Les modalités sensorielles ont un rôle essentiel dans la collecte des informations en provenance de l’environnement. En olfaction, l’échantillonnage actif des odeurs se fait via le flairage chez le rat (2-10 Hz). Chez l’animal qui se comporte, le flairage est un acte très dynamique, il varie en particulier en fréquence et en débit. Le flairage peut être modulé par des facteurs liés au stimulus, comme les propriétés physico-chimiques des odeurs ou leur concentration, ou par des facteurs plus « internes » comme l’attention, les émotions ou la motivation. Plusieurs auteurs ont également suggéré l’importance de la fréquence de flairage dans la performance. Dans une première partie de ma thèse, j’ai voulu caractériser l’impact d’un apprentissage olfactif sur la mise en place d’un pattern de flairage adapté à la discrimination. Pour cela, j’ai utilisé un système d’enregistrement de la respiration non invasif chez le rat (pléthysmographe) pendant que l’animal effectue une tâche de discrimination olfactive à double choix. Dans une seconde partie, j’ai cherché les corrélats neuronaux de l’acquisition de ce pattern de flairage en enregistrant simultanément l’activité respiratoire et les signaux neuronaux (potentiels de champ locaux) dans des aires olfactives, motrices et limbiques chez l’animal en comportement. J’ai cherché à caractériser les activités oscillatoires dans la bande bêta (15-30 Hz) et thêta (2-10 Hz). J’ai enfin discuté dans quelle mesure celles-ci pouvaient être reliées à l’apprentissage et/ou aux variations de l’activité respiratoire / Sensory modalities actively take part in collecting relevant information from the environment. In olfaction, active sampling amounts to sniffing in rodents (2-10 Hz). In behaving animals, sniffing is highly dynamic, notably in frequency and flow rate. Sniffing can be modulated by parameters related to the odorant stimulus, such as the physicochemical properties of the molecule or its concentration. It can also vary depending on “internal” parameters such as attention, emotions or motivation. Several studies highlighted the importance of the sniffing frequency in performance. First, I looked at the impact of olfactory learning on the acquisition of a specific sniffing pattern. For that purpose, I monitored sniffing activity in a non-invasive way, using a whole-body plethysmograph, on rats performing a two-alternative choice odor discrimination task. Second, I looked for neuronal correlates of the acquisition of such a sniffing pattern by simultaneously recording sniffing and neuronal activities (local field potentials) in olfactory, motor and limbic areas in behaving animals. I sought to characterize oscillatory activities in beta (15-30 Hz) and theta (2-10 Hz) ranges. I finally discussed to what extent they were related to learning and/or sniffing modulations

Neurofeedback (NF) is an important treatment for attention deficit/hyperactivity disorder (ADHD). In ADHD, cognitive control deficits pose considerable problems to patients. However, NF protocols are not yet optimized to enhance cognitive control alongside with clinical symptoms, partly because they are not driven by basic cognitive neuroscience. In this study, we evaluated different EEG theta and/or beta frequency band NF protocols designed to enhance cognitive control. Participants were n = 157 children and adolescents, n = 129 of them were patients with ADHD (n = 28 typically developing (TD) controls). Patients with ADHD were divided into five groups in the order of referral, with four of them taking part in different NF protocols systematically varying theta and beta power. The fifth ADHD group and the TD group did not undergo NF. All NF protocols resulted in reductions of ADHD symptoms. Importantly, only when beta frequencies were enhanced during NF (without any theta regulation or in combination with theta upregulation), consistent enhancing effects in both response inhibition and conflict control were achieved. The theta/beta NF protocol most widely used in clinical settings revealed comparatively limited effects. Enhancements in beta band activity are key when aiming to improve cognitive control functions in ADHD. This calls for a change in the use of theta/beta NF protocols and shows that protocols differing from the current clinical standard are effective in enhancing important facets of cognitive control in ADHD. Further studies need to examine regulation data within the neurofeedback sessions to provide more information about the mechanisms underlying the observed effects.