lecture 17: frontal lobes Flashcards
anatomy of the frontal lobes
- motor cortex
- premotor cortex (in front of the motor cortex)
- prefrontal cortex (in front of pre motor cortex)
- orbitofrontal cortex
what are the impairments in motor function associated with the frontal lobe
- loss in fine movements, speed, and strength
- Broca’s aphasia = difficulty with speech
what are the effects of damage to the frontal lobe (prefrontal cortex)
- impairments in IQ
- convergent vs divergent tests of IQ
- loss of divergent thinking
- impairments in response inhibition
- environmental dependency syndrome w
- changes in personality
convergent vs divergent tests of IQ
convergent:
- converge on a single answer (Qs that have one answer)
- focused, logical thinking, that aims to find the one correct answer to a problem
- damage to the prefrontal cortex doesn’t impact convergent
divergent:
- thinking outside of the box/thinking creatively/flexible thinking
- damage to the prefrontal cortex damages this type of IQ
loss of divergent thinking
- rigid, black and white thinking
- trouble generating ideas or brainstorming
- difficulty seeing alternative perspectives
tests for loss of divergent thinking
- word fluency test
- measures a persons ability to generate words under specific constraints
results:
- loss of divergent thinking = less words
- another symptom = rule breaking
eg: they were only allowed to use 4 letter words, they would start with 4 letter words then eventually get longer
- normally the participant hasn’t forgotten the instructions but have just ignored them - design fluency test
- A test where a person is asked to generate as many unique designs or patterns as possible under time constraints, usually by connecting dots in different ways
Results:- Fewer unique designs
- May repeat the same designs or have smaller variations, showing cognitive rigidity
- Rule violations
impairments in response inhibition
Response inhibition = the ability to stop or suppress an automatic, impulsive, or prepotent response especially when its inappropriate or no longer useful
What happens when its impaired?
- Impulsivity
- Poor self regulation
- Difficulty following rules
- Inappropriate behaviour
tests for impairments in response inhibition
- wisconsin card sorting test
4 target cards
Instructions:- Pick up cards from deck and match to a target card
- Can’t tell the participant the basis of matching they just need to match based on what they think
Results: - Speed of figuring it out, not much difference
- Person with damage to pre frontal cortex, has an impairment on inhibiting a response that was previously correct, they will figure out that the rule has changed eventually but it will take them a lot longer
Impairment comes in with shifting to a new rule
- stroop interference test
- selecting the correct colour of the word
- This test creates cognitive interference because reading is an automatic process, the test challenges your ability to inhibit that automatic response and instead focus on the task rule
Results:
- Longer reaction time
More errors
environmental dependency syndrome (Lhermitte, 1983, 1985)
EDS = a neurobehavioral condition in which a persons behavior is overly triggered or dominated by external environmental cues , often inappropriately ( even if those actions contradict the social or situational context
People with EDS lose voluntary control over their actions and instead respond reflexively to objects or settings around them
behaviours shown in environmental dependency syndrome
- imitation behaviour
- participants would follow what the experimenter was doing, no matter how strange
—> due to damage to the frontal lobe - utilisation behaviour
- tend to use objects how they are meant to be used, even if they aren’t asked to do that
eg: one participant was given a stethoscope and without being asked to she started measuring everyones heart rate even though she had no healthcare background and wasn’t asked to do that
examples for changes in personality
–> phinneas gage
- a pole went through his frontal lobes
- the equilibrium of balance, so to speak, between his intellectual faculties and animal propensities, seems to have been destroyed
personality changes:
Fitful
Irreverent
Profane, rude
Easily distracted
Childlike, impulsive
