The second of the Charlie Rose 12-part monthly series on the human brain aired November 24th.
His guests for the second show, “The Perceiving Brain – Sight and Visual Perception,” included:
- Eric Kandel — co-host of the series, 2000 Nobel Laureate (Physiology/Biology), professor, Columbia University Physiology & Cellular Biophysics
- Edward H. Adelson — John and Dorothy Wilson Professor of Vision Science at MIT
- Nancy Kanwisher — Professor in the McGovern Institute for Brain Research at MIT
- Anthony Movshon — Presidential Professor of Neural Science and Psychology at New York University and Adjunct Professor of Physiology and Neuroscience at New York University School of Medicine.
- Pawan Sinha — Associate Professor of Vision and Computational Neuroscience at MIT
The snippets posted here reflect what I found especially meaningful to my interests. Among the highlights:
Charlie Rose: 25% of the brain is devoted to visual perception; seeing happens in the brain, not the eyes; patterns are translated into objects.
Eric Kandel: We understand the visual system better than any other part of the brain; a model for understanding all of the brain. Four important points or themes:
- The eye is not a camera (although certain parts/functions are analogous).
- Sensory functions, including vision, are localized to specific areas in the brain.
- Visual computations are hierarchical, through a series of relays they process progressively complex associations (from thalamus to cortex).
- Plasticity of the brain/nerve cells is pervasive and critical to brain functioning.
Kandel: The visual system/brain makes guesses and can sometimes be fooled.
Anthony Movshon described the brain’s anatomy: It’s not a camera, but it functions like a camera.
- Photoreceptive cells funnel the image from the back of the retina to the optic nerve; compress 100 million receptor cells down to about 1 million fibers (100:1 compression).
- Acuity is only very good at the center of the retina, acuity falls off away from the center of the retina, have to move your eye around to capture multiple snapshots.
- The thalamus connects to all parts of the cerebral cortex, visual signals pass through thalamus; series of relays in hierarchical.
- Most amazing aspect of visual system is how it puts together and integrates all the data into a coherent image, hierarchy of processing, integrating images we have stored in memory. Transformation of the response from thalamus to cortex, a major operation that the brain performs, how it reconstructs a visual image.
- Localized regions of the brain for face recognition, words and letters, places and landscapes, bodies; all activated later/higher in the hierarchy.
- Humans have only been reading for a few thousand years, the part of the brain that recognizes words and language must be developed after birth, too young to have been genetically evolved.
- The last video clip summarizes several references that support what Alfred Korzybski termed abstracting (1933).
(17:20)