Dysfunction of ventrolateral prefrontal cortex underlying social anxiety disorder: A multi-channel NIRS study

Anxiety symptoms without depression are associated with cognitive control network (CNN) dysfunction: An fNIRS study

Anxiety is a common psychological disorder associated with other mental disorders, with depression being the most common comorbidity. Few studies have examined the neural mechanisms underlying anxiety after controlling for depression. This study aimed to explore whether there are differences in cortical activation in anxiety patients with different severities whose depression are normal. In the current study, depression levels were normal for 366 subjects-139 healthy subjects, 117 with mild anxiety, and 110 with major anxiety. Using the Hospital Anxiety and Depression Scale (HADS) and a verbal fluency task (VFT) to test subjects' anxiety and depression and cognitive function, respectively. A 53-channel guided near-infrared spectroscopic imaging technology (fNIRS) detected the concentration of oxyhemoglobin (oxy-Hb). Correlation analysis between anxiety severity and oxy-Hb concentration in the brain cortex was performed, as well as ANOVA analysis of oxy-Hb concentration among the three anxiety severity groups. The results showed that anxiety severity was significantly and negatively correlated with oxy-Hb concentrations in the left frontal eye field (lFEF) and in the right dorsolateral prefrontal area (rDLPFC). The oxy-Hb concentration in the lFEF and the rDLPFC were significantly lower in the major anxiety disorder group than that in the control group. This suggests that decreased cortical activity of the lFEF and rDLPFC may be neural markers of anxiety symptoms after controlling for depression. Anxiety symptoms without depression may be result from the dysfunction of the cognitive control network (CCN) which includes the lFEF and rDLPFC.

Neural correlates of stress-reactive rumination in depression - The role of childhood trauma and social anxiety

Recent work showed an association of prefrontal dysfunctions in patients with Major Depressive Disorder (MDD) and social stress induced rumination. However, up to date it is unclear which etiological features of MDD might cause prefrontal dysfunctions. In the study at hand, we aimed to replicate recent findings, that showed prefrontal activation alterations during the Trier Social Stress Test (TSST) and subsequently increased stress-reactive rumination in MDD compared to healthy controls. Moreover, we aimed to explore the role of adverse childhood experiences and other clinical variables in this relationship. N = 55 patients currently suffering from MDD and n = 42 healthy controls (HC) underwent the TSST, while cortical activity in areas of the Cognitive Control Network (CCN) was measured via functional near-infrared spectroscopy (fNIRS). The TSST successfully induced a stress reaction (physiologically, as well as indicated by subjective stress ratings) and state rumination in all subjects with moderate to large effect sizes. In comparison to HC, MDD patients showed elevated levels of state rumination with large effect sizes, as well as a typical pattern of reduced cortical oxygenation during stress in the CCN with moderate effect sizes. Self-reported emotional abuse and social anxiety were moderately positively associated with increased stress-reactive rumination. Within the MDD sample, emotional abuse was negatively and social anxiety positively associated with cortical oxygenation within the CCN with moderate to large effect sizes. In conclusion, our results replicate previous findings on MDD-associated prefrontal hypoactivity during stress and extends the research toward specific subtypes of depression.

Effects of high-definition transcranial direct current stimulation on implicit emotion regulation of social pain in healthy individuals

BACKGROUND

Implicit emotion regulation (ER), a form of ER, is essential for protecting mental health in the process of social interaction. Both the ventrolateral prefrontal cortex (VLPFC) and the dorsolateral prefrontal cortex (DLPFC) have been shown to be involved in ER processes, including explicit ER of social pain, but whether they play a role in implicit ER is unclear.

METHODS

We investigated whether anodal high-definition transcranial direct current stimulation (HD-tDCS) of the right VLPFC (rVLPFC) or the right DLPFC (rDLPFC) influences implicit ER. In total, 63 healthy participants completed an emotion priming task, which measures the implicit ER of social pain, before and after receiving active or sham HD-tDCS (2 mA for 20 min, 10 consecutive days). Event-related potentials (ERPs) were recorded during task performance.

RESULTS

Combined with the results of the behavioral and electrophysiological indices indicated that stimulation of both the rVLPFC and the rDLPFC by anodic HD-tDCS could significantly reduce the affective responses caused by social exclusion. The further results also suggested that rDLPFC activation may contribute to promoting the involvement of early cognitive resources in the implicit ER process of social pain, thus helping to reduce the subjective negative experience of individuals.

LIMITATIONS

There were no dynamic interactive emotional stimuli to induce social pain, and only static images of social exclusion were used.

