Resting-State Quantitative Electroencephalography Reveals Increased Neurophysiologic Connectivity in Depression

Symptoms of Major Depressive Disorder (MDD) are hypothesized to arise from dysfunction in brain networks linking the limbic system and cortical regions. Alterations in brain functional cortical connectivity in resting-state networks have been detected with functional imaging techniques, but neurophysiologic connectivity measures have not been systematically examined. We used weighted network analysis to examine resting state functional connectivity as measured by quantitative electroencephalographic (qEEG) coherence in 121 unmedicated subjects with MDD and 37 healthy controls. Subjects with MDD had significantly higher overall coherence as compared to controls in the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), and beta (12–20 Hz) frequency bands. The frontopolar region contained the greatest number of “hub nodes” (surface recording locations) with high connectivity. MDD subjects expressed higher theta and alpha coherence primarily in longer distance connections between frontopolar and temporal or parietooccipital regions, and higher beta coherence primarily in connections within and between electrodes overlying the dorsolateral prefrontal cortical (DLPFC) or temporal regions. Nearest centroid analysis indicated that MDD subjects were best characterized by six alpha band connections primarily involving the prefrontal region. The present findings indicate a loss of selectivity in resting functional connectivity in MDD. The overall greater coherence observed in depressed subjects establishes a new context for the interpretation of previous studies showing differences in frontal alpha power and synchrony between subjects with MDD and normal controls. These results can inform the development of qEEG state and trait biomarkers for MDD

Sports Participation and Juvenile Delinquency: A Meta-Analytic Review

Participation in sports activities is very popular among adolescents, and is frequently encouraged among youth. Many psychosocial health benefits in youth are attributed to sports participation, but to what extent this positive influence holds for juvenile delinquency is still not clear on both the theoretical and empirical level. There is much controversy on whether sports participation should be perceived as a protective or a risk factor for the development of juvenile delinquency. A multilevel meta-analysis of 51 published and unpublished studies, with 48 independent samples containing 431 effect sizes and N = 132,366 adolescents, was conducted to examine the relationship between sports participation and juvenile delinquency and possible moderating factors of this association. The results showed that there is no overall significant association between sports participation and juvenile delinquency, indicating that adolescent athletes are neither more nor less delinquent than non-athletes. Some study, sample and sports characteristics significantly moderated the relationship between sports participation and juvenile delinquency. However, this moderating influence was modest. Implications for theory and practice concerning the use of sports to prevent juvenile delinquency are discussed. Keywords Sports participation Juvenile delinquency Multilevel meta-analysis Revie

Emotive interference during cognitive processing in major depression: An investigation of lower alpha 1 activity

Background: Individuals with Major Depressive Disorder (MDD) tend to be more susceptible to distraction by negative emotional material than their non-depressed counterparts. This extends to an enhanced vulnerability to interference from mood-congruent stimuli during cognitive processing. The current study investigated the electrophysiological correlates of competing cognitive and emotional processing demands in MDD. Methods: Event-related alpha activity within the lower alpha 1 band was examined during the online information retention phase of a non-emotive WM task with extraneous emotional stimuli (positive, negative and neutral) presented as background images. EEG activity over posterior parietal cortex was compared between 15 acutely depressed and 16 never depressed right-handed women. Results: A valence specific dissociation in lower alpha 1 activity was observed between the two groups, consistent with greater attentional resource allocation to positive distracters in control participants and to negative distracters in MDD participants. No group differences were seen when neutral distracters were displayed. Conclusions: These results demonstrate that activity within the lower alpha 1 band is sensitive to competing emotional and cognitive processing demands and highlight the importance of posterior parietal regions in depression-related susceptibility to affective distractibility during cognitive processing. © 2012 Elsevier B.V

Individualized Alpha Activity and Frontal Asymmetry in Major Depression

Lateralized differences in frontal alpha power in individuals with major depressive disorder (MDD) are thought to reflect an aberrant affective processing style. However research into anterior alpha asymmetry and MDD has often produced conflicting results. The current study aimed to investigate whether individualized alpha bandwidths provide a more sensitive measure of anterior alpha asymmetry in MDD than the traditional fixed 8–13 Hz alpha band. Resting EEG was recorded from 34 right-handed female participants (18 controls, 16 MDD). Each participant's Individual Alpha Frequency was used to delineate a broad individualized alpha band and three individualized narrow alpha sub-bands: lower alpha1, lower alpha 2 and upper alpha. Activity within the broad and narrow individualized bandwidths and within the traditional fixed alpha band were used to compare a) controls and acutely depressed individuals and b) medicated and unmedicated MDD participants. Individualizing and subdividing the alpha bandwidth did not add appreciably to the sensitivity of anterior alpha asymmetry in MDD as no significant differences in lateralized alpha power between controls and MDD participants were observed in any alpha bandwidth. This finding was consistent under two reference schemes and across multiple scalp locations. Within the MDD group, antidepressant use was associated with significantly greater right than left hemispheric power in the lower alpha 1 band. The relevance of this finding is discussed in relation to the electrophysiological correlates of antidepressant medication use, lateralized differences in affective processing and treatment resistant MDD. </jats:p

