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1.  Depressive Rumination Alters Cortisol Decline in Major Depressive Disorder 
Biological psychology  2014;100:50-55.
Depressive rumination – a central characteristic of Major Depressive Disorder (MDD) – is a maladaptive emotion regulation strategy that prolongs sad mood and depressive episodes. Considerable research demonstrates the emotional and behavioral consequences of depressive rumination, yet few studies investigate its effect on neuroendocrine functioning. The current study examined the effect of an emotion regulation manipulation on the trajectory of cortisol concentrations among individuals with MDD and healthy controls (CTL). Sadness was induced via forced failure. Participants then were randomly assigned to a depressive rumination or distraction emotion regulation induction. MDDs in the rumination condition exhibited less cortisol decline compared to MDDs in the distraction condition and compared to CTLs in either condition. Findings suggest that depressive rumination alters the trajectory of cortisol secretion in MDD and may prolong cortisol production. Results thereby provide important insights into the interaction of biological and psychological factors through which distress contributes to MDD.
PMCID: PMC4101056  PMID: 24835412
cortisol; HPA axis; depression; rumination; emotion regulation; experimental
2.  Age-related changes in feature-based object memory retrieval as measured by event-related potentials 
Biological psychology  2014;100:106-114.
To investigate neural mechanisms that support semantic functions in aging, we recorded scalp EEG during an object retrieval task in 22 younger and 22 older adults. The task required determining if a particular object could be retrieved when two visual words representing object features were presented. Both age groups had comparable accuracy although response times were longer in older adults. In both groups a left fronto-temporal negative potential occurred at around 750 msec during object retrieval, consistent with previous findings (Brier et al., 2008). Only in older adults a later positive frontal potential was found peaking between 800 and 1000 msec during no retrieval. These findings suggest younger and older adults employ comparable neural mechanisms when features clearly facilitate retrieval of an object memory, but when features yield no retrieval, older adults use additional neural resources to engage in a more effortful and exhaustive search prior to making a decision.
PMCID: PMC4119884  PMID: 24911552
semantic; object memory; memory retrieval; feature; ERP; aging
3.  The Effects of Constrained Left versus Right Monocular Viewing on the Autonomic Nervous System 
Biological psychology  2014;100:79-85.
Asymmetrical activation of right and left hemispheres differentially influences the autonomic nervous system. Additionally, each hemisphere primarily receives retinocollicular projections from the contralateral eye. To learn if asymmetrical hemispheric activation induced by monocular viewing would influence relative pupillary size and respiratory hippus variability (RHV), a measure of parasympathetic activity, healthy participants had their left, right or neither eye patched. Pupillary sizes were then recorded with infrared pupillography. Pupillary dilation was significantly greater with left than right eye viewing. RHV, however, was not different between eye viewing conditions. These differences in pupil dilatation may have been caused by relatively greater activation of the right hemispheric-mediated sympathetic activity induced by left monocular viewing or relatively greater deactivation of the left hemispheric-mediated parasympathetic activity induced by right eye patching. The absence of an asymmetry in RHV, however, suggests that hemispheric asymmetry of sympathetic activation was primarily responsible for this ocular asymmetry of pupil dilation.
PMCID: PMC4156286  PMID: 24878321
Constrained Monocular Viewing; Autonomic Nervous System; Laterality; Pupillary Light Reflex; Hippus; Respiratory Sinus Arrhythmia; Monocular Occlusion; Eye Patching; Sprague effect; Pupillary Diameter
4.  Pregnancy Anxiety and Prenatal Cortisol Trajectories 
Biological psychology  2014;100:13-19.
