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ניורוביולוגיה ומדעי המח חלק 2 – מערכת הראייה Introduction to Neurobiology Part 2 – The Visual System. Shaul Hochstein. ניורוביולוגיה ומדעי המח Introduction to Neurobiology. Introduction to Sensory Systems The retina “From Neuron to Brain” Chapter 19: 379-405
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ניורוביולוגיה ומדעי המחחלק 2 – מערכת הראייהIntroduction to NeurobiologyPart 2 – The Visual System Shaul Hochstein
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems The retina “From Neuron to Brain” Chapter 19: 379-405 Transduction and signaling in the retina
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems The retina 1- Structure of the eye 2- Muscles of the eye – fixation; convergence; accommodation; 3- Structure of the retina 4- The blind spot 5- Rods and Cones 6- Visual Pigments 7- Color vision: Young & Helmholtz 8- Photoreceptor sensitivity and signal amplification 9- Structure-Function relationships 10- Ribbon synapses 11- The fovea: Comparing central and peripheral vision
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems Is the eye like a camera? Yes and No: lens, focus, pupil, inverted image, film=layer of photorceptors But: information processing
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems To where are retinal signals transmitted? Right sides of both retinas to right brain. Left sides of both retinas to left brain. BUT: image was inverted (up-down and right-left) by optical pin-hole (lens) effect.
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems layers of neurons & connections in the retina. Note 3 types of neurons at middle cell-body layer.
The Retina and its layers Cell bodies connections Cell bodies connections Cell bodies
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems Rods and cones - sensitivity vs. acuity & color; - located in central vs. peripheral retina - night vs. day
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems Pros and Cons for an inside-out retina.
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems Depolarizing and Hyperpolarizing receptor, generator, and action potential signals - still only one trick: change in conductance to specific ion(s).
The photoreceptor response: Receptor potential & generator potential Graded potentials vs. Action potentials
In the dark, Na channels are open, causing depolarization and allowing Na influx and K efflux, counteracted by pump. In light, Rhodopsin ultimately closes these channels stopping the flow.
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems The source of color vision: How many cone types do we need? 1 type: no color (confuse color and intensity) 2 types: full color spectrum but no combinations 3 types: color spectrum plus white (& other unsaturated colors) plus purple (red & blue) …
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems Transmission: Photoreceptor to Bipolar
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems The receptive field Definition – area in the world (or on retina) where change in stimulus induces change in response in recorded neuron. Extension – area in multi-dimensional stimulus space where … Physiological research – aids in guessing connectivity from area to area
ניורוביולוגיה ומדעי המחIntroduction to Neurobiology Introduction to Sensory Systems A first computation: Lateral Inhibition: mechanism, consequences and function