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TEMPLE / Psychology / PSY 2502 / What are the mental imagery tasks?

What are the mental imagery tasks?

What are the mental imagery tasks?

Description

School: Temple University
Department: Psychology
Course: Foundations of Cognitive Neuroscience
Professor: David waxler
Term: Spring 2017
Tags: Cognitive Psychology, cognitiveneuroscience, attention, Object, and Recognition
Cost: 25
Name: Overview of Notes
Description: Notes that cover mostly everything for the third test.
Uploaded: 04/02/2017
9 Pages 55 Views 9 Unlocks
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Cognitive neuroscience Exam 3 Study Guide  


What is the mental imagery tasks?



Major Areas covered:

- End of Sensory and perception/Visual System  

- Object Recognition  

- Attention  

- Disorders of Attention  

**End of Sensory and Perception/Visual System 

∙ Info begins to be sensed at the eye but we SEE with the Brain  ∙ Center surround receptive fields  

o Ganglion and Lateral geniculate nucleus cells  

o Makes our vision more sensitive to borders and edges  

∙ Primary Visual Cortex:

o Ocular dominance columns: way of segmenting and organizing  information based on which eye the info came from  

 Patient with vision in one eye will be “tiger striped”


What is the unilateral spatial neglect?



o Plasticity (adaptation or change over time) 

 Monkey experiments unequal cortex development if one eye  isn’t functional

o Simple cells in V1 

 Activation is dependent of the Orientation of light, have  

preferences based on this  

 Multiple organizational systems layered together: organized by: ∙ Left/right eye

∙ Orientation preference  

∙ General retinotopic mapping  

o Blobs (cones)/interblob (Rods)

∙ Know serial vs. Parallel processing in the Visual system  Don't forget about the age old question of What is the erection of the penis?

 ∙      Areas of the Visual Cortex: 

o V4: blobs, perceive color and shape  


What is the balint’s syndrome?



 Ventral stream

 Achromotopsia: full color blindness  

o MTV5: Motion and movement processing  

 Dorsal Stream

 Akinetopsia : Inability to perceive motion  

o Receptive fields get bigger the farther down in processing, complexity  increases as well  

∙ Subcortical Visual Processing  

o Midbrain (reflexive vision): some light goes to the superior colliculus   Blind sight:

∙ Functionally blind people do not need the cortex for visual

orientating, they still have reflexive sight  

o Cortical vs. Subcortical visual processing: Gerbil experiment

 Found double dissociation between discrimination task and  

Orientation task after making lesions to the Cortex and  

midbrain.  

∙ Reflexive vision is in the superior colliculus  

**Object Recognition

∙ Remember: processing is parallel in the visual system and earlier on, this  processing is more basic  Don't forget about the age old question of What are the causes of the russian revolution?

∙ Dorsal (Where/how) and ventral (What) stream

o V4: shapes and colors  

o MTV5: Motion  

∙ What/where pathways  

o Dissociation studies between temporal lobe and parietal lobe lesions   Monkeys could do an object discrimination task with a parietal  lobe lesion but not a temporal lobe lesion  

 They could do a localization task with temporal lobe lesion but  not with a parietal lobe lesion  

 o EEG evidence: 

 Ventral stream cells show strong object selectivity/ this is not  found in dorsal stream  

 o PET evidence: 

 Picture matching study: patient D.F. (visual agnosia)

∙ Explicit matching task (match the card orientation)

o WHAT task : cannot be done with visual agnosia

∙ Action task (Actually put the card into the slot)  

o WHERE task : cannot be done with Visual ataxia

∙ Object Constancy:  

o We can recognize as object no matter what orientation it is in; we will  perceive it as the circumstances changing, not the object itself  

o 2 theories of how it works:

  View dependent frame of reference  

∙ Recognition depends on a multitude of stored images we  Don't forget about the age old question of What is atrial fibrillation?

have of an object

∙ Problem: requires a lot of images, places heavy burden  

on perceptual memory  

  View invariant frame of reference  

∙ Recognition comes from being able to break an object  

down into its key features, in this case the view is  

irrelevant if we can make out enough details of an object  

 o Ventral stream neurons show object constancy: 

 Single unit recording evidence show that neurons in ventral  

stream will react to one single object such as a hand no matter  how it is orientated  

 o Hierarchical coding process  

 Simpler features such as edges are combined to create objects  that can be recognized by gnostic units or cells that are  

specialized to recognize one thing

  Grandmother cells: one cell is activated for every object  ∙    Problems: what about new objects, this could be an  

oversimplification

  Ensemble encoding: 

∙    Objects are defined by simultaneous activation of a set  

of defining properties  

o Your grandmother is not recognized by a hierarchy

leading to one cell, but rather a combination of  If you want to learn more check out What is the desire for immediate gratification?

multiple cells activating based on certain features  

such as hair, wrinkles, mouth, face shape etc.  

