L14- interaction btw perception and action

Question 1

re-excitation AKA reactivation

Answer 1

encoding required = first excitation

retrieval required second excitation.

Question 2

reactivation -

- give cue

Answer 2

auditory recalls better with sound cue than visual
fusiform face area recalls better with pic than with sound.
- more recall - area of brain relating to that mode of perception needed.

Question 3

common area for encoding and retrieval

Answer 3

though hippocampus - but maybe not.

seems as tho perceptual areas invovled with encoding and retrieval

Question 4

nyberg - explicit memory of actions

Answer 4

motor cortex reactivated when recalling memory/action.

Question 5

geng - saccades to remember location

Answer 5

fixate, target in spot. when disappears move eyes to it.

- reactive retinotopic visual cortex.

Question 6

skinner -FFA

Answer 6

FFA reactivation during recall of faces

Question 7

patient DF - what happened?
- cortical damage?
symptoms?

Answer 7

hypoxia from CO poisoning

• large lesions in ventrolateral occipital region, sparing v1.
• lesions: r/l lateral occipital cortex = LOC, ventral. left anterior parietal lobe.

visual form agnosia = problem recognizing object form. missing wholistic form.can draw from memory. orientations of hand - vision for action is intact.

Question 8

optic ataxia patient RV

Answer 8

• dorsal stream, posterior parietal lesion.
  poor visual motor transformation. good at perception of target & object.

– better at copying, but motor planning absent. cant estimate finger grasp.

Question 9

RV vs DF

• ID objects as same/diff
• interact w object

Answer 9

• RV&raquo_space; DF for naming.

- DF&raquo_space;> RV for gripping. RV does random, incorrect.

Question 10

perception ? Action?

• vvisual form agnosia
• optic ataxia

Answer 10

vfa; no perception, yes action = ventral damage

oa: yes perception, no action = dorsal stream

Question 11

ventral stream damage

Answer 11

visual form agnosia

Question 12

dorsal damage

Answer 12

optic ataxia

Question 13

effects on delay on grip scaling

Answer 13

actions that require memory.
- need to use memory to remember object. slow arm movement, open hand wide, earlier. but still difference in grip between two object.

Question 14

area used for object grasping?

Answer 14

AIP =dorsal.

Question 15

area used for recognition

Answer 15

LOC = ventral

Question 16

brain areas - activity for grasping/reaching and intact/scrambled

Answer 16

AIP - more active for grasping than reaching.
AIP - no difference in perception of intact vs scrambled.

LOC - same activtiy for reaching/grasping.
LOC - more activtiy for recognizing intact object than scrambled.

Question 17

DF - delayed grasping

Answer 17

• immediately - quite accurate at grasping

- delay, can no longer grasp properly because image not on retina. - memory system needs to be activated.

Question 18

DF doesnt have LOC, cant remember - so does LOC store info?

AIP store info? brain activity during action task

Answer 18

• see image, delay in dark, reach in dark.
  see image = brain peaks
  delay - moderately active brain. peaks again when touch.

Question 19

grasping/reaching in fMRI

Answer 19

audio - told action. 18 sec delay. told - go/ignore. 18 sec

Question 20

why 18 sec delay?

Answer 20

because of slow hemodynamic delay of BOLD signal

Question 21

2 tasks done to ID 2 areas of interest

Answer 21

1. grabbing vs reaching
2. object vs scrambled
   - frontal area & more posterior to visualize LOC

Question 22

Left and right AIP showed what?

Answer 22

more grasp than reach response.
activation stays high during delay - same level during delay for both conditions.
more selectivity/activtiy for grasping than reaching.

Question 23

left LOC - what is shown?

Answer 23

no activation over delay

- but can “see” thing in the dark. brain is coding for that spot in visual space even during the dark.

Question 24

conjunction test in brain areas activated for both tasks

Answer 24

• doesnt care about memory delay. cares about what task - more activation for richer object recognition.

Question 25

calcarine sulcus

- retinotopic mapping in the dark

Answer 25

v1 shows activation. greater for grasp than reach.
shows visual system can act in dark. not seeing, but trying to remember the space, activates it. proof that sensory areas are responsible for encoding and retrievall
- all objects reached for in lower vf, reactivation in upper vf = consistent. but, reactivation has that spatial info encoded.

Question 26

vision phase grasping vs reaching

Answer 26

dorsal premotor area - similar to what’s in AIP.

there is memory maintenance in dPMa but no preference for reach/grasp

Question 27

SMA - vision, action, delay.

Answer 27

preSMA = largest visual response
ant - midpoint
post SMA = smallest visual response

Question 28

summary

Answer 28

LOC EarlyVisualC actviated during VS and reactivated in darkn
- reactivation may reflect retrieval of object features from memory
- areas involved in recognition & vision re-recruited to provide info to dorsal stream. = may reflect mental imagery and hand needed for action. consistent w DF. LOC reactivation for delayed grasping.
EVC show crude retinotopic reactivation
delay activity observed in dorsal stram: AIP, SMA, dorsalPM, M1.
more grasping than reacing = more detailed features required for grasping.