Pregnancy anxiety is a potent predictor of adverse birth and infant outcomes. The goal of the current study was to examine one potential mechanism whereby these effects may occur by testing associations between pregnancy anxiety and maternal salivary cortisol on 4 occasions during pregnancy in a sample of 448 women. Higher mean levels of pregnancy anxiety over the course of pregnancy predicted steeper increases in cortisol trajectories compared to lower pregnancy anxiety. Significant differences between cortisol trajectories emerged between 30 to 31 weeks of gestation. Results remained significant when adjusted for state anxiety and perceived stress. Neither changes in pregnancy anxiety over gestation, nor pregnancy anxiety specific to only a particular time in pregnancy predicted cortisol. These findings provide support for one way in which pregnancy anxiety may influence maternal physiology and contribute to a growing literature on the complex biological pathways linking pregnancy anxiety to birth and infant outcomes.
PMCID: PMC4170592  PMID: 24769094
pregnancy anxiety; cortisol; anxiety; perceived stress; pregnancy; hypothalamic-pituitary-adrenal axis
5.  The conditioning and extinction of fear in youths: What’s sex got to do with it? 
Biological psychology  2014;100:97-105.
Adult work shows differences in emotional processing influenced by sexes of both the viewer and expresser of facial expressions. We investigated this in 120 healthy youths (57 boys; 10–17 years old) randomly assigned to fear conditioning and extinction tasks using either neutral male or female faces as the conditioned threat and safety cues, and a fearful face paired with a shrieking scream as the unconditioned stimulus. Fear ratings and skin conductance responses (SCRs) were assessed. Male faces triggered increased fear ratings in all participants during conditioning and extinction. Greater differential SCRs were observed in boys viewing male faces and in girls viewing female faces during conditioning. During extinction, differential SCR findings remained significant in boys viewing male faces. Our findings demonstrate how sex of participant and sex of target interact to shape fear responses in youths, and how the type of measure may lead to distinct profiles of fear responses.
PMCID: PMC4465596  PMID: 24929048
Sex; Gender; Youth; Fear conditioning; Fear extinction; Skin conductance
6.  Interleukin-6 and Soluble Interleukin-6 Receptor Levels in Posttraumatic Stress Disorder: Associations with Lifetime Diagnostic Status and Psychological Context 
Biological psychology  2014;99:150-159.
This study correlated lifetime PTSD diagnostic status with interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) levels, and tested whether these correlations are sensitive to psychological context. Midlife women attended two research visits where blood was drawn (beginning of visits) and saliva and oral mucosal transudate were collected (beginning and end of visits) to measure IL-6 and sIL-6R. Women were classified as PTSD−/− (past and current symptoms below subsyndromal levels), PTSD+/− (past symptoms at or above subsyndromal levels), or PTSD +/+ (past and current symptoms at or above subsyndromal levels). PTSD+/+ women, compared to the other women, showed more negative emotion at the beginning of the visits, higher salivary IL-6 levels at the beginning versus end of visits, and positive correlations between negative emotion, salivary IL-6, and plasma sIL-6R. Their plasma sIL-6R levels exceeded those of the PTSD+/− women. Overall, IL-6 sensitivity to anticipation and to negative emotions, and higher sIL-6R levels, differentiated persistent versus remitted PTSD.
PMCID: PMC4059765  PMID: 24695006
PTSD; remitted PTSD; inflammation; IL-6; sIL-6R; anticipation
7.  Amygdala-cingulate intrinsic connectivity is associated with degree of social inhibition 
Biological psychology  2014;99:15-25.
The tendency to approach or avoid novel people is a fundamental human behavior and is a core dimension of social anxiety. Resting state fMRI was used to test for an association between social inhibition and intrinsic connectivity in 40 young adults ranging from low to high in social inhibition. Higher levels of social inhibition were associated with specific patterns of reduced amygdala-cingulate cortex connectivity. Connectivity was reduced between the superficial amygdala and the rostral cingulate cortex and between the centromedial amygdala and the dorsal anterior cingulate cortex. Social inhibition also modulated connectivity in several well-established intrinsic networks; higher social inhibition correlated with reduced connectivity with default mode and dorsal attention networks and enhanced connectivity in salience and executive control networks. These findings provide important preliminary evidence that social inhibition reflects differences in the underlying intrinsic connectivity of the brain in the absence of social stimuli or stressors.
