Psychology Chapter 3 Flashcards

Study Notes

Lateral Inhibition

Lateral inhibition refers to the capacity of an excited neuron to inhibit its neighboring neurons, enhancing contrast in visual perception.
This phenomenon was first examined in the Limulus (horseshoe crab) due to its simple visual system, allowing for clearer observations of neuronal interactions.

Hermann Grid

The Hermann Grid illusion occurs because neurons at grid intersections experience heightened lateral inhibition compared to those along corridors.
This illusion disappears when observed directly, as the fovea’s smaller receptive fields reduce the impact of lateral inhibition.

Mach Bands

Mach Bands create an illusion of enhanced brightness at the edges of a shadow, providing sharper visual boundaries.
Lighter areas adjacent to darker regions receive stronger lateral inhibition, making them appear even brighter than uniformly lit areas.

Simultaneous Contrast

In simultaneous contrast, gray boxes surrounded by lighter backgrounds receive increased inhibition, making them appear darker.
Conversely, when surrounded by darker areas, the inhibition effect is diminished, altering perceived brightness.

White's Illusion

White's Illusion demonstrates that lateral inhibition alone cannot explain certain visual effects due to the influence of "belongingness," where an area's appearance is affected by its perceived relationship to surrounding elements.

Receptive Fields in the Optic Nerve and LGN

Receptive fields correspond to specific sensory regions that trigger neuronal firing when stimulated.
Approximately 90% of the information from the optic nerve is transmitted to the LGN with minimal alteration from the retina.

Receptive Field Types

Excitatory-center, inhibitory-surround receptive fields result in increased neuronal firing when the center is stimulated.
Conversely, inhibitory-center, excitatory-surround receptive fields show reduced firing in response to center activation.

Center-Surround Antagonism

Center-surround antagonism describes how neuronal response initially increases with light exposure in the receptive field but eventually diminishes as more of the field is illuminated.

Cortical Cells Responses

Simple cortical cells are primarily responsive to light stimuli arranged in specific orientations.
Complex cortical cells respond optimally to lines that move in particular directions.
End-stopped cortical cells react to lines of a specific length and to moving corners or edges.

Description

Test your knowledge on Chapter 3 of Psychology with these flashcards. Explore the concept of lateral inhibition and its significance in neurobiology, particularly its initial studies in the Limulus. Perfect for quick revision and deeper understanding.