69 research outputs found
Caractérisation du substrat neurologique impliqué dans le traitement de stimuli visuels dynamiques émotionnels : étude d'imagerie par résonance magnétique fonctionnelle
Malgré l’engouement pour les neurosciences cognitives des émotions et les nombreuses publications des dernières décennies tentant d’élucider les bases neurobiologiques des émotions, nos connaissances sur le domaine restent embryonnaires. Plusieurs questions importantes restent toujours sans réponses incluant s’il existe ou non un système unique pour le traitement de stimuli émotionnels et s’il y a ou non des différences entre les hommes et les femmes pour le traitement de stimuli émotionnels. L’objectif de cette thèse est d’apporter certains éléments de réponses à ces questions à travers une caractérisation du substrat neurobiologique impliqué dans le traitement de stimuli émotionnels visuels et dynamiques. Ce travail a été mené via l’imagerie par résonance magnétique fonctionnelle (IRMf) cérébrale.
Le premier chapitre, subdivisé en quatre sections, permet de présenter la perspective dans laquelle s’inscrit la thèse. La première section de ce chapitre sert à établir certaines balises définitionnelles liées aux émotions. La seconde section, basée sur une lecture des textes originaux, retrace les faits historiques saillants de la neurobiologie des émotions allant de Charles Darwin à Joseph Ledoux. La troisième section débute où la seconde s’arrête et continue l’histoire de la neurobiologie des émotions à travers un résumé de toutes les principales méta-analyses d’imagerie fonctionnelle cérébrale des émotions. La dernière section du chapitre permet de présenter la problématique de recherche. La recherche, à proprement parler, qui constitue le corps de la thèse est ensuite présentée sous forme de trois articles. Enfin, les résultats de cette recherche et la manière dont ils s’inscrivent dans la continuité de nos connaissances actuelles font l’objet d’une discussion générale.
Le premier article (chapitre II) rapporte, chez les hommes et les femmes, les régions du cerveau qui sont plus activées lors du traitement de films érotiques que lors du traitement de films dits ‘neutres’. Un chevauchement manifeste est observé entre les hommes et les femmes. Par contre, une activation significativement plus grande est observée chez les hommes pour l’hypothalamus, une région importante pour le comportement sexuel à travers la phylogénie. De plus, chez les hommes seulement, l’activation hypothalamique est corrélée à l’excitation sexuelle subjective.
Comme la recherche présentée dans le premier article se sert de conditions expérimentales relativement longues pour l’IRMf (i.e. extraits de films de 3 minutes) et que ceci peut induire une nette diminution de signal en lien avec certaines contraintes de l’IRMf, le second article (chapitre III) examine les corrélats du traitement de stimuli sexuels en utilisant, cette fois, un paradigme d’IRMf classique où plusieurs extraits de films de 33 secondes sont présentés à la place. Cette étude démontre que, pour le traitement de stimuli sexuels, ce paradigme classique d’IRMf est beaucoup plus sensible que celui du premier article. De plus, comme ce paradigme mène à une reproduction des résultats du premier papier, ce travail soutient la perspective selon laquelle les paradigmes à époques courtes sont une alternative valide aux longues époques comme méthode d’étude du traitement de stimuli émotionnels.
Le troisième article (chapitre IV) capitalise sur le protocole du second article et démontre que les patrons d’activation associés au visionnement de courts extraits de films induisant du dégoût, de l’amusement, ou de l’excitation sexuelle, sont très étendus. Une analyse de conjonction formelle démontre un large chevauchent de ces patrons à travers les différents affects étudiés.
Enfin, le cinquième chapitre sert de discussion générale. Les questions des différences entre les hommes et les femmes dans le traitement des émotions, de l’existence ou non d’un système général pour le traitement des émotions, ainsi que de la manière dont un tel système pourrait être conçu, sont des points saillants de la discussion. Ces points sont abordés à la lumières des connaissances actuelles et des résultats des trois articles.Despite the intense interest garnered by cognitive neurosciences of emotions and the numerous publications in recent decades attempting to partial the neurobiological basis of emotions, our knowledge of the area remains embryonic. Important questions that need to be answered include whether or not there exists a general system for processing emotional stimuli and whether or not there are differences between men and women in processing emotional stimuli. The main objective of this dissertation is to provide some answers to these questions by characterizing the neurobiological substrate involved in processing dynamic visual emotional stimuli. This work was conducted through cerebral functional magnetic resonance imaging (fMRI).
