Alpha-beta decoupling relevant to inhibition deficits leads to suicide attempt in major depressive disorder

BACKGROUND

One devastating outcome of major depressive disorder (MDD) is high suicidality, especially for patients with suicide attempt (SA). Evidence indicated that SA may be strongly associated with inhibitory control deficits. We hypothesized that the inhibition function deficits of patient with SA might be underpinned by abnormal neuronal oscillations.

METHODS

Our study recruited 111 subjects including 74 patients and 37 controls, who performed a GO/NOGO task during magnetoencephalography recording. Time-frequency-representations and phase-amplitude-coupling were measured for the brain circuits involved in the inhibitory function. Phase-slope-indexes were calculated between regions to determine the direction of power flow.

RESULTS

Significant increased reaction time and decreased judgment accuracy were observed in SA group. During the perception stage of GO task (approximately 125 ms), SA group manifested elevated alpha power in ventral prefrontal cortex (VPFC) and attenuated beta power in dorsal anterior cingulate (dACC) compared with other groups (p < 0.01). In the processing stage of NOGO task (approximately 300 ms), they showed decreased beta power in VPFC and increased alpha power in dACC (p < 0.01). Alpha-beta decoupling during both tasks was observed in SA group. Furthermore, the decoupling from VPFC to dACC under NOGO tasks was significantly correlated with suicide risk level.

LIMITATIONS

The number of participants was relatively small, and psychological elements were not involved in current study.

CONCLUSION

Dysregulated oscillatory activities of dACC and VPFC suggested deficits in execution and inhibition functions triggering high suicide risks. The alpha-beta decoupling from VPFC to dACC could be served as a neuro-electrophysiological biomarker for identifying potential suicide risk.

Cancellation but not restraint ability is modulated by trait anxiety: An event-related potential and oscillation study using Go-Nogo and stop-signal tasks

BACKGROUND

Trait anxiety has a detrimental effect on attention, which further leads to dysfunction of inhibitory control. However, there is no study examining how trait anxiety modulates inhibitory abilities on restraint and cancellation in the same subjects. Therefore, we aimed to use electrophysiological recordings to interrogate whether and to what extent trait anxiety modulated these two kinds of inhibitory functions. The Cognitive Failures Questionnaire (CFQ), a self-reported assessment of daily absentmindedness, was also used to examine its association with inhibition-related electrophysiological indicators.

METHODS

Forty subjects were recruited from the top 10% (Higher Trait Anxiety [HTA], n= 20) and last 10% (Lower Trait Anxiety [LTA], n= 20) of the trait anxiety score distribution from 400 college students. During electrophysiological recordings, the Go-Nogo and stop-signal tasks were performed, which evaluated the abilities of restraint and cancellation, respectively.

RESULTS

The HTA and LTA groups showed a comparable behavioral performance of restraint and cancellation abilities. However, the results of time-frequency analysis revealed that those with HTA demonstrated a stronger power of alpha oscillations (600‒1000 ms) in response to Stop trials in the stop-signal task, compared with individuals with LTA. Such oscillatory activity was positively correlated with the CFQ score. There was no significant between-group difference of the brain activation in the Go-Nogo task.

LIMITATIONS

Future studies can recruit both individuals with trait anxiety and anxiety disorders to clarify the boundaries between healthy and pathological worries in terms of cancellation ability.

CONCLUSIONS

cancellation, but not restraint, is modulated by trait anxiety.

Reduced coupling of somatosensory gating and gamma oscillation in panic disorder

Previous studies have reported that patients with panic disorder (PD) exhibited an aberrant level of GABA concentration, an inhibitory neurotransmitter in the human brain. However, it remains substantially unclear whether the inhibitory function regarding the neurophysiological characteristics is altered in this disease. Sensory gating (SG) is considered as an automatic inhibitory function in the sensory cortex. In addition, brain's gamma oscillation within the sensory cortex is another index to reflect inhibitory function. Here we aimed to investigate whether the patients with PD showed altered inhibitory function in the somatosensory system, including the primary (SI) and secondary (SII) somatosensory cortices. A total of 20 healthy controls and 21 patients with PD underwent magnetoencephalographic recordings. Paired-pulse and single-pulse paradigms were used to study SG and gamma oscillations, respectively. There were no significant between-group differences in the SG function in the SI and SII. However, patients with PD demonstrated a reduced gamma power in the SI. Among the healthy individuals, strong associations between SG ratios and gamma frequency values were observed in the SI. However, such a functional relationship disappeared among the patients with PD. We suggested the reduced coupling of SG and gamma oscillation as one of the neural signatures in PD.

Abnormal frontal generator during auditory sensory gating in panic disorder: An MEG study

Patients with panic disorder (PD) exhibit abnormalities in early-stage information processing, even for the nonthreatening stimuli. A previous event-related potential study reported that PD patients show a deficit in sensory gating (SG), a protective mechanism of the brain to filter out irrelevant sensory inputs. However, there is no clear understanding about the neural correlates of SG deficits in PD. Moreover, whether SG deficits, if any, are associated with clinical manifestations remain unknown. In this study, 18 patients with PD and 20 age- and gender-matched healthy controls were recruited to perform auditory paired-stimulus paradigm using magnetoencephalographic (MEG) recordings. Results showed that PD patients demonstrated significantly higher M50 SG ratios in the right inferior frontal gyrus (RIFG) and higher M100 SG ratios in both RIFG and right superior temporal gyrus (RSTG) than those of the control group. It was important to note that in the RIFG, the M50 SG ratios correlated significantly with the scores of Body Sensation Questionnaire (BSQ) and Distractibility scale of Sensory Gating Inventory among patients with PD. In conclusion, this study suggests that PD patients exhibited a deficient ability to filter out irrelevant information, and such a defect might lead to cognitive misinterpretation of somatic sensations and distractibility.

