Face processing; EEG; Neuropsychology; fMRI; Vision; Neglect syndrome; Consciousness; Neurofeedback; Neglect syndrome
Saj Arnaud, Pierce Jordan, Caroli Alice, Ronchi Roberta, Thomasson Marine, Vuilleumier Patrik (2020), Rightward exogenous attentional shifts impair perceptual memory of spatial locations in patients with left unilateral spatial neglect, in Cortex
, 122, 187-197.
Pierce Jordan E., Saj Arnaud, Vuilleumier Patrik (2019), Differential parietal activations for spatial remapping and saccadic control in a visual memory task, in Neuropsychologia
Kopel R., Sladky R., Laub P., Koush Y., Robineau F., Hutton C., Weiskopf N., Vuilleumier P., Van De Ville D., Scharnowski F. (2019), No time for drifting: Comparing performance and applicability of signal detrending algorithms for real-time fMRI, in NeuroImage
, 191, 421-429.
RosTomas, MichelaAbele, MeyerAnais, BellmannAnne, VuadensPhilippe, ZermattenVictorine, SajArnaud, vuilleumierpatrik (2019), Disruption of large-scale electrophysiological networks in stroke patients with visuospatial neglect, in biorxiv.org
Koush Yury, Pichon Swann, Eickhoff Simon B., Van De Ville Dimitri, Vuilleumier Patrik, Scharnowski Frank (2019), Brain networks for engaging oneself in positive-social emotion regulation, in NeuroImage
, 189, 106-115.
Bourgeois Alexia, Saj Arnaud, Vuilleumier Patrik (2018), Value-driven attentional capture in neglect, in Cortex
, 109, 260-271.
Sanz Leandro R.D., Vuilleumier Patrik, Bourgeois Alexia (2018), Cross-modal integration during value-driven attentional capture, in Neuropsychologia
, 120, 105-112.
Saj Arnaud, Verdon Vincent, Hauert Claude-Alain, Vuilleumier Patrik (2018), Dissociable components of spatial neglect associated with frontal and parietal lesions, in Neuropsychologia
, 115, 60-69.
Saj Arnaud, Ros Tomas, Michela Abele, Vuilleumier Patrik (2018), Effect of a single early EEG neurofeedback training on remediation of spatial neglect in the acute phase, in Annals of Physical and Rehabilitation Medicine
, 61(2), 111-112.
Robineau Fabien, Saj Arnaud, Neveu Rémi, Van De Ville Dimitri, Scharnowski Frank, Vuilleumier Patrik (2017), Using real-time fMRI neurofeedback to restore right occipital cortex activity in patients with left visuo-spatial neglect: proof-of-principle and preliminary results, in Neuropsychological Rehabilitation
, 29(3), 339-360.
Robineau Fabien, Meskaldji Djalel E., Koush Yury, Rieger Sebastian W., Mermoud Christophe, Morgenthaler Stephan, Van De Ville Dimitri, Vuilleumier Patrik, Scharnowski Frank (2017), Maintenance of Voluntary Self-regulation Learned through Real-Time fMRI Neurofeedback, in Frontiers in Human Neuroscience
, 11, 1-8.
Koush Yury, Meskaldji Djalel-E., Pichon Swann, Rey Gwladys, Rieger Sebastian W., Linden David E.J., Van De Ville Dimitri, Vuilleumier Patrik, Scharnowski Frank (2017), Learning Control Over Emotion Networks Through Connectivity-Based Neurofeedback, in Cerebral Cortex
Ros Tomas, Michela Abele, Bellman Anne, Vuadens Philippe, Saj Arnaud, Vuilleumier Patrik (2017), Increased Alpha-Rhythm Dynamic Range Promotes Recovery from Visuospatial Neglect: A Neurofeedback Study, in Neural Plasticity
, 2017, 1-9.
Neuropsychological and neuroimaging research (including our own) has consistently shown that sensory visual cortical areas can be activated without conscious awareness of the eliciting stimulus. In contrast, conscious detection is associated with an amplification of sensory responses through interactions with fronto-parietal networks controlling attention and goal-oriented behavior.Thus, in patients with left spatial neglect after right hemisphere stroke, intact regions in striate and extrastriate occipital cortex still exhibit residual responses to left visual stimuli, but these remain weak and short-lived due to losses in top-down modulation from fronto-parietal areas; hence they are insufficient to give rise to conscious perception. Furthermore, in the presence of right fronto-parietal damage, even central or bilateral visual stimuli tend to produce asymmetric responses along the anatomically intact right visual pathways, with a progressive attenuation from early to higher stages of processing, eventually leading to a suppression of left visual inputs from conscious visual awareness. The current project will exploit these observations, combined with recent developments in functional neuroimaging that allow not only measuring unconscious brain activity but also provide the opportunity to use such measure in real-time for neurofeedback (NFB) application. In the first part of the project, we will design a novel NFB procedure with fMRI enabling us to inform patients about ongoing activity in their right occipital cortex and train them to up-regulate this activity across several weekly sessions. We predict that achieving voluntary control over right occipital activity through real-time fMRI feedback will help restore functional top-down connectivity between the intact right visual areas and the disrupted attentional systems, and thus lead to an improvement in neglect symptoms in both short-term (after NFB sessions) and long-term (at 6 month follow-up). No such improvement should occur after standard rehabilitation only, without NFB.Impaired visual processing in neglect patients subsequent to lesions in attentional networks is also reflected by anomalies in ongoing rhythmic oscillations in EEG recordings. In particular, asymmetries in the alpha band (8-12Hz) over posterior brain areas correlate with neglect severity in patients, in keeping with observations in healthy people that transient reduction (desynchronization) of posterior alpha activity are associated with more efficient orienting to the contralateral field and enhanced detection of a subsequent visual stimuli on the contralateral side. In a second part of the project, we will therefore use EEG neurofeedback to train patients with left neglect to suppress alpha activity over their right visual areas. EEG provides anatomically less precise information about the exact locus of training but has the advantage of reflecting activity of distributed networks, and of being easier and cheaper to perform than fMRI for potential clinical applications. We predict that successful down-regulation of right parietal alpha activity will lead to improved performance in neglect tests and reduced asymmetries in ongoing oscillations after NFB, not seen in patients with standard rehabilitation without NFB.Similar to findings in neglect, research in healthy people indicate that briefly presented stimuli in masking paradigms can evoke subliminal activation in specific visual areas, although they are not consciously seen by the subject. However, emotionally significant stimuli can boost these subliminal sensory responses, even without attention or awareness, through distinct top-down modulatory influences from emotional circuits such as the amygdala. These effects, independent from top-down modulation by fronto-parietal areas, may promote quicker access of emotional stimuli to awareness as compared with neutral stimuli. In a third part of the project, we will use a similar NFB procedure with fMRI to train healthy volunteers to regulate brain responses evoked by subliminal faces presented in a backward masking paradigm. Three different groups will be trained to regulate the face-sensitive area in fusiform cortex, the amygdala, or posterior parietal areas implicated in top-down attention, respectively, allowing us to compare the effect of NFB training on visual responses driven by bottom-up (fusiform), top-down (parietal), or both bottom-up and top-down signals (amygdala). We predict that successful up-regulation of these areas will lead to improved visual detection of masked faces, and concomitant changes in functional brain connectivity of visual areas with fronto-parietal networks, not seen in a control group receiving sham NFB.Together, these studies will provide the first evidence that brain processes unavailable to conscious awareness can be modified by voluntary control through NFB, and thus lead to subsequent changes in visual perception, opening new avenues for innovative rehabilitation strategies in neurological or psychiatric patients.