John JB Allen

PMID: 20453038;PMCID: PMC3110431;Abstract:

To examine how stress affects cognitive functioning, individual differences in trait vulnerability (punishment sensitivity) and state reactivity (negative affect) to social evaluative threat were examined during concurrent reinforcement learning. Lower trait-level punishment sensitivity predicted better reward learning and poorer punishment learning; the opposite pattern was found in more punishment sensitive individuals. Increasing state-level negative affect was directly related to punishment learning accuracy in highly punishment sensitive individuals, but these measures were inversely related in less sensitive individuals. Combined electrophysiological measurement, performance accuracy and computational estimations of learning parameters suggest that trait and state vulnerability to stress alter cortico-striatal functioning during reinforcement learning, possibly mediated via medio-frontal cortical systems. © The Author (2010). Published by Oxford University Press.

PMID: 7635581;Abstract:

Higher frequency electroencephalographic (EEG) activity around 40 Hz has been shown to play a role in cognitive functions such as attention. Furthermore, event-related brain potential (ERP) components such as N1 and P1 are sensitive to selective attention. In the present study, 40-Hz EEG measures and early ERP components were employed to relate selective attention to hypnotic response. Participants were 20 low hypnotizable individuals, half assigned as simulators, and 21 high hypnotizable individuals. Each of these groups was subsequently divided into two groups based on recognition amnesia scores. The four groups differed in 40-Hz (36-44 Hz) EEG spectral amplitude recorded during preinduction resting conditions but not in EEG amplitude postinduction. The groups also differed in N1 amplitudes recorded during hypnosis. Regression analysis revealed that these effects only distinguish the high hypnotizable participants who experienced recognition amnesia from all other groups. The findings support the role of selective attention in hypnotic responsiveness, and the utility of subdividing high hypnotizable individuals is discussed.

PMID: 21497027;PMCID: PMC3114157;Abstract:

Breathing movements are one of the earliest fetal motor behaviors to emerge and are a hallmark of fetal well-being. Fetal respiratory sinus arrhythmia (RSA) has been documented but efforts to quantify the influence of breathing on heart rate (HR) and heart rate variability (HRV) are difficult due to the episodic nature of fetal breathing activity. We used a dedicated fetal biomagnetometer to acquire the magnetocardiogram (MCG) between 36 and 38. weeks gestational age (GA). We identified and characterized a waveform observed in the raw data and independent component decomposition that we attribute to fetal diaphragmatic movements during breathing episodes. RSA and increased high frequency power in a time-frequency analysis of the IBI time-series was observed during fetal breathing periods. Using the diaphragmatic magnetomyogram (dMMG) as a marker, we compared time and frequency domain metrics of heart rate and heart rate variability between breathing and non-breathing epochs. Fetal breathing activity resulted in significantly lower HR, increased high frequency power, greater sympathovagal balance, increased short-term HRV and greater parasympathetic input relative to non-breathing episodes confirming the specificity of fetal breathing movements on parasympathetic cardiac influence. No significant differences between breathing and non-breathing epochs were found in two metrics reflecting total HRV or very low, low and intermediate frequency bands. Using the fetal dMMG as a marker, biomagnetometry can help to elucidate the electrophysiologic mechanisms associated with diaphragmatic motor function and may be used to study the longitudinal development of human fetal cardiac autonomic control and breathing activity. © 2011 Elsevier Ireland Ltd.

Abstract:

Background: Premenstrual dysphoric disorder (PMDD) is a chronic condition that significantly affects a woman's well-being on a monthly basis. Although co-occurrence of PMDD and major depressive disorder (MDD) is common, most studies examine whether women with PMDD are at risk for depression and investigations of PMDD in depressed women are scant. Therefore, the present study examined rates of PMDD in young depressed women. Methods: PMDD was assessed using a structured clinical interview (SCID-PMDD) in a sample of 164 young women with (n=85) and without (n = 79) any history of depression. Results: Rates of PMDD were elevated among women with MDD in this sample. This result held true regardless of participants' MDD status (current, lifetime or past history-only symptoms of MDD) and regardless of whether all or most DSM-IV-TR PMDD criteria were met. Limitations: Sample size in the present study was relatively small, and daily diary data were not available to confirm a PMDD diagnosis. Conclusions: The current study highlights the need for clinicians to assess for PMDD in young female patients with major depression. Depressed women experiencing the added physical and psychological burden of PMDD may have a more severe disease course, and future studies will need to identify appropriate treatments for this subset of depressed women. © 2013 Elsevier B.V. All rights reserved.

PMID: 18729620;Abstract:

Controversy surrounding dissociative identity disorder (DID) has focused on conflicting findings regarding the validity and nature of interidentity amnesia, illustrating the need for objective methods of examining amnesia that can discriminate between explicit and implicit memory transfer. In the present study, the authors used a cross-modal manipulation designed to mitigate implicit memory effects. Explicit memory transfer between identities was examined in 7 DID participants and 34 matched control participants. After words were presented to one identity auditorily, the authors tested another identity for memory of those words in the visual modality using an exclusion paradigm. Despite self-reported interidentity amnesia, memory for experimental stimuli transferred between identities. DID patients showed no superior ability to compartmentalize information, as would be expected with interidentity amnesia. The cross-modal nature of the test makes it unlikely that memory transfer was implicit. These findings demonstrate that subjective reports of interidentity amnesia are not necessarily corroborated by objective tests of explicit memory transfer. © 2008 American Psychological Association.