| To understand vision one has to know the interplay between the neuronal activities of the many visual areas in our brain. To answer this question we study the role of cortical feedforward, horizontal and feedback connections in perceptual organization, attention and visual awareness. In man psychophysical assessments of visual percepts are combined with brain imaging, like functional MRI, and the recording of the electric and magnetic fields generated by visual stimulation. In animals trained to communicate their percepts behaviorally, we record at the level of single neurons or groups of neurons. To gain insight into the perceptual role of particular areas or connections between areas we use inactivation studies (lesions in animals, transcranial magnetic stimulation (TMS) in man). Finally neural models are employed to incorporate the results into a mechanistic understanding of the underlying processes. Another line of research concerns the development of visual, auditory and cognitive responses in (pre)mature neonates and children. This project is a combined (f)MRI and MEG study. Since magnetic signals are rather insensitive to the tissue inhomogeneities in the (infants) head, they are superior for source localization. In this project also children with localized brain malfunction or localized delayed maturation will be studied. The third and last project deals with the motor control of eye and eyelid muscles. We study the neuronal mechanisms in the brainstem during blinking which is a highly co-ordinated process of eye and eyelids. |
