Anders Sand
PhD Student
The goal of my research project is to investigate how different aspects of the alpha rhythm are related to detection performance. Earlier studies suggest that signal communication between the retina and early visual cortices is constant. Rather, there may be short (~50 ms) states of excitation or inhibition. The main hypothesis for my research project is that whether weak stimuli are presented in or out of phase with these states influence if the stimulus is detected or not. In the research project I use electroencephalography (EEG) to measure these fast changes in humans’ brain activity. The signal communication between thalamus and visual cortices is one source for the alpha rhythm recorded in the EEG. The short states of excitation and inhibition in the thalamocortical communication may be one source for the cyclic phase in the alpha rhythm.
My preliminary result suggests that both the amplitude (strength) and the phase of the alpha rhythm at stimuli presentation are related to if the stimuli will be detected or not. Such a result show the importance of taking ongoing brain activity into account when trying to relate brain activity to consciousness.
Publications
Sand, A., & Wiens, S. (2011). Processing of unattended, simple negative pictures resists perceptual load. NeuroReport, 22, 348-352.
Wiens, S., Sand, A., & Olofsson, J.K. (2011). Nonemotional features suppress early and enhance late emotional electrocortical responses to negative pictures. Biological Psychology, 86, 83-89.
Wiens, S., Sand, A., Norberg, J., & Andersson, P. (2011). Emotional event-related potentials are reduced if negative pictures presented at fixation are unattended. Neuroscience Letters, 495, 178-182.
Wiens, S., Molapour, T., Overfeld, J., & Sand, A. (in press). High negative valence does not pretect emotional event-related potentials from spatial inattention and perceptual load. Cognitive, Affective, and Behavioral Neuroscience.
