Related Neural Activity Research Articles

Brain activation during social cognition predicts everyday perspective-taking: A combined fMRI and ecological momentary assessment study of the social brain

Identifying distinct neural networks underlying social affect (empathy, compassion) and social cognition (Theory of Mind) has advanced our understanding of social interactions. However, little is known about the relation of activation in these networks to psychological experience in daily life. This study (N = 122) examined the ecological validity of neural activation patterns induced by a laboratory paradigm of social affect and cognition with respect to social interactions in everyday life. We used the EmpaToM task, a naturalistic video-based paradigm for the assessment of empathy, compassion, and Theory of Mind, and combined it with a subsequent 14-day ecological momentary assessment protocol on social interactions. Everyday social affect was predicted by social affect experienced during the EmpaToM task, but not by related neural activation in regions of interest from the social affect network. In contrast, everyday social cognition was predicted by neural activation differences in the medial prefrontal cortex – a region of interest from the social cognition network – but not by social cognition performance in the EmpaToM task. The relationship between medial prefrontal cortex activation and everyday social cognition was stronger for spontaneous rather than deliberate perspective taking during the EmpaToM task, pointing to a distinction between propensity and capacity in social cognition. Finally, this neural indicator of Theory of Mind explained variance in everyday social cognition to a similar extent as an established self-report scale. Taken together, this study provides evidence for the ecological validity of lab-based social affect and cognition paradigms when considering relevant moderating factors.

Multidimensional Tuning in Motor Cortical Neurons during Active Behavior.

A region within songbird cortex, dorsal intermediate arcopallium (AId), is functionally analogous to motor cortex in mammals and has been implicated in song learning during development. Non-vocal factors such as visual and social cues are known to mediate song learning and performance, yet previous chronic-recording studies of regions important for song behavior have focused exclusively on neural activity in relation to song production. Thus, we have little understanding of the range of non-vocal information that single neurons may encode. We made chronic recordings in AId of freely behaving juvenile zebra finches and evaluated neural activity during diverse motor behaviors throughout entire recording sessions, including song production as well as hopping, pecking, preening, fluff-ups, beak interactions, scratching, and stretching. These movements are part of natural behavioral repertoires and are important components of both song learning and courtship behavior. A large population of AId neurons showed significant modulation of activity during singing. In addition, single neurons demonstrated heterogeneous response patterns during multiple movements (including excitation during one movement type and suppression during another), and some neurons showed differential activity depending on the context in which movements occurred. Moreover, we found evidence of neurons that did not respond during discrete movements but were nonetheless modulated during active behavioral states compared with quiescence. Our results suggest that AId neurons process both vocal and non-vocal information, highlighting the importance of considering the variety of multimodal factors that can contribute to vocal motor learning during development.

Influence of Fluoxetine on Perseverative Behavior-Related Activity in Lateral Orbitofrontal Cortex

In patients with obsessive-compulsive disorder (OCD), abnormal orbitofrontal cortex (OFC) activity normalizes after fluoxetine treatment. However, little is known about how fluoxetine affects encoding of compulsive behaviors in OFC neurons. Using the Sapap3-KO mouse as a model for OCD-relevant perseverative behaviors, we measured self-grooming related neural activity with in vivo calcium imaging in lateral OFC (LOFC) before and after fluoxetine treatment.

Functional magnetic resonance imaging (fMRI) item analysis of empathy and theory of mind.

In contrast to conventional functional magnetic resonance imaging (fMRI) analysis across participants, item analysis allows generalizing the observed neural response patterns from a specific stimulus set to the entire population of stimuli. In the present study, we perform an item analysis on an fMRI paradigm (EmpaToM) that measures the neural correlates of empathy and Theory of Mind (ToM). The task includes a large stimulus set (240 emotional vs. neutral videos to probe empathic responding and 240 ToM or factual reasoning questions to probe ToM), which we tested in two large participant samples (N = 178, N = 130). Both, the empathy‐related network comprising anterior insula, anterior cingulate/dorsomedial prefrontal cortex, inferior frontal gyrus, and dorsal temporoparietal junction/supramarginal gyrus (TPJ) and the ToM related network including ventral TPJ, superior temporal gyrus, temporal poles, and anterior and posterior midline regions, were observed across participants and items. Regression analyses confirmed that these activations are predicted by the empathy or ToM condition of the stimuli, but not by low‐level features such as video length, number of words, syllables or syntactic complexity. The item analysis also allowed for the selection of the most effective items to create optimized stimulus sets that provide the most stable and reproducible results. Finally, reproducibility was shown in the replication of all analyses in the second participant sample. The data demonstrate (a) the generalizability of empathy and ToM related neural activity and (b) the reproducibility of the EmpaToM task and its applicability in intervention and clinical imaging studies.

