Lecture 24, 25: Amygdala, Orbitofrontal and Cingulate Cortex Flashcards
What is the origin of the word amygdala ?
Almond-like (from the Greek)
Where is the amygdala?
- Within the uncus
- Anterior to the hippocampus
True or False
The amygdala is not a single structure.
True
It consists of nuclei
What is a nuclei?
- group of cells
- Each nucleus has unique inputs and outputs and neurotransmitter systems
True or False
Each nuclei has a differen function
True
This is why they have different input, outputs and neurotransmitter systems
True or False
We can see the nuclei in the amygdala with stains
True!
What is the structure that provides an important route by which external stimuli can have an impact on emotions?
Amygdala
What is the path that an external stimuli has to take in order to have an impact on our emotions?
Sensory areas → Amygdata → Subcortical structures → Physiological responses and behaviour
What are the 3 different types of nuclei in the amygdala?
- Lateral nucleus
- Central nucleus
- Basal nucleus
What is the Lateral nucleus?
- Function:
- Input region or Gatekeeper of the amygdala
- Input:
- from sensory systems
- Output:
- central nucleus
What is the central nucleus?
- Function:
- output region for the expression of innate emotional and associated physiological responses
- Input:
- lateral nucleus
- Output:
- connections to brainstem areas that control specific behaviours and physiological responses
What is a basal nucleus?
- Function:
-
output to the striatal areas involved in the control of instrumental behaviours
- Actions reach a goal
-
output to the striatal areas involved in the control of instrumental behaviours
- Input:
- Output:
True or False
The nuclei in the amygdala are connected.
True
From where does the amygdala receive input from?
- Entorhinal cortex
- Sensory cortex
- Ventromedial frontal cortex
- Polysensory and limbic association areas
What does it mean when we say that the amygdala receives information from the entorhinal cortex?
It receives input from the sensory cortical areas
What does it mean when we say that the amygdala receives input from the polysensory and limbic association areas?
- Cingulate gyrus
- Temporal pole
- Insula
- Perihinal cortex
- Frontal cortex
Where is the cingulate gyrus?
It is in the medial view of the brain, on top of the CC
Where is the temporal pole?
Where is the insula?
It is inside the Silvian Fissure hidden under the frontal, parietal and temporal opercula
Where is the perirhinal cortex?
It is within the lateral bank of the rhinal sulcus
To where does the amygdala outputs information?
- Orbitofrontal cortex
- Neocortex
- Striatum
- Hypothalamus
What is the function of the orbitofrontal cortex?
Hyperactivity and impulse control
What is the neocortex?
- Almost every visual region in the temporal and occipital lobes (including V1)
What is the function of the neocortex?
Modulation of sensory processing by affective state.
Emotional information becomes linked to sensory information.
What is the striatum?
- The striatum is composed by:
- putamen
- caudate nucleuse
- globus pallidus
In purple in the image
Where is the hypothalamus?
What is the function of the hypothalamus?
- Receives sensory input from the amygdala
- Influence on the autonomic nervous system
- breathing, heart rate, arousal
- Influence on the physiological responses and our behaviour
What is the difference between the hippocampus, hypothalamus and thalamus?
-
Hippocampus:
- Memory
-
Hypothalamus:
- the autonomic nervous system, physiological responses and behaviour
- heart rate, breathing, arousal
- the autonomic nervous system, physiological responses and behaviour
-
Thalamus:
- grand central station for information
What is the role of the amygdala?
- Important affective processing
- recognition of unpleasant emotions
- Associate external stimuli and events with aversive sensory inputs
- Helps establish emotional significance of external stimuli
- Updating stimulus
- update associations
What are the symptoms of bilateral amygdala damage?
- Change in emotional behaviour/hypoemotionality
- decrease in aggression, increase in indifference
- Lack of fear to the stimuli and situations that commonly evoke fear
- Kluver-Bucy syndrome
- No effect on most memory tests (with selective amygdala damage)
- Impact on social learning rather than a global loss in affective behaviour
What are the two aspects of reward?
