Module 3: Neural Processing, Receptive Fields & Visual Streams

Center-Surround Receptive Field structure

Circular region in retinal ganglion cells with an excitatory center/inhibitory surround (or vice versa). Solves contrast enhancement and explains illusions like the Hermann Grid.

Ganglion Cells vs. Cortical Cells selectivity

Ganglion: Care about size, spot location, and contrast (no orientation specificity).

Cortical: Care about orientation, movement, and specific structural features.

Simple Cortical Cells

Prefer stationary bars of light with specific orientations and side-by-side ON/OFF arrangements.

Complex Cortical Cells

Prefer lines/bars of specific orientation and direction of movement.

End-Stopped Cortical Cells

Prefer moving corners, angles, or edges of specific lengths.

Retinotopic Mapping

Spatial arrangement preserved from retina to Lateral Geniculate Nucleus (LGN) and Primary Visual Cortex (V1) where adjacent points on retina map to adjacent points in brain.

Dorsal Stream ("Where/How")

Pathway running to Parietal Lobe; handles spatial location, movement, and action control.

Ventral Stream ("What")

Pathway running to Temporal Lobe; handles object recognition and color/form perception.