Lecture 23: Frontal Lobes (Medial Aspect) Flashcards
In the medial view of the brain, what is a boundary to the ventromedial frontal cortex?
Below the rostrum of the Corpus Callosum
Who is Phineas Gage?
- Man with rod that traversed his skull through his cheek
- Before accident:
- Moral man
- Temperate in hibit, strong and active
- Favourite among his men
- Having considerable energy
- Efficient and capable of their foreman
- Recovery:
- Less than a year after accident
- Good physical health
- Memory seemed impaired
- After the accident:
- planning
- self-regulation
- social interactions
How was Gage’s skill to plan affected?
- Capricious and vacillating in devising plans for the future
- Abandoning them for apparently more feasible ones
- Irregular and spasmodic activity
How was Gage’s ability to self regulate after the accident?
- child capacity and manifestations
- animal passions of a strong man
- gross profanity
- impatient of restraint or advice conflicting with his desires.
How were Gage’s social interactions affected by the accident?
Irreverent, Impolite
What main events happen in Phineas Gage’s life post-accident?
- Fondness for pets and children
- Chile
- Hotel stable and carriages
- Stage coach
- Seizures
For how many years did Gage live after the accident?
11
What is something surprisful about Gage’s life in Chile?
That he was able to be a stagecoach driver since it requires a great complexity of cognitive skills
What are the two reasons why Phineas Gage is so important in the history of neuroscience?
- Extraordinary physical recovery
- Dramatic chage in personality
- Planning impairment
- Self-regulation impairement
- Social interaction impairment
What part of the brain is associated with judgement, decision making, social conduct and personality?
Frontal lobe
Who modelled the trajectory of the iron rod that damaged Phineas Gage’s brain?
Damasio and Ratiu
They did this based on the skull since the brain was not conserved
True or False
Both groups had exactly the same results.
False
What did Damasio and Ratiu found?
- No damage to the motor and language areas of the frontal lobe
- No damage to the outside of the frontal lobes
- Damage to the ventromedial frontal cortex and orbitofrontal cortex of the left hemisphere
What could explain the differences in results between Damasio’s and Ratiu’s teams?
Maybe there because of different tech and methods accessible
What can cause damage to the ventromedial frontal cortex?
- Aneurysm located in the anterior cerebral or anterior communicating areas (bilateral)
- Surgical removal of tumours
- Head injury (bilateral)
What are the symptoms of the patients with damage to their ventromedial frontal cortex?
- Emotional and behavioural changes
- difficulty with decisions
- impaired processing of emotion
- Few, if any, cognitive deficits
- Normal performance/ability on/to:
- solve abstract problems
- recall and pay attention
- tests of executive function
- Normal performance/ability on/to:
True or False
ventromedial frontal cortex is the same thing as ventromedial PFC?
True
What are the different functions of the ventromedial frontal cortex?
- Emotional aspect of decision making, learning and social behaviour
- Connections with limbic and subcortical structures
Who is patient C.D.?
- Similar to Gage’s case
- Cognition:
- high intellect
- high verbal abilities
- Perceptual/organizational skills
- Word-finding skills
- Reading ability
- Drawing skills
- Block construction
- Simple motor speed
- Verbal and non verbal memory
What is the D-KEFS Color-Word Interference Test?
- Delis-Kaplan Executive Function System Color-Word Interference Test
- CWIT
- As fast as you can do:
- Color naming trial
- Name the color of red, green and blue squares
- Word reading trial
- Read words “red”, “green” and “blue” painted in black ink
- inhibition trial
- Say the color of the ink in which each word is printed as quikly as you can without making mistakes.
- Inhibition/Switching trial
- Say the color of the ink
- When the word is in a box, read the word out loud
- Measurement: Completion time on each trial
On which other test is the third part of the D-KEFS Color-Word Interference test based on?
Stroop test
What were the results of patient C. D. in the Delis-Kaplan Executive Function System Color-Word Interference Test?
- Fast:
- Color naming
- Word reating
- Inhibition trial
- inhibition/Switch trial
- HIGH ERROR RATE:
- Inhibition/Switch trial
Give a summary of patient C.D.
- Bilateral ventromedial frontal cortex damage
- Cognitive flexibility and assesses shifting skills
- Inability to slow down in order to provide more accurate responses
- Impulsivity and Disinhibition
True or False
Ventromedial frontal cortex contributes to cognitive functioning
True
What is depth electrophysiology recording?
It is the process of inserting different types of electrodes into the brain. For humans, this is usually done during a procedure and can be on top of the brain or deeper in it.
True or False
MRI’s are helpful to see where and how deed the electrodes are
True
Describe the study by Kawasaki et al. 2001
- Goal: investigate the involvement of the ventromedial frontal cortex in the processing of human emotion at the single-cell level.