- Feedback
- Intrinsic value
What is feedback?
- Feedback indicates correct responses on task
- ex)
- visual discrimination task
- delayed non-match to sample task (DNMS)
- ex)
What is Delayed non-match to sample task?
- An initial object is shown
- After some delay, two objects are shown
- Goal is to select the novel object
- If selected correctly gets reward
What is intrinsic value?
It is the preference, like and dislikes.
For example, smell and taste of a cup of coffee
True or False
The amygdala plays a role in the intrinsic value, not in feedback
True
True or False
Patients with bilateral lesions in the amygdala can learn visual discrimination and delayed non-match-to sample task using reward as feedback.
True
A+ animals can perform DNMS
Why do we say that the amygdala only plays a role in the intrinsic value and not the feedback?
The amygdala’s function is the formation of stimulus-value associations between discrete stimuli and their intrinsic reward value
What were the symptoms of damage to the amygdala in monkeys?
- Disturbed association between new items and their intrinsic value
- Put non-food into mouths
- Abnormal willingness to eat meat or other uncommon food
- Greater impact on learning new food preferences than on already established preferences
- can’t form new associations
- Can distinguish edible from non-edible items but they keep putting non-edible items in their mouth
*
Where are representations of expected stimulus value stored?
A) In the amygdala
B) in the hippocampus
C) in the orbitofrontal cortex
D) in the temporal lobe
C) in the orbitofrontal cortex
What is the Pavlovian fear conditioning?
A neutral conditioned stimulus (CS) is paired with an unpleasant unconditioned stimulus (US)
Recall Bechara et al. experiment regarding conditioning. They played a loid sound paired with a visual stimulus (picture). They had a group of participants who had bilateral amygdala lesions, what was the result?
They didn’t learn to associate the picture to the loud sound
What should normally happen if you play a loud sound and show an image to a person?
- Normally, CS begins to produce fear responses and related physiological changes in the body which is done thanks to the amygdala
True or False
Fear conditioning involves nuclei of amygdala
True
What is the role of the lateral nucleus during fear conditioning?
When convergence of the CS and US, then it leads to synaptic plasticity in the lateral nucleus.
Which nuclei plays a role when the CS is presented alone?
Signal flows through the lateral nucleus to the central nucleus which is the output region for the expression of innate emotional and physiological responses including conditional fear responses.
What study with rats was done to test Pavlovian conditioning and positive affect?
- Rats were exposed to a neutral conditioned stimuli or a CS
- Food is associated to one of the stimulus
- Both stimuli are presented without food
- Rats spent more time near the stimulus associated with food
What is the reinforcer-devaluation task?
- Training:
- learn to associate the pyramid with cherries and cube with peanuts
- Groups:
- Inflect bilateral amygdala damage to part of the trained monkeys
- Tests:
- Fed to satiety with cherries, peanuts or given an empty bowl
- Monkeys have to select one of the two objects
- Hypothesis: if had too much of one, will pick the other one. If empty bowl, then it will pick which ever they prefer.
- Results:
- Amygdala lesions:
- selected object with most preferred food regardless if they were satiated or not because they couldn’t update the value of the object
- Amygdala lesions:
True or False
Recall the reinforcer-devaluation task. Now, imagine that we do exactly the same process but in the test, we don’t hide the food but we display it. The monkeys will:
A) Take their prefered food regardless of the condition
B) Take preferred food when satiated
c) Avoid taking the food they are satiated for
c) Avoid taking the food they are satiated for
Describe the study with patient SM-046
- By Aldolph et al. 1995
- SM-046: Bilateral amygdala lesions
- 6 other patients: unilateral amygdala lesions
- Procedure:
-
Recognition of facial expressions of emotion
- Showed 39 black and white images of facial expressions
- They had to judge the expression with respect to several verbal labels and say how likely it was that it belonged to a given label (0 to 5 where 0 is not at all and 5 very much)
-
Recognition of facial expressions of emotion
What were the results from Alph et al. 1995 for recognition of facial expressions of emotion?
- The patients with unilateral amygdala damage where as good as the controls
- Patient SM-046:
- impaired ability to recognize expressions of fear
- Intact recognition of the remaining emotions
- Faces showing fear were judge to be less intense than for the other emotions
- Surprised and angry faces were judged to signal less surprise or anger than did controls
What were the results for Aldolph et al. 1995 for recognition of identity of a face?
-
bilateral amygdala damage:
- NO impairement
- When shown pictures of familiar faces, they could recognize the person
- NO impairement
What were the results from Adolph et al. 1995 for drawing facial expressions?
- Assessed subject’s ability to retrieve nonverbal information related to fear
- Draw from memory
- Results:
- SM-046:
-
Able to produce without difficulty drawings of all facial expressions except fear
- Didn’t know what an afraid face looks like
-
Able to produce without difficulty drawings of all facial expressions except fear
- SM-046:
How did Adolph et al. 1995 test the verbal concept of fear and what were the results?
- SM-046:
- Understand which situations would evoke fear
- Knows how frightened people normally behave
- Use of words “fear”, “afraid”, “frightened” appropriately
- Recognize the meaning or words representing emotions
True or False
Unilateral amygdala damage impairs the recognition and recall of facial expressions of fear. This compromises social behaviour
False
This is true for bilateral amygdala lesions
Summary of the amygdala’s daily activity
- affective associations (establishing and updating)
- changes from the neutral status of a stimulus to the affective status
- unconscious biases and preferences about stimuli
- feelings about abstract ideas, concepts, beliefs, hopes and dreams
- rational vs emotional decision making
- mediating the effect of stress on memory formation and consolidation
- promotes long-term storage of memories about emotional events
Where is the Orbitofrontal cortex?
What are the functions of the orbitofrontal cortex?
- High-level control of affective state
- Cognitive control of the amygdala
- “Conquer” fear, appear/act brave despite high heart rate and change in blood pressure
How do we know what functions does the orbitofrontal cortex have?
- Phineas Gage had damage to the orbitofrontal cortex and he lacked impulse control
What contribution does the orbitofrontal cortex has for stimulus-reward associations?
-
Amygdala:
- making and updating stimulus-reward associations
-
Orbitofrontal cortex:
- storage of associations
Given the function of the orbitofrontal cortex and the amygdala, what do you think will be the effects of having bilateral orbitofrontal cortex damage?
- Effects are very similar to the effect of a bilateral amygdala lesion
- note that new associations or updates do not get store so it is almost as if these associations weren’t formed or updated
What does multimodal mean?
That it has different modes of activity
What are the functions of the posterior orbitofrontal cortex?
-
Receives projections from:
- Primary olfactory aras
- Gustatory cortex
- High-order visual, somatosensory, gustatory and auditory association areas
- Amygdala
- Hypothalamus (bidirectional projections)
-
Sends direct projections to:
- Brain stem and spinal cord autonomic areas
Where is the itegrated sensory information processed?
In the orbitofrontal cortex
After being processed, where is the integrated sensory information sent?
To the perirhinal and entorhinal cortex
What is the last stop for the integrated sensory information?
At the hippocampus for long-term memory
What is the complete path that integrated sensory information follows?
- Orbitofrontal cortex
- Perirhinal, entorhinal cotex
- Hippocampus
What is the function of the perirhinal and entorhinal cortex?
Both are important for the process of familiarity of a stimuli
p.452
Descibe the neurophysiological studies of behaving non-lesioned animals
- By Wallis and Miller (2003)
- Procedure:
- The monkeys saw a picture A & B on the screen
- Monkey had to select one
- Depending on the image selected, they would get a certain amount of juice
- By trial and error, the monkey learns association of image and juice
What was found in the study Wallis and Miller (2003)?
- They noticed that the neurons in the orbitofrontal cortex differentiated between the value of each stimulus depending on how desirable it was, not on the amount of the reward.
- This was represented by the firing rate of the neurons
Where is the cingulate cortex?
