Attention II

Banich: Chapter 8

Test 1Back first week after break (in your lab)

Marks will be posted on or before:

Monday April 28 (web, noticeboard)

If you’re here during the break, feel free to

enquire

Office hours during breakCarolyn:

first week, as usual

second week: Wednesday 4-5 only

Carolina:

first week, as usual

second week: Wednesday 9-10

Attention/Spatial Lectures1. Spatial Processing (JL)

• Introduction• Examples of animal and fMRI studies

2. Attention (JL)• Introduction• Examples of animal and fMRI studies

• 3. Spatial Processing (CW) • Re-cap• Some illustrations from patient data

4. Attention (CW) THIS LECTURE• Re-cap• Some illustrations from patient data

What is Attention?

1. Locations in space

2. Individual objects

3. Individual features (e.g. colours)

4. Particular tasks

• Directing processing resources to where they’re Directing processing resources to where they’re most neededmost needed

Can have attention to:Can have attention to:

This lecture:This lecture:Illustrations of 1 and 2 from patient dataIllustrations of 1 and 2 from patient data

1. Attention to Locations

• Directing attention to particular areas in space

• Involves parietal lobeInvolves parietal lobe

• Contralateral organisationContralateral organisation

• Damage can produce Damage can produce unilateral neglectunilateral neglect or or hemineglecthemineglect

-> inability to attend to one side of space-> inability to attend to one side of space

Neglect: Case Description

A few days after suffering a mild stroke, Mrs. K began to realise things were not

quite right. When she had visitors in hospital, she would often lose track of where

they were in the room. She would inquire about someone's absence, only to be told

that the person had not left the room, but was in fact right by her side, sitting to her

left. Also, although Mrs. K normally took great care in her appearance, the nurses

would often tell her that she had forgotten to brush the left side of her hair, or to

apply lipstick on the left of her mouth. And finally, perhaps most troubling, she had

great difficulty navigating through the corridors of the hospital to get to the

bathroom. On one occasion, she was frustrated to find herself back where she

started without reaching her destination.

Neglect: Features

• Affects all sensory modalities (vision, hearing., etc.)

• Occurrence is asymmetric - much more common after RH damage than LH damage

• What side of space would be neglected after RH damage?

Neglect: Measures

Line bisection task:Line bisection task:

• lines on left omittedlines on left omitted

• lines bisected too far to rightlines bisected too far to right

Neglect: Measures

• Drawings show detail but left side ignored

Picture CopyingPicture Copying

Neglect: Measures

Mild cases only impaired when competing stimulus on good side

““Extinction”Extinction”

O + X

Questions about Neglect

1. How can we be sure its not just a perceptual problem?

2. Is it just a problem orienting (e.g. moving eyes to left)?

3. Why is left hemineglect more common than right?

1. How can we be sure its not just a perceptual problem?

i.i. Affects all modalitiesAffects all modalities

ii.ii. Don't move gaze to compensateDon't move gaze to compensate

iii.iii. Influenced by attentional factorsInfluenced by attentional factors• powerful stimulus can draw attentionpowerful stimulus can draw attention• motivational factors importantmotivational factors important

iv.iv. Affects internal imageryAffects internal imagery

1. How can we be sure its not just a perceptual problem?

Internal Imagery: Bisiach’s Milan Square Study

2. Is it just a problem orienting (e.g. moving eyes to left)?

• Occurs even when no eye movts required:

3. Why is left hemineglect more common than right?

• RH processes entire visual space

• LH has limited skills restricted to RVF

De Renzi: Because RH De Renzi: Because RH has broader spatial fieldhas broader spatial field

LHLHRHRH

Therefore, if RH damaged, attention is restricted to RVFTherefore, if RH damaged, attention is restricted to RVF-> -> BUT if LH damaged, RH can still "take over"BUT if LH damaged, RH can still "take over"

3. Why is left hemineglect more common than right?

– LH draws attention rightward

– RH draws attention leftward

– LH is dominant (in right-handers)

– R. parietal lobe must work hard to keep balance

Kinsbourne: Because hemispheres compete for attention, Kinsbourne: Because hemispheres compete for attention,

and the RH must work hard to maintain its shareand the RH must work hard to maintain its share

Therefore, if R. parietal lobe damaged, balance is lostTherefore, if R. parietal lobe damaged, balance is lost-> BUT if L. parietal lobe damaged, LH still dominant-> BUT if L. parietal lobe damaged, LH still dominant

What is Attention?

1. Locations in space

2. Individual objects

3. Individual features (e.g. colours)

4. Particular tasks (e.g. counting)

• Directing processing resources to where they’re Directing processing resources to where they’re most neededmost needed

Can have attention to:Can have attention to:

This lecture:This lecture:Illustrations of 1 and 2 from patient dataIllustrations of 1 and 2 from patient data

Attention to Individual Objects

Simultanagnosia:

• can identify objects BUT can't deal with more than one object!

• Usually bilateral damage

Regions on occipito-parietal border

Simultanagnosia

• Illustration:

Simultanagnosia

The patient described the elements in the drawing one after the

other, first mentioning the helmet, then the handlebars, then the

telegram, and finally the car. Only after quite a bit of time did she

infer that the girl was waving to flag down the car, but she never

really understood why because she never noticed that the front tyre

was disconnected from the bicycle. She could never "see" the whole

picture but could comprehend only parts at a time.

"One object in the world comes into focus while all the others fade"

Attention

• Demonstrates importance of left-right axis in attention

• Supports findings from cognitive psychology for different attentional systems

Patient data:Patient data: