Neural_Physiology_of_Eye ppt…………………………..

Neurophysiology of eye ppt

1. Neural Physiology of the Eye Postgraduate Level Presentation With Diagrams and Flowcharts

2. Overview of Visual Pathways The visual pathway begins at the retina and extends through the optic nerve, optic chiasma, optic tract, lateral geniculate body, optic radiations, and visual cortex. [Illustration: Visual pathway diagram]

3. Functional Anatomy of Retina The retina contains photoreceptors (rods and cones), bipolar cells, ganglion cells, horizontal and amacrine cells that process visual information. [Illustration: Retinal layers cross-section]

4. Phototransduction Mechanism Light activates photopigments in rods and cones, causing hyperpolarization and a graded potential transmitted to bipolar cells. [Illustration: Rhodopsin cascade flowchart]

5. Rods vs Cones Physiology Rods: scotopic vision (dim light), more sensitive. Cones: photopic vision (color, high acuity). [Illustration: Table comparing rods and cones]

6. Retinal Circuitry Bipolar cells act as intermediaries; horizontal and amacrine cells provide lateral inhibition and modulation of signals. [Illustration: Flowchart of retinal synaptic circuit]

7. Synaptic Transmission in Retina Glutamate is the major neurotransmitter; graded potentials instead of action potentials in most cells. [Illustration: Synaptic connection diagram]

8. Visual Field Organization Images are inverted and reversed on the retina; temporal fibers do not cross, nasal fibers cross at chiasma. [Illustration: Visual field mapping diagram]

9. Optic Nerve & Chiasma At the optic chiasma, nasal fibers cross to the opposite side; allows binocular vision and depth perception. [Illustration: Optic chiasma diagram]

10. Lateral Geniculate Body Processing LGB acts as a relay and modulator; 6 layers (magnocellular and parvocellular). [Illustration: LGB structure image]

11. Visual Cortex Physiology Primary visual cortex (V1) processes orientation, edges; higher areas interpret motion and color. [Illustration: Visual cortex map]

12. Binocular Vision Mechanisms Integration of images from both eyes gives stereopsis (depth perception). [Illustration: Depth perception illustration]

13. Accommodation Reflex Pathway Controlled via Edinger–Westphal nucleus and oculomotor nerve; changes lens curvature and pupil size. [Illustration: Accommodation reflex pathway chart]

14. Pupillary Light Reflex Afferent: optic nerve; Efferent: oculomotor nerve; mediated via pretectal nucleus. [Illustration: Pupillary reflex flowchart]

15. Dark & Light Adaptation Photoreceptor sensitivity changes with light intensity; involves retinal and cortical adjustments. [Illustration: Adaptation response graph]

16. Color Vision Neurophysiology Three cone types (S, M, L); opponent process theory explains color perception. [Illustration: Color wheel and cone sensitivity curve]

17. Eye Movement Control Cranial nerves III, IV, VI coordinate movement; frontal eye fields and superior colliculus involved. [Illustration: Oculomotor control diagram]

18. Visual Attention & Perception Cortical processing integrates visual input with attention and memory. [Illustration: Visual attention pathway illustration]

19. Common Neural Disorders Affecting Vision Lesions can cause field defects: optic neuritis, homonymous hemianopia, etc. [Illustration: Visual field defect diagram]

20. Summary & References Neural physiology integrates retinal phototransduction, signal transmission, cortical processing for vision. References: - Kandel et al., Principles of Neural Science - Guyton & Hall, Textbook of Medical Physiology