Sensory Processes III: Photoreception and Visual Processing

A comprehensive set of flashcards covering key concepts from the lecture on photoreception and visual processing in animal physiology.

What is photoreception?

The response of a sensory cell to light, detected by a receptor molecule called a photopigment.

What are the two major types of image-forming eyes?

Camera eyes and compound eyes.

What is the function of photopigments in photoreceptors?

Photopigments, made from opsin and chromophore, detect light and are involved in signal transduction.

What is the main difference between camera eyes and compound eyes?

Camera eyes have a lens that forms a single inverted image, while compound eyes consist of many ommatidia that create a mosaic image.

What happens during the process of dark adaptation?

The regeneration of visual pigments in photoreceptors after exposure to bright light.

What are rods and cones?

Rods are photoreceptors more sensitive to light; cones are involved in color vision and function best under brighter light.

What is transduction cascade in phototransduction?

A series of biochemical events triggered by the activation of opsin, leading to changes in cell membrane potential.

How do vertebrate eyes focus light?

Light is focused onto retinal rods and cones via the cornea and lens.

What is retinal integration?

The process by which the signals from multiple photoreceptors are combined to form a contrast-sensitive response.

What is the role of horizontal cells in the retina?

Horizontal cells modulate interactions between photoreceptors and bipolar cells, contributing to contrast sensitivity.

What is the significance of the receptive field in retinal neurons?

The area of the retina where the activity of a neuron can be influenced by light.

How do on-center and off-center ganglion cells differ in their response to light?

On-center cells increase firing with light in the center; off-center cells are inhibited by light in the center and excited by light in the surround.

What defines lateral inhibition in the retina?

It is the process where horizontal cells inhibit neighboring photoreceptors to enhance contrast in visual perception.

What is a phototransduction mechanism in rod cells?

Activation of rhodopsin leads to a reduction in cGMP levels, resulting in the closure of Na+ channels and hyperpolarization of the cell.