PMCID: PMC4274047  PMID: 24534162
Resting state; fMRI; Inhibited temperament; Anxiety; Prefrontal cortex; Social anxiety disorder
8.  Manipulating motor performance and memory through real-time fMRI neurofeedback 
Biological Psychology  2015;108:85-97.
•Neurofeedback training of motor cortex shortens reaction times.•Self-regulation of parahippocampal cortex activity interferes with memory encoding.•Differential neurofeedback reveals double dissociation between neurofeedback target areas.
Task performance depends on ongoing brain activity which can be influenced by attention, arousal, or motivation. However, such modulating factors of cognitive efficiency are unspecific, can be difficult to control, and are not suitable to facilitate neural processing in a regionally specific manner. Here, we non-pharmacologically manipulated regionally specific brain activity using technically sophisticated real-time fMRI neurofeedback. This was accomplished by training participants to simultaneously control ongoing brain activity in circumscribed motor and memory-related brain areas, namely the supplementary motor area and the parahippocampal cortex. We found that learned voluntary control over these functionally distinct brain areas caused functionally specific behavioral effects, i.e. shortening of motor reaction times and specific interference with memory encoding. The neurofeedback approach goes beyond improving cognitive efficiency by unspecific psychological factors such as attention, arousal, or motivation. It allows for directly manipulating sustained activity of task-relevant brain regions in order to yield specific behavioral or cognitive effects.
PMCID: PMC4433098  PMID: 25796342
Memory; Motor performance; Neurofeedback; Brain imaging; Functional magnetic resonance imaging (fMRI); Real-time fMRI; Self-regulation; Brain training
9.  Relation of frontal N100 to psychopathy-related differences in selective attention☆ 
Biological psychology  2014;103:107-116.
Research indicates that psychopathy may be characterized by early attentional abnormalities that undermine the processing of peripheral information during goal-directed activity (Baskin-Sommers & Newman, 2012). Past work has found that psychopathic individuals show reduced interference on the Box Stroop task, in which color names are spatially separated from (i.e., peripheral to) colored stimuli (Hiatt, Schmitt, & Newman, 2004). The present study sought to replicate and extend these findings. A priori predictions were that psychopathy scores would be inversely related to interference and that psychopathy-related differences in Box Stroop conflict processing would emerge at an early stage as measured by event-related potentials (ERP). Results supported both hypotheses. Moreover, the association between the early attention-related component (N100) and interference was moderated by level of psychopathy. These findings suggest that psychopathic individuals have less coordinated responses to conflict than healthy individuals, a conjecture that has implications for information integration and self-regulation.
PMCID: PMC4407830  PMID: 25179538
Psychopathy; Attention; Interference; ERP; N100
10.  DeCon: A tool to detect emotional concordance in multivariate time series data of emotional responding 
Biological psychology  2013;98:29-42.
The occurrence of concordance among different response components during an emotional episode is a key feature of several contemporary accounts and definitions of emotion. Yet, capturing such response concordance in empirical data has proven to be elusive, in large part because of a lack of appropriate statistical tools that are tailored to measure the intricacies of response concordance in the context of data on emotional responding. In this article, we present a tool we developed to detect two different forms of response concordance—response patterning and synchronization—in multivariate time series data of emotional responding, and apply this tool to data concerning physiological responding to emotional stimuli. While the findings provide partial evidence for both response patterning and synchronization, they also show that the presence and nature of such patterning and synchronization is strongly person-dependent.
PMCID: PMC4016122  PMID: 24220647
emotion; affect; concordance; patterning; synchronization; synchronicity
11.  Emotion dysregulation and dyadic conflict in depressed and typical adolescents: Evaluating concordance across psychophysiological and observational measures 
Biological psychology  2014;98:50-58.