CONCLUSION

Our study provides cognitive and neurological evidence that expands our knowledge of the role of the rDLPFC and the rVLPFC in social ER. It can also serve as a reference for targeted intervention of implicit ER in social pain.

Neural association between cognitive function and anhedonia in adolescents with melancholic major depressive disorder: A fNIRS study

BACKGROUND

Cognitive dysfunction is common among adolescent patients with major depressive disorder (MDD). However, the pattern and magnitude of cognition impairment in patients during melancholic episodes remains unclear. The purpose of this study was to compare the neurocognitive performance and the underlying cerebral blood flow activation of adolescent patients with melancholic and non-melancholic features.

METHODS

Fifty-seven and 44 adolescent patients with MDD with or without melancholic feature (MDD-MEL/nMEL) and 58 healthy controls (HCs) were recruited. We used the repeatable battery for the assessment of neuropsychological status (RBANS) measuring neurocognitive function, and used functional near infrared spectroscopy (fNIRS) monitoring cerebral hemodynamic changes, described by β value. The non-parametric test and post-hoc analysis were conducted in RBANS scores and β values among three groups. Spearman correlation and mediating analysis was performed for RBANS scores, β values, and clinical symptoms in the MDD-MEL group.

RESULTS

There were no significant difference in RBANS scores between MDD-MEL and MDD-nMEL group. Compared with patients in MDD-nMEL, patients in MDD-MEL have lower β values in eight channels (ch10, ch16, ch20, ch25, ch27, ch37, ch41, ch45). The cognitive function is significantly correlated with anhedonia, and the β values play a partial mediating role between anhedonia and cognitive function.

LIMITATION

It's a cross-sectional study and monitoring longitudinal effects are needed to further elucidate the mechanism.

CONCLUSION

The cognitive function in adolescents with MDD-MEL may not significantly differ from those with MDD-nMEL. However, the anhedonia may influenced the cognitive function by altering the function of medial frontal cortex.

A Two-Person Neuroscience Approach for Social Anxiety: A Paradigm With Interbrain Synchrony and Neurofeedback

Social anxiety disorder has been widely recognised as one of the most commonly diagnosed mental disorders. Individuals with social anxiety disorder experience difficulties during social interactions that are essential in the regular functioning of daily routines; perpetually motivating research into the aetiology, maintenance and treatment methods. Traditionally, social and clinical neuroscience studies incorporated protocols testing one participant at a time. However, it has been recently suggested that such protocols are unable to directly assess social interaction performance, which can be revealed by testing multiple individuals simultaneously. The principle of two-person neuroscience highlights the interpersonal aspect of social interactions that observes behaviour and brain activity from both (or all) constituents of the interaction, rather than analysing on an individual level or an individual observation of a social situation. Therefore, two-person neuroscience could be a promising direction for assessment and intervention of the social anxiety disorder. In this paper, we propose a novel paradigm which integrates two-person neuroscience in a neurofeedback protocol. Neurofeedback and interbrain synchrony, a branch of two-person neuroscience, are discussed in their own capacities for their relationship with social anxiety disorder and relevance to the paradigm. The newly proposed paradigm sets out to assess the social interaction performance using interbrain synchrony between interacting individuals, and to employ a multi-user neurofeedback protocol for intervention of the social anxiety.

AI-Based Prediction and Prevention of Psychological and Behavioral Changes in Ex-COVID-19 Patients

The COVID-19 pandemic has adverse consequences on human psychology and behavior long after initial recovery from the virus. These COVID-19 health sequelae, if undetected and left untreated, may lead to more enduring mental health problems, and put vulnerable individuals at risk of developing more serious psychopathologies. Therefore, an early distinction of such vulnerable individuals from those who are more resilient is important to undertake timely preventive interventions. The main aim of this article is to present a comprehensive multimodal conceptual approach for addressing these potential psychological and behavioral mental health changes using state-of-the-art tools and means of artificial intelligence (AI). Mental health COVID-19 recovery programs at post-COVID clinics based on AI prediction and prevention strategies may significantly improve the global mental health of ex-COVID-19 patients. Most COVID-19 recovery programs currently involve specialists such as pulmonologists, cardiologists, and neurologists, but there is a lack of psychiatrist care. The focus of this article is on new tools which can enhance the current limited psychiatrist resources and capabilities in coping with the upcoming challenges related to widespread mental health disorders. Patients affected by COVID-19 are more vulnerable to psychological and behavioral changes than non-COVID populations and therefore they deserve careful clinical psychological screening in post-COVID clinics. However, despite significant advances in research, the pace of progress in prevention of psychiatric disorders in these patients is still insufficient. Current approaches for the diagnosis of psychiatric disorders largely rely on clinical rating scales, as well as self-rating questionnaires that are inadequate for comprehensive assessment of ex-COVID-19 patients' susceptibility to mental health deterioration. These limitations can presumably be overcome by applying state-of-the-art AI-based tools in diagnosis, prevention, and treatment of psychiatric disorders in acute phase of disease to prevent more chronic psychiatric consequences.

