Projects
From SensorimotorLab.com
Spatial constancy mechanisms in goal-directed motor behavior
Moving through the environment causes complex changes of sensory and motor inputs to the brain. Yet, despite our motion, we perceive the world as stable and interact with the objects in it with great accuracy. This ability to maintain a veridical representation of space during self-motion is called spatial constancy and is an important component in the control of goal-directed actions. We study the signals and mechanisms involved in making spatially-accurate eye and reaching movements in a dynamic 3-D environment. Projects are:
- 1. Spatial updating in eye-hand coordination
- 2. Spatial updating in interceptive motor behavior
- 3. Spatially-guided motor behavior during self-motion
Recent publications:
- Medendorp W.P.
- Spatial constancy mechanisms in motor control
- Philos Trans R Soc Lond B Biol Sci., in press
- Van Pelt, S. & Medendorp, W.P.
- Updating target distance across eye movements in depth.
- J Neurophysiol, 99(5), 2281-2290, 2008
- Van Pelt S. Medendorp W.P.
- Gaze-centered updating of remembered visual space during active body translations.
- Journal of Neurophysiology, 97: 1209-1220, 2007
Dynamic perception using ambiguous signals
To ensure perceptual stability, we use information about self-orientation and self-motion from various sensory modalities, in particular the visual and vestibular system. The vestibular system has specialized organs for detecting rotational acceleration (the semicircular canals) and for sensing linear acceleration (the otoliths), but they provide noisy and partly ambiguous information. We study how brain deals with imperfect sensory signals when creating a percept of the world. Projects are:
- 1. Dynamic perceptual updating by vestibular signals
- 2. Role of top-down signals in visual motion detection
- 3. Dynamic perception during linear motion
Recent publications:
- Vingerhoets, R.A.A., De Vrijer, M., Van Gisbergen, J.A.M. & Medendorp, W.P.
- Fusion of visual and vestibular tilt cues in the perception of visual vertical.
- J Neurophysiol, 101(3), 1321-1333, 2009
- De Vrijer, M., Medendorp, W.P. & Van Gisbergen, J.A.M.
- Shared computational mechanism for tilt compensation accounts for biased verticality percepts in motion and pattern vision.
- J Neurophysiol, 99(2), 915-930, 2008
Neural dynamics in sensorimotor integration
How are spatial signals integrated with motor effector signals in order to plan an action? The posterior parietal cortex is known to be an important site for sensorimotor integration in the brain, but its temporal dynamics and computational constraints are not well understood. We examine sensorimotor integration in saccade and reaching tasks, recording neural activity with fMRI and and whole-head magnetoencephalography (MEG). Projects are:
- 1. Effector selection in the human brain
- 2. Temporal dynamics of human brain activity in sensorimotor integration
- 3. Decoding global maps in the human motor system
- 4. Role of oscillatory activity in coding multimodal spatial representations for eye and hand actions
- 5. Motor planning for multiple effectors in the human intraparietal sulcus
Recent publications:
- Van Der Werf J., Jensen O., Fries P., Medendorp W.P.
- Neuronal synchronization in human posterior parietal cortex during reach planning.
- Journal of Neuroscience, 30:1402-12, 2010.
- Heed T., Beurze S.M., Toni I., Roder B., Medendorp W.P.
- Functional rather than effector-specific organization of human posterior parietal cortex.
- Journal of Neuroscience, in press