L18: Limbic System Flashcards
What is the limbic system involved in
Emotion
What is emotion
A combination of psychological and physiological response to a stimulus, only the individual can feel what their psychological state is
What are the 2 types of emotion
Positive
Negative
Why do we have emotion
We use expression of emotion for communication
Emotion aids memory e.g episodic memory with an emotional component
Are the any discrete regions in the brain for emotion e.g a primary emotion cortex
No
Is there a discrete region for each type of emotion e.g a funny primary cortex
No
What does the current evidence suggest about where in the brain we have emotion
There is a network of neurones that are connected
Which structures in the brain are involved in emotion
Structures around the brainstem that join to the major part of the brain = border region/limbus
What are the 2 aspects to emotions
Expression of emotion by activating ANS via hypothalamus
Awareness that involves the neocortex
Where is the neocortex located
Pre frontal cortex
How is the neocortex (awareness) and hypothalamus (activation of ANS) linked i.e describe the papez circuit
1) Hypothalamus singles to the anterior thalami nuclei
2) Anterior thalamix nuclie passes signal to cingulate gyrus
3) Cingulate gyrus passes into the neocortex
4) Neocortex passes info back to the cingulate gyrus into the hippocampus
5) Hippocampus associates with back to the hypothalamus
What is the orbitofrontol cortex part of
Neocortex
Which emotion is the orbit to frontal cortex associated with
Pleasure
Which elements of the papez circuit are not just involved in emotion
Hippocampus
What is hippocampus involved in
Memory
Where is the amygdala located
In the temporal lobe adjacent to the hippocampus
What are the nuclei in the amygdala
Corticomedial nuclei
Central nucleus
Basolateral nuclei
What are the 2 evidences that support that the amygdala is involved in emotion
Urbach wiethe disease
Temporal lobe epilepsy
What is the urbach wiethe disease
Degeneration of the amygdala that results in fearless patients this shows that a removal of the amygdala results in loss of fear
What is temporal lobe epilepsy
Epilepsy in the temporal lobe that results in a strong feeling of fear before the epilepsy- this shows that a stimulation of the amygdala results in fear
Why do we need memory involved in emotion
To allow us to interpret the sensory input and compare with previous sensory inputs
Which structure in the Brain is involved in emotional memory
Amygdala that acts as the central processing nucleus
What happens when there is a stimulus associated with the memory e.g auditory stimulus
1) stimulus goes to the sensory cortex
2) from the sensory cortex information goes to the amygdala
3) if it’s associated with memory then it can give a response
4) information can pass into the central nucleus to trigger the hypothalmus to give ANS response
5) it can also pass to the central nucleus to triage the periaqueductal grey matter (PAG) to produce a behavioural response
6) information can also pass basolateral nuclei of the amygdala to pass to the neocortex to give an emotional experience
What other emotion is the amygdala involved in
Aggression
Which side of the hemisphere is important in recognising emotion
Right hemisphere which takes information from the left side of a picture
With the evidence of the role of the amygdala in emotion what has this lead to
Changing the papez circuit to involve the amygdala to produce the revised circuit
Overall what are theroles of the amygdala
1) emotional memory
2) stimulate hypothalmus for ANS
3) fear and aggression emotion
4) emotional response by stimulating the neocortex
5) behaviour response by stimulating the peri aqueducts gray (PAG)
