L'hyperbarie a-t-elle des effets à long terme sur la mémoire et l'attention ? : corrélations entre performances neuropsychologiques et imagerie cérébrale fonctionnelle (original) (raw)

Interférences émotionnelle et attentive et potentiels lents cérébraux (V.C.N. - P 300)

1979

Emotional and attentive interferences and slow cerebral potentials (CNV-P 300). A study was conducted to establish possible correlations between electrophysiological indices and performance under neutral situations and those involving completing a double task of increasing complexity, by studying CN V and P 300 in young healthy men. The results demonstrated that : 1. After habituation, the CNV amplitudes were not related to performance. A significant correlation was noted only during the most complex tasks. 2. The CNV appears to depend mainly on endogenous factors, that is to say the aptitude and readiness of an individual to treat the information, rather than on the performance resulting from this" treatment. 3. The amplitude of the P 300 is related to performance, as a function of detection rate and the complexity of the taslcs. The funetional duality of the CNV and the differences between it and the P 300 have been emphasized. The indices obtained from slow potentials appear to be of value for an evaluation of behaviour. Rather than analyzing the characteristics of the potentials in a supposedly << neutral>> situation it would appear preferable to establish, from the indices, profiles of individual reactivity and adaptation to different experimental situations.

Neurofeedback dans le trouble déficit de l’attention avec hyperactivité : de l’efficacité à la spécificité de l’effet neurophysiologique

Annales Médico-psychologiques, revue psychiatrique, 2011

Clinical guidelines for attention deficit/hyperactivity disorder (ADHD) recommend a multimodal treatment encompassing pharmacological medication with methylphenidate, cognitive-behavioral therapy (CBT) and family treatments. Methylphenidate is the most effective treatment, though the relatively high rate of partial responders, and the possible parental reluctance against the pharmacological treatment. Thus, it is interesting to consider new nonpharmacological therapies based, such as CBT, on the learning capacity of children to self-regulate their behavior. Neurofeedback is interesting insofar as it would allow children to acquire self-control over certain brain activity patterns to improve the regulation of their behavior in daily-life situation. Early studies on neurofeedback in ADHD are nearly 30 years old. Two training protocols were created, based on EEG abnormalities in ADHD. First training allows the modulation of EEG frequency bands: increased activity in the beta band, or decreased activity in the theta rhythm. The second allows an increase in a slow cortical potential. In both protocols, feedback of the brain activity patterns is given to children in real time as a kind of computer game, and changes that are made in the desired direction are rewarded, i.e., positively reinforced. The evidence-based level of the neurofeedback is still unclear. But, unlike other mental disorders, many studies have investigated the effect of this treatment on symptoms of ADHD. Thus, we propose to analyze the data of literature and especially recent studies. A meta-analysis and randomized controlled studies seem to confirm the efficacy and the possible place of neurofeedback in the multimodal treatment strategies of ADHD. But, if this treatment supposes to allow self-regulation of children behavior by learning the control of EEG activity, the specific mechanisms of action on brain activity remains problematic. Thus, we propose to identify methodological and neurophysiological areas for future research on this therapy involving the subject and electrophysiology in psychiatry.

Détection de l’activation cérébrale : de la spectroscopie à l’imagerie proche infrarouge à fenêtre temporelle

Irbm, 2009

La spectroscopie proche infrarouge est largement utilisée en clinique et en recherche biomédicale pour le suivi de la perfusion et de l'oxygénation tissulaire, notamment lors d'activations cérébrales. Nous proposons une technique de sélection des photons détectés en fonction de leur temps de propagation dans les tissus. La sensibilité de détection d'une activation corticale et sa discrimination par rapport aux fluctuations cutanées sont grandement améliorées en ne traitant que les données fournies par les photons les plus tardifs. Une analyse plus détaillée des profils temporels, pouvant être à l'origine d'une réelle méthode d'imagerie spectroscopique, ainsi qu'une instrumentation permettant des acquisitions volumiques sans contact avec le patient sont en cours de réalisation.

La mémoire défaillante de l'entreprise ou le syndrome d'alzheimer à l'?uvre

Humanisme et entreprise, 2009

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Intérêt clinique de l’IRMf et des méthodes d’exploration fonctionnelle de l’activité et de l’interactivité cérébrales : considérations physiques et neurophysiologiques

Journal of Neuroradiology - J NEURORADIOL, 2008

After having provided a brief reminder of the principle of the blood oxygen leveldependent (BOLD) contrast effect, the physiological bases of brain activity and the concepts of functional integration and effective connectivity, we describe the most recent approaches, which permit to explore brain activity and putative networks of interconnected active areas in order to examine the normal brain physiology and its dysfunctions. We present various methods and studies of brain activity analysis clinically applicable, and we detail the concepts of functional and effective connectivity, which allow to study the cerebral plasticity which occurs at the child's during the maturation (e.g., dyslexia), at the adult during the ageing (e.g., Alzheimer disease), or still in schizophrenia or Parkinson disease. The study of specific circuits in networks has to allow defining in a more realistic way the dynamic of the central nervous system, which underlies various cerebral functions, both in physiological and pathological conditions. This connectivity approach should improve the diagnostic and facilitate the development of new therapeutic strategies.