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1. ATTENTION
‫در‬ ‫شده‬ ‫ارائه‬
‫تخصصی‬ ‫کارگاه‬
‫توجه‬ ‫توانبخشی‬
‫شناختی‬ ‫های‬ ‫هفته‬ ‫آخر‬ ‫های‬ ‫کارگاه‬ ‫سری‬ ‫از‬
‫تابستان‬1396
‫تنظیم‬ ‫و‬ ‫تهیه‬:
‫مهدی‬ ‫دکتر‬
‫علیزاده‬

2. ATTENTION
WILLIAM JAMES (1907)
“EVERYONE KNOWS WHAT ATTENTION IS. IT IS
THE TAKING POSSESSION BY THE MIND IN CLEAR
AND VIVID FORM OF ONE OUT OF WHAT SEEM
SEVERAL SIMULTANEOUS OBJECTS OR TRAINS OF
THOUGHT”.

3. ATTENTION REQUIRED!
• SEARCH FOR A BLUE THING.
• FEEL THE SEAT AGAINST YOUR BACK.
• LISTEN TO EXTRANEOUS NOISE
• PREPARE TO TAP THE DESK NEXT TIME YOU HEAR A
COUGH.
• ALL REQUIRE “ATTENTION” TO DIFFERENT INTERNAL OR
ENVIRONMENTAL INFORMATION AND “SETTING UP”.

4. OUTLINE
• WHAT IS ATTENTION?
• NEUROANATOMICAL STRUCTURES OF ATTENTION
• MODELS OF ATTENTION: POSNER & PETERSEN
• ORIENTING
• APPLICATION: NEGLECT
• ALERTING
• APPLICATION: NEGLECT
• EXECUTIVE
• APPLICATION: NEGLECT
• ATTENTIONAL IMPAIRMENTS

5. “ATTENTION CAN BE
LIKENED TO A
SPOTLIGHT THAT
ENHANCES THE
EFFICIENCY OF THE
DETECTION OF EVENTS
WITHIN ITS BEAM”
POSNER ET AL (1980).

6. UNDERSTANDING ATTENTION
• ATTENTION IS REQUIRED TO LIMIT ENTRY TO A FINITE
CAPACITY PROCESSING SYSTEM BY SELECTING ONLY A SUBSET
OF ALL AVAILABLE INFORMATION.
• ATTENTION ITSELF IS A RESOURCE OF LIMITED CAPACITY
WHICH CAN BE DIVIDED BETWEEN TASKS.
• ATTENTION IS RESPONSIBLE FOR VIGILANCE OVER TIME
• PROCESSING AND ATTENTIONAL CAPACITY IS LINKED TO
AROUSAL AND ALERTNESS.

7. ATTENTIONAL NETWORKS
(MESULAM, 1990)
• ATTENTION IS NOT A PROPERTY OF A SINGLE CELL NOR
THE COLLECTIVE FUNCTION OF THE WHOLE BRAIN

8. RETICULAR ACTIVATING SYSTEM

9. SUPERIOR COLLICULUS

10. THALAMUS

11. PARIETAL LOBE

12. ANTERIOR CINGULATE CORTEX

13. FRONTAL LOBES

14. MODELS OF ATTENTION:
POSNER & PETERSEN (1990)
• ATTENTION SYSTEM ANATOMICALLY SEPARATE
• ATTENTION CARRIED OUT BY A NETWORK OF ANATOMICAL
AREAS
• AREAS INVOLVED CARRY OUT DIFFERENT FUNCTIONS THAT
CAN BE SPECIFIED IN COGNITIVE TERMS

15. POSNER & PETERSEN’S MODEL OF
ATTENTION
• ORIENTING:
• DIRECTED ATTENTION
• DISENGAGE AND SHIFT ATTENTION
• ALERTNESS: (SUSTAINED ATTENTION/ AROUSAL/
VIGILANCE)
• MAINTAINING FOCUS OVER A PERIOD OF TIME
• EXECUTIVE: TARGET DETECTION; SUPERVISORY
CONTROL

