4.11 Understanding Lateral Inhibition in Vision

These flashcards cover key concepts of lateral inhibition, the role of horizontal cells, and perceptual effects like the Mach Band effect as discussed in the lecture.

What is lateral inhibition and how does it help us perceive contrast in images?

Lateral inhibition is a process where activated photoreceptors inhibit surrounding neurons, enhancing the contrast at the edges of images.

What role do horizontal cells play in lateral inhibition?

Horizontal cells are inhibitory interneurons that connect photoreceptors, primarily releasing GABA to inhibit neighboring neurons.

What is the Mach Band effect?

The Mach Band effect is an optical illusion that makes edges between bands of color appear lighter or darker than they actually are, due to lateral inhibition.

How do horizontal cells affect the perception of lightness?

When photoreceptors are activated by light, their horizontal cells inhibit neighboring photoreceptors, causing an illusion of varying lightness at borders.

How does a change in light intensity influence photoreceptor firing?

Photoreceptors exposed to high intensity light fire more intensely, causing more inhibition in neighboring cells, affecting perceived brightness.

What occurs at the left edge of the border in terms of inhibition?

At the left edge, photoreceptors receive less inhibition due to neighboring cells firing less intensely, leading to a perception of lightness.

Why does the right edge of a darker band appear even darker?

The right edge appears darker because photoreceptors there receive more inhibition from intensely firing neighboring photoreceptors, reducing their firing rate.

What is the physiological basis for perceived lightness or darkness at image borders?

The balance of excitation from photoreceptors and inhibition from horizontal cells determines the lightness or darkness perceived at borders.