∙    Failures of Object recognition

o Visual agnosia:  

  Appercpetive:  

∙    Damage early in processing, unable to discriminate  

between objects, cannot copy a drawing they see of an  

object  

  Associative  

∙    Damage later in processing, can discriminate between  

objects and copy drawings  

  Two areas affected:  

∙    Visual object recognition  

∙    Semantic Knowledge  

o In associative agnosia both areas are fine but it is  

the CONNECTION between the two that is  

damaged  

  Integrative Visual agnosia: 

∙    Can perceive parts of an object but have difficulties  

perceiving the object as a whole  We also discuss several other topics like What are the main determinants of biological form?

o Drew picture of 3 shapes as one big shape  

  Category specific agnosias  

∙    Not dependent on general inability to recognize objects,  just specific types of objects  

o Animate (moving, dorsal)

o Inanimate (object constancy, Ventral)

 In matching task patients can identity an  

inanimate object but not when the object  

changes view  

∙    More often there are problems perceiving animate  

objects  

 ∙     Theories why: 

o It is harder to discriminate animals than inanimate

objects  

 o Sensory motor hypothesis for category  Don't forget about the age old question of What is the size of africa?

specific agnosias  

 Animate things: one area responsible for  

recognizing them: visual area

 Inanimate: have both the visual areas and  

the sensorimotor areas of the brain  

o This explains the variety of inanimate agnosias  

∙    Prosopagnosia: Face blindness

o STS neurons are selective for faces – maybe it  

plays a role?

o FFA: fusiform face area (ventral stream)

 Difficulty theory  

∙    Faces are just a special kind of object  

that are difficult to recognize, FFA is  

just advanced processing area  

 Sheep experiment supports that there is a  

special face area though  

Attention:

∙ Arousal : Global states --- sleep/wake

∙ Selective attention:

o Just because we are awake does not mean we are attending to  everything  

 Gorilla study shows inattentional blindness

∙ Sometimes do not notice things right in front of us

o Properties of selective Attention:

 Prioritize info for processing while ignoring others  

∙ Can be reflexive (bottom up) or voluntary (conceptual, top

down)

∙ Covert vs. Overt: not obvious vs. obvious attn.  

o Studying Covert spatial attention:

 The spotlight metaphor : visual spatial  

attention  

∙ idea that we can move the spotlight of

our attention independent of eye  

movement  

∙ Herman von Helmholtz did experiment

 Spatial cueing paradigm: participants  

demonstrate covert attention  

 Experiment had valid and invalid cued in  

which the participant was either guided to  

the target or their attention was mislead  

 Found that there were COSTS and BENEFITS  

to paying attention  

∙ Slower if you are paying attention  

elsewhere  

∙ Faster if you were paying attention to  

the target

  Selective Auditory Attention:

∙ Cocktail party effect: being able to focus on one  

conversation in a room full of people  

∙ Intrusion: something highly salient is said that has  

personal relevance and draws your attention  

o This is an example of reflexive attention

∙ Dichotic Listening task:  

o Listen to two different things in each ear but told to

pay attention to one ear  

o Participant will only remember what they attended  

to  

o Early vs. Late selection Debate:

 Where is info selected for and filtered out when we perceive  stimuli?

∙ RegistrationPerceptual analysis semantic encoding   The purpose of selective attention is to discern what is important and what is not, BUT when does this happen?  

  Descending Auditory Pathway may modulate very early  auditory processing: 

∙ Potential for VERY early processing  

∙ Axons lead to cochlea, which contributes to an active  choice in what we choose to focus our auditory attention  on by sending signals down to the hair cells (different  

than visual system)

 ∙      Otoacoustic emissions and attention: 

o We start filtering out information that we want to  

pay attention to very early on  

o Deciding to pay attention gives some information  

priority  

 ∙      ERP evidence in the Dichotic listening task: 

o Figures out the timing of the listening task  

o N1 response (1st negative deflection) occurs early  

on  

o This supports Early selection  

 ∙      MEG evidence  

o Primary Auditory cortex is area associated with  

early processing  

o MEG showed activation---- further support for early  

selection  

  Selective Attention in the Visual system: 

 ∙      ERP in Spatial attention task: 

o Experiment was able to compare brain activity  

while people were attending to a target and while  

they were not  

o Found a positive deflection (P1 response) that is  

larger if the stimulation in the experiment occurred  

where the person was paying attention

 It was not the visual field that was changing,  just how the participant was attending to the

stimulus  

 Suggests paying attention changes how we  perceive a stimulus  

o Because the visual system is more complex than  the auditory system it took longer for the P1  

response than the N1 response (70 ms)  

o But this still supports early processing, that visual  processing is affected by attention and that it  

happens early on in the visual cortex  

∙     Spatial Attention Effects in the LGN and the Cortex  o If a participant is asked to look forward they can  covertly attend to the left  

∙     right visual areas are activated more,  

and will process the information,  

suggesting that attention affects  

visual processing  

∙     If this were not the case we would  

expect to see equal activity in left and  

right visual areas but it seems that  

Attending to one side activates it more 

o Evidence for the Thalamus:

 If processing started in the visual cortex we  should see equal activation in the thalamus,  

but we do not  

 The eyes will process things no matter what  you attend to  

 The thalamus will not  

 Question: does processing occur twice  at the thalamus and visual cortex? Or  

once at the thalamus?

