Attention II Banich: Chapter 8

Test 1 Back 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 break Carolyn: first week, as usual second week: Wednesday 4-5 only Carolina: first week, as usual second week: Wednesday 9-10

Attention/Spatial Lectures 1. 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 most neededDirecting processing resources to where they’re most needed Can have attention to: This lecture: Illustrations 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 unilateral neglect or hemineglectDamage can produce unilateral neglect or hemineglect -> 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: lines on left omitted lines on left omitted lines bisected too far to right lines bisected too far to right

Neglect: Measures Drawings show detail but left side ignored Picture Copying

Neglect: Measures Mild cases only impaired when competing stimulus on good side  “Extinction” O+XO+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.Affects all modalities ii.Don't move gaze to compensate iii.Influenced by attentional factors powerful stimulus can draw attention powerful stimulus can draw attention motivational factors important motivational factors important iv.Affects 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 has broader spatial field LHRH Therefore, if RH damaged, attention is restricted to RVF -> 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, and the RH must work hard to maintain its share Therefore, if R. parietal lobe damaged, balance is lost -> 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 most neededDirecting processing resources to where they’re most needed Can have attention to: This lecture: Illustrations 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: