Week 7: Attention and Spatial Navigation

What is selective attention?

The brain's ability to determine what is important and focus on specific stimuli while ignoring others.

What happens when there is damage to V1?

It causes loss of visual awareness, known as homonymous hemianopia or cortical blindness, but unconscious processing may remain.

What is blindsight?

A phenomenon where patients with unilateral V1 damage show above-chance visual performance in their blind hemifield for certain tasks despite lacking conscious awareness.

What supports the neural basis of blindsight?

Evolutionarily older pathways like the superior colliculus and pulvinar nucleus, which do not support visually guided behavior under conscious control.

What is change blindness?

The failure to notice large changes in a scene when attention is not directed to it.

What is inattentional blindness?

The failure to notice an unexpected object when attention is focused elsewhere.

What are some reasons we are aware of only a small part of our visual world?

Neural limitations, metabolic limitations, computational efficiency, computational complexity, and conscious decision making.

How did William James define attention?

As 'taking possession by the mind of one out of simultaneously possible objects'.

What aspects does attention include?

Selectivity (spatial, temporal, motoric), capacity limitation, vigilance (sustained attention), perceptual set (expectation), and switching.

What is covert selective attention?

Allocating attention without eye movements, revealing prioritization by the brain.

What is unilateral spatial neglect?

A failure of spatial awareness after damage to one side of the brain, usually the right hemisphere, leading to ignoring the affected side of space.

What are place cells?

Neurons in the hippocampus that fire at specific real-world locations, supporting a spatial map.

What are grid cells?

Neurons in the medial entorhinal cortex that fire in a regular hexagonal lattice of locations, contributing to spatial navigation.

What are head direction (HD) cells?

Neurons that fire based on the direction the head is facing, found in several cortical and subcortical structures.

What are border/boundary cells?

Neurons that fire when the animal is at set distances from navigational boundaries, found in the entorhinal cortex and subiculum.

What is a cognitive map?

A mental representation of spatial relationships, allowing for flexible navigation.

How does human navigation compare to rodent navigation?

Humans have similar anatomical structures but differences in complexity; damage to navigation areas in humans causes broader memory deficits.

What is the Parahippocampal Place Area (PPA)?

A brain region important for scene recognition, responding to scenes based on their global spatial layout.

What does distance coding in the hippocampus involve?

Activity in the hippocampus scales with the distance between landmarks, similar to border/boundary cells in rats.

What evidence supports place cells in the human hippocampus?

Recordings from individual neurons in presurgical epilepsy patients showed cells responding to specific spatial locations.

What is viewpoint-independent direction coding?

Evidence of allocentric heading representation in the retrosplenial complex, active during navigational tasks.

How does navigational expertise affect hippocampal volume?

Studies show structural plasticity in London taxi drivers, with increased posterior hippocampal volume and decreased anterior volume.

What is the difference in navigation skills between taxi drivers and bus drivers?

Taxi drivers excel in complex navigational tasks while bus drivers are better at recalling newly-learned visual information.