The first chapter, which is divided into four sections, lays the groundwork for the thesis. The first section of this chapter serves to clarify some definitional background related to emotions. The second section, based on a reading of the original texts, traces the salient historical facts of the neurobiology of emotions from Charles Darwin to Joseph Ledoux. The third section begins where the second ends and continues the history of the neurobiology of emotions through a summary of all the main functional brain imaging meta-analyzes of emotions. The final section of the chapter introduces the research problematic. The research itself, which constitutes the body of the dissertation, is then presented in the form of three articles. Finally, results of this research and how they fit into the continuity of our current knowledge form the basis of a general discussion.
The first paper (Chapter II) reports, in men and women, the brain regions that are more activated during the processing of erotic film excerpts than during the processing of so-called 'neutral' film excerpts. A clear overlap is observed between men and women. This being said, a significantly greater activation is observed in men for the hypothalamus, a region important for sexual behavior across the phylogeny. In addition, in men only, hypothalamic activation is correlated with reported sexual arousal.
As the research presented in the first paper uses relatively long experimental conditions for fMRI (i.e. 3-minute film excerpts) and as this can lead to a net signal decrease due to certain fMRI constraints, the second paper (Chapter III) examines correlates of processing sexual stimuli using, this time, a classic fMRI paradigm where several short film clips of 33 seconds are used instead. This study shows that, for the processing of sexual stimuli, this conventional fMRI paradigm is much more sensitive than the one used in the first paper. Importantly, given that this paradigm leads to a reproduction of results of the first paper, this work supports the view that short epochs are a valid alternative to long epochs as a method of studying the processing of emotional stimuli.
The third section (Chapter IV) capitalizes on the protocol of the second paper and demonstrates that the activation patterns associated with the viewing of short film excerpts inducing disgust, amusement, or sexual arousal, are extensive. A formal conjunction analysis shows a broad overlap of these patterns across the various affects studied.
Finally, the fifth chapter provides a general discussion of the results. The question of gender differences in processing emotional stimuli, of whether or not a general system for processing emotions exists, and of how it may be understood, represent important elements of the discussion. These points are discussed in light of current knowledge and of the results of the three papers
Investigating the relation between striatal volume and IQ.
The volume of the input region of the basal ganglia, the striatum, is reduced with aging and in a number of conditions associated with cognitive impairment. The aim of the current study was to investigate the relation between the volume of striatum and general cognitive ability in a sample of 303 healthy children that were sampled to be representative of the population of the United States. Correlations between the WASI-IQ and the left striatum, composed of the caudate nucleus and putamen, were significant. When these data were analyzed separately for male and female children, positive correlations were significant for the left striatum in male children only. This brain structure-behavior relation further promotes the increasingly accepted view that the striatum is intimately involved in higher order cognitive functions. Our results also suggest that the importance of these brain regions in cognitive ability might differ for male and female children
Time-lagged associations between cognitive and cortical development from childhood to early adulthood
Throughout childhood and adolescence, humans experience marked changes in cortical structure and cognitive ability. Cortical thickness and surface area, in particular, have been associated with cognitive ability. Here we ask the question: What are the time
related associations between cognitive changes and cortical structure maturation. Identifying a developmental sequence requires multiple measurements of these variables from the same individuals across time. This allows capturing relations among the variables and, thus, finding whether: (a) developmental cognitive changes follow cortical structure maturation, (b) cortical structure maturation follows cognitive changes, or (c) both processes influence each other over time. 430 children and adolescents (age range = 6.01 22.28 years) completed the WASI battery and were MRI scanned at three time points separated by ≈ 2 years (mean age t1 = 10.60, SD = 3.58, mean age t2=12.63, SD=3.62, mean age t3=14.49, SD=3.55). Latent Change Score (LCS) models were applied to quantify age related relationships among the variables of interest. Our results indicate that cortical and cognitive changes related to each other reciprocally. Specifically, the magnitude or rate of the change in each variable at any occasion and not the previous level was predictive of later changes. These results were replicated for brain regions selected according to the coordinates identified in the Basten et al.’s (2015) meta analysis, to the Parieto Frontal Integration Theory (P FIT, Jung & Haier, 2007) and to the whole cortex. Potential implications regarding brain plasticity and cognitive enhancement are discusse
Brain-intelligence relationships across childhood and adolescence: a latent-variable approach
The analysis of the relationships between cortical and intellectual development is a
complex matter. Greater brain plasticity in brighter individuals has been suggested, but
the associations between developmental cortical changes and variations in the general
factor of intelligence (g) across time at the latent level have not been addressed. For filling
this gap, here we relate longitudinal changes in g with developmental changes in cortical
thickness and cortical surface area. One hundred and thirty-two children and adolescents
representative of the population from the Pediatric MRI Data Repository completed the
Wechsler Abbreviated Scale of Intelligence in three time points and MRI scans were also
obtained (mean inter-registration interval » 2 yrs., age range = 6.1 to 21.3 yrs.).
