Emotions and the amygdala Flashcards
What does the limbic system include?
The thalamus, hypothalamus, hippocampus and amygdala
What does Mcleans circuit include?
Amygdala (subcortical)
Orbital cortex (most directly involved with emotions)
Prefrnotal cortex (planning, strategies)
Dorsolateral nucleus of thalamus (subcortical)
Basal ganglia (ventral structure)
Via which structure does the limbic system influence emotional behaviour?
Hypothalamus
How do the structures of the limbic system influence aspect of emotion? Thalamus (mediodorsal nuclei) Hippocampus Amygdala Hypothalamus (mammillary body)
Thalamus (medio-dorsal nuclei) - declerative memory (facts)
Hippocampus - memory acquisition (volatile to non-volatile)
Amygdala - fear conditioning
Hypothalamus (mammilary body) - declarative memory
Which part of the limbic system is most involved in emotion
Amygdala
Location of amygdala
Anterior-medial part of temporal lobe, rostral to hippocampus
What does the amygdala do?
Connects areas responsible for
somatic expression -
Conscious feeling -
What is the role of amygdala within limbic system?
Connect areas responsible for:
Somatic expression - hypothalamus & brainstem
Conscious feeling - fear - parahippocampal gyrus, cingulate cortex, prefrontal cortex
Which areas are responsible for somatic expression of emotion
Hypothalamus and brainstem
areas responsible for conscious feeling such as fear
Para hippocampal gyrus
Prefrontal cortex
Cingulate cortex
What does electrical stimulation of amygdala lead to?
Fear and apprehension
The amygdala consists of 3 heterogeneous nucleus, what are the main functional subdivisions?
medial
Basolateral
Central
Role of basolateral amygdala
Conditioned fear
Router to/from basal ganglia, motor system, cortex, sensory nuclei of thalamus
Output to central nucleus of amygdala
Connections: it is connected to hippocampus
What is the basolateral region made of
basolateral
basomdial
lateral
Role of central nucleus of amygdala
General fear
Input: receives input from the thalamus and cortex which provide it with info about the sensory stimuli animal is expreincing
Output: projections to ears which control fear such as paraventricular area of hypothalamus (cortisol), lateral hypothalamus (autonomic nervous system) and pariaqueductal gray (freezing due to fear)
Connections: hypothalamus
Result sin physiological response - increased HR, etc
What does the central nucleus of amygdala stimulate?
paraventricular area of hypothalamus (cortisol) Lateral hypothalamus (autonomic nervous system) pariaqueductal gray (freezing due to fear)
What physioclogical responses does central nucleus of amygdala lead to?
Cortisol releasee, sweating, increased heart rate, freezing due to fear, startles response
How does basolateral nucleus acquire conditioned fear?
It has a memory enhancing effect
important for remembering emotionally arorunsing events
Makes memories more vivid
Lesions in BLA = drastic reduction to conditioned fear response but shocked STILL REMAINS
What is Kluver-Bucy syndrome?
Bilateral ablation of inferior temporal lobe (includes hippocampus and amygdala) –> fearless, emotionless, mellow –> hyper sexuality, hype-orality, failure to recognise familiar faces, compulsive reactions/observation
Amygdaloid lesions manifest in humans
Rare
caused by calcium disposition in the amygdala
bilateral degenerations can lead to failures to recognise familiar faces, or failure to identify fear, anger, surprise
how do Affective mood disorders affect the amygdala?
AFFECTIVE MOOD DISORDERS = abnormal regulation of emotions
increased levels of activity int he amygdala, orbital and medial prefrontal cortex in patients with depression
Scans shows increased blood flow in amygdala, orbital, and medial prefrontal cortex