Measuring facets of reward sensitivity, inhibition, and impulse control in individuals with problematic Internet use

INTRODUCTION

Problematic Internet Use (PIU) is the inability to control the amount of time spent on the Internet. Research indicates that abnormalities in reward sensitivity, sensitivity to punishment, and impulse control drive addictive behaviors such as substance abuse and gambling disorders, but it is unclear whether this is also the case in PIU.

METHODS

Behavioral tasks and scales were completed by 62 participants (32 PIU individuals and 30 no-PIU individuals) to assess reward sensitivity, sensitivity to punishment, as well as inhibitory function and impulse control. Measures administered included Go/No-Go, delay discounting, Behavioral Inhibition/Activation (BIS/BAS) scales and the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ).

RESULTS

The PIU group endorsed greater reward sensitivity and punishment sensitivity as indexed by the SPSRQ. However, there were no group differences with regards to delay discounting, performance in the Go/No-Go task, or endorsement in the BIS/BAS scales.

DISCUSSION

The present study found increased reward sensitivity and sensitivity to punishment in PIU individuals, though impulse control was not observably affected. Future experimental studies are needed to inform our conceptualization of the etiology of addictive behavior as it pertains to PIU. Further investigation will aid in informing prevention and intervention efforts.

Meta-analysis of sensorimotor gating in patients with autism spectrum disorders

Prepulse inhibition (PPI) of startle response is a well-established neurophysiological marker of sensorimotor gating ability in psychiatric patients including those with autism spectrum disorders (ASD). PPI has been utilized as an indicator of the central inhibitory function and is potentially linked to the clinical features of this disease. However, it remains inconclusive whether ASD patients exhibit PPI deficits compared with healthy controls. The present meta-analysis aimed to explore the pooled effect sizes of PPI in ASD patients. We searched major electronic databases from 1990 to January 2017. Seven studies, consisting of 21 individual investigations with 135 healthy controls and 99 ASD patients, were obtained. The effect size, calculated as Hedges's g and 95% confidence interval, were estimated. Overall, we found ASD patients exhibited an impaired PPI compared with healthy controls (p = 0.008). Specifically, significant PPI deficits were observed among ASD children/adolescents, compared with their healthy counterparts (p = 0.019). However, differences in PPI responses were not observed among adults. Conclusively, our results reconciled the previous studies and showed that ASD children/adolescents, but not adults, exhibit reduced sensorimotor gating function compared to healthy controls. We also suggest that the parameters of PPI are particularly important and the results should be interpreted with cautions.

Dysfunctional frontal lobe activity during inhibitory tasks in individuals with childhood trauma: An event-related potential study

Background

Individuals who experience childhood trauma are vulnerable to various psychological and behavioral problems throughout their lifetime. This study aimed to investigate whether individuals with childhood trauma show altered frontal lobe activity during response inhibition tasks.

Methods

In total, 157 healthy individuals were recruited and instructed to perform a Go/Nogo task during electroencephalography recording. Source activities of N2 and P3 of Nogo event-related potentials (ERP) were analyzed. The Childhood Trauma Questionnaire (CTQ) and Barratt Impulsivity Scale (BIS) were applied. Individuals were divided into three groups based on their total CTQ score: low CTQ, middle CTQ, and high CTQ groups.

Results

The high CTQ group exhibited significantly higher BIS scores than the low CTQ group. P3 amplitudes of the differences between Nogo and Go ERP waves exhibited higher mean values in the low CTQ than the high CTQ group, with trending effects. In Nogo-P3, the source activities of the right anterior cingulate cortex, bilateral medial frontal cortex (MFC), bilateral superior frontal gyrus (SFG), and right precentral gyrus were significantly lower in the high CTQ than the low CTQ group. Motor impulsivity showed a significant negative correlation with activities of the bilateral MFC and SFG in Nogo-P3 conditions.

Conclusions

Our study revealed that individuals with childhood trauma have inhibitory failure and frontal lobe dysfunction in regions related to Nogo-P3.

Effects of walking on bilateral differences in spatial attention control: a cross-over design

Background

Walking requires a high attentional cost for balance control and interferes with the control of attention. However, it is unclear whether the performance of visual spatial attention control, which is one of the functions of attention control, is also decreased during walking. In addition, although previous studies have shown right-hemispheric dominance and lower ability of left side visual spatial attention control during sitting, it remains unknown whether walking accentuates bilateral differences in visual spatial attention control. We tested the hypothesis that walking interferes with visual spatial attention control on both sides and accentuates its bilateral differences.

Methods

Twenty healthy right-handed subjects (24.3 ± 2.0 years) participated in this study. Subjects performed a random stimulus–response compatibility (SRC) task during both sitting and walking situations. To evaluate the effects of walking, reaction time was measured on both sides for the two situations. In comparison to the both situations (sitting and walking), the amount of change of the SRC effect on both sides was used. In the comparing the bilateral difference (left and right), the difference of the SRC effect was evaluated in each situation. The paired t-test was applied to both comparisons for statistical analysis.

Results

The SRC effect on both sides during walking was significantly larger than during sitting (P < 0.05). In addition, walking significantly accentuated the bilateral differences in visual spatial attention control (P < 0.05).

Conclusions

These results suggest that walking affects the performance of visual spatial attention control on both sides and accentuates its bilateral differences. These results have implications for development of practice methods of gait disorder with higher brain dysfunction.