"The brain as a sensory-motor task machine: what did visual deprivation and visual substitution studies teach us about brain (re)-organization"
Last modified: 2011-08-22
Abstract
About one-quarter of our brain “real estate” is devoted to the processing of vision. So what happens to this vast “vision” part of the brain when no visual input is received? We are working with novel high-tech multisensory ‘glasses’ that convert visual information from a tiny video camera into sensory signals that the blind can interpret. In this talk I will mainly highlight work done using The-vOICe algorithm (Meijer et al 1992). We have devised a training program which teaches blind individuals to use such a device. Following approximately ~30 hours of training, congenitally blind individuals can use this device to recognize what and where various objects are, for instance within a room (like a chair, glass, and even people and their body posture; e.g. see http://brain.huji.ac.il/press.asp). Additional training is given specifically for encouraging free “visual” orientation enabling blind individuals to walk in corridors while avoiding obstacles and applying hand-“eye” coordination (e.g. playing bowling). A main focus of the project is using this unique “set-up” to study brain organization and brain’s flexibility. For example, we are elucidating how the subjects’ brains use preserved functions on one hand and on the other hand, reorganize to enable to process this new sensory language (e.g See Amedi et al Nature Neurosience 2007; Stiem-Amit et al. 2011; Reich et al. 2011). I will also focus on novel spectral analysis approaches to study large-scale brain dynamics and to look into the binding problem: how we integrate information into a coherent percept, an old question in neuroscience which has relatively poor answers, especially in humans. On the rehabilitation front, we have demonstrated that visual training can create massive adult plasticity in the ‘visual’ cortex to process functions like recognizing objects and localizing where they are located, much like the original division of labor in the visual system in which the ventral stream recognize objects and the dorsal stream help to localize them in order to orient action. Such visual cortex recruitment for ‘visual’ processing of soundscapes may greatly promote sight restoration efforts both via such technologies and by training people undergoing clinical procedures to restore vision. This approach might also be relevant, in other cases in which massive adult brain plasticity / flexibility is needed, e.g. after a stroke.
References
Amedi, A.PI, #, Stern, W. PD, Camprodon, JA.PD, Bermpohl, F. PD, Merabet, L. PD, Rotman, S.S, Hemond, CC.S, Meijer, P.C, Pascual-Leone, A.PI (2007). Shape conveyed by visual-to-auditory sensory substitution activates the lateral occipital complex. Nature Neuroscience 10: 687-689.
Bubic, A.PD, Striem-Amit E.S, Amedi, A.PI, #. (2010). 351-380. Large-scale brain plasticity following blindness and the use of sensory substitution devices. In: Multisensory object perception in the primate brain (Eds. J. Kaiser and M.J. Naumer). Springer Press, New York, USA.
Reich, L S., Szwed, M S, Cohen, L C, Amedi, API, # (2011). A Ventral Visual Stream Reading Center Independent of Visual Experience. Current Biology 21: 1–6.
Bubic, A.PD, Striem-Amit E.S, Amedi, A.PI, #. (2010). 351-380. Large-scale brain plasticity following blindness and the use of sensory substitution devices. In: Multisensory object perception in the primate brain (Eds. J. Kaiser and M.J. Naumer). Springer Press, New York, USA.
Reich, L S., Szwed, M S, Cohen, L C, Amedi, API, # (2011). A Ventral Visual Stream Reading Center Independent of Visual Experience. Current Biology 21: 1–6.