John JB Allen

PMID: 21228910;PMCID: PMC3017362;Abstract:

Asymmetry in frontal electrocortical alpha-band (8-13 Hz) activity recorded during resting situations (i.e., in absence of a specific task) has been investigated in relation to emotion and depression for over 30 years. This asymmetry reflects an aspect of endogenous cortical dynamics that is stable over repeated measurements and that may serve as an endophenotype for mood or other psychiatric disorders. In nearly all of this research, EEG activity is averaged across several minutes, obscuring transient dynamics that unfold on the scale of milliseconds to seconds. Such dynamic states may ultimately have greater value in linking brain activity to surface EEG asymmetry, thus improving its status as an endophenotype for depression. Here we introduce novel metrics for characterizing frontal alpha asymmetry that provide a more in-depth neurodynamical understanding of recurrent endogenous cortical processes during the resting-state. The metrics are based on transient ''bursts'' of asymmetry that occur frequently during the resting-state. In a sample of 306 young adults, 143 with a lifetime diagnosis of major depressive disorder (62 currently symptomatic), three questions were addressed: (1) How do novel peri-burst metrics of dynamic asymmetry compare to conventional fast-Fourier transform-based metrics? (2) Do peri-burst metrics adequately differentiate depressed from non-depressed participants? and, (3) what EEG dynamics surround the asymmetry bursts? Peri-burst metrics correlated with traditional measures of asymmetry, and were sensitive to both current and past episodes of major depression. Moreover, asymmetry bursts were characterized by a transient lateralized alpha suppression that is highly consistent in phase across bursts, and a concurrent contralateral transient alpha enhancement that is less tightly phase-locked across bursts. This approach opens new possibilities for investigating rapid cortical dynamics during resting-state EEG. © 2010 Allen and Cohen.

PMID: 3585311;Abstract:

Subjects who scored deviantly high on the combined Perceptual Aberration-Magical Ideation (Per-Mag) Scale and subjects who scored low on the scale were compared on two putative measures of cognitive slippage - a continued word association task and a task of referential communication. The Per-Mag subjects performed more deviantly than did the control subjects on both tasks, but those Per-Mag subjects who also scored above the mean on the General Behavior Inventory (GBI) depression subscale were most deviant. The Per-Mag Scale and the GBI are recommended for concurrent use in mass screening to identify a group of individuals who exhibit signs of cognitive slippage and who may, therefore, be at risk for the development of severe psychopathology.

PMID: 17320191;PMCID: PMC2212818;Abstract:

Background: Impaired cardiac vagal control (CVC), as indexed by respiratory sinus arrhythmia, has been investigated as a risk factor for major depressive disorder (MDD), but prior findings are mixed with respect to whether impaired CVC predicts greater global depression severity and/or a more severe course of disorder. One possible explanation for mixed findings is that CVC abnormalities in MDD are related more closely to specific depression symptoms than to the syndrome as a whole. Methods: Depression severity (both global and symptom-specific indices) and electrocardiogram measures of resting CVC were obtained from 151 diagnosed MDD participants at intake, before randomization to a novel treatment for depression (acupuncture), and again after 8 and 16 weeks. Results: Resting CVC did not predict global indices of depression in cross-sectional or longitudinal analyses. In symptom-specific analyses, resting CVC was positively related to sad mood and crying and inversely related to middle and late insomnia. Improvement in late insomnia was related to increases in CVC over time. Limitations: Relationships between CVC and MDD were studied only within the clinical range of severity. Symptom analyses were exploratory and hence did not correct for Type I error. Conclusions: Resting CVC did not exhibit concurrent or prospective relations with overall depression severity but a few specific symptoms did. Symptomatic heterogeneity across samples may account for mixed findings within the CVC-depression literature. © 2007 Elsevier B.V. All rights reserved.

PMID: 18633842;Abstract:

The utility of using indices of neural function to identify deception relies on finding highly reliable and valid approaches that adequately identify the guilty and exonerate the innocent. A class of approaches, based on the guilty knowledge technique (GKT), assume that guilty individuals will recognize specific crime-relevant details, whereas innocent individuals will not. Memory distortions, however, may limit the accuracy of such procedures. To investigate these limits, two studies were conducted to examine whether brain electrical activity could differentiate true from false recollections elicited by the Deese-Roediger-McDermott (DRM) paradigm. The design of each study maximized the opportunity of finding electrocortical differences between true and false recognition. Each study found very high rates of false recognition, with little evidence that brain electrical activity could differentiate true from false memories. Results suggested that under certain conditions both true and false recollections can produce a pattern of brain activity indicative of recognition.

PMID: 15546651;Abstract:

Few medically acceptable treatments for depression during pregnancy are available. The aim of this randomized controlled pilot study was to determine whether acupuncture holds promise as a treatment for depression during pregnancy. Sixty-one pregnant women with major depressive disorder and a 17-item Hamilton Rating Scale for Depression (HRSD 17) score ≥14 were randomly assigned to one of three treatments, delivered over 8 weeks: an active acupuncture (SPEC, N=20), an active control acupuncture (NSPEC, N=21), and massage (MSSG, N=20). Acupuncture treatments were standardized, but individually tailored, and were provided in a double-blind fashion. Responders to acute phase treatment (HRSD 17 score14 and ≥50% reduction from baseline) continued the treatment they were initially randomized to until 10 weeks postpartum. Response rates at the end of the acute phase were statistically significantly higher for SPEC (69%) than for MSSG (32%), with an intermediate NSPEC response rate (47%). The SPEC group also exhibited a significantly higher average rate of reduction in BDI scores from baseline to the end of the first month of treatment than the MSSG group. Responders to the acute phase of all treatments combined had significantly lower depression scores at 10 weeks postpartum than nonresponders. Generalizability is limited by the small sample and its relative homogeneity. Acupuncture holds promise for the treatment of depression during pregnancy. © 2004 Elsevier B.V. All rights reserved.