Dose-dependent effects of estrogen on prediction error related neural activity in the nucleus accumbens of healthy young women.

Whereas the effect of the sex steroid 17-beta-estradiol (E2) on dopaminergic (DA) transmission in the nucleus accumbens (NAc) is well evidenced in female rats, studies in humans are inconsistent. Moreover, linear and inverted u-shaped dose response curves have been observed for E2's effects on hippocampal plasticity, but the shape of dose response curves for E2's effects on the NAc is much less characterized. Investigation of dose response curves for E2's effects on DA-related neural activity in the human NAc. Placebo or E2 valerate in doses of 2, 4, 6 or 12 mg was orally administered to 125 naturally cycling young women during the low-hormone menstruation phase on two consecutive days using a randomized, double-blinded design. The E2 treatment regimen induced a wide range of E2 levels, from physiological (2- and 4-mg groups; equivalent to cycle peak) to supraphysiological levels (6- and 12-mg groups; equivalent to early pregnancy). This made it possible to study different dose response functions for E2's effects on NAc activity. During E2 peak, participants performed a well-established reversal learning paradigm. We used trial-wise prediction errors (PE) estimated via a computational reinforcement learning model as a proxy for dopaminergic activity. Linear and quadratic regression analyses predicting PE-related NAc activity from salivary E2 levels were calculated. There was a positive linear relationship between PE-associated NAc activity and salivary E2 increases. The randomized, placebo-controlled elevation of E2 levels stimulates NAc activity in the human brain, likely mediated by dopaminergic processes.

Mindfulness meditators show altered distributions of early and late neural activity markers of attention in a response inhibition task.

Attention is vital for optimal behavioural performance in every-day life. Mindfulness meditation has been shown to enhance attention. However, the components of attention altered by meditation and the related neural activities are underexplored. In particular, the contributions of inhibitory processes and sustained attention are not well understood. To address these points, 34 meditators were compared to 28 age and gender matched controls during electroencephalography (EEG) recordings of neural activity during a Go/Nogo response inhibition task. This task generates a P3 event related potential, which is related to response inhibition processes in Nogo trials, and attention processes across both trial types. Compared with controls, meditators were more accurate at responding to Go and Nogo trials. Meditators showed a more frontally distributed P3 to both Go and Nogo trials, suggesting more frontal involvement in sustained attention rather than activity specific to response inhibition. Unexpectedly, meditators also showed increased positivity over the right parietal cortex prior to visual information reaching the occipital cortex (during the pre-C1 window). Both results were positively related to increased accuracy across both groups. The results suggest that meditators show altered engagement of neural regions related to attention, including both higher order processes generated by frontal regions, and sensory anticipation processes generated by poster regions. This activity may reflect an increased capacity to modulate a range of neural processes in order to meet task requirements. This increased capacity may underlie the improved attentional function observed in mindfulness meditators.

Ecological Representations

Representations feature heavily in cognitive science theories about our behavioral repertoire. Their critical feature is its ability to designate (stand in for) spatially or temporally distant properties, so that organizing our behavior with respect to mental/neural representations means organizing our behavior with respect to the otherwise unavailable property they designate. Representations are a powerful tool, but serious problems (grounding, system-detectable error) remain unsolved. Ecological explanations reject representations. However, this has left us without a straightforward vocabulary to engage with “representation-hungry” problems involving spatial or temporal distance, nor the role of the nervous system in cognition. To develop such a vocabulary, here we show that ecological information functions to designate the ecologically scaled dynamical world to an organism. We then show that this designation analysis of information leads to an ecological conceptualization of the neural activity caused by information, and finally we argue these together can support intentional behavior with respect to spatially and temporally distal properties. The way they do so (via designation) does mean information and the related neural activity can be conceptualized as representations; but they do so in a grounded way that remains true to key ecological ontological commitments. We advocate this path for expanding the ecological approach.