The Effects of Virtual Reality Treatment on Prefrontal Cortex Activity in Patients With Social Anxiety Disorder: Participatory and Interactive Virtual Reality Treatment Study

BACKGROUND

Attempts to use virtual reality (VR) as a treatment for various psychiatric disorders have been made recently, and many researchers have identified the effects of VR in psychiatric disorders. Studies have reported that VR therapy is effective in social anxiety disorder (SAD). However, there is no prior study on the neural correlates of VR therapy in patients with SAD.

OBJECTIVE

The aim of this study is to find the neural correlates of VR therapy by evaluating the treatment effectiveness of VR in patients with SAD using portable functional near-infrared spectroscopy (fNIRS).

METHODS

Patients with SAD (n=28) were provided with 6 sessions of VR treatment that was developed for exposure to social situations with a recording system of each participant's self-introduction in VR. After each VR treatment session, the first-person view (video 1) and third-person view (video 2) clips of the participant's self-introduction were automatically generated. The functional activities of prefrontal regions were measured by fNIRS while watching videos 1 and 2 with a cognitive task, before and after whole VR treatment sessions, and after the first session of VR treatment. We compared the data of fNIRS between patients with SAD and healthy controls (HCs; n=27).

RESULTS

We found that reduction in activities of the right frontopolar prefrontal cortex (FPPFC) in HCs was greater than in the SAD group at baseline (t=-2.01, P=.049). Comparing the frontal cortex activation before and after VR treatment sessions in the SAD group showed significant differences in activities of the FPPFC (right: t=-2.93, P<.001; left: t=-2.25, P=.03) and the orbitofrontal cortex (OFC) (right: t=-2.10, P=.045; left: t=-2.21, P=.04) while watching video 2.

CONCLUSIONS

Activities of the FPPFC and OFC were associated with symptom reduction after VR treatment for SAD. Our study findings might provide a clue to understanding the mechanisms underlying VR treatment for SAD.

TRIAL REGISTRATION

Clinical Research Information Service (CRIS) KCT0003854; https://tinyurl.com/559jp2kp.

Socioeconomic and Cognitive Roots of Trait Anxiety in Young Adults

In 54 participants (41% women) from the Czech arm of the European Longitudinal Study of Pregnancy and Childhood, a national birth cohort with prospectively collected data from their birth until young adulthood, we aimed to study the association between early-life socioeconomic deprivation (ELSD), cognitive ability in adolescence, trait anxiety and resting state functional connectivity of the lateral prefrontal cortex (LPFC) in young adulthood. We found that ELSD was associated with lower cognitive ability in adolescence (at age 13) as well as higher trait anxiety in young adulthood (at age 23/24). Higher cognitive ability in adolescence predicted lower trait anxiety in young adulthood. Resting state functional connectivity between the right LPFC and a cluster of voxels including left precentral gyrus, left postcentral gyrus and superior frontal gyrus mediated the relationship between lower cognitive ability in adolescence and higher trait anxiety in young adulthood. These findings indicate that lower cognitive ability and higher trait anxiety may be both consequences of socioeconomic deprivation in early life. The recruitment of the right LPFC may be the underlying mechanism, through which higher cognitive ability may ameliorate trait anxiety.

Prefrontal cortex alterations in major depressive disorder, generalized anxiety disorder and their comorbidity during a verbal fluency task assessed by multi-channel near-infrared spectroscopy

Major depressive disorder (MDD) and generalized anxiety disorder (GAD) are frequently comorbid with each other, and both associated with substantial cognitive impairments; however, it is still unclear whether their impairments are neurobiologically similar or distinct. This study aims to investigate the cognitive functions of the prefrontal cortex (PFC) in patients with MDD and GAD during the verbal fluency task (VFT) using functional near-infrared spectroscopy (fNIRS). Fifty-two patients with MDD, fifty-one patients with GAD, fifty-two patients with the comorbidity of MDD and GAD (CMG), and forty-seven healthy controls (HC) participated in the study. Significant hypoactivation in the left ventrolateral and the left dorsolateral PFC was common in all patient groups when compared to HCs, suggesting a shared etiology. Furthermore,  MDD patients showed significant hypoactivation at the right frontal pole cortex (FPoC) when compared to HCs and significant hypoactivation at the middle FPoC when compared to the CMG patients. Our work is the first fNIRS study to reveal the shared and unique neurobiological profiles of MDD, GAD and their comorbidity under the same standard experimentation condition, suggesting fNIRS holds promise as an adjutant to assist clinical diagnosis.

