quiz 1 - sensation/perception

Question 1

what nuclei are responsible for coincidence detectors and what is there general function?

Answer 1

superior olivary nuclei (SON)
auditory processing & location

Question 2

how do coincidence detectors

Answer 2

they fire when they receive a simultaneous signal, allows for location coding

Question 3

what are the 3 ways that visual cortical areas can be defined by?

Answer 3

1. retinotopic organization - spatial organization of visual info from the retina
2. cytoarchitecture - functional mapping of microscopic structure
3. visual features - different areas of the visual cortex respnd to different types of visual information

Question 4

what is the parvocellular pathway, how is it structured, and what are its characteristics?

thalamus pathway

Answer 4

• pathway that originates in the retina and extends to the LGN
• top 4 layers of the LGN, small cell bodies
• slow conduction (smaller axon diameter), sensitive to high spatial frequency, sensitive to form & color

Question 5

what is the magnocellular pathway, how is it structured, and what are its characteristics?

Answer 5

• pathway that originates in the retina and extends to the LGN
• bottom 2 layers, large cell bodies
  fast conduction, sensitive to low spatial frequency & motion, detects moving objects & speeds, achromatic, high temporal resolution

Question 6

magnocellular vs parvocellular

Answer 6

parvocellular = color & fine spatial detail, but slow
magno = motion & spatial layout, fast

Question 7

what are the specialized receptors in each sensory modalities

Answer 7

1. visual = photoreceptors (1 rod, 3 cones)
2. gustatory = salty, sweet, bitter, umami, sour
3. auditory = hair cells
4. olfactory = ~400 types
5. somatosensory = markel cells, meissner’s corpuscles, pacinian’s corpuscles, Ruffini’s corpuscles, nociceptors

Question 8

how do visual cortical neurons work

Answer 8

• stimulated by afferent signals from the opposite visual field
• the right neurons show ocular dominance (certain neurons respond stronger to inputs from one eye)

Question 9

where and how does motion perception occur?

Answer 9

• occurs in area MT (V5)
• specialized system that contains neurons that responds to direction
• firing of neurons correlates with speed of motion
• selective to direction & amount of motion

Question 10

what is the McGurk effect

Answer 10

• illusory audiovisual percept, bias of one sense over another
• when an individual is presented with auditory stimulus but visual stimulus shows movement of mouth differently

Question 11

what is synesthsia? why does it occur?

Answer 11

• def: an illusory multimodal percepts, abnormal mixing of sense data
• varies across individuals but consistent within an individual –> potential heritability
• thought to be because of the lack of synaptic pruning during development

Question 12

what are the types of synesthesia with examples

Answer 12

across modalities - ex: chromosthesia
(sounds –> colors)

within modality - ex: grapheme-color (letters/#s –> colors)

Question 13

what is the effect of GABA on sensory & motor cortices

Answer 13

GABA = inhibitory NT
- normal function = slows reaction time & improves motor control + sensory discrimination
- helps maintain precise tuning

Question 14

what happens to the sensory & motor cortices when GABA is blocked?

Answer 14

• inhibitory control is lost, more frequency & less selectively
• receptive fields expand & respond to more = poor sensory discrimination and increased noise

Question 15

what is the flicker fusion test for and how does it work?

Answer 15

• used to test cerebral arousal & visual system parameter
• presents flickering light stimulus & determining the light frequency @ which light appears steady
• separates sensory stimulation from perceptual experiences