Neurophysiology of Active Perception

======= Neurophysiological processes underlying sensory expectation; an investigation using invasive recordings from the rat somatosensory system ====== ===== Group members involved in the project ===== Anne Fransen, George Dimitriadis, Eric Maris ===== Background and aim of the project ===== It has become clear that attentive expectation has a direct effect on the way information is processed in sensory cortical areas (Lee & Maunsell, 2009; Li & Ebner, 2007; Roberts et al., 2008; Womelsdorf et al., 2008). This begs the question how these effects come about. Studies from our lab and others have tried to answer this question using human subjects (Van Ede et al., 2010). This has lead to interesting results, involving that expectation/attention induces a spatially and temporally specific desynchronization in the beta band. However, there seems to be more to the story: current work in our lab has shown that the attentional benifit at the behavioral level is largely unexplained by changes in the beta power. It is unlcear what other mechanisms play a role in bringing about effects of expectation and attention. In addition, it is unclear how beta synchronisation relates to the firing patterns of sensory neurons. In this project we use epidural ECoG recordings over the tactile cortex of rats to study the way (different forms of) expectation and attention bring about changes in the local network activity of sensory cortex. Currently, we are running experiments in which we compare brain activity during passive stimulation in different brain states (up and down states in anesthesia, behavioural states in awake, freely moving animals). In these states we will also compare activity due to expected stimuli with that due to unexpected stimuli using a classical conditioning paradigm. ===== Occupations within the lab-rotation ===== Students are welcome to join experimental session in which data is collected from awake and/or anesthethised rats which receive tactile stimulation. They are also encouraged to look at data analyses and analysed data, and are made familiar with the daily practice of working with live animals to collect neurophysiological data. They are also made familiar with the literature, and welcomed to join the systems neuroscience journal club. ===== Internship ===== Students are encouraged to design their own project with us, in which ECoG data from rat somatosensory cortex plays a central role. My focus is on expectation and learning based on the somatosensory data, but other cognitive topics are also welcomed. The question will then be answered with data from sessions in which the rat receives (cued) (audio-)tactile stimuli in anesthesia, and/or passive awake and/or task conditions. Thus there is a lot of freedom for your own input and ideas. Students will also join in implantation surgeries, and post-mortem staining experiments, and perform their own analyses in matlab. ===== References ===== Yoshida T, Katz DB (2011) Control of Prestimulus Activity Related to Improved Sensory Coding within a Discrimination Task. The Journal of Neuroscience 31:4101-4112. van Ede F, Jensen O, Maris E (2010) Tactile expectation modulates pre-stimulus beta-band oscillations in human sensorimotor cortex. Neuroimage 51:867-876. Cohen MR, Maunsell JHR (2009) Attention improves performance primarily by reducing interneuronal correlations. Nat Neurosci 12:1594-U1148. Castro-Alamancos MA (2009) Cortical Up and Activated States: Implications for Sensory Information Processing. Neuroscientist 15:625-634. ===== Contact Information ===== Anne Fransen (a.fransen at donders.ru.nl)