Hemodynamic and metabolic correspondence of resting-state voxel-based physiological metrics in healthy adults.

Voxel-based physiological (VBP) variables derived from blood oxygen level dependent (BOLD) fMRI time-course variations include: amplitude of low frequency fluctuations (ALFF), fractional amplitude of low frequency fluctuations (fALFF) and regional homogeneity (ReHo). Although these BOLD-derived variables can detect between-group (e.g. disease vs control) spatial pattern differences, physiological interpretations are not well established. The primary objective of this study was to quantify spatial correspondences between BOLD VBP variables and PET measurements of cerebral metabolic rate and hemodynamics, being well-validated physiological standards. To this end, quantitative, whole-brain PET images of metabolic rate of glucose (MRGlu; 18FDG) and oxygen (MRO2; 15OO), blood flow (BF; H215O) and blood volume (BV; C15O) were obtained in 16 healthy controls. In the same subjects, BOLD time-courses were obtained for computation of ALFF, fALFF and ReHo images. PET variables were compared pair-wise with BOLD variables. In group-averaged, across-region analyses, ALFF corresponded significantly only with BV (R = 0.64; p < 0.0001). fALFF corresponded most strongly with MRGlu (R = 0.79; p < 0.0001), but also significantly (p < 0.0001) with MRO2 (R = 0.68), BF (R = 0.68) and BV (R=0.68). ReHo performed similarly to fALFF, with significant strong correspondence (p < 0.0001) with MRGlu (R = 0.78), MRO2 (R = 0.54), and, but less strongly with BF (R = 0.50) and BV (R=0.50). Mutual information analyses further clarified these physiological interpretations. When conditioned by BV, ALFF retained no significant MRGlu, MRO2 or BF information. When conditioned by MRGlu, fALFF and ReHo retained no significant MRO2, BF or BV information. Of concern, however, the strength of PET-BOLD correspondences varied markedly by brain region, which calls for future investigation on physiological interpretations at a regional and per-subject basis.

Resting-State Functional Magnetic Resonance Imaging of Interhemispheric Functional Connectivity in Experimental Traumatic Brain Injury.

Although resting-state functional magnetic resonance imaging (rsfMRI) has the potential to offer insights into changes in functional connectivity networks after traumatic brain injury (TBI), there are few studies that examine the effects of moderate TBI for monitoring functional recovery in experimental TBI, and thus the neural correlates of brain recovery from moderate TBI remain incompletely understood. Non-invasive rsfMRI was used to longitudinally investigate changes in interhemispheric functional connectivity (IFC) after a moderate TBI to the unilateral sensorimotor cortex in rats (n = 9) up to 14 days. Independent component analysis of the rsfMRI data was performed. Correlations of rsfMRI sensorimotor networks were made with changes in behavioral scores, lesion volume, and T2- and diffusion-weighted images across time. TBI animals showed less localized rsfMRI patterns in the sensorimotor network compared to sham (n = 6) and normal (n = 5) animals. rsfMRI clusters in the sensorimotor network showed less bilateral symmetry compared to sham and normal animals, indicative of IFC disruption. With time after injury, many of the rsfMRI patterns in the sensorimotor network showed more bilateral symmetry, indicative of IFC recovery. The disrupted IFC in the sensorimotor and subsequent partial recovery showed a positive correlation with changes in behavioral scores. Overall, rsfMRI detected widespread disruption and subsequent recovery of IFC within the sensorimotor networks post-TBI, which correlated with behavioral changes. Therefore, rsfMRI offers the means to probe functional brain reorganization and thus has the potential to serve as an imaging marker to longitudinally stage TBI and monitor for novel treatments.

Contributions from functional neuroimaging studies to the comprehension of traumatic child experiences: preliminary findings / Aportes de los estudios de neuroimagen funcional a la comprensión del trauma infantil: estudio preliminar

Abstract This study aimed to describe the cerebral activation patterns using fMRI (Functional Magnetic Resonance Imaging) technology in a sample of 15 children with Posttraumatic Stress Disorder (PTSD) and 7 with no PTSD. The study used a Quasi-experimental methodology where two experimental tasks were applied: an emotional face task and a version of an emotional Stroop task. The results point out differences in the group of PTSD on the processing of negative stimuli and changes in their frontal lobe activation. These preliminary results suggest that early traumatic experiences affect typical brain development patterns. And explicit and implicit variables involved in the traumatic experiences are discussed as a part of any intervention process.