Self-focused attention related to social anxiety during free speaking tasks activates the right frontopolar area

Self-focused attention (SFA) and other-focused attention (OFA) are central maintenance factors of social anxiety. Tomita et al., Cognitive Therapy and Research 44:511–525, 2020 investigated brain activities when manipulating SFA and OFA during speech tasks, after controlling for social anxiety, using near-infrared spectroscopy (NIRS) and eye-tracking. Compared with the control condition, the SFA condition demonstrated greater activity in the right frontopolar area (rFPA) and right dorsolateral prefrontal cortex. In the OFA condition, relative to controls, activity was greater in the left superior temporal gyrus. We investigated whether the activity in these brain areas increased in healthy individuals in proportion to their social anxiety tendency without manipulating SFA and OFA. Thirty-nine participants performed speech tasks under a no attentional manipulation (no-instruction) condition and a control (looking at various places) condition. Brain activity was measured using NIRS (oxy-Hb responses), and eye movements were tracked. We found that higher social anxiety was associated with higher rFPA activity in the no-instruction condition compared to the control condition and that higher subjective SFA during the no-instruction condition with higher social anxiety was associated with increased rFPA between the no-instruction and control conditions. These results suggest that greater activity in the rFPA is a useful objective measure of SFA related to social anxiety during speech tasks.

Negative mood is associated with decreased prefrontal cortex functioning during working memory in young adults

The prefrontal-subcortical model of emotion regulation postulates that decreased prefrontal cortex (PFC) functioning may underlie the emergence of clinical affective disorders. In addition, accumulated evidence suggests that there is considerable variability in negative affect in the nonclinical population. This study examined whether negative affective symptoms were associated with decreased PFC functioning in nonclinical young adults. Forty college students aged 18-24 years (ten males) underwent an n-back paradigm (i.e., a frontal executive task) with a working memory (WM) load (i.e., 3-back) and a vigilance control condition (i.e., 0-back) while their hemodynamics changes in the lateral and medial PFC on both sides were monitored using a 16-channel functional near-infrared spectroscopy (fNIRS) system. They also filled out the Depression Anxiety Stress Scales (DASS) to estimate the levels of their negative emotions in the preceding week. Young adults exhibited an increased concentration of oxyhemoglobin and a decreased concentration of deoxyhemoglobin (i.e., activation), primarily in the lateral PFC, in response to the WM load (i.e., 3-back > 0-back). Importantly, higher DASS scores indicating higher levels of recent negative mood, especially depression and stress rather than anxiety symptoms, correlated with lower WM-related activation in the lateral PFC. Thus, recent negative mood is associated with decreased lateral PFC functioning during the executive control of WM in healthy young adults. Our findings suggest that decreased PFC functioning is also present in the nonclinical population with increased levels of negative mood and that fNIRS is a promising tool for elucidating individual differences in negative affective symptoms.

Cortical activity during social acceptance and rejection task in social anxiety disorder: A controlled functional near infrared spectroscopy study

BACKGROUND

The cognitive and emotional vulnerability of individuals with social anxiety disorder (SAD) and their response to repeated experiences of social rejection and social acceptance are important factors for the emergence and maintenance of symptoms of the disorder. Functional neuroimaging studies of SAD reveal hyperactivity in regions involved in the fear circuit such as amygdala, insula, anterior cingulate, and prefrontal cortices (PFC) in response to human faces with negative emotions. Observation of brain activity, however, involving studies of responses to standardized human interaction of social acceptance and social rejection have been lacking.

METHODS

We compared a group of index subjects with SAD (N = 22, mean age:26.3 ± 5.4, female/male: 7/15) (SADG) with a group of healthy controls (CG) (N = 21, mean age:28.7 ± 4.5, female/male: 14/7) in measures of cortical activity during standardized experiences of human interaction involving social acceptance (SA) and social rejection (SR) video-simulated handshaking tasks performed by real actors. In a third, control condition (CC), the subjects were expected to press a switch button in an equivalent space. Subjects with a concurrent mood episode were excluded and the severity of subclinical depressive symptoms was controlled. 52-channel functional near-infrared spectroscopy (fNIRS) was used to measure cortical activity.