Many depressed adolescents experience difficulty regulating their emotions. These emotion regulation difficulties appear to emerge in part from socialization processes within families and then generalize to other contexts. However, emotion dysregulation is typically assessed within the individual, rather than in the social relationships that shape and maintain dysregulation. In this study, we evaluated concordance of physiological and observational measures of emotion dysregulation during interpersonal conflict, using a multilevel actor-partner interdependence model (APIM). Participants were 75 mother-daughter dyads, including 50 depressed adolescents with or without a history of self-injury, and 25 typically developing controls. Behavior dysregulation was operationalized as observed aversiveness during a conflict discussion, and physiological dysregulation was indexed by respiratory sinus arrhythmia (RSA). Results revealed different patterns of concordance for control versus depressed participants. Controls evidenced a concordant partner (between-person) effect, and showed increased physiological regulation during minutes when their partner was more aversive. In contrast, clinical dyad members displayed a concordant actor (within-person) effect, becoming simultaneously physiologically and behaviorally dysregulated. Results inform current understanding of emotion dysregulation across multiple levels of analysis.
PMCID: PMC4026166  PMID: 24607894
Emotion dysregulation; respiratory sinus arrhythmia (RSA); depression; dyadic conflict
12.  Is there consistency and specificity of autonomic changes during emotional episodes? Guidance from the conceptual act theory and psychophysiology 
Biological psychology  2014;98:82-94.
The consistency and specificity of autonomic nervous system (ANS) responses during emotional episodes remains a topic of debate with relevance for emotional concordance. We present a recent model of how mental states are constructed, the Conceptual Act Theory (CAT), and then review findings from existing meta-analyses and a qualitative review along with studies using pattern classification of multivariate ANS patterns to determine if there is across-study evidence for consistency and specificity of ANS responses during emotional episodes. We conclude that there is thus far minimal evidence for ANS response consistency and specificity across studies. We then review the current understanding of the functional and anatomical features of ANS including its efferent and afferent connections with the central nervous system, which suggests the need to reformulate how we conceptualize ANS response consistency and specificity. We conclude by showing how this reformulation is consistent with the CAT, and how we suggest the model to propose when we would and would not expect to see consistency and specificity in ANS responses, and concordance more generally, during emotional episodes.
PMCID: PMC4041070  PMID: 24388802
autonomic nervous system; emotion; psychological construction; situational response specificity; individual response specificity; psychophysiology
13.  Brain, body, and cognition: Neural, physiological and self-report correlates of phobic and normative fear 
Biological psychology  2014;98:59-69.
The phobic fear response appears to resemble an intense form of normal threat responding that can be induced in a nonthreatening situation. However, normative and phobic fear are rarely contrasted directly, thus the degree to which these two types of fear elicit similar neural and bodily responses is not well understood. To examine biological correlates of normal and phobic fear, 21 snake phobic and 21 nonphobic controls saw videos of slithering snakes, attacking snakes and fish in an event-related fMRI design. Simultaneous eletrodermal, pupillary, and self-reported affective responses were collected. Nonphobic fear activated a network of threat-responsive brain regions and involved pupillary dilation, electrodermal response and self-reported affect selective to the attacking snakes. Phobic fear recruited a large array of brain regions including those active in normal fear plus additional structures and also engendered increased pupil dilation, electrodermal and self-reported responses that were greater to any snake versus fish. Importantly, phobics showed greater between- and within-subject concordance among neural, electrodermal, pupillary, and subjective report measures. These results suggest phobic responses recruit overlapping but more strongly activated and more extensive networks of brain activity as compared to normative fear, and are characterized by greater concordance among neural activation, peripheral physiology and self-report. It is yet unclear whether concordance is unique to psychopathology, or rather simply an indicator of the intense fear seen in the phobic response, but these results underscore the importance of synchrony between brain, body, and cognition during the phobic reaction.
PMCID: PMC4251669  PMID: 24561099
Emotion; Concordance; Phobia; Fear; Brain; Autonomic nervous system; Self-report
14.  Increased Insula Coactivation with Salience Networks in Insomnia 
Biological psychology  2014;97:1-8.