Resumen El presente estudio tuvo como objetivo describir patrones de activación cerebral mediante una técnica de Imagen por resonancia magnética funcional -fMRI- (abreviatura en inglés de Functional Magnetic Resonance Imaging) en una muestra de niños con Trastorno de estrés postraumático (TEPT) y compararlos con un grupo de controles. Estudio cuasi-experimental en el que se tomó un grupo de 15 niños con TEPT y se comparó con un grupo de 7 niños sin TEPT. Se emplearon dos tareas experimentales: una prueba de caras y una versión del Stroop emocional. Los resultados preliminares, señalan diferencias en el procesamiento de estímulos, principalmente de carácter negativo en los niños con TEPT y cambios en los patrones de activación a nivel de estructuras frontales. Se concluye que el trauma a edad temprana afecta el curso normal del desarrollo cerebral y se evidencia la importancia de abordar los aspectos explícitos e implícitos asociados a la experiencia traumática como parte de la intervención.

Intraocular Injection of HyStem Hydrogel Is Tolerated Well in the Rabbit Eye.

Purpose: To determine the long-term biocompatibility of HyStem® hydrogel in the rabbit eye for use as a carrier for cell or drug delivery into the ocular space. Methods: HyStem hydrogel formulation solidifies ∼20 min after reconstitution, thus can potentially form a solid deposit after injection in situ. To study the ocular disposition of fluorescein-labeled HyStem, we delivered 50 µL/eye over 1 min into the vitreous space of the rabbit. We used 3 Dutch-Belted and 3 New Zealand-pigmented rabbits, all females, delivered the gel into the right eyes, and injected 50 µL BSS Plus into the left eyes as a control. Retinal morphology was assessed by optical coherence tomography (OCT) and white light fundus photography. Fluorescence fundus photography enabled measurement of the clearance of the labeled hydrogel from the posterior chamber. Visual function was evaluated using flash and flicker electroretinography (ERG) pre- and postinjection and at weekly intervals thereafter for 6 weeks. Retinal immunohistochemistry for microglial inflammatory markers was carried out with antiglial fibrillary acidic protein (GFAP) antibody, isolectin B4 (IB4), and 4',6-diamidino-2-phenylindole (DAPI). Results: The gel was successfully delivered into the vitreous space without the formation of a discrete retinal deposit. Fundus imaging, OCT measurements of retinal thickness, and immunohistochemical data indicated an absence of retinal inflammation, and ERG indicated no impact on retinal function. The half-time of HyStem clearance calculated from the loss of fundus fluorescence was 3.9 days. Conclusions: HyStem hydrogel appears to be biocompatible in the ocular space of a large eye and safe for long-term intraocular application.

Validation of T2 -based oxygen extraction fraction measurement with 15 O positron emission tomography.

PURPOSE: To evaluate the accuracy of T2 -based whole-brain oxygen extraction fraction (OEF) estimation by comparing it with gold standard 15 O-PET measurements. METHODS: Sixteen healthy adult subjects underwent MRI and 15 O-PET OEF measurements on the same day. On MRI, whole-brain OEF was quantified by T2 -relaxation-under-spin-tagging (TRUST) MRI, based on subject-specific hematocrit. The TRUST OEF was compared to the whole-brain averaged OEF produced by 15 O-PET. Agreement between TRUST and 15 O-PET whole-brain OEF measurements was examined in terms of intraclass correlation coefficient (ICC) and in absolute OEF values. In a subset of 10 subjects, test-retest reproducibility of whole-brain OEF was also evaluated and compared between the two modalities. RESULTS: Across the 16 subjects, the mean whole-brain OEF of TRUST and 15 O-PET were 36.44 ± 4.07% and 36.45 ± 3.65%, respectively, showing no difference between the two modalities (P = .99). TRUST whole-brain OEF strongly correlated with that of 15 O-PET (N = 16, ICC = 0.90, P = 4 × 10-7 ). The coefficient-of-variation of TRUST and 15 O-PET whole-brain OEF measurements were 1.79 ± 0.67% and 2.06 ± 1.55%, respectively, showing no difference between the two modalities (N = 10, P = .64). Further analyses on the effect of hematocrit revealed that correlation between PET OEF and TRUST OEF with assumed hematocrit remained significant (ICC = 0.8, P < 2 × 10-5 ). CONCLUSION: Whole-brain OEF measured by TRUST was in excellent agreement with gold standard 15 O-PET, with highly comparable accuracy and reproducibility. These findings suggest that TRUST MRI can provide accurate quantification of whole-brain OEF noninvasively.

