Lecture 17: Pain and the Brain Flashcards
What is the point of the brain?
How we navigate a very dangerous world (environment) to survive
What is a basic overview of what is happening in the brain?
- The brain takes a snapshot of the environment
- This is received by 1º and 2º cortical regions
- They decide whether we should pay attention to the stimuli
- They activate the sympathetic nervous system and the frontal cortex determines a response
What parts of the brain determine if we should pay attention to a stimuli and if the stimuli matters?
The insula, cingulate and limbic system
What parts of the brain determines if we should pay attention or focus on a stimuli?
The insula and cingulate
What system determines emotional appraisal of a stimuli?
The limbic system
Generally what do the insula and cingulate do?
Determine if we should pay attention and focus on a stimuli
Generally what does the limbic system do?
Assigns emotional appraisal to a stimuli. Ask the question, does it matter?
Where is information from an environmental snapshot organized into an interpretable form?
Secondary cortical regions
What do secondary cortical regions do?
Organizes information from an environmental snapshot into an organized interpretable form
Where is the insula located?
On the lateral surface of the frontal lobe
What sits on the lateral surface of the frontal lobe?
The insula
What is the formal definition of the insula?
The Insula inter-relates our understanding and perception of self with our perception of the environment
What part of the brain inter-relates our understanding and perception of self with our perception of the environment?
The Insula
What is the casual definition of the insula?
The insula is involved in determining or understanding how we fit into the world around us
What are the three parts of the inusla?
- Posterior
- Middle
- Anterior
What the function of the posterior insula?
Identification/perception of stimulus (do we feel something)
What part of the insula is responsible for identification/perception of stimulus?
The posterior insula
In what situation would the posterior insula be activated?
Someone touches your hand and you feel something touching your hand
What is the function of the middle insula?
Ownership/relation of stimulus (is that related to us?)
What part of the insula is responsible for ownership/relation of a stimulus?
The middle insula
In what situation would the middle insula be activated?
If you touch your own hand, if you see yourself in the mirror, etc
What is the function of the Anterior Insula?
Redirecting attention or conscious awareness - filters out stimuli to see which ones we should be paying attention to
Which part of the insula redirects attention or conscious awareness - filters out stimuli to see which ones we should be paying attention to?
The anterior insula
In what direction does the insula work?
Anteriorly to posteriorly
What are some characteristics of the insula?
Somatotopic organization
Sided-asymmetry
Ipsilateral-contralateral activation
What is meant by somatotopic organization of the insula?
Certain parts of the insula will activate in connection with certain parts of the body wall
What is meant by sided-asymmetry, ipsilateral-contralateral activation of the insula?
The right hand will activate the left insula and the left hand will be represented on the right side
Which side of the insula is implicated in pain?
The right side
What is the insula jointly activated with?
The anterior cingulate
What is the anterior cingulate jointly activated with?
The insula
What network is the posterior cingulate apart of?
The default mode network (DMN)
What is a brain network?
A brain network consisting of multiple brain structures that are activated at the same time or during the same situations
What is the Default Mode Network (DMN)?
A network of interacting brain regions that is active when a person is not focused on the outside world and helps us to find something to pay attention to
What is the key hub in the Default Mode Network?
The posterior cingulate
What is the Default Mode Network active?
When the mind is wandering or focused on something internally
When is the Default Mode Network inactive?
When we are focussed on the outside world
Aside from the DMN what can the posterior cingulate be connected to?
Links hippocampal function to high-level cortex and the limbic system
What does the connection of the posterior cingulate to the hippocampus do?
In integrates emotion with environment
Why are we unable to focus when we are emotional?
Because the posterior cingulate is connected to the hippocampus and other limbic system structures which process emotion
Which part of the cingulate is most involved in pain?
The anterior cingulate
What is the anterior cingulate involved in?
Pain
What is the difference between structural and functional segregation?
Structural: the real estate and where they are located
Functional: when they are active
What are the parts of the anterior cingulate?
- Sub-genu anterior cingulate (sgACC)
- Pre-genu ACC (pgACC)
- Anterior middle cingulate (aMCC)
- Posterior middle cingulate (pMCC)
What can the functional segregation of the anterior/middle cingulate be divided into?
Negative affect
Pain
Cognitive control
What is the anterior middle cingulate aMCC involved in?
Pain, negative affect and cognitive control
What is negative affect?
Experiences of negative emotion
Which part of the cingulate is involved in pain, negative affect and cognitive control?
The Anterior middle cingulate
What are the characteristics of the anterior middle cingulate?
Somatotropic organization
Sided-asymmetry
Ipsilateral-contalateral activation
What is meant by somatotopic organization of the anterior middle cingulate?
Certain regions of the body wall are represented in different areas of the cingulate
What is meant by sided-asymmetry of the anterior middle cingulate?
The right hand will activate the left cingulate
Which side of the anterior middle cingulate is more active in pain?
The right side
What are the six structures of the limbic system?
Hippocampal formation
Amygdala
Hypothalamus
Cingulate gyrus
Thalamus
Limbic associated cortices
What is the hippocampal formation composed of?
The hippocampus, fornix, dentate gyrus
What is the hippocampus an important component of?
The limbic system
What is the most important structure of the limbic system?
The hippocampus
What is the hippocampus important for?
Learning and memory and retrieval of old memories
What is important for learning and memory and retrieval of old memories?
The hippocampus
What is the amygdala important for?
- Very quick object recognition
- Secondary fear or anxiety response
What is important for object recognition and secondary fear and anxiety response?
The Amygdala
What is the cingulate gyrus important for?
Cognition and pain
What is the function of the thalamus?
Sensory relay station
What is the sensory relay station of the brain?
The thalamus
What are the limbic associated cortices?
Other brain areas that are grouped in when the limbic system is active and helps the limbic system understand what is going on
What are the functions of the limbic system?
Emotion and memory
Behaviour
Motivation
Learning/memory
What is the function of the limbic system?
- Provides emotional-appraisal of our current position in time and space
- So how does this snapshot in time relate to us in an emotional context
How are the size of the hippocampus and pain related?
People with larger hippocampi estimate their previous pain to be higher than what it was
How is the limbic system involved in perceived pain?
The limbic system is active in perceived pain even when there is nothing happening to a person
What is seen in the chronification of pain?
- acute pain patients has a large overlap with the pain network but not the emotional region
- chronic pain patients had a lot of overlap with the emotional regions and very little overlap with the pain regions
If fixing pain doesn’t work what may be other methods?
Target attention and focus in higher brain regions