Insomnia is among the most prevalent and costly of all sleep-related disorders. To characterize the neural mechanisms underlying subjective dysfunction in insomnia, we examined brain activity in 17 female insomniacs and 17 female healthy controls using simultaneous functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) while they were resting and while they were trying to fall asleep. In examining the dynamic regional activity within intrinsic brain networks, we found that, compared with controls, insomniacs had greater involvement of the anterior insula with salience networks, as well as insula BOLD correlation with EEG gamma frequency power during rest in insomniacs. This increased involvement of the anterior insula was associated with negative affect in insomniacs. Aberrant activation of the insula, which integrates temporal and bodily states, in arousal networks may underlie the misperception of sleep quality and subjective distress in insomnia.
PMCID: PMC3961550  PMID: 24412227
insomnia; fMRI; EEG; resting state; insula; salience networks
15.  Neural and Genetic Correlates of Binge Drinking Among College Women 
Biological psychology  2014;97:43-48.
Ninety-seven female students, aged 18–20 yrs, were assigned to groups consisting of 55 infrequent (less than monthly) and 42 frequent (at least monthly) binge drinkers. The groups were compared on self-report measures of impulsivity, sensation seeking, and alexithymia. The groups were also compared on several objective measures relevant to neural and genetic mechanisms, such as brain activation during a time estimation task and selected genotypes. Analyses of stimulus-locked brain activity revealed a slow cortical potential generated over the right parietal cortex during time estimation that was more negative in the frequent binge drinking group. This group also showed a greater prevalence of a CHRM2 genotype previously associated with substance dependence and Major Depressive Disorder as well as a modest elevation on a non-planning impulsiveness self-report scale. We conclude that the enhanced brain activation shown by binge drinkers during time estimation compensates for an underlying deficit. That deficit may be reflected in poor planning skills and a genetic difference indicating increased risk for both externalizing and internalizing disorders in later life.
PMCID: PMC3974158  PMID: 24530440
alcohol; binge drinking; gene; CHRM2; contingent negative variation; evoked potential; electroencephalography; college students; time
16.  High cardiac vagal control is related to better subjective and objective sleep quality 
Biological Psychology  2015;106:79-85.
•Cardiac vagal control (CVC) was measured during an extended standardized baseline.•Subjective and polysomnographic variables of sleep quality were assessed.•Higher CVC was found to be associated with better subjective and objective sleep quality.
Cardiac vagal control (CVC) has been linked to both physical and mental health. One critical aspect of health, that has not received much attention, is sleep. We hypothesized that adults with higher CVC – operationalized by high-frequency heart rate variability (HF-HRV) – will exhibit better sleep quality assessed both subjectively (i.e., with Pittsburgh Sleep Quality Index) and objectively (i.e., with polysomnography). HF-HRV was measured in 29 healthy young women during an extended neutral film clip. Participants then underwent full polysomnography to obtain objective measures of sleep quality and HF-HRV during a night of sleep. As expected, higher resting HF-HRV was associated with higher subjective and objective sleep quality (i.e., shorter sleep latency and fewer arousals). HF-HRV during sleep (overall or separated by sleep phases) showed less consistent relationships with sleep quality. These findings indicate that high waking CVC may be a key predictor of healthy sleep.
PMCID: PMC4364614  PMID: 25709072
Parasympathetic nervous system; Heart rate variability; Respiratory sinus arrhythmia; Sleep quality; Polysomnography
17.  [No title available] 
PMCID: PMC3946695  PMID: 24192273
18.  [No title available] 
PMCID: PMC3946712  PMID: 24192272
19.  [No title available] 
PMCID: PMC3947287  PMID: 24355244
20.  A head-to-head comparison of SCRalyze and Ledalab, two model-based methods for skin conductance analysis 
Biological Psychology  2014;103:63-68.