The effect of pre-exercise Nordic hamstring exercise on hamstring neuromuscular response during soccer-specific activity.

Background: The Nordic hamstring exercise (NHE) has emerged as a popular intervention for improving eccentric hamstring strength, however recent literature suggests there is a potential for an increase in injury risk during subsequent exercise.Methods: To quantify the influence of pre-exercise NHE on the electromyographical response of the hamstrings, 10 male soccer players completed an experimental trial comprising 6 sets x 5 repetitions of NHE prior to the completion of a 45 minute soccer-specific protocol. Post-exercise NHE were performed in the experimental and control (no pre-exercise NHE) trials. Electromyographic (EMG) response (integrated, mean and peak amplitude) of the biceps femoris to the pre- and post-exercise NHE and the soccer-specific exercise protocol was quantified.Results: Integrated (P= 0.025) and mean (P= 0.020) EMG elicited a significant main effect for time in the soccer-specific protocol with higher values during the first 15 mins indicative of a fatigue effect. However, there was no trial x time interaction (P ≥ 0.78). There was no difference between trials in the EMG response to pre-exercise (P≥ 0.30) or post-exercise (P≥ 0.16) NHE trials.Conclusions: Therefore, although previous studies suggest performing pre-exercise NHE might impair maximal strength metrics, the current study's results suggest that it does not impair the electromyographical response to subsequent soccer-specific exercise or NHE repetitions.

Emotional memory processing in post-traumatic stress disorder affected Colombian youth.

Post-traumatic stress disorder (PTSD) is a neuropsychological condition caused by exposure to chronic stressors and extreme trauma. In past decades, Colombia (South America) has experienced high levels of armed conflict, which created an environment of chronic stress, resulting in an increased incidence of PTSD in children. Limited research exists on the effects of PTSD on emotional memory functioning of these Colombian youth living in chronically stressful environments. In the present study, 23 PTSD affected youth and 26 controls were asked to recall items from a memorised word list, as well as remembering details from a short emotional story. Although no significant differences were found for word list memory, deficits for emotional story content were found in the PTSD youth, particularly for facts involving negative emotional details. The latter may suggest a deficit in executive functioning for the integration of emotionally laden stimuli, perhaps induced as a by-product of their traumatic experiences.

Implicit processing of emotional words by children with Post-Traumatic Stress Disorder: An fMRI investigation / Procesamiento implícito de palabras emocionales en niños con Trastorno de Estrés Postraumático: investigación con resonancia magnética funcional

BACKGROUND/OBJECTIVE: In the last decade, socio-political violence in Colombia (South America) has created an environment of extreme/chronic stress. In this study, brain imaging technology (fMRI) and behavioral task performance were used to measure potential deficits in executive functioning for emotional processing in Colombian children. METHOD: Participants (22 Post-Traumatic Stress Disorder, PTSD and 22 neurotypical, NT) were asked to perform a word task with implicit emotional salience, which required them to report the color of the ink in which a positive, negative or neutral word was printed. RESULTS: Mixed design analysis of variance showed no group differences in accuracy for determining ink color when presented as a positive or neutral word. However, PTSD children were significantly less accurate (negative words) and notably slower (both positive and negative words) at determining ink color when presented in the context of an emotional word. PTSD processing of positive and negative words was associated with hypoactivation in the superior and middle frontal gyri of the right hemisphere in comparison to NT children. CONCLUSIONS: These results may reflect a deficit in executive functioning for emotionally laden stimuli, perhaps induced as a by-product of their traumatic experiences

