Sensation and Perception

Question 1

What do the sensory systems detect?

Answer 1

Physical events in the world, process this info to some extent and convey it to the brain.

Question 2

Is sensory processing conscious?

Answer 2

Most of it happens below the level of conscious awareness.

Question 3

What 4 attributes do the sensory systems mediate?

Answer 3

Modality, location, intensity and duration.

Question 4

What range of frequencies is the human ear sensitive to?

Answer 4

20Hz - 20Khz

Question 5

What cells in the ear are sensitive to sound?

Answer 5

Hair cells, they have differential sensitivity.

Question 6

Whats the minimum intensity for hair cells to detect sound?

Answer 6

2KHz

Question 7

What 3 perceptual abilities does spatial awareness involve?

Answer 7

1. Locating the site of stimulation on the body or the stimulus source in space.
2. Discriminating the size and shape of objects.
3. Resolving the fine detail of the stimulus.

Question 8

What 2 things is the capacity of sensory systems to extract information about the magnitude of the stimulus important for?

Answer 8

1. Distinguishing among stimuli that differ only in strength.
2. Evaluating stimulus amplitude.

Question 9

What does the relation between a subjects estimate of the intensity of the stimulus and its strength resemble?

Answer 9

The relation between the discharge frequency of a sensory neurone and the stimulus strength.

Question 10

What is the duration of a sensation determined by?

Answer 10

The adaptation rates of receptors.

Question 11

When do slowly adapting mechanoreceptors respond?

Answer 11

Throughout a continuous stimuli. These receptors also sense how rapidly pressure is applied to the skin.

Question 12

When is the firing rate higher from slowly adapting mechanoreceptors?

Answer 12

At the beginning of skin contact than during steady pressure.

Question 13

When do rapidly adapting mechanoreceptors respond?

Answer 13

Only at the beginning and end of the stimulus, signalling the rate at which the stimulus is being applied or removed.

Question 14

What does slowly applied pressure evoke in rapidly adapting mechanoreceptors?

Answer 14

A long-lasting burst of low frequency firing. Rapid indentation produce a very brief burst of high frequency firing.

Question 15

How many rods are there in the retina?

Answer 15

20 million

Question 16

How many cones are there in the retina?

Answer 16

6 million

Question 17

How is a visual image received at the foveola?

Answer 17

The light passes through layers of nerve cells and their processes.

Then reaches the photoreceptors.

The centre of the fovea, these proximal neurones are shifted to the side so that light has a direct path to the photoreceptors.

Finally, the visual image is received at the fovea, is the least distorted.

Question 18

What is a limitation of the trichromatic theory?

Answer 18

It tells us when colours look alike but not what they look like.

Cannot explain visual phenomenons.

Question 19

Where is the ventral pathway?

Answer 19

Extending to the inferior tempura cortex and is more concerned with form and colour.

Question 20

What does the ventral pathway do?

Answer 20

Visual areas may also be involved in higher cognitive functions such as working memory and visual imagery and anterior regions of the fusiform gyrus contain brain regions that are important in object and word recognition.

Question 21

What does the inferior temporal cortex do? What can damage to this area cause?

Answer 21

1. Cells respond to meaningful objects - object recognition
2. Damage produces visual agnosia
3. Face recognition.

Question 22

What does the middle temporal cortex-medial superior temporal cortex do? What can damage to this area do?

Answer 22

1. Cells in MT repsond to motion / speed - photos implying motion.
2. Cells in MST repsond to contraction / extension / rotation.
3. Damage produces motion blindness.

Question 23

Lesioning method (Uneidergerl&Mishkin 1982): What is object discrimination and what makes this task difficult?

Answer 23

Pick the correct shape / lesion to the temporal lobe makes this task difficult.

Question 24

Lesioning method (Ungerleider&Mishkin 1982): What is landmark discrimination / what makes this task difficult?

Answer 24

Pick the food close to the rod. Lesion to the parietal lobe makes this task difficult.