Coding of movements in the motor cortex
A focus on female vets
Brain Sciences Centerat the Minneapolis Veterans Affairs Medical Center in 2010, the young scientist was very much aware that researchers there had just shown that
Magnetoencephalographycould be used to diagnose post-traumatic stress disorder (
Posttraumatic Stress Disorder). In a 2010 article published in the Journal of Neural Engineering, they reported being able to distinguish, with better than 90 percent accuracy, between brain scans of people who did and did not have
PTSD.James was interested in building on that work, most of which had been done using male veterans as subjects. But she had a fresh question: What about female veterans?James knew women had higher rates of
PTSDthan men (the rate is estimated at 20 percent for women compared with 8 percent overall) and experienced different types of trauma. "Whereas combat exposure might be more common in male veterans, things like sexual trauma...
Brain oscillatory activity during motor preparation: effect of directional uncertainty on beta, but not alpha, frequency band
permalinkFrontiers in Neuroscience - 2015-07-21Tzagarakis C, West S, Pellizzer G10.3389/fnins.2015.00246In time-constraint activities, such as sports, it is advantageous to be prepared to act even before knowing precisely what action will be needed. Here, we studied the relation between neural oscillations during motor preparation and amount of uncertainty about the direction of the upcoming target. Ten right-handed volunteers participated in a cued center-out task. A brief visual cue identified the region of space in which the target would appear. Three cue sizes were used to vary the amount of information about the direction of the upcoming target. The target appeared at a random location within the region indicated by the cue, and the participants moved a joystick-controlled cursor toward it. Time-frequency analyses showed phasic increases of power in low (delta/theta: <7 Hz) and high (gamma: >30 Hz) frequency-bands in relation to the onset of visual stimuli and of the motor response. More importantly in regard to motor preparation, there was a tonic reduction of power in7>7>7>7>7>...
Neural communication in posttraumatic growth
permalinkExperimental Brain Research - 2015-07-01Anders S, Peterson C, James L, Engdahl B, Leuthold A, Georgopoulos AP10.1007/s00221-015-4272-2Posttraumatic growth (PTG), or positive psychological changes following exposure to traumatic events, is commonly reported among trauma survivors. In the present study, we examined neural correlates of PTG in 106 veterans with
PTSDand 193 veteran controls using task-free
MEG, diagnostic interviews and measures of PTG, and traumatic event exposure. Global
Synchronous Neural Interactions(SNIs) were significantly modulated downward with increasing PTG scores in controls (p = .005), but not in veterans with
PTSD(p = .601). This effect was primarily characterized by negative slopes in local neural networks, was strongest in the medial prefrontal cortex, and was much stronger and more extensive in the control than the
PTSDgroup. The present study complements previous research highlighting the role of neural adaptation in healthy functioning.
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition personality traits discriminate between PTSD and control groups
permalinkExperimental Brain Research - 2015-07-01James L, Anders S, Peterson C, Engdahl B, Krueger RF, Georgopoulos AP10.1007/s00221-015-4273-1The relevance of personality traits to the study of psychopathology has long been recognized, particularly in terms of understanding patterns of comorbidity. In fact, a multidimensional personality trait model reflecting five higher-order personality dimensions-negative affect, detachment, antagonism, disinhibition, and psychoticism-is included in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) and represented in the Personality Inventory for
DSM-5(PID-5). However, evaluation of these dimensions and underlying personality facets within clinical samples has been limited. In the present study, we utilized the PID-5 to evaluate the personality profile elevation and composition of 150 control veterans and 35 veterans diagnosed with
PTSD. Results indicated that veterans with
PTSDendorsed significantly more personality pathology than control veterans, with scores on detachment and psychoticism domains most clearly discriminating between the two groups. When personality domain scores were considered as parts of each subject's personality profile, a slightly...
White Noise Test: detecting autocorrelation and nonstationarities in long time series after ARIMA modeling
permalinkProceedings of the 14th Python in Science Conference - 2015-06-01Mahan M, Chorn C, Georgopoulos AP10.25080/majora-7b98e3ed-00fTime series analysis has been a dominant technique for assessing relations within atasets collected over time and is becoming increasingly prevalent in the scientific community; for example, assessing brain networks by calculating pairwise correlations of time series generated from different areas of the brain. The assessment of these relations relies, in turn, on the proper calculation of interactions between time series, which is achieved by rendering each individual series stationary and nonautocorrelated (i.e., white noise, or to "prewhiten" the series). This ensures that the relations computed subsequently are due to the interactions between the series and do not reflect internal dependencies of the series themselves. An established method for prewhitening time series is to apply an Autoregressive (AR, p) Integrative (I, d) Moving Average (MA, q) model (ARIMA) and retain the residuals. To diagnostically check whether the model orders (p, d, q) are sufficient, both visualization and statistical tests (e.g., Ljung-Box...