ANTECEDENTES/OBJETIVO: En la última década, la violencia socio-política en Colombia, ha propiciado un ambiente generador de situaciones de estrés crónico/extremo. El presente estudio empleó resonancia magnética funcional, junto con tareas conductuales, para medir posibles déficits en el funcionamiento ejecutivo en una tarea de palabras con contenido emocional en una muestra de niños colombianos. MÉTODO: A los participantes (22 TEPT y 22 controles), se les pidió indicar el color de la palabra impresa, omitiendo el contenido emocional implícito positivo, neutro o negativo. RESULTADOS: El análisis de varianza de diseño mixto, no arrojó diferencias entre los grupos, en número de aciertos al determinar el color en que estaban impresas las palabras positivas o neutras. Sin embargo, los niños con TEPT tuvieron más errores con las palabras de contenido emocional negativo y fueron más lentos que los controles con palabras de valencia positiva o negativa. En cuanto a las palabras positivas y negativas, el grupo con TEPT se asoció a hipoactivación de los giros superior y medio frontal del hemisferio derecho, al compararlos con los controles. CONCLUSIONES: Estos resultados sugieren déficits en el funcionamiento ejecutivo para estímulos con contenido emocional, quizás como consecuencia de las experiencias traumáticas vividas por el grupo de TEPT

Integrative Review of Dietary Choice Revealed by fMRI: Considerations for Obesity Prevention and Weight-Loss Education.

BACKGROUND: Emerging findings from neuroimaging studies investigating brain activity associated with dietary behavior are illuminating the interaction of biological and behavioral mechanisms that have implications for obesity prevention. Globally, A total of 1.9 billion adults are overweight, and 650 million are obese. Obesity and being overweight are major risk factors for chronic illness and death. Behaviorally based health interventions have had limited success in curbing the obesity epidemic. Greater understanding of brain responses to food cues will contribute to new knowledge and shape public health efforts in obesity prevention. However, an integration of this knowledge for obesity prevention education has not been published. AIMS: This study links evidence generated from brain activation studies generated in response to diet and food images and highlights educational recommendations for nurses engaged in obesity prevention and weight-loss education. METHODS: An integrative review of the literature was conducted using the MeSH keywords "magnetic resonance imaging," "diet," and "food images" in PubMed, MEDLINE Complete, CINAHL, and Cochrane databases from their first appearance in 2006 through March 2018. Studies published in English and using functional magnetic resonance imaging to measure brain response to diet, and food images were initially identified. Animal models, those whose primary focus was a specific disease, and intervention studies were excluded. RESULTS: Of 159 studies identified, 26 met inclusion criteria. Findings from neuroimaging studies may help explain the relationship between brain mechanisms and behavioral aspects of dietary choice and inform patient education in obesity prevention. Awareness of this evidence is applicable to nursing education efforts. This review contributes several recommendations that should be considered by nurses providing individualized weight-loss education. LINKING EVIDENCE TO ACTION: Nurses engaged in patient education for obesity prevention should consider personalized interventions that cultivate internal awareness for dietary adherence, self-care, exercise, hydration, and mood state; avoid using caloric deprivation approaches, such as skipping breakfast, for weight-loss interventions; and note the importance of individualized obesity prevention and weight-loss education.

Implicit processing of emotional words by children with Post-Traumatic Stress Disorder: An fMRI investigation.

BACKGROUND/OBJECTIVE: In the last decade, socio-political violence in Colombia (South America) has created an environment of extreme/chronic stress. In this study, brain imaging technology (fMRI) and behavioral task performance were used to measure potential deficits in executive functioning for emotional processing in Colombian children. METHOD: Participants (22 Post-Traumatic Stress Disorder, PTSD and 22 neurotypical, NT) were asked to perform a word task with implicit emotional salience, which required them to report the color of the ink in which a positive, negative or neutral word was printed. RESULTS: Mixed design analysis of variance showed no group differences in accuracy for determining ink color when presented as a positive or neutral word. However, PTSD children were significantly less accurate (negative words) and notably slower (both positive and negative words) at determining ink color when presented in the context of an emotional word. PTSD processing of positive and negative words was associated with hypoactivation in the superior and middle frontal gyri of the right hemisphere in comparison to NT children. CONCLUSIONS: These results may reflect a deficit in executive functioning for emotionally laden stimuli, perhaps induced as a by-product of their traumatic experiences.

