Lecture 3: Vision - From retina to cortex

Question 1

Cornea and Lens

Answer 1

The cornea is the transparent, curved front part of the eye that refracts light as it enters the eye, while the lens further focuses the light onto the retina. Together, they work to create a sharp image on the retina.

Question 2

Accommodation

Answer 2

The process by which the ciliary body adjusts the shape of the lens to focus light from objects at varying distances onto the retina.

Question 3

Pupil

Answer 3

The adjustable opening in the iris that regulates the amount of light entering the eye.

Question 4

Photoreceptors

Answer 4

Specialized cells (rods and cones) in the retina that detect light and convert it into neural signals.

Question 5

Photopigments

Answer 5

Light-sensitive molecules within photoreceptors that initiate the process of visual signal transduction.

Question 6

Rhodopsin

Answer 6

A photopigment found in rods, highly sensitive to dim light and crucial for night vision.

Question 7

Cones

Answer 7

Photoreceptors responsible for color vision and sharp detail in bright light, sensitive to red, green, or blue wavelengths.

Question 8

Rods

Answer 8

Photoreceptors sensitive to light intensity, enabling vision in low-light conditions.

Question 9

Ganglion Cell

Answer 9

Neurons in the retina that process and transmit visual signals to the brain.

Question 10

Parasol Ganglion Cells

Answer 10

Large receptive fields, part of the magnocellular pathway, sensitive to movement and flicker.

Question 11

Midget Ganglion Cells

Answer 11

Small receptive fields, part of the parvocellular pathway, responsible for processing color and fine detail.

Question 12

Koniocellular Cells

Answer 12

A third pathway in the LGN, involved in processing color and other visual details.

Question 13

Receptive Field

Answer 13

The specific area of the retina from which a ganglion cell receives and processes visual input.

Question 14

Thalamus

Answer 14

The brain’s sensory relay station, forwarding visual information to the visual cortex.

Question 15

LGN (Lateral Geniculate Nucleus)

Answer 15

A part of the thalamus organized into layers (magnocellular, parvocellular, koniocellular) that relay and process visual signals.

Question 16

Retinotopy

Answer 16

The spatial mapping of visual input from the retina to specific brain areas, preserving the arrangement of visual fields.

Question 17

Visual Cortex (V1)

Answer 17

The primary visual processing area in the brain, representing every point in the visual field.

Question 18

Pinwheel Arrangement

Answer 18

The organization of orientation-specific cells in V1, responding to lines and edges in different orientations.

Question 19

Intrinsic Optical Imaging

Answer 19

A technique to study brain activity in the visual cortex by measuring changes in light absorption due to neural activity.

Question 20

Processing Hierarchy

Answer 20

The stages of visual processing, from detecting basic features (edges, orientation) to more complex forms (faces, objects).

Question 21

Specialized Processing

Answer 21

Neural systems or areas in the brain specifically adapted to process unique types of information, such as motion or facial recognition.

Question 22

Retinal Ganglion Processing

Answer 22

Initial visual signal integration and transmission from the retina to the brain, involving parasol, midget, and koniocellular cells.

Question 23

Neural Plasticity

Answer 23

The brain’s ability to adapt and reorganize based on experience or environmental changes.

Question 24

Critical Period

Answer 24

A time-sensitive phase during which the brain must receive proper stimulation to develop specific functions, or the ability may be lost (“use it or lose it”).

Question 25

Ventral Stream

Answer 25

The “what pathway,” responsible for identifying objects, features, and color

Question 26

Dorsal Stream

Answer 26

The “where pathway,” responsible for spatial awareness, movements, and motion

Question 27

Face Processing

Answer 27

Specialized neurons in the brain adapted for efficiently detecting and recognizing faces.

Question 28

Quiroga et al. (2009)

Answer 28

A study investigating neurons in the medial temporal lobe during epilepsy surgery. Using single-cell recordings, it revealed that specific neurons respond selectively to particular stimuli, such as faces, objects, or even abstract concepts (e.g., the “Jennifer Aniston neuron”). This highlights the brain’s ability to efficiently encode information about specific visual or conceptual stimuli.

Question 29

Hubel and Wiesel (1960s)

Answer 29

Investigated V1 neurons in cats. Found neurons respond to edges and specific orientations (orientation tuning). Identified simple and complex cells.

Question 30

Blakemore and Cooper (1970)

Answer 30

Studied kittens raised in striped environments. Found neurons only responded to the exposed orientation. Demonstrated critical period and neural plasticity.