The serotonin transporter gene variants modulate acute stress-induced hippocampus and dorsomedial prefrontal cortex activity during memory retrieval.

The short (s) allele of a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) is related to reduced serotonin transporter efficiency and an increased vulnerability to stress and mental disorders. In the present study, we investigated how 5-HTTLPR impacts on memory retrieval under stress and related neural activity by reanalyzing a small genetic neuroimaging data set. Twenty-seven healthy male volunteers participated in both the Trier Social Stress Test (TSST) and a respective control procedure and then their brain activity was measured with functional MRI (fMRI) while they performed an emotional-face-recognition task. Sixteen participants were carriers of the short allele (ss/sl carriers) and 11 were homozygous for the long allele (ll carriers). Genotype groups were compared with respect to stress-related physiological changes, memory performance, and brain activity. No significant genotype-dependent effects on memory performance or cortisol levels were found. The ss/sl carriers showed significantly higher systolic and diastolic blood pressure than the ll carriers, independent of stress. The ss/sl carriers reported stronger stress-induced nervous mood than the ll carriers. Our fMRI data revealed that the ss/sl carriers showed significantly weaker left hippocampus activation and stronger dorsomedial prefrontal cortex (dmPFC) deactivation when retrieving memories under stress as compared with the ll carriers. Subsequent analyses revealed that the distinct hippocampal activation pattern in both genotypes was associated with stress-induced cortisol elevation, while the distinct dmPFC activation pattern in both genotypes was associated with stress-induced changes in reaction times. Our results thus add new evidence that serotonin signaling modulates neural activity in the hippocampus and dmPFC during memory retrieval under acute psychosocial stress.

Age and Race-Related Differences in Sleep Discontinuity Linked to Associative Memory Performance and Its Neural Underpinnings.

There is a strong relationship between sleep and memory for the details of past events. In old age, both episodic memory performance and related neural activity decline. These changes occur in parallel to age-related decreases in sleep quality. Thus, poor sleep quality may be an explanatory factor for poor memory in older adulthood. Furthermore, Black adults tend to sleep more poorly than White adults, and this could be explained by differences in health and psychosocial factors (e.g., socioeconomic status, race-related stress). However, there have been no studies investigating the effect of race on sleep quality, episodic memory, and memory-related neural function. In the current pilot study, we recruited a diverse sample of older and younger adults and measured their habitual sleep using a wrist-worn accelerometer for 1 week. We recorded their electroencephalography (EEG) as they performed an episodic memory task to assess the impact of habitual sleep on memory-related neural oscillations. We found that more variable sleep quality was associated with worse memory performance, particularly for older adults. Additionally, Black participants demonstrated greater intraindividual sleep variance than White participants, and greater sleep variance was strongly linked to reduced memory-related neural activity in Black participants. Taken together, maintaining good sleep quality is especially important for memory performance in older adulthood, and greater sleep variation, that is evident in Black adults, may hamper memory-related neural function.

Contextual effects on binocular matching are evident in primary visual cortex

Global context can dramatically influence local visual perception. This phenomenon is well-documented for monocular features, e.g., the Kanizsa triangle. It has been demonstrated for binocular matching: the disambiguation of the Wallpaper Illusion via the luminance of the background. For monocular features, there is evidence that global context can influence neuronal responses as early as V1. However, for binocular matching, the activity in this area of the visual cortex is thought to represent local processing, suggesting that the influence of global context may occur at later stages of cortical processing. Here we sought to test if binocular matching is influenced by contextual effects in V1, using fMRI to measure brain activity while participants viewed perceptually ambiguous “wallpaper” stereograms whose depth was disambiguated by the luminance of the surrounding region. We localized voxels in V1 corresponding to the ambiguous region of the pattern, i.e., where the signal received from the eyes was not predictive of depth, and despite the ambiguity of the input signal, using multi-voxel pattern analysis we were able to reliably decode perceived (near/far) depth from the activity of these voxels. These findings indicate that stereoscopic related neural activity is influenced by global context as early as V1.