The effect of Apolipoprotein E4 on SNI in brain cultures
permalinkExperimental Brain Research - 2015-06-01Christopoulos V, Georgopoulos A, Georgopoulos AP10.1007/s00221-015-4270-4In a previous study, we assessed the
SNIin a developing neural network in brain cultures on multielectrode arrays (Christopoulos et al. in J Neural Eng 9:046008, 2012). Here, we report on the effects of
Apolipoprotein E4 (
ApoE4) on these neural interactions. We carried out six experiments (five using rodent brain cultures and one using neuroblastoma cultures) in which we recorded local field potentials (LFP) from 59 sites for several days in vitro under the following conditions. In one experiment, we added to the culture media triglyceride (TG)-rich lipoproteins from a human subject with the
ApoE4/4 genotype, whereas in the other experiments, we added recombinant human
ApoE4. We found that
ApoE4-treated cultures had higher coefficient of
SNIvariation, as compared to control cultures. These findings further document the role of
SNIas a fundamental aspect of the dynamic organization of neural networks (Langheim et al....
Posttraumatic Stress Disorder in Women Veterans
PTSDin women and genetic tests to understand why some women will develop
PTSDwhile others won't.
The Danieli Inventory of Multigenerational Legacies of Trauma, Part II: Reparative Adaptational Impacts
permalinkAmerican Journal of Orthopsychiatry - 2015-05-01Danieli Y, Norris FH, Lindert J, Paisner V, Kronenberg S, Engdahl B, Richter J10.1037/ort0000055The impacts of the Holocaust on children of survivors have been widely investigated. However, consensus is limited, and no validated measures have been tailored with or to them. We aimed to develop and validate a scale that measures these specific impacts (Part II of the Danieli Inventory of Multigenerational Legacies of Trauma). We studied 484 adult children of survivors who participated in a cross-sectional web-based survey in English or Hebrew; of these, 191 participated in a clinical interview. Exploratory factor analyses of 58 items to reduce and refine the measure yielded a 36-item scale, Reparative Adaptational Impacts, that had excellent internal consistency (α = .91) and congruence between English and Hebrew versions (φ ≥ .95). Associations between impacts and SCID-based diagnoses of major depressive episode,
PTSD, and generalized anxiety disorder were moderate to strong (ds = 0.48-0.89). Strong associations also emerged between severity of offspring's reparative adaptational impacts and...
Spatial attentional control is not impaired in schizophrenia: Dissociating specific deficits from generalized impairments
permalinkJournal of Abnormal Psychology - 2015-05-01Elshaikh AA, Sponheim S, Chafee M, MacDonald III AW10.1037/a0038537A large literature has established that people with schizophrenia are impaired on tasks that require attentional control. However, evidence is mixed as to whether these impairments are specific deficits (Oltmanns & Neale, 1975) or merely reflect a generalized impairment (Dickinson & Harvey, 2009). Recent evidence also suggests visual attentional control for encoding into working memory may be selectively spared in people with schizophrenia (Gold et al., 2006). The current study used a cued backward masking task to investigate 23 people with schizophrenia and 27 healthy controls. People with schizophrenia were hypothesized to perform better on invalidly cued trials when making a simple identification or location judgment. However, we found schizophrenia impaired performance on both valid and invalid cues to the same degree whether the cue was a stored representation (top-down) or presented at the location of the stimulus (bottom-up). In contrast to a large neuropsychological literature, these findings suggest that people...
Client report of spirituality in recovery from serious mental illness
Cognitive mechanisms underlying instructed choice exploration of small city maps
permalinkFrontiers in Neuroscience - 2015-03-20Sakellaridi S, Christova P, Christopoulos V, Vialard A, Peponis J, Georgopoulos AP10.3389/fnins.2015.00060We investigated the cognitive mechanisms underlying the exploration and decision-making in realistic and novel environments. Twelve human subjects were shown small circular U.S. city maps with two locations highlighted on the circumference, as possible choices for a post office ("targets"). At the beginning of a trial, subjects fixated a spot at the center of the map and ultimately chose one of the two locations. A space syntax analysis of the map paths (from the center to each target) revealed that the chosen location was associated with the less convoluted path, as if subjects navigated mentally the paths in an "ant's way," i.e., by staying within street boundaries, and ultimately choosing the target that could be reached from the center in the shortest way, and the fewest turns and intersections. The subjects' strategy for map exploration and decision making was investigated by monitoring eye position during the task. This revealed a restricted...
