Exploring the Mind: Dr. Takeo Watanabe
“Effects of Reward on Perceptual Learning”
| What | Exploring the Mind |
|---|---|
| When |
2007-01-19 12:10 PM
2007-01-19 01:00 PM
January 19, 2007 from 12:10 pm to 01:00 pm |
| Where | CMB Conference Room |
| Contact Name | Noelle Blalock |
| Contact Email | nsblalock@ucdavis.edu |
| Contact Phone | 530-297-4452 |
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ABSTRACT for 1/19/07 talk:
What gates visual plasticity?
How can the brain adapt to new environments while protecting its architecture from modification from the continual bombardment of undesirable information? The goal of the present talk is to clarify how low-level sensory systems solve this stability-plasticity dilemma. Until recently, it was thought that low-level sensory systems were rigid and, therefore, resistant to environmental changes, and that only with persistent and focused attention on primitive features can these systems be modified. Recently it has been found that low-level visual stages are more plastic than previously thought, since PL can occur without attention to, and even awareness of, a stimulus. The sensitivity to motion direction increased as a result of exposure to a direction which was both sub-threshold and irrelevant to a given task (Watanabe et al, 2001). A recent fMRI study (Tsushima et al, 2006) has confirmed that such a task-irrelevant subthreshold stimulus is not subject to attentional control. Further evidence suggests that this type of PL occurs only at a low-level stage of visual processing (Watanabe et al, 2002). We call this new type of learning task-irrelevant PL. If attention does not prevent the low-level visual architecture from undesirable plasticity, what mechanism protects the architecture while allowing adaptation to useful information that is too weak or noisy to perceive? Seitz & Watanabe (2003) have found that the occurrence of task -irrelevant learning is restricted to the case in which an exposed, irrelevant, and sub-threshold feature was paired with a task-target. This indicates that plasticity is gated by a spatially diffusive learning signal that is triggered by presentation of a task target and enhances sensitivity to the paired irrelevant feature.
Seitz AR, Watanabe T. Nature. 2003 422:36.
Tsushima Y, Sasaki Y, Watanabe T. Science. 2006 314:1786-8.
Watanabe T, Nanez JE, Sasaki Y. Nature. 2001 413:844-8.
Watanabe, T. et al. (2002). Nature Neuroscience 5: 1002-9.
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