ANTECEDENTES/OBJETIVO: En la última década, la violencia socio-política en Colombia, ha propiciado un ambiente generador de situaciones de estrés crónico/extremo. El presente estudio empleó resonancia magnética funcional, junto con tareas conductuales, para medir posibles déficits en el funcionamiento ejecutivo en una tarea de palabras con contenido emocional en una muestra de niños colombianos. MÉTODO: A los participantes (22 TEPT y 22 controles), se les pidió indicar el color de la palabra impresa, omitiendo el contenido emocional implícito positivo, neutro o negativo. RESULTADOS: El análisis de varianza de diseño mixto, no arrojó diferencias entre los grupos, en número de aciertos al determinar el color en que estaban impresas las palabras positivas o neutras. Sin embargo, los niños con TEPT tuvieron más errores con las palabras de contenido emocional negativo y fueron más lentos que los controles con palabras de valencia positiva o negativa. En cuanto a las palabras positivas y negativas, el grupo con TEPT se asoció a hipoactivación de los giros superior y medio frontal del hemisferio derecho, al compararlos con los controles. CONCLUSIONES: Estos resultados sugieren déficits en el funcionamiento ejecutivo para estímulos con contenido emocional, quizás como consecuencia de las experiencias traumáticas vividas por el grupo de TEPT.

Brain activation and affective judgements in response to personal dietary images: An fMRI preliminary study.

Emerging evidence from functional magnetic resonance imaging (fMRI) brain activation studies associated with dietary behavior reveals significant interaction of biological and behavioral mechanisms in response to visualized food stimuli. Because food intake is influenced by neurosensory stimulation and memory cues, personalized food images may be useful in prompting appropriate affective responses to food intake, which may subsequently lead to healthier eating behaviors. The current study used a cross-sectional mixed methods approach to explore neural responses and self-perceptions of eating behavior during review of personalized food images. A sample of college students (N = 16; 9 females; M age = 21.44) used cell-phone cameras and an online dietary tracking website to collect and report three days of diet. Within 2-3 weeks of completing dietary tracking activity, participants underwent an fMRI scan while reviewing recorded personal images and text descriptions of their diet. They also responded to three questions related to memory for the food items and future eating intentions. Post-scan interviews explored how participants felt after reviewing personal food images and the possible impact that such review might have on future food choices. Whole brain analyses suggested, compared to a written dietary record, that the visualization of personal images of diet evoked greater brain activation in memory regions (e.g., superior frontal gyrus) along with mediating emotion (e.g., thalamus, putamen, anterior cingulate cortex), imagery and executive functions (e.g., inferior orbitofrontal gyrus, fusiform, and parietal lobe). This study offers preliminary support for the use of personal food images to strengthen dietary monitoring.

Spatial task-related brain activity and its association with preferred and fast pace gait speed in older adults.

Task-related brain activity is associated with preferred pace gait speed in older adults. Whether similar regional brain activity relates to fast pace gait speed has yet to be determined, but may provide insight into neural substrate important for walking under various conditions. This study measured regional blood-oxygen-level dependent (BOLD) changes using functional magnetic resonance imaging (fMRI) in response to a spatial Simon/Stroop task in community-dwelling older adults (N = 20, 63-80y). Preferred pace, fast pace, and dual-task gait speeds (picking up objects at preferred pace; fast walking over obstacles) were measured across a 7-meter course. Time to complete a fast pace 400 m walk test was also recorded. Partial correlations were used for all analyses after adjusting for age. Accuracy on incongruent trials of the spatial task was positively correlated with all fast walking conditions (all p < 0.01), but not preferred pace walking conditions. BOLD signal change in the left middle frontal gyrus during the spatial task was associated with preferred pace gait speed (r = 0.51, p = 0.02) and fast walking over obstacles (r = 0.53, p = 0.01). Interestingly, BOLD signal change in the bilateral precuneus was associated with fast pace gait speed (r = 0.58, p < 0.01), fast walking over obstacles (r = 0.48, p = 0.03), and 400 m walk time (r=-0.49, p = 0.02). These results find preferred and fast pace gait speed are associated with different regional task-related brain activity, with activation in the precuneus related with greater performance during fast pace walking.