16. ANATOMY
• ORIENTING:
• POSTERIOR ATTENTIONAL SYSTEM
• ALERTNESS: (SUSTAINED ATTENTION/
AROUSAL/ VIGILANCE)
• RIGHT LATERALIZED, FRONTAL-PARIETAL-THALAMIC
NETWORK
• EXECUTIVE:
• ANTERIOR ATTENTIONAL SYSTEM

17. ORIENTING: POSTERIOR
ATTENTION SYSTEM
• ORIENTING
• VISUAL LOCATIONS
• OVERT
• COVERT
• THREE COGNITIVE OPERATIONS OF ORIENTING
• DISENGAGING
• SHIFTING
• RE-ENGAGING/READING

18. POSNER’S CUED ATTENTIONAL
TASK

19. ANATOMY OF POSTERIOR
ATTENTION SYSTEM
• DISENGAGING  POSTERIOR PARIETAL LOBE
• SHIFTING  SUPERIOR COLLICULUS
• RE-ENGAGING/READING  LATERAL PULVINAR NUCLEUS
OF THE POSTEREOLATERAL THALAMUS

21. LESION EFFECTS
• DAMAGE TO POSTERIOR PARIETAL
• INABILITY TO DISENGAGE FROM ATTENTIONAL FOCUS TO A
TARGET LOCATED IN A DIRECTION CONTRALATERAL TO
LESION SITE
• NEGLECT/BEHAVIOURAL INATTENTION
• DAMAGE TO SUPERIOR COLLICULUS
• INABILITY TO SHIFT ATTENTION REGARDLESS OF WHETHER
ATTENTION IS DIRECTED ELSEWHERE INITIALLY
• SUPRANUCLEAR PALSY
• DAMAGE TO PULVINAR
• SLOWED RESPONSE TO A VALID OR INVALID CUED TARGET
ON SIDE CONTRALATERAL TO LESION
• LABERGE & BUCHSBAUM (1990)

22. PULVINAR & GATING FUNCTION
Right Visual Field Left Visual Field
LaBerge & Buchsbaum (1990)
N O Q W
M R A S
O

23. HEMI-NEGLECT
• ASSOCIATED WITH RIGHT POSTERIOR PARIETAL LESIONS.
• PATIENTS TESTED ON POSNER’S ORIENTING TASKS HAVE
DIFFICULTY ORIENTING ATTENTION TO THE NEGLECTED
SIDE.
• DEFICIT IN ATTENTIONAL PROCESSING

24. Movie: Neglect

30. HEMI-NEGLECT
• PROBLEM IN UNILATERAL VISUAL NEGLECT IS IN
DISENGAGING FROM NON-NEGLECTED SIDE TO SHIFT TO
NEGLECTED SIDE?

31. SIMULTANAGNOSIA AND VISUAL
EXTINCTION
• OFTEN EXHIBITED BY INDIVIDUALS WITH VISUAL NEGLECT.
• SIMULTANAGNOSIA, CHARACTERISED BY INABILITY TO “SEE”
MORE THAN ONE OBJECT CONCURRENTLY.

32. NEGLECT OF OTHER “SPACES”
• REPRESENTATIONAL SPACE (BISIACH AND LUZZATTI(1978).
• SENSORY SPACE (BISIACH 1988).
• OBJECT CENTRED SPACE.( E.G. DRIVER AND HALLIGAN
1991).
• PERSONAL SPACE
• SUGGESTS A VERY COMPLEX VARIETY OF “SPATIAL”
SYSTEMS WITHIN WHICH ATTENTION CAN OPERATE.

33. SPATIAL VS. OBJECT BASED
ATTENTION
• MOST OF THE EVIDENCE FOR THE POSTERIOR
ATTENTIONAL SYSTEM DERIVED FROM SPATIAL TASKS
• SPACE-BASED THEORIES
• WHAT ABOUT OBJECTS? CAN ATTENTION BE OBJECT-
BASED?
• IS THE SAME POSTERIOR PARIETAL ATTENTIONAL NETWORK
ENGAGED IN OBJECT-BASED BOTTOM-UP ATTENTIONAL
TASKS?