∙     Bouncer and VIP room metaphor  

 ∙      Thalamus: bouncer

 ∙      Visual cortex: VIP room  

o This metaphor supports the idea

that processing occurs in 2  

places  

o But it could just be done at the  

thalamus then sent to the visual

cortex  

∙     Bestmann study:

o designed a study to test if  

attentional selection can bypass

the thalamus and go straight to  

the Visual cortex

 used to TMS to isolate  

visual cortex response  

 Measured costs/benefits  

based on how high they  

had to set the TMS (High:

not paying attention,  

LOW: paying attention)

o Study concluded that attention  

modulates visual processing  

even if it bypasses the thalamus

o Support for late selection:

 Intrusion: sometimes we are able to comprehend semantic late processing in others people’s conversations that we are not  

attending to --- this should not happen if we processed  

information early  

  Band width model: 

∙     Idea that we never truly devote 100 percent of our  

attention to something  

∙     It may not be all or nothing (70/30, 90/10)

∙     This makes the idea of intrusions and salient info breaking

through our attentional barriers more plausible  

**Disorders of Attention

∙ Balint’s syndrome: characterized by 3 different disorders  

o Optic Ataxia : difficulty using vision to interact with objects; dorsal  stream damage  

 Cannot grab a cup in front of them  

o Oculomoror ataxia : difficulty moving eyes  

o Simultanagnosia : Difficulty in seeing more than one part of a scene  at once  

 The KEY symptom of Balint’s  

∙ Unilateral Spatial neglect:  

o Half of their world disappears (most often the Left side/ right  hemisphere damage)  

o WHY: Theory is because the right can attend to both left and right,  when it is damaged neglect can occur

 Copying task

∙ Copy a picture ---- will only draw the right side of it but not

realize it unless someone points it out to them  

  Mental imagery tasks  

∙ Asked to recall an image from memory  

∙ Find that the memory is intact but, even in the mind’s eye

the neglect of the left side is still there (cathedral in Milan  

example)

o 2 types of neglect  

 Extra personal: only attending to the right side of the visual  field

 Object centered: sees only the right side of every individual  object f

∙ Often people present with both  

  Line cancelation task 

∙ Patient is instructed to bisect the horizontal lines  

∙ Evidence of both types of neglect is present  

 o Extinction and neglect: 

 Extinction is a symptom of a milder form of neglect --- NOT a  separate disorder  

 Patient can perceive objects in the Left and Right spatial areas   But only if they are tested individually

 If both stimuli are presented at the same time (competition) the  right side will win out and whatever the person would have seen  in the left area will become “extinct” it will no longer be  

noticed/attended to  

 ∙      Reflexive cueing task 

o Same as spatial attention cueing task except it testing reflexive  attention  

o They do this by making the cues meaningless --- the participant never  associates that the cue will tell them where the target is  

 Uses exogenous cueing instead of endogenous cues  

∙ External responses instead of internal conscious decision  

making  

o Question: will you see Cost and benefits? (same as voluntary cueing)  Yes--- if there is only a brief period between the cue and target   NO--- if there is a 300 ms period between the cue and target   ∙      Inhibition of Return: 

o Reflexive attention is hesitant to return to an area it

has already seen there was nothing  

o Because of this it is harder for us to return our  

attention to a target after we have been misled  

o Longer time between cue and trial produced a  

slower response time  

 Suggests that voluntary and reflexive attention are two different  systems

 ∙      Object Based attention; 

o Wanted to test response time for switching BETWEEN objects and  WITHIN objects  

 Showed that it took longer for us to switch attention between 2 objects than it did for us to switch our attention to another part  of something we perceive as still a part of the same object

 ∙      Visual Search  

o Pop out search;  

 Time is the same to find the object no matter how big the set is   Completely different system than conjunction searches ---- “Pre attentional” 

o Conjunction search

 Time goes up the bigger the set is  

 More than one feature to look for  

∙ Tells us:

o Our attentional spotlight looks for one thing at a  

time which is important for looking for specific  

details  

 ∙      Sources of Attention 

o Dorsal Attention network  

 Goal directed attention  

 Frontal Eye fields

 Bilateral  

o Ventral Attention Network

 Ability to disengage and reorient attention

 Involves;

∙ Temporoparietal junction TPJ

∙ Ventral frontal Cortex  

o Common areas damaged in neglect  

 Lateralized to the RIGHT

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