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1

Areas of brain associated with intact and impaired executive processes

Largely associated with pre frontal lobes

Last area to fully develop (teens/early adulthood) & first to become less efficient with age

2

Panning action sequence

Create plan
Execute
Alter if circumstances require change
Evaluate outcome

3

Tests of executive process : Tower of London/Hanoi

Must pre plan to complete

3 moves in order to complete

Patients with frontal love damage find difficult as have to be counterintuitive

BUT can do tasks with same components that do not require planning - block design

4

Verbal fluency task

Strategy generation task
Given 60 seconds to generate as many words beginning with a letter or within a category

Frontal lobe damage = fewer responses - tend to repeat derivatives of the same word

5

Wisonsin word sort task

Looks at ability to follow rules and use feedback to amend actions

Work out sorting rule of cards - sorting rule changes after 6 successful trials so must adapt to new rule

Frontal lobe damage perseverate - continue to follow old rule despite negative feedback and being explicitly told the rule has changed

6

Luria 1966 frontal lobe use

Frontal lobes contain system for programming, regulation and verification of activity

7

Symptoms of frontal lobe damage

Distractability - hard to focus
Inability to initiate tasks - plan but don't do
Carry out irrelevant/inappropriate actions

8

Norman and shallice model of control and coordination of actions

Two modes of action control

Routine or novel

Routine: Cues or triggers activate the action schema and allows the routine to be performed - under the control of contention scheduling

9

Define contention scheduling - Norman and shallice

Internal or external cues trigger units to activate schema

Schema activation exceeds threshold level and schema is selected

- action initiated
- competing schemas inhibited

(Common parts of schema shares so must inhibit to prevent absent minded errors)

10

Contention scheduling and intended actions

Novel and infrequent actions more subject to error

CS system = driving familiar route to work

BUT when must deviate from the route, the supervisory system must activate

SS biases way CS works by applying extra exit cation or inhibition to select required action - override CS we point in toting to activate/inhibit and alter the normal process

11

Frontal live damage and the SS and CS

Fail to alter sequence in WCST - supervisory system in frontal lobe is damaged do does not override CS

CS in posterior brain region and intact &I so not moderated by SS

12

Define perseveration

Strong cue schema response

Follow most well learned or recently executed response to a cue and fail to alter

13

Define inertia

Inappropriate action when cue schema link is week

Can't select schema or alternate between actions

14

simple executive processes

Task switching - ability to shift back and forth between tasks or between mental sets

Inhibition - ability to suppress and dominant or automatic response

Updating - ability to actively monitor and update info in working memory (evaluate)

Ie required in planning and completing future tasks (PM) - inhibit current activity, switch to PM, update memory and encode if successful

15

Miyake et al 2000 tasks for simple executive processes

tasks for switching:

'Plus minus task'
- add numbers in list
- subtract numbers in list
- add and subtract numbers in list (switch)

Tasks for inhibition:

'Stroop task'
Inhibit read of word and read colour instead

Test of updating:
'Letter memory task'
Present letter one at a time for 2 secs
Task to remember last 4 letters presented (constantly update)

16

Describe Sylvester et al 2003
Executive skill overlap in brain

Two executive tasks if linked by SS should show overlap in frontal lobe activation

Basic task: see series of arrows in blocks pointing to left or right & press key for next arrow - count no left and right arrows

Switch task: no switch - x2 right arrows, switch - left and right arrow

Response inhibition:
No inhibit- left key after left arrow and vise versa
Inhibit- left key for right arrow and vise Versa

17

Results sylvester et al 2003 executive skill overlap in brain

Areas of activation in both switching and inhibition trials:
Paretial, left dlPFC, medial frontal cortex

Distinguishing areas of activation:
Switch task: posterior
Inhibition: pre motor and fronto polar

- evidence for independence in skills but SA activate different regions - inter correlate (not whole unitary system but not fully fractionated)

18

Miyake et al interrelation between complex executive and simple tasks

Complex ie WCST/ToH

Simple ie switching, inhibition l, updating

WCST relate to switch
ToH relate to inhibition

BUT not only assessment
- WCST complex and require more than one skill

19

What are executive processes

Mentally stimulating higher order cognitive processes

Ie planning, organising, thinking ahead, decision making, multi tasking, focusing attention