Acute and past subjective stress influence working memory and related neural substrates

Stress has been proposed to affect cognitive control capacities, including working memory (WM) maintenance. This effect may depend on variability in stress reactivity and past subjective stress. However, as most studies employed between-subjects designs, evidence for within-subject stress effects remains scarce. To understand the role of intra-individual stress effects on WM, we adopted a within-subject design to study how acute stress, variability in stress reactivity, and past subjective stress influence behavioral and neural WM mechanisms. Thirty-four healthy males performed a WM task during functional magnetic resonance imaging (fMRI) in a control versus acute stress condition following the Trier Social Stress Test, a validated psychosocial stressor method. We tested for stress effects on WM performance and related neural activation by associating them with individual acute stress responsivity and past subjective stress experience using retrospective self-report questionnaires. We found no evidence of an effect of acute stress or related stress-reactivity on intra-individual WM performance. However, past subjective stress negatively influenced acute stress-induced changes to WM. On the neural level, acute stress reduced WM-related activation in the dorsolateral prefrontal cortex (dlPFC). The observed negative influence of inter-individual variability in past subjective stress experience on changes in WM performance, suggests that past subjective stress might induce vulnerability for impairing effects of acute stress on cognitive functioning. Because acute stress reduced WM-related dlPFC activation while WM performance remained unaffected, acute stress might boost neural processing efficiency in this group of high performing healthy individuals. Our study suggests that measures of past subjective stress should be considered when studying and interpreting the effects of acute stress on cognition.

GAD65 Promoter Polymorphism rs2236418 Modulates Harm Avoidance in Women via Inhibition/Excitation Balance in the Rostral ACC.

Anxiety disorders are common and debilitating conditions with higher prevalence in women. However, factors that predispose women to anxiety phenotypes are not clarified. Here we investigated potential contribution of the single nucleotide polymorphism rs2236418 in GAD2 gene to changes in regional inhibition/excitation balance, anxiety-like traits, and related neural activity in both sexes. One hundred and five healthy individuals were examined with high-field (7T) multimodal magnetic resonance imaging (MRI); including resting-state functional MRI in combination with assessment of GABA and glutamate (Glu) levels via MR spectroscopy. Regional GABA/Glu levels in anterior cingulate cortex (ACC) subregions were assessed as mediators of gene-personality interaction for the trait harm avoidance and moderation by sex was tested. In AA homozygotes, with putatively lower GAD2 promoter activity, we observed increased intrinsic neuronal activity and higher inhibition/excitation balance in pregenual ACC (pgACC) compared with G carriers. The pgACC drove a significant interaction of genotype, region, and sex, where inhibition/excitation balance was significantly reduced only in female AA carriers. This finding was specific for rs2236418 as other investigated single nucleotide polymorphisms of the GABA synthesis related enzymes (GAD1, GAD2, and GLS) were not significant. Furthermore, only in women there was a negative association of pgACC GABA/Glu ratios with harm avoidance. A moderated-mediation model revealed that pgACC GABA/Glu also mediated the association between the genotype variant and level of harm avoidance, dependent on sex. Our data thus provide new insights into the neurochemical mechanisms that control emotional endophenotypes in humans and constitute predisposing factors for the development of anxiety disorders in women.SIGNIFICANCE STATEMENT Anxiety disorders are among the most common and burdensome psychiatric disorders, with higher prevalence rates in women. The causal mechanisms are, however, poorly understood. In this study we propose a neurobiological basis that could help to explain female bias of anxiety endophenotypes. Using magnetic resonance brain imaging and personality questionnaires we show an interaction of the genetic variation rs2236418 in the GAD2 gene and sex on GABA/glutamate (Glu) balance in the pregenual anterior cingulate cortex (pgACC), a region previously connected to affect regulation and anxiety disorders. The GAD2 gene polymorphism further influenced baseline neuronal activity in the pgACC. Importantly, GABA/Glu was shown to mediate the relationship between the genetic variant and harm avoidance, however, only in women.