Do scores on the Food Craving Inventory and Three-Factor Eating Questionnaire correlate with expected brain regions of interest in people with obesity?

OBJECTIVE: To examine whether subscales of Food Craving Inventory (FCI) and Three-factor Eating Questionnaire (TFEQ) correlate with brain functional magnetic resonance imaging food-cue reactivity (fMRI-FCR) in the brain. METHODS: Thirty-two male and female adults with obesity (19-60years; 30-39.9kg/m2) participated in a 3-week dietary intervention (1120kcal/day from either 1) total meal replacement shakes, 2) portion-controlled typical food. FCI, TFEQ and fMRI-FCR were measured pre- and post-intervention. Correlations between pre-intervention fMRI-FCR and standardized pre-intervention FCI and TFEQ subscales; and also post- versus pre-intervention change in fMRI-FCR (ΔfMRI-FCR) and standardized changes in FCI and TFEQ subscales were examined at the whole brain level using tools in FMRIB Software Library. RESULTS: Twenty-eight subjects completed the intervention. Pre-intervention high-fat food cravings (P=0.041) and fast-food cravings (P=0.017) were negatively correlated with fMRI-FCR of several brain regions that regulate executive control over ingestion (i.e. bilateral lateral frontal pole, dorsolateral prefrontal cortex and dorsal anterior cingulate cortex). Post- vs. pre-intervention change in sweet (P=0.012) and fast food cravings (P=0.004) were negatively correlated with ΔfMRI-FCR of bilateral lateral frontal pole, dorsolateral prefrontal cortex, inferior frontal gyrus (pars opercularis) and dorsal anterior cingulate cortex (i.e. brain regions that regulate executive control over ingestion). Negative correlations were also observed between the changes in sweet and fast food cravings and ΔfMRI-FCR of brain regions that regulate food reward (i.e. bilateral mid-anterior insula, right nucleus accumbens), motor readiness to ingest (i.e. bilateral precentral gyrus), internally focused attention (i.e. bilateral precuneus and posterior cingulate cortex) and visual object recognition (i.e. occipital pole, lateral occipital cortex and middle and inferior temporal cortices). Changes in cravings for starchy food (P=0.032) and overall food cravings (P=0.027) were also negatively correlated with ΔfMRI-FCR of brain regions involved in regulating internally focused attention and visual object recognition. CONCLUSIONS: In individuals with obesity, decreased food cravings seem to be reflective of increased fMRI-FCR of brain regions that regulate executive control over ingestion. Taken together, constructs measured by FCI seem to be reflective of neurophysiological processes underlying ingestive behavior and the changes in neurophysiological processes occurring during calorie restriction. CLINICAL TRIALS REGISTRY NUMBER: NCT02637271; the protocol is available at https://clinicaltrials.gov/ct2/show/NCT02637271.

Effects of 3-week total meal replacement vs. typical food-based diet on human brain functional magnetic resonance imaging food-cue reactivity and functional connectivity in people with obesity.

OBJECTIVES: Calorie restriction via total meal replacement (TMR) results in greater reduction of food cravings compared to reduced-calorie typical diet (TD). Direct evidence of the impact of these interventions on human brain fMRI food-cue reactivity (fMRI-FCR) and functional connectivity is absent. We examined the effects of a 3-week 1120 kcal/d TMR intervention as compared to an iso-caloric TD intervention using an fMRI-FCR paradigm. METHODS: Thirty-two male and female subjects with obesity (19-60 years; 30-39.9 kg/m2) participated in a randomized two-group repeated measures dietary intervention study consisting of 1120 kcal/d from either 1) TMR (shakes), 2) TD (portion control). Pre-intervention and following the 3-week diet fMRI-FCR, functional connectivity, food cravings (Food Craving Inventory) and weight were considered. RESULTS: Compared to TD, TMR showed increased fMRI-FCR of the bilateral dorsolateral prefrontal (dlPFC), orbitofrontal, anterior cingulate, primary motor and left insular cortices and bilateral nucleus accumbens regions in the post-intervention state relative to the pre-intervention state. Compared to TD, TMR was also associated with negative modulation of fMRI-FCR of the nucleus accumbens, orbitofrontal cortex and amygdala by dlPFC. Reduced body weight (4.87 kg, P < 0.001), body fat (2.19 kg, P = 0.004) and overall food cravings (0.41, P = 0.047) were seen in the TMR group. In the TD group reduced body weight (2.37 kg, P = 0.004) and body fat (1.64 kg, P = 0.002) were noted. Weight loss was significantly greater in TMR versus TD (2.50 kg, P = 0.007). CONCLUSIONS: Greater weight loss and reduced cravings, coupled with stronger activations and potential negative modulation of the food reward related regions by the dlPFC during exposure to visual food cues is consistent with increased executive control in TMR vs. TD.