34. OBJECT-BASED ATTENTIONAL
PROCESSING
• OVERLAPPING FACES AND HOUSES (ALL IN SAME
LOCATION), ONE STIMULUS MOVING
• ATTEND TO: FACES, HOUSE, OR DIRECTION OF MOTION
• ACTIVITY GREATER WHEN ATTENDING TO PREFERRED
STIMULUS (EG. FUSIFORM FACE AREA GREATER DURING
FACES)--OBJECT-BASED ATTENTIONAL MODULATION
SINCE ALL STIMULI IN SAME LOCATION.
O’CRAVEN ET AL. (1999)

35. POSNER & PETERSEN’S MODEL OF
ATTENTION
• ORIENTING:
• DIRECTED ATTENTION
• DISENGAGE AND SHIFT ATTENTION
• ALERTNESS: (SUSTAINED ATTENTION/ AROUSAL/
VIGILANCE)
• MAINTAINING FOCUS OVER A PERIOD OF TIME
• EXECUTIVE: TARGET DETECTION; SUPERVISORY
CONTROL

36. ALERTING: VIGILANCE &
SUSTAINED ATTENTION
• VIGILANCE REQUIRES CONSTANT MONITORING FOR SIGNAL
OCCURRENCE.
• SUSTAINED ATTENTION IS REQUIRED ONCE SELECTION HAS
OCCURRED AND FURTHER PROCESSING IS NECESSARY TO
COMPLETE TASK.
• BOTH INVOLVE GOAL MAINTENANCE OVER TIME. (MORE AN
ISSUE OF EXECUTIVE CONTROL.)
• RELATED TO AROUSAL LEVELS.

37. Neuroanatomy of
Sustained Attention
•Evidence from lesion
& neuroimaging
studies (i.e. Sturm et al., 1999)
•R-lateralized network
•DLPFC, posterior
parietal cortex,
subcortical (thalamic)
RDLPFC
PPC
MD Thalamus

38. IMPAIRED SUSTAINED ATTENTION
•SUSTAINED ATTENTION IS
SUSTAINED CONTROL
•PATHOLOGICAL “TIME ON TASK”
EFFECTS

39. ROLE OF SUSTAINED ATTENTION
• ROBERTSON AND MANLY (1999) SUGGEST
UNILATERAL NEGLECT ASSOCIATED WITH
NON-LATERALISED ATTENTIONAL DEFICITS.
• RIGHT HEMISPHERE (PARTICULARLY
DORSOLATERAL PREFRONTAL) IS MORE
IMPORTANT FOR SUSTAINING ATTENTION
THAN SHIFTING IT.
• CONTRIBUTIONS TO NEGLECT, EXTINCTION
AND SIMULTANAGNOSIA MAY RESULT FROM
A MORE GENERAL EFFECT OF REDUCED
AROUSAL, IMPAIRED SPATIAL ATTENTION
AND REDUCED ATTENTIONAL CAPACITY.

40. POSNER & PETERSEN’S MODEL OF
ATTENTION
• ORIENTING:
• DIRECTED ATTENTION
• DISENGAGE AND SHIFT ATTENTION
• ALERTNESS: (SUSTAINED ATTENTION/ AROUSAL/
VIGILANCE)
• MAINTAINING FOCUS OVER A PERIOD OF TIME
• EXECUTIVE: TARGET DETECTION; SUPERVISORY
CONTROL

41. ANTERIOR ATTENTIONAL SYSTEM
• EXECUTIVE CONTROL OF DIRECTED ATTENTION
• TOP-DOWN PROCESSING
• OVERT, INTENTIONALLY CONTROLLED ORIENTING SYSTEM
• INVOLVES FRONTAL AREAS
• E.G. DIVIDED ATTENTION
• ALLOCATION OF ATTENTIONAL RESOURCES