RESULTS

Activity was higher in the SAD subjects compared to healthy controls, in particular in channels that project to middle and superior temporal gyri (STG), frontal eye fields (FEF) and dorsolateral prefrontal cortex (DLPFC) in terms of both SA and SR conditions. Cortical activity during the CC was not different between the groups. Only in the SAD-group, activity in the pre-motor and supplementary motor cortices, inferior and middle temporal gyri and fronto-polar area was higher during the rejection condition than the other two conditions. Anxiety scores were correlated with activity in STG, DLPFC, FEF and premotor cortex, while avoidance scores were correlated with activity in STG and FEF.

CONCLUSIONS

SA and SR are represented differently in terms of cortical activity in SAD subjects compared to healthy controls. Higher activity in both social conditions in SAD subjects compared to controls may imply biological sensitivity to these experiences and may underscore the importance of increased cortical activity during social interaction experiences as a putative mediator of vulnerability to SAD. Higher cortical activity in the SADG may possibly indicate stronger need for inhibitory control mechanisms and higher recruitment of theory of mind functions during social stress. Higher activity during the SR compared to the SA condition in the SAD subjects may also suggest distinct processing of social cues, whether they involve acceptance or rejection.

Trait Anxiety Mediated by Amygdala Serotonin Transporter in the Common Marmoset

High trait anxiety is associated with altered activity across emotion regulation circuitry and a higher risk of developing anxiety disorders and depression. This circuitry is extensively modulated by serotonin. Here, to understand why some people may be more vulnerable to developing affective disorders, we investigated whether serotonin-related gene expression across the brain's emotion regulation circuitry may underlie individual differences in trait anxiety using the common marmoset (Callithrix jacchus, mixed sexes) as a model. First, we assessed the association of region-specific expression of the serotonin transporter (SLC6A4) and serotonin receptor (HTR1A, HTR2A, HTR2C) genes with anxiety-like behavior; and second, we investigated their causal role in two key features of the high trait anxious phenotype: high responsivity to anxiety-provoking stimuli and an exaggerated conditioned threat response. While the expression of the serotonin receptors did not show a significant relationship with anxiety-like behavior in any of the targeted brain regions, serotonin transporter expression, specifically within the right ventrolateral prefrontal cortex (vlPFC) and most strongly in the right amygdala, was associated positively with anxiety-like behavior. The causal relationship between amygdala serotonin levels and an animal's sensitivity to threat was confirmed via direct amygdala infusions of a selective serotonin reuptake inhibitor (SSRI), citalopram. Both anxiety-like behaviors, and conditioned threat-induced responses were reduced by the blockade of serotonin reuptake in the amygdala. Together, these findings provide evidence that high amygdala serotonin transporter expression contributes to the high trait anxious phenotype and suggest that reduction of threat reactivity by SSRIs may be mediated by their actions in the amygdala.SIGNIFICANCE STATEMENT Findings here contribute to our understanding of how the serotonin system underlies an individual's expression of threat-elicited negative emotions such as anxiety and fear within nonhuman primates. Exploration of serotonergic gene expression across brain regions implicated in emotion regulation revealed that serotonin transporter gene expression in the ventrolateral prefrontal cortex (vlPFC) and most strongly in the amygdala, but none of the serotonin receptor genes, were predictive of interindividual differences in anxiety-like behavior. Targeting of amygdala serotonin reuptake with selective serotonin reuptake inhibitors (SSRIs) confirmed the causal relationship between amygdala serotonin transporter and an animal's sensitivity to threat by reversing expression of two key features of the high trait-like anxiety phenotype: high responsivity to anxiety-provoking uncertain threat and responsivity to certain conditioned threat.

Relationships Between Cortically Mediated Attentional Dysfunction and Social Anxiety, Self-Focused Attention, and External Attention Bias

Social anxiety disorder is characterized by a marked fear and avoidance of social situations or a fear of being evaluated by others. Although training for top-down attentional control has been an effective treatment for social anxiety disorder, few studies have demonstrated that individuals with social anxiety have top-down attentional dysfunction. This study used dichotic listening (DL) tasks to investigate the relationship between social anxiety and top-down attentional control over relevant brain activities. We also investigated relationships between both social situation-dependent self-focused attention and external attention bias and situation-independent attentional control. Thirty-six healthy participants underwent near-infrared spectroscopy scanning while performing top-down selective and divided attention DL tasks. Then, they undertook a speech task and completed a questionnaire to assess the degrees of their self-focused attention and external attention bias. The results showed that the degree of social fear and self-focused attention during the speech task were negatively correlated with scores on the selective attention task and with the activity of the left pars opercularis during the selective DL task, which were related to each other. These results suggest that a relationship exists between social fear, self-focused attention in a social situation, and top-down selective attentional dysfunction as assessed both behaviorally and by brain activity changes.

