Unit 6 Flashcards
(43 cards)
Is the limbic system a single structure?
no, its a phylogenetically ancient network of structres
What are the structures of the limbic sytsem involved in?
motivation and emotion
learning and memory
Where do the structures of the limbic system lie?
middle of the brain
hidden by cerebral cortex
What is the role of the hypothalamus?
regulating our physiological state
provoking emotions
What are physiological responses driven by?
autonomic and hormonal reactions
What do emotional responses involve in addition to autonomic and hormonal reactions?
conscious perception of emotions
-> often results in behaviour
When looking at the responses to emotional stimuli, what is the limbic sytsem responsible for?
integrating physiological, autonomic, hormonal and behavioural responses
The Papez cricuit
first neuroscientific theory
neural circuit responsible for expression of emotion
How does the Papez circuit work?
Nuclei in thalamus receive information
-> sent to sensory areas in cortex (for processing) and hypothalamus (prepares physiological response)
-> sent from hypothalamus to anterior nuclei of thalamus
-> sent to cingulate cortex
-> conscious experience of emotion
-> entorhinal cortex via cingulum
-> input to hippocampus
-> mamillary bodies via fornix
entorhinal cortex
extension of cingulate cortex next to hippocampus
Is the Papez circuit fully accurate?
no, oversimplified
-> gives framework
-> new regions added
What does the limbic system consist of?
limbic cortex
amygdala
hippocampus
mamillary bodies of hypothalamus
septum
What are important connections of the limbic system?
hypothalamus
anterior nucleus of thalamus
orbitofrontal cortex
olfactory bulb
What is the amygdala and what is it responsible for?
almond shaped structure in temporal lobe (anterior to the hippocampus)
processing emotions
What is most research on the amygdala concerned with?
fear and aggression
-> normally shown in animal subjects
-> occurs in many species
-> can be produced in controlled experiments
How many nuclei does the amygdala consist of and which nuclei are the most well-researched?
~ 12
lateral nucleus
basal nucleus
central nucleus
central nucleus
end of fear processing
-> produces response
sends information to hypothalamus and autonomic nuclei of brainstem
most important structre for expression of emotional responses
lateral nucleus
receives sensory information from thalamus, hippocampus and vetromedial prefrontal cortex
sends it to basal nucleus and dorsomedial nucleus of thalamus
important for learning
What does bilateral damage to the amygdala result in? (syndrome)
Klüver-Bucy syndrome
Klüver-Bucy Syndrome
previously agressive monkeys fail to show normal fears
-> hyperorality
-> picking up snakes or lit matches
-> characterised by excessive docility and hypersexuality
What does bilateral damage to the amygdala also cause in humans?
amnesia
aphasia
agnosia (disrupted recognition ability)
Example of Klüver-Bucy syndrome
40-y/o patient with status epilepticus developed syndrome
started eating paper towels, etc.
inappropriately touched other patients and was very docile
died from asphyxiation after stuffing mouth with surgical gaze
What are the structures mainly important for learning?
hippocampus
limbic cortex
what does the limbic cortex consist of?
medial temporal lobe
cingulate cortex
parahippocampal gyrus
entorhinal cortex
piriform cortex
perirhinal cortex