42. ANTERIOR ATTENTIONAL SYSTEM
• EXECUTIVE CONTROL OF DIRECTED ATTENTION: INVOLVED
IN BOTH SELECTIVE AND SUSTAINED ATTENTION
• TOP-DOWN PROCESSING
• COMPONENTS OF THE ANTERIOR
ATTENTIONAL/SUPERVISORY SYSTEM:
• CONCENTRATION OF ATTENTION
• SHARING ATTENTION (DIVIDED ATTENTION)
• SUPPRESSING ATTENTION
• SHIFTING ATTENTION
• PREPARATORY ATTENTION
• SETTING ATTENTION
• SUSTAINING ATTENTION
(STUSS ET AL., 1995)

43. Major Neuro-
anatomical
Structures:
Frontal lobes
&
Anterior
Cingulate

44. ANOTHER MODEL: DISTRIBUTED
NETWORK
Reticular
System
AC
Parietal Frontal
Thalamus
(Mesulam, 1985)
Sensory Representation:
Directed Attention
Executive Control of
Attentional Direction
Motivational
Representation
Arousal

45. Impairments of Attention
Cerebral Vascular Accident (stroke) - diverse
impairments, dependent on site, hemi-neglect
Alzheimers- impairments in control over focused
and divided attention, progressive
Brain Injury - slowness of information processing,
in some individuals impaired control as well. Some
recovery in slowness.

46. Complaints of subjects two years after
severe brain injury, in percentages:
- forgetfulness 54
- mental slowness 33
- poor concentration 33
- mental fatigue 30
- unable to do 2 things 21
- intolerance of bustle 19

47. Leclercq and Azouvi (2002):
“Impairments in control processes may be
demonstrated, apart from slowed processing,
- in more complex situations
- under time pressure
- under high working memory load
- in the more severely injured patients”.

48. Ponsford and Kinsella (1991),
Attentional Rating Scale 0 - 4
mental slowness 2.78
inability 2 things 2.44
easily distracted 2.14

49. ATTENTION DEFICIT AND
HYPERACTIVITY DISORDER
• SYMPTOMS: DISTRACTIBILITY, IMPULSIVITY AND
OVERACTIVITY
• POOR AT CONTINUOUS PERFORMANCE TASKS
• PROBLEMS WITH SUSTAINED ATTENTION AND SHIFTING
ATTENTION (BREWER ET AL., 2001)
• POORER PERFORMANCE ON SUSTAINED ATTENTION
RELATED TO SMALLER VOLUME OF WHITE MATTER IN
RIGHT HEMISPHERE (SIMRUD-CLIKEMAN ET AL.,
2000)

50. CONCLUSIONS
• “….ATTENTIONAL COMPUTATIONS ARE CARRIED OUT BY A
COMPLEX BUT SPECIFIABLE ANATOMICAL NETWORK AND ...
EACH AREA OF THE NETWORK HAS ITS OWN
COMPUTATIONS.
FARAH AND RATCLIFF (1998).
• ..ATTENTION ... A WIDELY DISTRIBUTED STATE IN WHICH
SEVERAL BRAIN SYSTEMS WORK ON THE DIFFERENT
PROPERTIES AND ACTION IMPLICATIONS OF THE SAME
SELECTED OBJECT.”
DUNCAN (1999).

51. CONCLUSIONS
• A MAJOR CHALLENGE FOR THE FUTURE IS TO DETERMINE
HOW THESE MULTIPLE ATTENTIONAL MECHANISMS
OPERATE IN A COORDINATED MANNER TO MAINTAIN
UNITY OF BEHAVIOUR. (POSNER AND PETERSEN 1990).

52. ‫تخصصی‬ ‫کارگاه‬
‫توجه‬ ‫توانبخشی‬
‫سپاسگزاریم‬
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@farvardin_group_channel
@neuroscience4family
@farvardin_group96