Longitudinal latent variable analyses revealed an increase in g scores amounting to a full
standard deviation on average. Intelligence differences estimated at the latent level were
significantly correlated related with cortical changes. Older individuals showed greater
decrease in cortical values along with smaller increase in intelligence. Furthermore,
thickness preservation in brighter individuals was observed at early adolescence (10-14
years
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Negative Associations between Corpus Callosum Midsagittal Area and IQ in a Representative Sample of Healthy Children and Adolescents
Documented associations between corpus callosum size and cognitive ability have heretofore been inconsistent potentially owing to differences in sample characteristics, differing methodologies in measuring CC size, or the use of absolute versus relative measures. We investigated the relationship between CC size and intelligence quotient (IQ) in the NIH MRI Study of Normal Brain Development sample, a large cohort of healthy children and adolescents (aged six to 18, n = 198) recruited to be representative of the US population. CC midsagittal area was measured using an automated system that partitioned the CC into 25 subregions. IQ was measured using the Wechsler Abbreviated Scale of Intelligence (WASI). After correcting for total brain volume and age, a significant negative correlation was found between total CC midsagittal area and IQ (r = −0.147; p = 0.040). Post hoc analyses revealed a significant negative correlation in children (age<12) (r = −0.279; p = 0.004) but not in adolescents (age 12) (r = −0.005; p = 0.962). Partitioning the subjects by gender revealed a negative correlation in males (r = −0.231; p = 0.034) but not in females (r = 0.083; p = 0.389). Results suggest that the association between CC and intelligence is mostly driven by male children. In children, a significant gender difference was observed for FSIQ and PIQ, and in males, a significant age-group difference was observed for FSIQ and PIQ. These findings suggest that the correlation between CC midsagittal area and IQ may be related to age and gender
Anxious/depressed symptoms are related to microstructural maturation of white matter in typically developing youths
AbstractThere are multiple recent reports of an association between anxious/depressed (A/D) symptomatology and the rate of cerebral cortical thickness maturation in typically developing youths. We investigated the degree to which anxious/depressed symptoms are tied to age-related microstructural changes in cerebral fiber pathways. The participants were part of the NIH MRI Study of Normal Brain Development. Child Behavior Checklist A/D scores and diffusion imaging were available for 175 youths (84 males, 91 females; 241 magnetic resonance imagings) at up to three visits. The participants ranged from 5.7 to 18.4 years of age at the time of the scan. Alignment of fractional anisotropy data was implemented using FSL/Tract-Based Spatial Statistics, and linear mixed model regression was carried out using SPSS. Child Behavior Checklist A/D was associated with the rate of microstructural development in several white matter pathways, including the bilateral anterior thalamic radiation, bilateral inferior longitudinal fasciculus, left superior longitudinal fasciculus, and right cingulum. Across these pathways, greater age-related fractional anisotropy increases were observed at lower levels of A/D. The results suggest that subclinical A/D symptoms are associated with the rate of microstructural development within several white matter pathways that have been implicated in affect regulation, as well as mood and anxiety psychopathology.</jats:p
Negative associations between corpus callosum midsagittal area and IQ in a representative sample of healthy children and adolescents.