Cognitive profiles of Post-traumatic Stress Disorder and depression in children and adolescents / Perfiles cognitivos en el trastorno del trastorno de estrés postraumático y la depresión en niños y adolescentes

Background/Objective: Several diagnostic criteria of Post-traumatic Stress Disorder (PTSD) are remarkably similar to symptoms reported by individuals with depression, particularly as they manifest as cognitive processing deficits in children. Because of this overlap in profile and the high rate of comorbidity of PTSD and depression (48% to 69%), pinpointing similarities/differences in cognitive processes related to each of these disorders is essential to accurate diagnosis. This study aims to examine cognitive performance profiles of 23 children who have been victims of PTSD and to compare their results with 23 children with depression and 24 controls. Method: Empirical study, observational and descriptive methodologies were performed using several neuropsychological tests to assess IQ, attention, memory and executive function. Statistical comparisons between groups were made using the non-parametric Kruskall-Wallis test and post-hoc analyses were conducted using a Mann Whitney U test, as well as Quade's co-variance analysis. Results: Data show different profiles of cognitive performance in those with PTSD compared to those with depression and controls. Conclusions: The findings suggests that PTSD and depressed children differ somewhat in their cognitive profiles, and the differences in IQ found between those with PTSD and those without are not necessarily a confounding variable, but may rather be a consequence of their traumatic experience (AU)

Antecedentes/Objetivo: Varios criterios diagnósticos del trastorno de estrés post-traumático (PTSD, por sus siglas en inglés) son similares a los síntomas de la depresión, particularmente relacionados con aspectos cognitivos de niños afectados por estas condiciones. Debido a esta superposición del perfil cognitivo y dada la alta comorbilidad entre PTSD y depresión (48% y 69%), identificar las características en los perfiles cognitivos de cada trastorno pudiera ser útil para hacer diagnósticos más precisos. El objetivo fue examinar el rendimiento cognitivo en 23 niños con PTSD y comparar sus resultados con 23 niños con depresión y 24 controles. Método: Estudio empírico, observacional y descriptivo mediante aplicación de una batería neuropsicológica que evaluó inteligencia, atención, memoria y función ejecutiva. Las comparaciones estadísticas se realizaron mediante la prueba no paramétrica Kruskal-Wallis. Los análisis post-hoc se realizaron utilizando U de Mann Whitney y el análisis de covarianza de Quade. Resultados: Los datos muestran diferentes perfiles cognitivos del grupo con PTSD en comparación con los grupos de depresión y controles. Conclusiones: Los hallazgos sugieren que el grupo de PTSD y el grupo de depresión difieren en sus perfiles cognitivos y que las diferencias en el nivel intelectual encontradas en los niños con PTSD pudieran no ser una variable de confusión sino una consecuencia de la experiencia traumática (AU)

Hyper-brain connectivity in binge drinking college students: a diffusion tensor imaging study.

The current study used diffusion tensor imaging to examine patterns/degree of brain connectivity in 12 college-aged binge drinking (BD) and 12 moderate drinking individuals. Voxel-level and region-of-interest analyses revealed increased connectivity of the BD brain in the right corona radiata, right external capsule, and both the right and left cingulum. Also, fractional anisotropy and axial diffusivity values of these regions correlated with a number of drinking behaviors of the BD as well as both groups combined. It is hypothesized that increased connectivity in the BD may produce difficulties with regulatory control, contributing to their propensity to binge.

Lower Activation in Frontal Cortex and Posterior Cingulate Cortex Observed during Sex Determination Test in Early-Stage Dementia of the Alzheimer Type.