- Procedure:
-
right ventromedial frontal cortex
- 93 cells
- Stimuli:
- visual scenes and facial expressions
-
right ventromedial frontal cortex
- Results:
- Single neuron responses to aversive visual scenes ≠ pleasant or neutral scenes
- Single neuron responses to facial expressions of fear ≠ facial expressions of happiness
- Observed responses may be related to increased emotional arousal or increased allocation of attention to such affective stimui
- Conclusion:
- Single neurons in the ventromedial frontal cortex encode the emotional value of visual stimuli
True or False
From Kawasaki et al. 2001, we know that the single neurons in the ventromedial frontal cortex encode emotional value of visual stimuli, with which other brain part do you think it is connected?
Ventromedial frontal cortex and amygdala are reciprocally connected.
What causes the pathological experience of negative affect in anxiety disorders?
- Common damage/dysfunctional interaction between the ventromedial frontal cortex and the amygdala
What could be the result of having a ventromedial frontal cortex dysfunction?
- Major depressive disorder (MDD)
- Post-traumatic stress disorder (PTSD)
What happens to the ventromedial frontal cortex when you have Major Depressive Disorder?
- ventromedial frontal cortex is dysfunctional
- Abnormally high activity in ventromedial frontal cortex
What are the two main hypothesis about the ventromedial frontal cortical contribution to specific mood and anxiety disorders?
- Failure of the ventromedial frontal cortex to downregulate the amygdala
- Enhanced activity of the ventromedial frontal cortex which means that there is an increase in autonomic responses and negative affect
How can we confirm or backup the hypotheses about how the ventromedial frontal cortex contributes to mood and anxiety disorders?
We would have to explore how different subregions of the ventromedial frontal cortex contributes to particular types of affective states
Which subregion of the ventromedial frontal cortex is positively associated with negative affect?
Posterior ventromedial frontal cortex
What are the negative affect behaviours that can be caused by the posterior ventromedial frontal cortex?
- Negative mood
- Distress of social exclusion
- Anticipatory anxiety
- Stress-related cortisol levels
- Major depression
Which subregion of the ventromedial frontal cortex is positively associated with positive affect?
Perigenual ventromedial frontal cortex
What are the positive affect behaviours that can be caused by the perigenual ventromedial frontal cortex?
- Subjective value and subjective social status
- Subjective pleasantness of primary rewards
- Positive social feedback
- Decreased thermal pain
- Fear extinction and suppression
- Perception of attractive faces
- Perception of traumatic/stressful versus neutral events
- Enjoyable music listening
How do we make decisions?
- Two extreme positions in human reasoning:
- Rule-based
- Associative
What does it mean to do rule-based reasoning?
- Insensitive to content or context
- Uses formal logic
What does it mean to do associative reasoning?
- Familiarity and social context of a specific situation
- Compare to situations encountered before
- Look at each problem individually
- Solve problems in a case-by-case basis
True or False
Most theories of human reasoning fall in either one extreme or the other positions.
FALSE
Most theories of human reasoning fall in between these two extreme positions.
We use different strategies to solve problems depending on the rules, context and our goals.
What effects doe damage to the ventromedial frontal cortex has on decision making?
-
Impairment in decision-making:
- Failure to guide choice by feeling
- Failure to use familiarity in decision making
- Fail to normally process emotional information of situations
- CAN:
- process and can access the knowledge necessary to imagine different actions and their future outcomes
- CAN’T:
- Act on their knowledge when making a decision
What did Bechara et al. (1996) said about decision making and damage on the ventromedial frontal cortex?
“An emotional.somatic signal derived from previous experience with reward or punishment facilitates the implementation of an advantageous choice under conditions of uncertainty”
We saw that patients with ventromedial frontal cortex damage can retrieve information and imginve certain outcomes, why can’t they act based on this knowledge when they have to make a decision?
- According to Bechara et al. (1996): “Representations of future outcomes might not be marked with a negative or positive value”
Who developped the Somatic Marker Hypothesis?
Damasio, Bechara et al.
What are the somatic markers?
“Emotions-related signals in our physical body or neural representation of our body, which are changes in the viceral state such as changes in heart rate, blood pressure, gut motility and glandular secretion.”
i.e. somatic markers are changes in the body and mind
How are somatic markers useful?
- Help our cognitive processes make decisions
- Help distinguish good choices from bad choices
- Acquired from past experiences with rewards and punishments
What is the somatic marker hypothesis?
- Emotional (somatic) machanism may indicate the potential consequences of an action and so help make an advantageous decision when selecting among different responses
What is an interpretation of the somatic marker hypothesis?
- Imagine you have background knowledge and 2 possible outcomes
- If I do X then long term outcome is Y
- If I do Z then long term outcome is W
How do we make choices accoding to the somatic marker hypothesis?