Neuroimaging depression and anxiety in essential tremor: A diffusion tensor imaging study

OBJECTIVE

Patients with essential tremor (ET) may exhibit non-motor features, including those that are neuropsychiatric. Depression and anxiety are the most common among these. This study aims to investigate the possible relationship between microstructural brain changes and symptoms of depression and anxiety in ET.

METHODS

We assessed 62 ET patients (40 women and 22 men, mean age 46.0 ± 20.4) for symptoms of depression and anxiety using the Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). Thirty-two patients had severe or moderate symptoms of anxiety, and 15 patients had severe or moderate depressive symptoms. Microstructural brain changes were evaluated using diffusion tensor imaging (DTI), which was reported using fractional anisotropy (FA), mean diffusivity (MD), apparent diffusion coefficient (ADC), radial diffusivity (RD), and axial diffusivity (AD) values calculated for 17 regions of interest including the prefrontal cortex, paralimbic and limbic structures and cerebellar peduncles. We evaluated the relationship between observed changes in brain regions and symptoms of depression and anxiety.

RESULTS

Decreased left amygdala FA (p = 0.003) and increased left amygdala RD (p = 0.04) were detected in depressed vs. non-depressed ET patients. Left ventrolateral prefrontal cortex (VLPFC) FA (p = 0.02) and left precuneus FA (p = 0.02) values differed between anxious patients vs. non-anxious ET patients. BDI scores were correlated with left amygdala FA and left RD, while BAI scores were correlated with left VLPFC FA and left precuneus FA.

DISCUSSION

Our results provide evidence that symptoms of depression and anxiety could be based in structural brain changes observed in patients with ET.

Basolateral amygdalar inactivation blocks chronic stress-induced lamina-specific reduction in prefrontal cortex volume and associated anxiety-like behavior

Chronic exposure to stress causes cognitive deficits, anxiety and depression. Earlier studies have suggested that the prefrontal cortex (PFC) and basolateral amygdala (BLA) can differentially modulate the stress-induced alterations either by their action on HPA axis or via direct reciprocal connections between them. The PFC dysfunction and BLA hypertrophy following stress are known to cause anxiety and affective symptoms. Recent studies indicate that inactivation of BLA projections to PFC remarkably decreases anxiety. However, the effect of BLA inactivation on stress-induced anxiety and associated volume loss in prelimbic (PrL) and anterior cingulate (ACC) subregions of PFC is not known. Accordingly, we evaluated the effect of BLA lesion or inactivation during chronic immobilization stress (CIS) on an approach-avoidance task and associated volume loss in the PFC. The stressed rats showed a significant volumetric reduction in layer I and II of the PrL and ACC. Interestingly, BLA lesion prior to stress prevented the volume loss in PrL and ACC. Further, BLA lesion blocked the anxiety-like behavior in stressed rats. However, in the absence of stress, BLA lesion increased the number of shocks as compared to controls. As BLA lesion produced an anticonflict effect, we performed temporary inactivation of BLA specifically during stress. Similar to BLA lesion, lidocaine-induced inactivation prevented the stress-induced volume loss and anxiety-like behavior. We demonstrate that inactivation of BLA during stress prevents CIS-induced anxiety and associated structural correlates in the PFC. The present study extends the hypothesis of amygdalar silencing as a possible management strategy for stress and associated disorders.

Solving the prefrontal conundrum of high-order anxiety: conciliating HOTEC and hypofrontality. A theoretical review

INTRODUCTION

According to the High-order Theory of Emotional Consciousness (HOTEC), every emotional process is a conscious and high-order state of mind carried out by the General Networks of Cognition (GNC), which consists mainly of prefrontal mechanisms. This means that anxiety is also an emotional state of mind carried out by the GNC (positive correlation). However, numerous studies have suggested what is commonly called "hypofrontality" during states of anxiety (negative correlation), which seems to give rise to a theoretical and empirical contraction.

METHODS

I present a theoretical review to address the following issue: how to advocate a HOTEC view of anxiety in the face of a growing paradigm of hypofrontality during states of anxiety?

RESULTS

Here I propose that dmPFC, the dACC, and the anterior insula are GNC areas positively correlated with anxiety, which, along with the prefrontal areas responsible for regulating the activation of survival circuits and driving the attention to adaptive ways to overcome potential threats, form an interconnective model of anticipatory and regulatory mechanisms related to learned threats based on autobiographical memories.

CONCLUSIONS

Through this model, I propose that HOTEC is still a valid way to approach and understand both healthy and unhealthy anxious states of mind.

