. Sad mood induction activated visual, limbic and right prefrontal areas. A lateralization effect of emotion-attention interaction was reflected in a stronger response to right-ear deviants in the right auditory cortex during sad mood. This imbalance of resources may be a neurophysiological correlate of laterality in sad mood and depression. Conceivably, the compensatory right-hemispheric enhancement of resources elicits increased ipsilateral processing.

Emotional prosody rarely affects the spatial distribution of visual attention

Emotional manipulations have been demonstrated to produce leftward shifts in perceptual asymmetries. However, much of this research has used linguistic tasks to assess perceptual asymmetry and there are therefore two interpretations of the leftward shift. It may reflect a leftward shift in the spatial distribution of attention as a consequence of emotional activation of the right hemisphere; alternatively it may reflect emotional facilitation of right hemisphere linguistic processing. The current study used two non-linguistic attention tasks to determine whether emotional prosody influences the spatial distribution of visual attention. In a dual-task paradigm participants listened to semantically neutral sentences in neutral, happy or sad prosodies while completing a target discrimination task (Experiment 1) and a target detection task (Experiments 2 and 3). There was only one condition in one experiment that induced perceptual asymmetries that interacted with emotional prosody, suggesting that task-irrelevant emotional prosody only rarely directs attention. Instead a more likely cause of the leftward perceptual shift for comprehension of emotional speech is facilitation of right hemisphere linguistic processing.

The sad, the angry, and the asymmetrical brain: dichotic listening studies of negative affect and depression

Dichotic Listening (DL) is a valuable tool to study emotional brain lateralization. Regarding the perception of sadness and anger through affective prosody, the main finding has been a left ear advantage (LEA) for the sad but contradictory data for the anger prosody. Regarding an induced mood in the laboratory, its consequences upon DL were a diminished right ear advantage (REA) for the induction of sadness and an increased REA for the induction of anger. The global results fit with the approach-withdrawal motivational model of emotional processing, pointing to sadness as a right hemisphere emotion but anger processed bilaterally or even in the left hemisphere, depending on the subject's preferred mode of expression. On the other hand, the study of DL in clinically depressed patients found an abnormally larger REA in verbal DL tasks which was predictive of therapeutic pharmacological response. However, the mobilization of the available left hemisphere resources in these responders (reflected in a higher REA) would indicate a remission of the episode but would not assure the absence of new relapses.

Dichotic listening performance suggests right hemisphere involvement in PTSD

The present study focuses on language laterality as measured with dichotic listening (DL) to consonant-vowel syllables (CV syllables) in refugees with post-traumatic stress disorder (PTSD). PTSD is associated with impaired callosal transfer and with increased right hemisphere activation and impaired executive skills that could influence the processing of dichotic stimuli. A total of 22 participants with PTSD were compared to 23 participants without a diagnosis of PTSD. All participants had similar experiences of acts of war and political violence. They were tested with dichotic listening to CV syllables with free recall and directed attention following the forced attention paradigm. The PTSD group showed increased right ear advantage due to impaired left ear reporting and also smaller attention modulation compared to the control group, and the performance shared variance with self-report measures of arousal and intrusive memories. The results are discussed towards a model of impaired functionality of the frontal lobe and right hemisphere versus impaired callosal transfer, both yielding predictions for the processing of the left ear input and the ability to attention modulation of the performance.

What happens when we get angry? Hormonal, cardiovascular and asymmetrical brain responses

This study aimed to evaluate neuroendocrine and cardiovascular responses together with changes in brain asymmetry following an anger mood induction laboratory task. Previous research has shown an increase in heart rate and blood pressure when anger is experienced. Increased testosterone and decreased cortisol in response to anger and aggressive behavior have also been reported. With regard to asymmetrical frontal brain activity and emotion, the valence model links negative affect (as anger) to the right hemisphere while the motivational direction model links approach-related emotions (as anger) to the left hemisphere. From the subjective perception and from the neuroendocrine and cardiovascular response of the subjects, we can conclude that the self-referent statement anger induction method by Engebretson et al. (1999) was able to generate an experience of an anger affect in 30 healthy men. Another question was to analyze the consequences of that experience upon perceptual asymmetry when measured with a non-emotional laterality task. Regarding dichotic listening, an enhanced REA (right ear advantage) was observed after anger which indicates greater left hemisphere activity, supporting the motivational direction model.

The effect of stimulus intensity on the right ear advantage in dichotic listening

The dichotic listening test is non-invasive behavioural technique to study brain lateralization and it has been shown, that its results can be systematically modulated by varying stimulation properties (bottom-up effects) or attentional instructions (top-down effects) of the testing procedure. The goal of the present study was to further investigate the bottom-up modulation, by examining the effect of differences in the right or left ear stimulus intensity on the ear advantage. For this purpose, interaural intensity difference were gradually varied in steps of 3 dB from -21 dB in favour of the left ear to +21 dB in favour of the right ear, also including a no difference baseline condition. Thirty-three right-handed adult participants with normal hearing acuity were tested. The dichotic listening paradigm was based on consonant-vowel stimuli pairs. Only pairs with the same voicing (voice or non-voiced) of the consonant sound were used. The results showed: (a) a significant right ear advantage (REA) for interaural intensity differences from 21 to -3 dB, (b) no ear advantage (NEA) for the -6 dB difference, and (c) a significant left ear advantage (LEA) for differences form -9 to -21 dB. It is concluded that the right ear advantage in dichotic listening to CV syllables withstands an interaural intensity difference of -9 dB before yielding to a significant left ear advantage. This finding could have implications for theories of auditory laterality and hemispheric asymmetry for phonological processing.

Emotion and Pain: A Functional Cerebral Systems Integration

Emotion and pain are psychological constructs that have received extensive attention in neuropsychological research. However, neuropsychological models of emotional processing have made more progress in describing how brain regions interact to process emotion. Theories of emotional processing can describe inter-hemispheric and intra-hemispheric interactions during emotional processing. Due to similarities between emotion and pain, it is thought that emotional models can be applied to pain. The following review examines the neuropsychology of emotion and pain using a functional cerebral systems approach. Specific comparisons are made between pain and anger. Attention is given to differences in cerebral function and physiology that may contribute to the processing of emotion and pain. Suggestions for future research in emotion and pain are given.