Multiple Regions of a Cortical Network Commonly Encode the Meaning of Words in Multiple Grammatical Positions of Read Sentences.

Deciphering how sentence meaning is represented in the brain remains a major challenge to science. Semantically related neural activity has recently been shown to arise concurrently in distributed brain regions as successive words in a sentence are read. However, what semantic content is represented by different regions, what is common across them, and how this relates to words in different grammatical positions of sentences is weakly understood. To address these questions, we apply a semantic model of word meaning to interpret brain activation patterns elicited in sentence reading. The model is based on human ratings of 65 sensory/motor/emotional and cognitive features of experience with words (and their referents). Through a process of mapping functional Magnetic Resonance Imaging activation back into model space we test: which brain regions semantically encode content words in different grammatical positions (e.g., subject/verb/object); and what semantic features are encoded by different regions. In left temporal, inferior parietal, and inferior/superior frontal regions we detect the semantic encoding of words in all grammatical positions tested and reveal multiple common components of semantic representation. This suggests that sentence comprehension involves a common core representation of multiple words' meaning being encoded in a network of regions distributed across the brain.

Higher-order cognitive training effects on processing speed–related neural activity: a randomized trial

Higher-order cognitive training has shown to enhance performance in older adults, but the neural mechanisms underlying performance enhancement have yet to be fully disambiguated. This randomized trial examined changes in processing speed and processing speed–related neural activity in older participants (57–71 years of age) who underwent cognitive training (CT, N = 12) compared with wait-listed (WLC, N = 15) or exercise-training active (AC, N = 14) controls. The cognitive training taught cognitive control functions of strategic attention, integrative reasoning, and innovation over 12 weeks. All 3 groups worked through a functional magnetic resonance imaging processing speed task during 3 sessions (baseline, mid-training, and post-training). Although all groups showed faster reaction times (RTs) across sessions, the CT group showed a significant increase, and the WLC and AC groups showed significant decreases across sessions in the association between RT and BOLD signal change within the left prefrontal cortex (PFC). Thus, cognitive training led to a change in processing speed–related neural activity where faster processing speed was associated with reduced PFC activation, fitting previously identified neural efficiency profiles.

Neural correlates of emotional inhibitory control in autism spectrum disorders

Atypical inhibitory function is often present in individuals with autism spectrum disorder (ASD), who may have difficulty suppressing context-inappropriate behaviors. We investigated the neural correlates of inhibition in ASD in response to both emotional and non-emotional stimuli using an fMRI Go/NoGo inhibition task with human faces and letters. We also related neural activation to behavioral dysfunction in ASD. Our sample consisted of 19 individuals with ASD (mean age=25.84) and 22 typically developing (TD) control participants (mean age=29.03). As expected, no group differences in task performance (inhibition accuracy and response time) were found. However, adults with ASD exhibited greater angular gyrus activation in face response inhibition blocks, as well as greater fusiform gyrus activation than controls, in a condition comparing face inhibition to letter inhibition. In contrast, control participants yielded significantly greater anterior cingulate cortex (ACC) activation in letter inhibition blocks. A positive relationship between communication and language impairment and angular gyrus activation during face inhibition was also found. Group activation differences during inhibition tasks in the context of comparable task performance and the relationship between activation and dysfunction highlight brain regions that may be related to ASD-specific dysfunction.