Differences in frontotemporal dysfunction during social and non-social cognition tasks between patients with autism spectrum disorder and schizophrenia

Although literature evidence suggests deficits in social and non-social cognition in patients with autistic spectrum disorder (ASD) and schizophrenia (SCZ), the difference in neural correlates of the impairments between the two disorders has not been elucidated. We examined brain function in response to a non-social cognition and a social cognition task using functional near-infrared spectroscopy (fNIRS) in 13 patients with ASD, 15 patients with SCZ, and 18 healthy subjects. We assessed the brain function of participants using a verbal fluency task and an emotional facial recognition task. The patients with ASD showed significantly reduced brain activation in the left frontotemporal area during both tasks compared to healthy subjects. The patients with ASD with larger score in ‘attention to detail’ in the autism spectrum quotient showed lower activation of the left frontotemporal area during the two tasks. The patients with SCZ showed significantly reduced activation, compared to healthy subjects, and greater activation, compared to patients with ASD, in the area during the verbal fluency task. The patients with SCZ with more severe symptoms had lower brain activation during the task in this area. Our results suggest that two distinct areas are involved in the distinctive brain pathophysiology relevant to cognitive processing in patients with ASD and SCZ.

Neuroanatomy of Anxiety: A Brief Review

Anxiety disorders are among the most prevalent psychological issues worldwide, displaying the youngest age of onset and greatest chronicity of any mood or substance abuse disorder. Given the high social and economic cost imposed by these disorders, developing effective treatments is of the utmost importance. Anxiety disorders manifest in a variety of symptomatic phenotypes and are highly comorbid with other psychological diseases such as depression. These facts have made unraveling the complex underlying neural circuity an ever-present challenge for researchers. We offer a brief review on the neuroanatomy of anxiety disorders and discuss several currently available therapeutic options.

Abnormal prefrontal brain activation during a verbal fluency task in bipolar disorder patients with psychotic symptoms using multichannel NIRS

PURPOSE

Bipolar disorder (BD) patients with psychotic symptoms (BDp) worsens prognosis and decreases rates of recovery. The study investigated cognitive performance and brain function between BD patients in depressive episode with and without psychotic symptoms to find potential neurobiological markers associated with psychotic features of BD patients in depressive episode.

PATIENTS AND METHODS

Thirty-one patients without psychotic symptoms and 29 patients with psychotic symptoms diagnosed with bipolar I disorder with a current depressive episode were included in the present study. The neural function of prefrontal cortex (PFC) and cognitive performance among BDp, BD patients without psychotic symptoms, and 23 healthy controls (HC) were examined using near-infrared spectroscopy during verbal fluency task (VFT).

RESULTS

1) Both the BD groups exhibited significantly worse performance of VFT and lower activation of oxygenated hemoglobin (oxy-Hb) changes in the bilateral ventrolateral PFC compared with the HC group. 2) Within the BD group, VFT performance was not significantly different. 3) The prefrontal activation of oxy-Hb changes in the BDp patients was significantly lower than that in the BD patients without psychotic symptoms in the right dorsolateral PFC. 4) Activation of oxy-Hb changes in right dorsolateral PFC was negatively correlated with the severity of psychotic symptoms in BDp patients.

CONCLUSION

The prefrontal function differs between BD patients in depressive episode with or without psychotic symptoms measured with near-infrared spectroscopy.

Neural basis for the relationship between frequency of going outdoors and depressive mood in older adults

OBJECTIVE

Low frequency of going outdoors (e.g. being homebound) is associated with depressive mood; however, the underlying neural mechanism of this association is unclear. We therefore investigated the neural substrate involved in the relationship between frequency of going outdoors and depressive mood using positron emission tomography (PET), focusing on the frontal lobe and the limbic system.

METHODS

One hundred fifty-eight community-dwelling older adults aged 65-85 years underwent PET with ¹⁸ F-fluorodeoxyglucose to evaluate regional cerebral metabolic rates of glucose normalized in reference to cerebellar glucose metabolic value (normalized-rCMRglc) in six regions of interest. We also assessed depressive mood, frequency of going outdoors, and potential covariates. Depressive mood was assessed using the Geriatric Depression Scale (GDS).

RESULTS

The proportion of participants who reported low frequency of going outdoors (LG, every 2-3 days or less) was 36.1%. The LG group showed significantly higher GDS scores than those who reported high (once a day or more) frequency of going outdoors. A multiple linear regression analysis adjusted for potential covariates showed higher GDS scores were associated with lower normalized-rCMRglc in the ventrolateral prefrontal and orbitofrontal cortices. Adjusting for frequency of going outdoors, the association between GDS score and normalized-rCMRglc in the orbitofrontal cortex was attenuated.

