Spatial Vision and Visual Cortex: Acuity, Receptive Fields, and Development

What is the role of the contralateral visual field?

It represents the opposite side of the body.

What does ipsilateral mean in the context of visual pathways?

It refers to the same side of the body.

What is the pathway of visual information from the retina to the brain?

Retina → LGN → V1

How is visual acuity defined?

Resolution acuity measured in degrees of visual angle.

What is the significance of visual angle in measuring visual stimuli?

It describes how large the image appears on the retina.

What does a Snellen acuity of 20/40 indicate?

You see something at 20 feet that most people can see at 40 feet.

What is grating acuity?

It measures the visual angle of the finest grating a person can see.

What is the tradeoff in retinal convergence?

High acuity with low sensitivity in a small field of view versus low acuity with high sensitivity in a large field of view.

What is minimum visible acuity?

The lowest level of vision at which a person can reliably detect an object.

Define minimum discriminable acuity.

The lowest level of vision at which someone can reliably perceive a change in a visual feature.

What is hyperacuity?

The ability to detect small differences in spatial locations of stimuli.

What is spatial frequency in visual perception?

The number of cycles of a grating per unit of visual angle.

What is Fourier decomposition in the context of vision?

The process of breaking down images into sine wave components.

What does the Contrast Sensitivity Function (CSF) measure?

It measures which frequencies we are most sensitive to and which ones we overlook.

How does dark/light adaptation affect the CSF?

It varies the sensitivity to different visual frequencies based on adaptation level.

What is the primary function of the Lateral Geniculate Nucleus (LGN)?

It processes visual information from the retina before it reaches the visual cortex.

How does V1 differ from LGN in processing visual information?

V1 responds to information from both eyes, while LGN responds to one eye at a time.

What is retinotopic mapping in V1?

Neurons that respond to similar stimuli are located near each other based on their position in the visual field.

What is cortical magnification?

The scaling of information from different parts of the visual field, with more focus on the fovea.

What is a hypercolumn in V1?

A 1mm block of V1 that contains all the machinery necessary to process any possible orientation and inputs from both eyes.

What is visual crowding?

Stimuli are harder to discern when other stimuli are nearby, affecting peripheral object detection.

What do simple cells in V1 respond best to?

Bars of light or dark in specific regions of their receptive field.

What distinguishes complex cells from simple cells in V1?

Complex cells respond to both bars of light and dark anywhere in their receptive field and are phase-insensitive.

What is neural adaptation?

The gradually diminishing response of a sensory organ to a sustained stimulus.

How can selective adaptation inform us about visual encoding?

It reveals which neurons are tuned for specific properties based on observed adaptive aftereffects.

How does the spatial vision of infants compare to adults?

Infants prefer complex stimuli and are less sensitive to high spatial frequencies.

What techniques are used to study infants' visual responses?

Eye tracking and Visual Evoked Potentials (VEP).