Detailed Analysis of High Frequency Auditory Brainstem Response in Patients with Tinnitus: A Preliminary Study

Increased spontaneous activity and aberrant neural synchrony is thought to be the underlying cause of tinnitus. The perceived pitch of tinnitus may be dictated by frequency specific neural fibers of the subcortical pathway, or the projection of altered cortical activity by-way-of tonotopic reorganizations. Subcortical neural activity in relation to tinnitus was characterized using ABR measurements. In the present study, 11 patients (21 ears) with constant tonal tinnitus underwent a two-part experiment. Experiment 1 involved click ABR measurements and included two experimental groups: tinnitus with normal hearing from 2000-4000 Hz (GI) and tinnitus with hearing loss within the range of 2000-4000 Hz (GII). Experiment 2 utilized tone burst ABRs matched to each participant's perceived tinnitus pitch and included two experimental groups: tinnitus with normal hearing at the tinnitus pitch (GIa) and tinnitus with hearing loss at the tinnitus pitch (GIIa). These groups were compared to a control group (GIII) of ten monaurally tested (10 ears) participants with normal hearing thresholds at 250-20000 Hz and no tinnitus. Click ABR results indicate significantly prolonged V-III IPLs for GI and GII and a significantly extended absolute V latency for GII only. Tone burst ABRs matched to tinnitus pitch revealed significantly prolonged absolute latencies and IPLs at three of the seven frequencies for GIIa. ABR threshold seeking was completed and revealed negative eHL values for two of the four different stimuli for GI and GIa and four of the eight stimuli for GII and GIIa. Click ABRs results are suggestive of upper brainstem abnormalities for both groups. While GI demonstrated prolonged V-III IPLs, no significant differences were found for GIa. This suggests that there is no frequency specific subcortical characteristic associated with tinnitus with normal hearing. Frequency specific properties for subcortical activity could not be characterized due to varying results of GIIa.

Exposition on Eye Movements in Managerial Decision

Exploration on Managerial decision making has extended from Managerial decision behaviourist approach to cognitive approach that focuses on decision processes that ensue prior to response. In neural computational simulations, each Managerial decision during decision task is represented by node of neural activity. Decision related neural activity has components of intensification of activity and decision inception for neural activity to overcome for decision to be completed. One way to investigate computational Managerial decision making is to scan positioning of Managerial decision behaviour leading to judgment point. Eye movements are central measure of Managerial decision. Eye movements are indissolubly linked to optical consideration as both are prime tools for choosing stimulating shares of chromatic prospects for enriched perceptual and rational processing. Investigating eye movements is expedient in providing evidence of orientation of Managerial decision Managerial decision behaviour replicating computational decision during decision formation. Role of eye movements, intentional or reflex, help in gaining, possessing and tracing visual inducements, during Managerial decision formation is not entirely clear. Current proof suggests that orientation of eye movement itself may not be an essential constituent. Rather, it can be as a result of intensification in contact to incitement as an e influential factor in Managerial decision formation. Purpose of present scholarship is to survey foregoing conclusions that eye movements have contributory stimulus on Managerial decision formation in a rational fashion. We review experiential studies that employ eye movement monitoring as process tracing and tracking method with gazing in Managerial decision-making research. Using Kowlerian Model, we present an investigation that explains experimental methods and analysis with contemporary eye tracking savoir-faire. This paper countenances a specific hypothesis about role of eye movements in Managerial decision Managerial decision; understanding how eye movements are premeditated, carried out notwithstanding recurrent vicissitudes in optical assortment that eye movement harvest. One major effort is understanding how should Managers’ decide, deal with risks and uncertainties, create options better than originally available, potential responses to problems and evaluate strengths and weaknesses of each prospective action using apparatus of eye tracking/tracing and gazing.

White matter integrity between left basal ganglia and left prefrontal cortex is compromised in gambling disorder

Pathological gambling (PG) is a behavioral addiction characterized by an inability to stop gambling despite the negative consequences, which may be mediated by cognitive flexibility deficits. Indeed, impaired cognitive flexibility has previously been linked to PG and also to reduced integrity of white matter connections between the basal ganglia and the prefrontal cortex. It remains unclear, however, how white matter integrity problems relate to cognitive inflexibility seen in PG. We used a cognitive switch paradigm during functional magnetic resonance imaging in pathological gamblers (PGs; n = 26) and healthy controls (HCs; n = 26). Cognitive flexibility performance was measured behaviorally by accuracy and reaction time on the switch task, while brain activity was measured in terms of blood oxygen level-dependent responses. We also used diffusion tensor imaging on a subset of data (PGs = 21; HCs = 21) in combination with tract-based spatial statistics and probabilistic fiber tracking to assess white matter integrity between the basal ganglia and the dorsolateral prefrontal cortex. Although there were no significant group differences in either task performance, related neural activity or tract-based spatial statistics, PGs did show decreased white matter integrity between the left basal ganglia and prefrontal cortex. Our results complement and expand similar findings from a previous study in alcohol-dependent patients. Although we found no association between white matter integrity and task performance here, decreased white matter connections may contribute to a diminished ability to recruit prefrontal networks needed for regulating behavior in PG. Hence, our findings could resonate an underlying risk factor for PG, and we speculate that these findings may extend to addiction in general.