The Number of Cysteine Residues per Mole in Apolipoprotein E Is Associated With the Severity of PTSD Re-Experiencing Symptoms
permalinkJournal of Neuropsychiatry and Clinical Neurosciences - 2015-03-09Peterson C, James L, Anders S, Engdahl B, Georgopoulos AP10.1176/appi.neuropsych.13090205Apolipoprotien E (
ApoE) is involved in critical neural functions and is associated with various neuropsychiatric disorders.
ApoEexists in three isoforms that differ in the number of cysteine residues per mole (CysR/mole). This study evaluated associations between this informative ordinal biochemical scale (CysR/mole) and symptom severity in veterans with
PTSD. Results demonstrated a significant negative relationship between the CysR/mole and severity of
PTSDre-experiencing symptoms, adjusted for trauma. The findings suggest a genetic influence on
PTSDsymptomatology and dovetail with recent advances regarding the molecular mechanisms underlying the differential effects of
ApoEin the brain.
An information theory analysis of spatial decisions in cognitive development
permalinkFrontiers in Neuroscience - 2015-02-04Scott NM, Sera MD, Georgopoulos AP10.3389/fnins.2015.00014Performance in a cognitive task can be considered as the outcome of a decision-making process operating across various knowledge domains or aspects of a single domain. Therefore, an analysis of these decisions in various tasks can shed light on the interplay and integration of these domains (or elements within a single domain) as they are associated with specific task characteristics. In this study, we applied an information theoretic approach to assess quantitatively the gain of knowledge across various elements of the cognitive domain of spatial, relational knowledge, as a function of development. Specifically, we examined changing spatial relational knowledge from ages 5 to 10 years. Our analyses consisted of a two-step process. First, we performed a hierarchical clustering analysis on the decisions made in 16 different tasks of spatial relational knowledge to determine which tasks were performed similarly at each age group as well as to discover how the tasks clustered...
Development and application of a diagnostic algorithm for Posttraumatic Stress Disorder
permalinkPsychiatry Research: Neuroimaging - 2015-01-30James L, Belitskaya-Levy I, Lu Y, Wang H, Engdahl B, Leuthold A, Georgopoulos AP10.1016/j.pscychresns.2014.11.007Intact cognitive functions rely on synchronous neural activity; conversely, alterations in synchrony are thought to underlie psychopathology. We recently demonstrated that anomalies in
SNIdetermined by magnetoencephalography represent a putative
PTSDbiomarker. Here we develop and apply a regression-based diagnostic algorithm to further validate
PTSDbiomarker in 432 veterans (235 controls; 138 pure
PTSDplus comorbid disorders). Correlation coefficients served as proximities in multidimensional scaling (MDS) to obtain a two-dimensional representation of the data. In addition, least absolute shrinkage and selection operator (LASSO) regression was used to derive a diagnostic algorithm for
PTSD. Performance of this algorithm was assessed by the area under the receiver operating characteristic (ROC) curves, sensitivity, and specificity in 1000 randomly divided testing and validation datasets and in independent samples. MDS revealed that individuals with
PTSD, regardless of comorbid psychiatric conditions, are highly distinct from controls. Similarly, application of...
Columnar Organization of the Motor Cortex: Direction of Movement
Cognitive modulation of local and callosal neural interactions in decision making
permalinkFrontiers in Neuroscience - 2014-08-11Merchant H, Crowe D, Fortes A, Georgopoulos AP10.3389/fnins.2014.00245Traditionally, the neurophysiological mechanisms of cognitive processing have been investigated at the single cell level. Here we show that the dynamic, millisecond-by-millisecond, interactions between neuronal events measured by local field potentials are modulated in an orderly fashion by key task variables of a space categorization task performed by monkeys. These interactions were stronger during periods of higher cognitive load and varied in sign (positive, negative). They were observed both within area 7a of the posterior parietal cortex and between symmetric 7a areas of the two hemispheres. Time lags for maximum interactions were longer for opposite- vs. same-hemisphere recordings, and lags for negative interactions were longer than for positive interactions in both recording sites. These findings underscore the involvement of dynamic neuronal interactions in cognitive processing within and across hemispheres. They also provide accurate estimates of lags in callosal interactions, very comparable to similar estimates of callosal conduction delays derived from neuroanatomical...
Social support as a mediator in the relationship between religious comforts and strains and trauma symptoms
Cell directional spread determines accuracy, precision, and length of the neuronal population vector
Understanding Posttraumatic Stress Disorder
PTSDand how those suffering from the disorder can get effective help