Biopsychology Chapter 6 Final

Retina and Vision

• The fovea, located in the retina, is responsible for high-acuity vision, containing densely packed cones.
• The iris regulates the size of the pupil, controlling the amount of light entering the eye.
• Binocular disparity refers to the difference in perspective between the two eyes.
• The lens focuses light onto the retina, allowing for clear images.
• The blind spot is an area in the retina devoid of photoreceptors where the optic nerve exits, resulting in no visual information.
• A compromise in pupil size balances light intake with depth of field, affecting focus and clarity.

Visual Processing Systems

• Dorsal and ventral streams differ in function: the dorsal stream ("where" pathway) processes spatial awareness; the ventral stream ("what" pathway) processes object recognition.
• The secondary visual cortex integrates and interprets information from the primary visual cortex.
• Young and Helmholtz's trichromatic theory explains color vision through three types of cone photoreceptors sensitive to different wavelengths (red, green, blue).

Neuronal Structure and Function

• Simple striate cells respond primarily to bars or edges, while complex striate cells process movements and are less sensitive to the position of stimuli.
• Retinex theory proposes that the perceived color of an object remains consistent under varying lighting conditions.
• Photopic vision is characterized by high acuity and low sensitivity, relying on cone receptors; scotopic vision, in contrast, involves rod receptors, providing lower acuity but higher sensitivity in low light.

Eye Movements and Transduction

• Saccades are rapid eye movements that reposition the line of sight, enhancing visual attention and focus.
• Transduction in visual perception involves converting light stimuli into electrical signals by photoreceptors.

Brain and Vision

• The primary visual cortex processes visual information, featuring a retinotopic organization where different areas correspond to specific regions in the visual field.
• Receptive fields in the retina-geniculate-striate system demonstrate center-surround organization, responding to contrasts.

Visual Recognition and Disorders

• The fusiform face area is specifically dedicated to facial recognition, playing a vital role in identifying individuals.
• Prosopagnosia is the term for the inability to recognize faces, often associated with damage to the fusiform gyrus.
• Akinetopsia refers to the deficiency in perceiving smooth movement, typically resulting from damage to the motion-processing area of the brain.
• Agnosia describes the inability to recognize visually similar stimuli due to brain damage affecting visual processing pathways.
• Motion blindness is the inability to consciously recognize movement, associated with damage to specific visual processing areas.

Test your knowledge on the organization and receptive fields of neurons in the primary visual cortex. Learn about different types of striate cells and their responses to visual stimuli. Explore the conclusions drawn by Hubel and Wiesel regarding the organization of neurons in the visual cortex.