Bright-light intervention induces a dose-dependent increase in striatal response to risk in healthy volunteers

Bright-light interventions have successfully been used to reduce depression symptoms in patients with seasonal affective disorder, a depressive disorder most frequently occurring during seasons with reduced daylight availability. Yet, little is known about how light exposure impacts human brain function, for instance on risk taking, a process affected in depressive disorders.Here we examined the modulatory effects of bright-light exposure on brain activity during a risk-taking task. Thirty-two healthy male volunteers living in the greater Copenhagen area received 3weeks of bright-light intervention during the winter season. Adopting a double-blinded dose-response design, bright-light was applied for 30minutes continuously every morning. The individual dose varied between 100 and 11.000lx. Whole-brain functional MRI was performed before and after bright-light intervention to probe how the intervention modifies risk-taking related neural activity during a two-choice gambling task. We also assessed whether inter-individual differences in the serotonin transporter-linked polymorphic region (5-HTTLPR) genotype influenced the effects of bright-light intervention on risk processing.Bright-light intervention led to a dose-dependent increase in risk-taking in the LA/LA group relative to the non-LA/LA group. Further, bright-light intervention enhanced risk-related activity in ventral striatum and head of caudate nucleus in proportion with the individual bright-light dose. The augmentation effect of light exposure on striatal risk processing was not influenced by the 5-HTTLPR-genotype.This study provides novel evidence that in healthy non-depressive individuals bright-light intervention increases striatal processing to risk in a dose-dependent fashion. The findings provide converging evidence that risk processing is sensitive to bright-light exposure during winter.

Enhancing inhibition-induced plasticity in tinnitus--spectral energy contrasts in tailor-made notched music matter.

Chronic tinnitus seems to be caused by reduced inhibition among frequency selective neurons in the auditory cortex. One possibility to reduce tinnitus perception is to induce inhibition onto over-activated neurons representing the tinnitus frequency via tailor-made notched music (TMNM). Since lateral inhibition is modifiable by spectral energy contrasts, the question arises if the effects of inhibition-induced plasticity can be enhanced by introducing increased spectral energy contrasts (ISEC) in TMNM. Eighteen participants suffering from chronic tonal tinnitus, pseudo randomly assigned to either a classical TMNM or an ISEC-TMNM group, listened to notched music for three hours on three consecutive days. The music was filtered for both groups by introducing a notch filter centered at the individual tinnitus frequency. For the ISEC-TMNM group a frequency bandwidth of 3/8 octaves on each side of the notch was amplified, additionally, by about 20 dB. Before and after each music exposure, participants rated their subjectively perceived tinnitus loudness on a visual analog scale. During the magnetoencephalographic recordings, participants were stimulated with either a reference tone of 500 Hz or a test tone with a carrier frequency representing the individual tinnitus pitch. Perceived tinnitus loudness was significantly reduced after TMNM exposure, though TMNM type did not influence the loudness ratings. Tinnitus related neural activity in the N1m time window and in the so called tinnitus network comprising temporal, parietal and frontal regions was reduced after TMNM exposure. The ISEC-TMNM group revealed even enhanced inhibition-induced plasticity in a temporal and a frontal cortical area. Overall, inhibition of tinnitus related neural activity could be strengthened in people affected with tinnitus by increasing spectral energy contrast in TMNM, confirming the concepts of inhibition-induced plasticity via TMNM and spectral energy contrasts.