Face-labeling refers to the ability to classify faces into social categories. This plays a critical role in human interaction as it serves to define concepts of socially acceptable interpersonal behavior. The purpose of the current study was to characterize, what, if any, impairments in face-labeling are detectable in participants with early-stage clinically diagnosed dementia of the Alzheimer type (CDDAT) through the use of the sex determination test (SDT). In the current study, four (1 female, 3 males) CDDAT and nine (4 females, 5 males) age-matched neurotypicals (NT) completed the SDT using chimeric faces while undergoing BOLD fMRI. It was expected that CDDAT participants would have poor verbal fluency, which would correspond to poor performance on the SDT. This could be explained by decreased activation and connectivity patterns within the fusiform face area (FFA) and anterior cingulate cortex (ACC). DTI was also performed to test the association of pathological deterioration of connectivity in the uncinate fasciculus (UF) and verbally-mediated performance. CDDAT showed lower verbal fluency test (VFT) performance, but VFT was not significantly correlated to SDT and no significant difference was seen between CDDAT and NT for SDT performance as half of the CDDAT performed substantially worse than NT while the other half performed similarly. BOLD fMRI of SDT displayed differences in the left superior frontal gyrus and posterior cingulate cortex (PCC), but not the FFA or ACC. Furthermore, although DTI showed deterioration of the right inferior and superior longitudinal fasciculi, as well as the PCC, it did not demonstrate significant deterioration of UF tracts. Taken together, early-stage CDDAT may represent a common emerging point for the loss of face labeling ability.

Mirror neuron activation of musicians and non-musicians in response to motion captured piano performances.

Mirror neurons (MNs) activate when performing an action and when an observer witnesses the same action performed by another individual. Functional magnetic resonance imaging (fMRI) and presentation of motion captured piano performances were used to identify differences in MN activation for musicians/non-musicians when viewing piano pieces played in a "Correct" mode (i.e., emphasis on technical correctness) or an "Enjoyment" mode (i.e., simply told to "enjoy" playing the piece). Results showed greater MN activation in a variety of brain regions for musicians, with these differences more pronounced in the "Enjoyment" mode. Our findings suggest that activation of MNs is not only initiated by the imagined action of an observed movement, but such activation is modulated by the level of musical expertise and knowledge of associated motor movements that the observer brings to the viewing situation. Enhanced MN activation in musicians may stem from imagining themselves actually playing the observed piece.

Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking.

AIM: Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT. METHODS: Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and ß-stiffness index in the common carotid artery. RESULTS: The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p <0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85±0.43 vs. 1.47±0.42, p=0.02) and resistance (0.75±0.07 vs. 0.68±0.07, p=0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and ß-stiffness did not contribute to these tertile differences. CONCLUSION: Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks.

White Matter Deterioration May Foreshadow Impairment of Emotional Valence Determination in Early-Stage Dementia of the Alzheimer Type.

In Alzheimer Disease (AD), non-verbal skills often remain intact for far longer than verbally mediated processes. Four (1 female, 3 males) participants with early-stage Clinically Diagnosed Dementia of the Alzheimer Type (CDDAT) and eight neurotypicals (NTs; 4 females, 4 males) completed the emotional valence determination test (EVDT) while undergoing BOLD functional magnetic resonance imaging (fMRI). We expected CDDAT participants to perform just as well as NTs on the EVDT, and to display increased activity within the bilateral amygdala and right anterior cingulate cortex (r-ACC). We hypothesized that such activity would reflect an increased reliance on these structures to compensate for on-going neuronal loss in frontoparietal regions due to the disease. We used diffusion tensor imaging (DTI) to determine if white matter (WM) damage had occurred in frontoparietal regions as well. CDDAT participants had similar behavioral performance and no differences were observed in brain activity or connectivity patterns within the amygdalae or r-ACC. Decreased fractional anisotropy (FA) values were noted, however, for the bilateral superior longitudinal fasciculi and posterior cingulate cortex (PCC). We interpret these findings to suggest that emotional valence determination and non-verbal skill sets are largely intact at this stage of the disease, but signs foreshadowing future decline were revealed by possible WM deterioration. Understanding how non-verbal skill sets are altered, while remaining largely intact, offers new insights into how non-verbal communication may be more successfully implemented in the care of AD patients and highlights the potential role of DTI as a presymptomatic biomarker.