CONCLUSIONS

Our results suggest that the orbitofrontal cortex may mediate the relationship between low frequency of going outdoors and depressive mood among community-dwelling older adults. These findings may help disentangle the role of going outdoors in regulating brain function to improve and/or maintain mental health among community-dwelling older adults. Copyright © 2016 John Wiley & Sons, Ltd.

Use of Multichannel Near Infrared Spectroscopy to Study Relationships Between Brain Regions and Neurocognitive Tasks of Selective/Divided Attention and 2-Back Working Memory

While dichotic listening (DL) was originally intended to measure bottom-up selective attention, it has also become a tool for measuring top-down selective attention. This study investigated the brain regions related to top-down selective and divided attention DL tasks and a 2-back task using alphanumeric and Japanese numeric sounds. Thirty-six healthy participants underwent near-infrared spectroscopy scanning while performing a top-down selective attentional DL task, a top-down divided attentional DL task, and a 2-back task. Pearson's correlations were calculated to show relationships between oxy-Hb concentration in each brain region and the score of each cognitive task. Different brain regions were activated during the DL and 2-back tasks. Brain regions activated in the top-down selective attention DL task were the left inferior prefrontal gyrus and left pars opercularis. The left temporopolar area was activated in the top-down divided attention DL task, and the left frontopolar area and left dorsolateral prefrontal cortex were activated in the 2-back task. As further evidence for the finding that each task measured different cognitive and brain area functions, neither the percentages of correct answers for the three tasks nor the response times for the selective attentional task and the divided attentional task were correlated to one another. Thus, the DL and 2-back tasks used in this study can assess multiple areas of cognitive, brain-related dysfunction to explore their relationship to different psychiatric and neurodevelopmental disorders.

Hyperfunction of left lateral prefrontal cortex and automatic thoughts in social anxiety disorder: A near-infrared spectroscopy study

BACKGROUND

Patients with social anxiety disorder (SAD) experience unusual fear in normal social situations. The verbal fluency task (VFT) was administered while subjects were undergoing near-infrared spectroscopy (NIRS) scanning. The purpose of VFT was to examine the functions of the frontal and temporal lobes.

METHODS

Subjects included 145 drug-naïve patients with SAD and 152 healthy controls (HCs). All subjects underwent psychological testing to determine levels of anxiety and depression and to evaluate cognition.

RESULTS

The scores of patients with SAD indicated significantly higher anxiety and depressive states than those in HCs on several measures: Leibowitz Social Anxiety Scale (LSAS), Profile of Mood States (POMS), Spielberger Anxiety Inventory (STAI), Beck Depression Inventory (BDI), and Social Adaptation Self-evaluation Scale (SASS). The patients with SAD also had higher scores on the future denial, threat prediction, self-denial, past denial, and interpersonal threat sections of the Depression and Anxiety Cognition Scale (DACS). NIRS scanning revealed hyperactivity in the left frontal cortex of patients with SAD. Threat prediction scores on DACS were negatively correlated with oxy-Hb responses in the right frontal cortex.

LIMITATIONS

Further studies with a larger sample size are required to verify our findings.

CONCLUSIONS

The results of this study demonstrate the different mechanisms of the right and left frontal cortex in situations of social anxiety disorder.

A Brief Review of Research Using Near-Infrared Spectroscopy to Measure Activation of the Prefrontal Cortex during Emotional Processing: The Importance of Experimental Design

During the past two decades there has been a pronounced increase in the number of published research studies that have employed near-infrared spectroscopy (NIRS) to measure neural activation. The technique is now an accepted neuroimaging tool adopted by cognitive neuroscientists to investigate a number of fields, one of which is the study of emotional processing. Crucially, one brain region that is important to the processing of emotional information is the prefrontal cortex (PFC) and NIRS is ideally suited to measuring activity in this region. Compared to other methods used to record neural activation, NIRS reduces the discomfort to participants, makes data collection from larger sample sizes more achievable, and allows measurement of activation during tasks involving physical movement. However, the use of NIRS to investigate the links between emotion and cognition has revealed mixed findings. For instance, whilst some studies report increased PFC activity associated with the processing of negative information, others show increased activity in relation to positive information. Research shows differences in PFC activity between different cognitive tasks, yet findings also vary within similar tasks. This work reviews a selection of recent studies that have adopted NIRS to study PFC activity during emotional processing in both healthy individuals and patient populations. It highlights the key differences between research findings and argues that variations in experimental design could be a contributing factor to the mixed results. Guidance is provided for future work in this area in order to improve consistency within this growing field.