Sensation and Perception

Question 1

Define sensation

Answer 1

conversion, transduction, or physical, or electromagnetic, auditory and other information from the internal and external environment into signals in the nervous system

Question 2

Define perception

Answer 2

processing of sensory information to make sense of its significance

Question 3

Describe how a sensation is received

Answer 3

sensory neurons are associated with sensory ganglia which are collections of cell bodies outside of the CNS

these stimuli are transmitted to projection areas in the brain which analyze the input

Question 4

Define a threshold and describe the different kinds of threshold

Answer 4

the minimum stimulus that causes a change in signal transduction

absolute threshold- minimum of stimulus energy that is needed to activate a system
threshold of conscious perception- minimum stimulus energy that will create a signal large enough and long enough in duration that it will be brought into awareness
difference threshold- min diff in magnitude between 2 stimuli that will allow someone to perceive the differences

Question 5

Define webers law

Answer 5

the jnd for a stimulus is proportional to the magnitude of a stimulus and this proportion remains constant

Question 6

Describe signal detection theory

Answer 6

effects of non sensory factors such as experiences, motives, and expectations on the perception of stimuli

Question 7

Define sclera

Answer 7

thick structural layer that covers the eye

Question 8

What is the blood supply to the eye?

Answer 8

choroid vessels and the retinal vessels

Question 9

Describe the retina

Answer 9

is the innermost later and contains the photoreceptors including the rods and the cones

cones are used for color vision and rods are used for the sensation of light and dark due to rhodopsin

Question 10

Define the macula

Answer 10

center portion of the retina that contains a high concentration of cones and includes the fovea

Question 11

Describe what happens as you move farther or closer away from/to the fovea?

Answer 11

As you move towards the fovea, the concentration of cones increases and the visual acuity is at its best. The fovea is most sensitive in daylight situations

AS you move away, the concentration of rods increases and the concentration of cones decreases. there is more night vision but less acuity

Question 12

Describe the blind spot that is present in the eye

Answer 12

occurs where the optic nerves leave the eye and there are no photoreceptors

Question 13

Describe the path of light through the eye

Answer 13

passes first through the cornea where the light is gathered and focused then it foes through the anterior chamber, posterior chamber, and through the iris and to the lens which refracts the incoming light, then it goes into the retina to the rods and cones, and to the brain via the optic nerve where it is perceived by the brain

Question 14

What are the various muscles that are involved in vision? Describe it in terms of sympathetic versus parasympathetic

Answer 14

Under sympathetic (fight or flight)
-the dilator pupillae which opens the pupil
Under parasympathetic stimulation
-the constrictor pupillae constricts the pupil and then the ciliary muscle is contracted which changes the shape of lens, which contracts the suspensory ligaments, which changes the shape of the lens, leading to accommodation

Question 15

Describe how the signals from the rods and cones are able to get to the optic nerve? In terms of neurons

Answer 15

They connect to each other with bipolar cells which then synapse with ganglion cells, who cluster together to form the optic nerve

amacrine cells also receive input from retinal cells and pass on info the the ganglion cells (edge detection)

Question 16

Describe the visual pathway in the brain, where do the right and left visual fields go?

Answer 16

the left visual fields go to the right side of the brain and the right goes to the left side of the brain

Question 17

Where do the visual paths travel after going through the optic chiasm?

Answer 17

To the lateral geniculate nucleus in the thalamus, the visual cortex of the occipital lobe, or the superior colliculus

Question 18

Define parallel processing

Answer 18

the ability to simultaneously analyze and combine information regarding color, shape, and motion which can then be compared to our memories

Question 19

How are shapes identified in the visual system?

Answer 19

parvocellular cells which lead to spatial resolution

Question 20

How is motion detected in regards to vision?

Answer 20

magnocellular cells because they have high temporal resolution

Question 21

Describe the inner ear in regards to sensations that can be detected

Answer 21

The cochlea detects sounds

The utricle and saccule detects linear acceleration

and the semicircular canals detect rotational acceleration

Question 22

Describe the auditory pathway

Answer 22

Travels from the cochlea to the vestibular nerve and then foes to the medial geniculate nucleus of the thalamus and then to the auditory cortex of the temporal lobe

Question 23

Define somatosensation

Answer 23

the four touch modalities; pressure, vibration, pain, and temperature

Question 24

Describe bottom up processing

Answer 24

recognition of objects by parallel processing and feature detection; slower but less mistakes

Question 25

Describe top down processing

Answer 25

recognition of an object through memories and expectations, with little attention to detail; it is fast but accident prone

Question 26

Define a Gestalt principle

Answer 26

the ability of the brain to infer missing parts of a picture and fill in the gaps basically

Question 27

What are the 6 “laws” of the Gestalt principle?

Answer 27

1. law of proximity; if they are close together they can be perceived as one unit
2. law of similarity; similar objects are grouped together
3. law of good continuation- elements that tend to follow the same pathway may be grouped together
4. subjective contours- using the env or surroundings to infer the edges of something
5. law of closure-brain completes a line
6. law of pragnanz- perceptual organization will always be as symmetrical as possible