•Comparison of two developed methods for model-based analysis of phasic skin conductance responses.•Four datasets are used to compare predictive validity.•SCRalyze shows higher predictive validity than Ledalab in 4 of 5 comparisons, and equal predictive validity in the fifth.•SCRalyze shows higher predictive validity than peak-scoring in all comparisons.
Model-based analysis of skin conductance responses (SCR) can furnish less noisy estimates of sympathetic arousal (SA) than operational peak scoring approaches, as shown in previous work. Here, I compare two model-based methods for analysis of evoked (stimulus-locked) SCR, implemented in two software packages, SCRalyze and Ledalab, with respect to their sensitivity in recovering SA. Four datasets are analysed to compare predictive validity, i.e. the sensitivity to distinguish pairs of SA states that are known to be different. SCRalyze was significantly better able than Ledalab to recover this known difference in four out of five tested contrasts and comparable in the remaining one. SCRalyze performed significantly better than conventional analysis in all contrasts. I conclude that the model-based method engendered in SCRalyze is currently the best available approach to provide robust and sensitive estimates of sympathetic arousal.
PMCID: PMC4266536  PMID: 25148785
SCR; EDA; GSR; Model-based method; Biophysical model; Model inversion
21.  Dissociation between arithmetic relatedness and distance effects is modulated by task properties: An ERP study comparing explicit vs. implicit arithmetic processing 
Biological Psychology  2014;103:305-316.
•ERPs were recorded while performing number matching and arithmetic verification tasks.•Access to the arithmetic facts lexicon is modulated by task properties.•Arithmetic relatedness and distance effects are sensitive to task properties.•Matching tasks involve semantic processes.•Verification tasks involve semantic and detection of mismatch processes.
Event-related potential (ERP) studies have detected several characteristic consecutive amplitude modulations in both implicit and explicit mental arithmetic tasks. Implicit tasks typically focused on the arithmetic relatedness effect (in which performance is affected by semantic associations between numbers) while explicit tasks focused on the distance effect (in which performance is affected by the numerical difference of to-be-compared numbers). Both task types elicit morphologically similar ERP waves which were explained in functionally similar terms. However, to date, the relationship between these tasks has not been investigated explicitly and systematically. In order to fill this gap, here we examined whether ERP effects and their underlying cognitive processes in implicit and explicit mental arithmetic tasks differ from each other. The same group of participants performed both an implicit number-matching task (in which arithmetic knowledge is task-irrelevant) and an explicit arithmetic-verification task (in which arithmetic knowledge is task-relevant). 129-channel ERP data differed substantially between tasks. In the number-matching task, the arithmetic relatedness effect appeared as a negativity over left-frontal electrodes whereas the distance effect was more prominent over right centro-parietal electrodes. In the verification task, all probe types elicited similar N2b waves over right fronto-central electrodes and typical centro-parietal N400 effects over central electrodes. The distance effect appeared as an early-rising, long-lasting left parietal negativity. We suggest that ERP effects in the implicit task reflect access to semantic memory networks and to magnitude discrimination, respectively. In contrast, effects of expectation violation are more prominent in explicit tasks and may mask more delicate cognitive processes.
PMCID: PMC4266537  PMID: 25450162
ERPs; Mental arithmetic; Arithmetic relatedness; Distance effect; Magnitude representation
22.  Neural adaptation to non-symbolic number and visual shape: An electrophysiological study 
Biological Psychology  2014;103:203-211.
•We compare EEG indicators of automatic change detection to numbers vs shape.•We apply stringent control of perceptual variables.•Shape change is detected early in the cognitive processing stream.•Number change is detected only later in the cognitive processing stream.•Nonsymbolic number is not a perceptual property extracted automatically.