Just above the corpus callosum, bellow the cingulate sulcus
Where are the cingulate motor areas?
They are inside the cingulate cortex.
To see them you have to cut along the cingulate sulcus
What are the names and locations of the different cingulate motor areas?
-
Cingulate motro area rostral
- on the frontal lobe
- just under the Pre-supplementary Motor Area
-
Cingulate motor area caudal
- Divided into 2
- cingulate motor area caudal dorsal and ventral
- Both are under the supplementary motor area
- Divided into 2
Where are the cingulate motor areas (CMAs) of primates?
- Located in the banks of the cingulate sulcus
- Subdivided into rostral and caudal parts
From where does the cingulate cortex gets its input from?
From the limbic structure and prefrontal cortex
What are the functions of the limbic structures and the prefrontal cortex?
- Information about motivation and internal state of the subjects
- Cognitive assessment of the environment
Where does the CMAs send their output?
- to the primary and secondary motor areas
- motor structures in the brainsteam and spinal cord
True or False
The cingulate motor areas act as an interface between the and the motor areas
True
What are the functions of the cingulatate motor areas?
- Higher-order motor areas
- Processing of information necessary for voluntary movement
When is the CMAr the most active?
When the subjects is required to select movements voluntarily in different motor tasks
Give an example of a study where it was observed that the CMAr was most active when the subjects had to choose a movement.
- By Sima & Tanji (1998)
- Process:
- Show a visual stimuli
- Two arm movements in response:
- Pushing a handle
- Turning a handle
- The subjects had to select one of the two movements
- They would have to switch to the alternate movement when the reward was decreasing
What were the results that Shima & Tanji (1998) found?
- The neurons in the CMAr would change their firing activity during the time when the animal received the reduced reward and initiated the alternative movement
- This could be related to the decision of choosing a different movement
True or False
CMAd is critically involved in voluntary motor selection based on the amount of reward.
False
It is the CMAr** that is critically involved in movement selection based on the amount of reward
How does the CMAr is involved in voluntary motor selection?
- Assessment of the reward for the current movement
- Then, select the next movement if the reward is not acceptable
How is the information about reward values that are directly linked to the goals of motor acts processed?
This is the limbic projections
- Amygdala and ventral striatum
- Anterior cingulate cortex and cingulate gyrus
- CMAr
What is the role of the PFC when it comes to the Shima and Tanji (1998) paper?
It keeps track of the movements when there is multiple trials
How does the PFC keeps track of the movements over multiple trials?
-
PFC → CMAr
- Information about the occurence of events in the motor task in the previous trial
So what does the CMAr uses to select an appropriate motor act?
- It uses the information from the Limbic structures which has the information about the reward association to the movements and the information from the PFC which keeps track of previous movements
True or False
CMAr detects when an action leads to errors and less rewarding outcomes and selects a different action to increase reward.
True
True or False
CMAr uses a reward-based motor selection
True
Decribe the study by Bush et al. (2002)
- Procedure:
- Reward-based motor decision task
- Similar to Shima and Tanji (1998)
- With humans
- Press a button 1 or 2 depending on the visual stimuli
What are the results found by Bush et al. (2002)?
- Activation of the dorsal anterior cingulate cortex
- Includes cortex on the dorsal and ventral banks of the cingulate sulcus
- Roughly corresponds to the rostral cingulate motor area (CMAr) in monkeys
- Reward-based decision making, learning and the performance of novel tasks
- So the results are similar to Shima and Tanji (1998)
So in summary, the cingulate cortex?
- Functions:
- Monitoring of errors and other outcomes
- Encoding a reward prediction
- Encoding the expected value of actions
- Processing the information about the consequence of actions
True or False
Removal of the cingulate cortex does not impair learning of visual discriminations.
True
What are some keywords related to the amygdala?
- Emotion
- Fear
- Anxiety
- Reward value
Which CMA takes care of the processing of information for voluntary action selection?
Both rostral and caudal
When required to select movements voluntarily in different motor tasks, which area is the most active?
CMAr