- After evaluating previous knowledge, we get one or many outcomes
- The outcomes have to have a “positive” or “negative” value associated to it.
- Your body, nervous system and neural representation of a “positive” or “negative” feeling
What is the critical structure to make decisions?
ventromedial frontal cortex
Recap: What are the symptoms for patients with damage to the ventromedial frontal cortex?
- Immediate consequences of an action and not the long term consequences influence decision making
- Insensitive to the future consequences of their actions
- Decision making is guided by the immediate prospects (immediate rewards)
What is the Iowa Gambling task?
- Start with 2000$ load of fake money
- 4 decks of cards
- Select any card in any deck
- Every card brings reward
- Some cards bring both reward and penalty
- GOAL:
- maximize profit
Who developped the Iowa Gambling Task?
Damasio, Bechara et al.
True or False
The Iowa Gambling Task can only be done in person.
False
It can be also done on a computer
Describe the experiment by Damasio, Bechara et al. involving the Iowa Gambling Task.
- Hypothesis:
- Show somatic state activation when they try to choose between the good and the bad decks
- Subjects:
- Group 1: Patients with bilateral damage with overlap on the ventral and medial frontal cortex
- Group 2: Patients with bilateral damage with overlap on the amygdala
- Procedure:
- Set up the task with 4 decks
- The participants can take from any deck
- They know:
- Deck A or B → 100$ and high penalty
- Deck C or D → 50$ and low penalty
- They don’t know:
- A penalty more frequent but smaller in $ than in deck B
- C penalty more frequent but smaller in $ than in deck D
- Results:
- Both groups didn’t learned which decks were more advantageous and kept taking from A and/or B
- Did not generated SCRs in reaction to reward or punishment
Which deck(s) was/were more advantageous?
- After turning 10 cards from A or B:
- Reward = 1000$
- Penalized 5 times = -1250$
- Result = -250 (disadvantage)
- After turning 10 cards from C or D:
- Reward = 500$
- Penalized 5 times = -250$
- Result = +250 (advantageous)
In the Bechara et al. Study with the Iowa Gambling Task, what was the hypothesis?
Subjects should demonstrate somatic state activation when they try to choose between good and bad decks
What is SCR?
Skin conductance response
What is electrodermal skin conductance response?
- Galvanic skin response (GSR)
- Used to demonstrate somatic state activation
- Change in electrical resistance of the skin caused by emotional stress (seat) measurable with a sensitive galvanometer.
What was measured in the Bechara et al. experiment with the Iowa Gambling Task?
- Their skin conductance while they were completing the task
What are the 3 kinds/categories of SCRs measurements that Bechara et al. observed while doing the Iowa Gambling task?
- Reward SCRs
- Punishment SCRs
- Anticipatory SCRs
What is Reward SCRs?
Measurement produced after turning rewarding cards
What is punishment SCRs?
Produced after turning a card for which there was a reward followed immediately by a penalty
What is anticipatory SCRs?
Produces prior to turning a card
While deciding
What where the results from Bechara et al. in the Iowa Gambling task?
- Control: Learned which decks were advantageous (C and D)
- Generated SCRs
- Groups 1 and 2: Didn’t learned and kept picking more from A and B than C and D
- No generation of SCRs
What does this graph mean?
- The patients with damage to the amygdala reacted less, created less SCRs than the control and the VMF group.
What were the results of the Iowa Gambling task for the control group?
- Experience:
- generate anticipatory SCRs
- Anticipatory SCRs increased with experience
- generate anticipatory SCRs
What were the results of the Iowa Gambling task for the VMF group?
- No banticipatory SCRs
- Unable to change somatic states when they think about which card to choose
- Have full understanding about the rewarding and punishing cards
- Generate reward SCRs and punishment SCRs
What were the results of the Iowa Gambling task for the amygdala group?
NO SCRs OF ANY KIND
Can patients with bilateral amygdala damage produce SCRs at some point?
- Yes
- Unconditioned SCR to aversive loud sound
What was the reaction of patients with bilateral amygdala damage to the Pavlovian conditioning/conditioned SCRs?
No, SCRs
Failed to associate visual stimulus to aversive sound
What is the function of the amygdala?
To form associations between unconditioned and conditioned stimuli.
It attaches an affective (emotional) quality to the stimuli.
What is the effect of the damage to patients with bilateral amygdala lesion?
- Impaired processing of the affective qualities of a stimuli
- Unable to experience normally the emotional aspect of a situation
- Do not have the internalized experience of feeling
Overall, what are the real-life consequences of damage to the ventral medial prefrontal cortex?
- Difficulties planning
- Difficulties choosing
- Inability to learn from mistakes
- Actions lead to multiple loses