Neurophysiology of Active Perception

====== Neurophysiological mechanisms involved in the behavioral benefit associated with attentional orienting ====== ===== Group members involved in the project ===== Freek van Ede, Malte Köster, Eric Maris ===== Background and aim of the project ===== Our perception is facilitated when we know when and where an upcoming stimulus will occur. From a cognitive point of view this is accounted for by orienting of attention. Recently, EEG and MEG have begun to outline the neurophysiological mechanisms involved in such orienting of attention. From these studies it has become increasingly clear that anticipation of a sensory event involves a spatio-temporally specific modulation of ongoing oscillations within the sensory cortex where the upcoming stimulus will be processed. For example, this has been shown with respect to posterior alpha-band oscillations in anticipation of a visual stimulus (Worden et al., 2000; Thut et al., 2006) and sensorimotor alpha- and beta-band oscillations in anticipation of a somatosensory stimulus (Jones et al., 2010; van Ede et al., in press). At the same time it has been shown that these ongoing oscillations within sensory cortices relate inversely to cortical excitability (Romei et al., 2008) as well as behavioral performance in perception tasks (van Dijk et al., 2008; Jones et al., 2010). The picture emerges in which ongoing oscillations within sensory cortex are modulated (e.g. contralaterally suppressed) prior to the anticipated sensory stimulus such that when this stimulus arrives, the system is in a state of high excitability and the sensory information can be transmitted to downstream areas with high efficacy.    On the basis of these studies is has thus been suggested that the pre-stimulus modulation of ongoing oscillations within sensory cortex provides a neurophysiological mechanism by which knowledge about the location and timing of a sensory stimulus improves perception of that stimulus. It is at present nevertheless unclear to what extent this mechanism is sufficient to account for the behavioral benefit that occurs when subjects know (compared to not know) when and where an upcoming behaviorally stimulus will occur. It is this question that we aim to address in the present study. We will address this question in the human somatosensory system using magnetoencephalography (MEG). ===== Occupations within the lab-rotation ===== The student will be made familiar with running an MEG experiment. The student will assist in the data collection, both from the perspective of a participant as well as the researcher. The student will also take part in the analysis of the collected MEG data that will be performed in FieldTrip (a MATLAB toolbox for EEG/MEG analysis that is developed at the Donders Institute). Also will the student become familiar with the current literature concerning top-down attentional orienting, neuronal oscillations and sensory processing. The student is furthermore welcome to join to weekly meeting on these topics as for example the Systems Neuroscience Journal Club or the Eletrophysiological Data Analysis (EDA) meeting. ===== References ===== Jones SR, Kerr CE, Wan Q, Pritchett DL, Hamalainen M, Moore CI (2010) Cued spatial attention drives functionally relevant modulation of the mu rhythm in primary somatosensory cortex. J Neurosci 30:13760-13765. Romei V, Brodbeck V, Michel C, Amedi A, Pascual-Leone A, Thut G (2008) Spontaneous fluctuations in posterior alpha-band EEG activity reflect variability in excitability of human visual areas. Cerebral Cortex 18:2010-2018. Thut G, Nietzel A, Brandt SA, Pascual-Leone A (2006) Alpha-band electroencephalographic activity over occipital cortex indexes visuospatial attention bias and predicts visual target detection. J Neurosci 26:9494-9502. van Dijk H, Schoffelen JM, Oostenveld R, Jensen O (2008) Prestimulus oscillatory activity in the alpha band predicts visual discrimination ability. J Neurosci 28:1816-1823. van Ede F, de Lange F, Jensen O, Maris E (2012) Orienting attention to an upcoming tactile event involves a spatially and temporally specific modulation of sensorimotor alpha- and beta-band oscillations. J Neurosci. Worden MS, Foxe JJ, Wang N, Simpson GV (2000) Anticipatory biasing of visuospatial attention indexed by retinotopically specific α-band electroencephalography increases over occipital cortex. J Neurosci 20:RC63:1-6. ===== Contact information ===== In case you are interested in participating in the above outline experiment, in the form of a lab-rotation, please contact Freek van Ede. E-mail: f.vanede@donders.ru.nl. You can also come by my office in the Spinoze building, B-building, third floor: office B.03.43.