Documented associations between corpus callosum size and cognitive ability have heretofore been inconsistent potentially owing to differences in sample characteristics, differing methodologies in measuring CC size, or the use of absolute versus relative measures. We investigated the relationship between CC size and intelligence quotient (IQ) in the NIH MRI Study of Normal Brain Development sample, a large cohort of healthy children and adolescents (aged six to 18, n = 198) recruited to be representative of the US population. CC midsagittal area was measured using an automated system that partitioned the CC into 25 subregions. IQ was measured using the Wechsler Abbreviated Scale of Intelligence (WASI). After correcting for total brain volume and age, a significant negative correlation was found between total CC midsagittal area and IQ (r = -0.147; p = 0.040). Post hoc analyses revealed a significant negative correlation in children (ag
Mediterranean-type diet and brain structural change from 73 to 76 years in a Scottish cohort
STUDY FUNDING The data were collected by a Research into Ageing programme grant; research continues as part of the Age UK–funded Disconnected Mind project. The work was undertaken by The University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology, part of the cross-council Lifelong Health and Wellbeing Initiative (MR/K026992/1), with funding from the BBSRC and Medical Research Council. Imaging and image analysis was performed at the Brain Research Imaging Centre (sbirc.ed.ac.uk/), Edinburgh, supported by the Scottish Funding Council SINAPSE Collaboration. Derivation of mean cortical thickness measures was funded by the Scottish Funding Council’s Postdoctoral and Early Career Researchers Exchange Fund awarded by SINAPSE to David Alexander Dickie. L.C.A.C. acknowledges funding from the Scottish Government's Rural and Environment Science and Analytical Services (RESAS) division.Peer reviewedPublisher PD
Las variaciones de superficie cortical en la corteza dorsolateral prefrontal predicen mejor el futuro desempeño cognitivo que la inteligencia fluida y la memoria operativa
Are cognitive and biological variables useful for predicting
future behavioral outcomes? Method: In two independent groups, we
measured a set of cognitive (fluid and crystallized intelligence, working
memory, and attention control) and biological (cortical thickness and
cortical surface area) variables on two occasions separated by six months,
to predict behavioral outcomes of interest (performance on an adaptive
version of the n-back task) measured twelve and eighteen months later.
We followed three stages: discovery, validation, and generalization. In
the discovery stage, cognitive/biological variables and the behavioral
outcome of interest were assessed in a group of individuals (in-sample).
In the validation stage, the cognitive and biological variables were related
with a parallel version of the behavioral outcome assessed several months
later. In the generalization stage, the validation findings were tested in
an independent group of individuals (out-of-sample). Results: The key
fi nding revealed that cortical surface area variations within the right
dorsolateral prefrontal cortex predict the behavioral outcome of interest
in both groups, whereas the cognitive variables failed to show reliable
predictive validity. Conclusions: Individual differences in biological
variables might predict future behavioral outcomes better than cognitive
variables concurrently correlated with these behavioral outcomesAntecedentes: ¿Predicen las variables cognitivas
y biológicas el futuro desempeño cognitivo? Método: en dos grupos
independientes de participantes se miden variables cognitivas (inteligencia
fluida y cristalizada, memoria operativa y control atencional) y biológicas
(grosor y superficie cortical) en dos ocasiones separadas por seis meses,
para predecir el desempeño en la tarea n-back valorado doce y dieciocho
meses después. Se completan tres etapas: descubrimiento, validación
y generalización. En la de descubrimiento se valoran en un grupo de
individuos las variables cognitivas/biológicas y el desempeño a predecir.
En la de validación, se relacionan las mismas variables con una versión
paralela de la n-back completada meses después. En la de generalización,
los resultados de la validación se replican en un grupo independiente de
individuos. Resultados: las variaciones de superficie cortical en la corteza
dorsolateral prefrontal derecha predicen el desempeño cognitivo en los dos
grupos independientes de individuos, mientras que las variables cognitivas
no contribuyen a la predicción del desempeño futuro. Conclusiones: las
diferencias individuales en determinadas variables biológicas predicen el
desempeño cognitivo mejor que las variables cognitivas que correlacionan
concurrentemente con ese desempeñoThis project was supported by PSI2017-82218-P (Ministerio de
Economía, Industria y Competitividad, Spain
Changes in resting-state functionally connected parieto-frontal networks after videogame practice
Neuroimaging studies provide evidence for organized intrinsic activity under task-free conditions. This activity serves functionally relevant brain systems supporting cognition. Here, we analyze changes in resting-state functional connectivity after videogame practice applying a test–retest design. Twenty young females were selected from a group of 100 participants tested on four standardized cognitive ability tests. The practice and control groups were carefully matched on their ability scores. The practice group played during two sessions per week across 4 weeks (16 h total) under strict supervision in the laboratory, showing systematic performance improvements in the game. A group independent component analysis (GICA) applying multisession temporal concatenation on test–retest resting-state fMRI, jointly with a dual-regression approach, was computed. Supporting the main hypothesis, the key finding reveals an increased correlated activity during rest in certain predefined resting state networks (albeit using uncorrected statistics) attributable to practice with the cognitively demanding tasks of the videogame. Observed changes were mainly concentrated on parietofrontal networks involved in heterogeneous cognitive functions
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