lecture 9 - frontal lobe Flashcards
localisation of function
The different regions of the brain are physio-logically different (different neuronal organization, different connections to other brain areas).
Hypothesis: should also have different roles in cognitive processing.
How do we find out what these roles are?
different parts of brain from these lectures and what they do
temporal lobe - what is it,
parietal lobe - what can i do with it
-frontal lobe -all this info travels to the frontal lobe- picks the best thing to do
frontal lobe-prefrontal cortex - executive function
those abilities that enable
a person to
-determine goals,
-formulate new and useful ways of achieving them, and
-,then follow and adapt this proposed course in the face of competing demands and challenging circumstances ,often over long periods of time.
phineas gage and damaged cortex
-what was he like before and after his accident
Pre-accident: well respected, hard-working
no impairment of movement or speech, new learning intact. Memory and intelligence unaffected
. Personality changes: disinhibited, capricious, disregards social conventions, unable to hold a job.
“He is no longer Gage.
-his executive functions were diminished
the chimp who hated visitors
-what did his behaviour tell us
The chimp hates visitors: throws stones at them as soon as they arrive.
When not busy, he goes to collect stones and stashes them for later use.
First demonstration of “premeditated attacks” and long term planning by primates - use of prefrontal cortex
what separates frontal lobe and parietal/temporal lobe
central sulcus
4 major parts of frontal lobe
-precentral gyrus -primary motor cortex
-premotor cortex
-prefrontal cortex : 2 parts - dorsolateral PFC and ventromedial PFC
precentral gyrus : primary motor cortex
-controls bodily movements
-electrical stimulation evokes movements of different body parts, depending where you stimulate
-contralateral organisation (left controls right, right controls left)
-somatotopic organisation-mouth,hands,arms etc
premotor cortex
action plans
-the more forward you go in the pre motor cortex- the more the long term the action plans are that the cortex helps you decide on
-neurons fire for specific action
-eg grasping object,cracking peanut
-makes sure actions are not affected by distractors and seen through to the end
prefrontal cortex : dorsolateral PFC
-following of long term plans
-long term planning
-goal corrected behaviour
hierarchy- top level goal and then smaller goals to acheive top level goal
eg making a sandwhich (very abstract, independent of situation)
- Slicing bread (get bread, get knife)
- spreading butter (get from fridge, open)
- put ham on top (get from fridge, open)(more concrete goals)
Concrete motor movements(lower level goals)
what do dorsolateral PFC lesions imapir?
they can impair the detection of such errors in action sequences
eg making a cup of tea but forgetting the tea bag step
brocas aphasia
-problems not with speech understanding but speech production
-also with coordinating longer sentences
-ungrammatical speech
tower of london test
a test used in applied clinical neuropsychology for the assessment of executive functioning specifically to detect deficits in planning
tower of london task
-frontal patients
-parietal patients
-frontal patients are impaired in tower of London (requires planning) but fine with WAIS (spatial skills)
-damage to prefrontal cortex (dorsolateral) makes it really tricky to do this
-parietal patients are fine with tower of London but impaired in the wais
-double dissociation highlights frontal deficit in strategic planning
dorsolateral prefrontal cortex is also important in
following of long term plans even when distracted
-what is the stroop task
-what is the luria hand test
-consists of colour words printed in different colors of ink
-prefrontal cortex helps us with naming the colours here
is a task that requires a patient to imitate three hand motions performed by a clinician.
utilisation behaviour
denotes the appropriate usage of an object by a patient, however at an inappropriate situation
-the sight of an object elicits a stereotyped action which is inappropriate in the wider context
The sight of an object elicits a stereotyped action which is inappropriate in the wider context.
give an example of this
If there is a glass within reach, the patient will grasp it.
If a bottle is placed on the desk he will grasp this too and pour water into the glass and drink it
. Why: `You held them out to me, I thought I had to use them.’
Examiner “from now on don’t grasp any of the objects I will show you, and in no case must you use them.”
behaviour remains unchanged.
Patients remember instruction not to grasp the objects, but: “you held out the objects to me and I thought I had to reach and grasp them.”
Ventromedial Prefrontal cortex
-emotional evaluation of actions and plans
ventromedial prefrontal cortex is connected to the _____
-explain
amygdala
the amygdala sends information about emotional value to the ventromedial prefrontal cortex
-
Wisconsin card sorting task
-allows us to see work of ventromedial prefrontal cortex
-patient has to draw from two different decks
-pile a has huge wins and losses and pile b has smaller wins and losses
-people start to notice their loosing alot when they keep picking A so they usually switch decks
-but those with ventromedial cortex damage dont often switch
