Limbic System Flashcards
(39 cards)
what body responses are involved in the fight or flight response
- heart rate increases
- sweating
- resp. rate etc.
- defecation
- micturition
- fascial expression
- evacuation
- muscle blood blood to prepare to fight
what are the two main parts of the limbic cortex
cingulate gyrus
insula
what does the limbic system process
emotion and related brain activity, memories, environmental cues and state of the individual and acts on this information to maximise survival strategies
what does the amygdala focus on
emotion
what does the hippocampus focus on
memory
what are the two structures which allow output from this area of processing
hypothalamus and brainstem structures
where is the amygdala located
in the anterior temporal lobe at the tail of the caudate nucleus and rostral to the hippocampus
what are the four nuclei of the amygdala
central nucleus, corticomedial nuclei and the basal and lateral nuclei
what is Klüver-Bucy syndrome
associated with damage to the anterior temporal lobes
• Hyperorality
• Placidity (lack of fear)
can be caused by:
- herpes encephalitis
- trauma
- tumours
- hypoxia
- picks disease
if one experiences fear what nuclei in the amygdala is activated
the central nucleus and the bed nucleus of the stria terminalis (BST)
it is this area in which the centres are enhanced in anxiety disorders
where does input enter the amygdala
lateral nuclei
where does output exit the amygdala
the central nucleus
there are three types of fear pathway, all related to different aspects of the fear
- stimulus
- concept
- context
stimulus pathway
this takes a fast tracked pathway to the thalamus - doesn’t reach our actual consciousness (subliminal short route)
(view of a snake or hiss of a snake)
the concept pathway
this is via the cerebral cortex
this is the idea of a snake or a previous memory you may have
the context pathway
this is via the hippocampus and insinuates the snake is in the room with you
how can the amygdala learn - stimulus pairing
this is noise or scene associated with a fear stimulus can itself elicit fear
this extends to context as well such as a place or a person
the lateral nucleus responds to the stimulus pairing
then the central nucleus droves the response via two main centres:
- the hypothalamus (this is via the stria terminalis
- the brainstem
what is the stria terminalis
a c shaped structure that ends in the hypothalamus and the BST (basal nucleus of the stria terminalis)
if the central nucleus of the amygdala outputs via the brainstem, where does this take place
- periaqueductal grey matter (PAG)
- locus coeruleus (LC)
- parasympathetics (solitary nucleus, dorsal vagal nucleus)
- ventral tagmental area
what is valency
determining if something you are experiencing is good or bad
there are three areas of the cingulate gyrus, what are these known as?
- ACC
- MCC
- PCC
anterior/middle/posterior Cingulate gyrus
what makes up the limbic cortex - this processes emotion
the ACC and anterior portion of the MCC
also as a side note remember that the insulation is also considered to be part of the limbic cortex
ACC connects to where when thinking about effectors
the amygdala and to effectors in the brainstem
this encodes basic emotions such as happiness, sadness and fear, also focuses on emotional memory of fear
MCC connects to where when thinking about effectors
to the motor Cortex so primarily movement and behaviour