Upper alpha activity during working memory processing reflects abnormal inhibition in major depression

Background: EEG studies examining 'resting' state (i.e. non-task) state brain activity in major depressive disorder (MDD) have reported numerous abnormalities within the alpha bandwidth. These findings are discussed extensively within affective disorders literature but their relationship to functional aspects of depressive psychopathology remains unclear. Investigating alpha modulation during active cognitive processing may provide a more targeted means of relating aberrant alpha activity to specific aspects of depression symptomatology. Alpha activity is reliably modulated during working memory (WM) processing and WM impairments are a common neuropsychological consequence of MDD. Moreover, it has been suggested that alpha activity reflects internally mediated inhibitory process and attenuated inhibition has been suggested to contribute to WM inefficacy. Aim: The current investigation examined whether alpha was modulated differently in MDD participants during WM processing and whether the pattern of alpha activity was consistent with impairments in inhibitory processes. Method: Event related synchronisation (ERS) within the upper alpha band over the retention interval of a modified Sternberg WM task was examined in 15 acutely depressed and 15 never depressed right-handed female participants. Results: MDD participants displayed greater upper alpha ERS than controls during the online information maintenance component of WM processing. This was evident over left, but not right, parieto-occipital cortex. Conclusion: The results are consistent with increased inhibition of extraneous material during WM processing in depression. This may reflect a neurobiological compensation strategy whereby additional neural resources are required to achieve comparable performance accuracy during effortful cognitive processing in MDD. © 2010 Elsevier B.V. All rights reserved

Effects of rTMS on an Auditory Oddball Task: A Pilot Study of Cortical Plasticity and the EEG

The objective of this study was to explore the effects of 1Hz repetitive transcranial magnetic stimulation (rTMS) applied to dorsal lateral prefrontal cortex (DLPFC) on both an EEG index of cortical excitation and inhibition, event-related desynchronization/synchronization (ERD/S) and on the P300 component of an auditory oddball-induced ERP. Eight normal participants received 15 minutes of 1Hz rTMS at 110% of the resting motor threshold to right DLPFC. ERD/S of alpha and beta bands was measured during an auditory oddball task immediately before and after stimulation. There was significantly less alpha desynchronization post-TMS, and this effect was widespread excepting posterior midline sites. No changes were found to oddball-P300 amplitudes or latencies. In conclusion, the findings of less alpha desynchronization post-TMS are compatible with notions of slow rTMS causing a decrease in cortical excitation. </jats:p

Lifestyle risk factors for obsessive-compulsive symptoms and related phenomena: What should lifestyle interventions target?

Objective: Understanding the impact of lifestyle on mental illness symptoms is important for informing psycho-education and developing interventions which target mental and physical comorbidities. Obsessive-compulsive and related disorders can have a significant impact on health-related quality of life and physical health. However, our understanding of the impact of lifestyle on obsessive-compulsive symptoms and broader compulsive and impulsive problematic repetitive behaviours is limited. Aims: We investigated whether lifestyle factors predicted change in obsessive-compulsive symptoms and problematic repetitive behaviours in a general population sample over a 3-month period. Methods: Eight hundred thirty-five participants completed an online questionnaire battery assessing lifestyle and mental health. Of these, 538 participants completed the same battery 3&thinsp;months later. We conducted negative binomial regressions to analyse the association of lifestyle factors at baseline with future (1) obsessive-compulsive symptoms, (2) compulsive problematic repetitive behaviours and (3) impulsive problematic repetitive behaviours, adjusting for baseline obsessive-compulsive symptoms and problematic repetitive behaviours. Results: Lower vegetable ( p&thinsp;=&thinsp;0.020) and oily fish ( p&thinsp;=&thinsp;0.040) intake and lower moderate intensity physical activity ( p&thinsp;=&thinsp;0.008) predicted higher obsessive-compulsive symptoms at follow-up. Higher intake of high-fat foods ( p&thinsp;&lt;&thinsp;0.001) predicted higher compulsive problematic repetitive behaviours at follow-up. No lifestyle factors significantly predicted impulsive problematic repetitive behaviours at follow-up. Conclusion: Our results speak to the potential importance of lifestyle quality screening, education and lifestyle interventions (e.g. an anti-inflammatory diet) for individuals experiencing compulsivity-related behaviours and/or symptoms. Further research into potential mechanisms of action will allow for more targeted approaches to lifestyle interventions for transdiagnostic compulsive behaviours. </jats:sec