Several studies assumed that the analysis of numerical information happens in a fast and automatic manner in the human brain. Utilizing the high temporal resolution of electroencephalography (EEG) in a passive oddball adaptation paradigm, we compared event-related brain potentials (ERPs) evoked by unattended shape changes and unattended numerosity changes. We controlled visual stimulus properties in a stringent manner. Unattended changes in shape elicited significant, gradual adaptation effects in the range of early visual components, indicating the fast and automatic processing of shapes. Changes in numerosity did not elicit significant changes in these early ERP components. The lack of early number-specific effects was qualified by a significant interaction between Shape and Number conditions. Number change elicited gradual ERP effects only on late ERP components. We conclude that numerosity is a higher-level property assembled from naturally correlating perceptual cues and hence, it is identified later in the cognitive processing stream.
PMCID: PMC4266538  PMID: 25258032
EEG; Numerical cognition; Neural adaptation; Number sense; Number comparison
23.  Reduced negative affect response in female psychopaths 
Biological psychology  2013;94(2):310-318.
Studies that investigate the differences between high and low psychopathic persons in brain activity during emotional facial expression processing are rare and commonly focus on males. The current study assessed whether previously reported behavioral differences would be reflected in differential brain activity in a sample of female offenders.
The participants included 23 female forensic inpatients with high and low scores on the Psychopathy Checklist Revised (PCL-R). ERPs were recorded during presentation of emotional facial expressions (i.e., fear, angry, and happy). Results revealed no differences in N170, P3 and late positive potential components between groups, but a significant difference in N2 only for angry and fear facial expressions, with high psychopathic participants showing lower reactivity. This N2 effect was found to be related to Factor 2 but not Factor 1 of the PCL-R. In time frequency analysis, theta activity underlying N2 best reflected these differences.
Findings in this female sample are consistent with a cortical deficit in processing facial expression of negative emotions in psychopathic men. In addition, differences in processing seem to appear relatively early.
PMCID: PMC3797150  PMID: 23896396
facial affect; psychopathy; female; time-frequency; event-related potentials
24.  Evening-type military veterans report worse lifetime posttraumatic stress symptoms and greater brainstem activity across wakefulness and REM sleep 
Biological psychology  2013;94(2):255-262.
Evening chronotypes exhibit increased rates of affective dyregulation and sleep disturbances (e.g., insomnia and nightmares). Such symptoms are common to military veterans with posttraumatic stress disorder (PTSD); however, the influence of chronotype on this population remains unknown. We examined behavioral, psychological, and neural correlates of chronotype in 36 combat-exposed military veterans with varying degrees of posttraumatic stress symptomatology. We employed FDG-PET to assess neural activity across wakefulness and rapid eye movement (REM) sleep. We used polysomnography and diaries to monitor sleep, and a self-report survey to measure chronotype. Eveningness was associated with greater lifetime PTSD symptoms, more disturbed sleep, and more frequent and intense nightmares. Eveningness was also associated with greater brain activity in posterior cingulate/precuneus and brainstem regions across wakefulness and REM sleep, overlapping with regions related to arousal and REM sleep generation. Chronotype may be an important correlate of neural activity in REM sleep-generating and/or arousal regulatory regions among combat-exposed veterans with PTSD symptoms. Further investigations of the role of chronotype in PTSD are warranted.
PMCID: PMC3797161  PMID: 23831547
imaging; chronotype; sleep; PTSD; veterans; nightmares
25.  Two-Year Stability of the Late Positive Potential across Middle Childhood and Adolescence 
Biological psychology  2013;94(2):290-296.
The late positive potential (LPP) may be a useful measure of individual differences in emotional processing across development, but little is known about the stability of the LPP across time. We assessed the LPP and behavioral measures of emotional interference following pleasant, unpleasant, and neutral images in 8- to 13-year-old youth. Approximately two years later, the same participants completed the task again (N=34). Results indicated that the LPP is moderately-to-highly reliable across development. Stability was lower and more inconsistent for behavioral measures. In addition, consistent with previous cross-sectional analyses, a decrease in occipital activity was observed at the second assessment. Results indicate that the LPP appears to be a stable measure of emotional processing, even across a fairly large period of development.
PMCID: PMC3797196  PMID: 23872165
Event-related potentials; late positive potential; emotion; reliability; development

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