Lecture 2- The Amygdala Complex Flashcards
What is the Amygdala
Collection of nuclei
lateral, central and basal
Location of Amygdala
Anterior portion of temporal lobe
Deep to uncus of parahyppocampus
Anterior to pez hippocampus and temporal horn of lateral ventricle
Subdivisions of Amygdala
Accessory basal nucleus Basal nucleus (magnocellular and intermediate divisions) Basal nucleus (parvicellular division) Medial nucleus Central nucleus Lateral nucleus Paraleminar nucleus Perlamygdaloid cortex
Amygdaloid nuclear complex function
Receives integrated sensory info from higher cortical centres
Provides details to help identify objects
Amygdaloid nuclear complex connections
Hippocampus (direct and indirect via entorhinal cortex) Hypothalamus Ventral tegmental area Orbital prefrontal cortex Septal nucleus/ nucleus accumbens
Efferent projections of Amygdaloid nuclear complex
Stria terminalis (arches dorsally to terminate in hypothalamus, thalamus and nuclear accumbens) Vertical projection of fibres to septal nucleus, orbital PFC, hypothalamus and thalamus
Subcortical inputs
Ventral striatum
Hypothalamus
Dorsal thalamus
Dopaminergic brainstem
Subcortical outputs
Ventral striatum and basal forebrain
Hypothalamus
Midbrain tegmentum
Autonomic brainstem
Corpus striatum
Projections mainly with ventral striatopallidal complex
Ventral pallidum projects to dorsal thalamus, and then onto prefrontal
cortex= provides a pathway with which amygdala can interact
with the prefrontal cortex
Connection of amygdala to basal forebrain
Strong reciprocal connectivity
Via this connection, amygdala can
influence activity of neurons in neocortex
Dorsal thalamus
Another pathway to effect cortical activity
Receives from:
- midline thalamic nuclei (gustatory)
- posterior group of thalamic nuclei (vision, touch and hearing)
The input of sensory stimuli for amygdala processing
Connection of amygdala to hypothalamus
Major projection to bed nucleus of stria terminalis (BNST)
Also to medial and lateral hypothalamus
Connections of amygdala with hippocampal formation
Major connections are with entorhinal cortex
Also hippocampus proper & subiculum
Corticomedial nucleus afferent
From olfactory bulb and olfactory cortex
Corticomedial nucleus efferent
To ventromedial nucleus of hypothalamus
Corticomedial nucleus function
Behaviour associated with hunger and eating
Basolateral nucleus connections (reciprocally)
Connected to sensory association cortical areas
Basolateral nucleus efferent
To medial dorsal nuclei of thalamus, basal nucleus of Meynart and ventral striatum
Basolateral nucleus functions
Behaviour associated with hunger and drinking
Behavioural reaction to stressful situations
Autonomic and somatic reflex activity
Central nucleus connections
Reciprocally connected to visceral sensory and autonomic nuclei in brainstem
Central nucleus funtions
Respiratory and cardiovascular responses
Amygdala functions
Activating 3 components
- Recruits appropriate autonomic and endorcrine responses (via hypoth)
- reaffirms emotional significance (Via hippocamp)
- Creates memory of event (via sensory assoc ctxs and HF)
Improves efficiency of response learned over time
Forumates reactions to socially significant stimuli
Deja vu
Hypothalamic control of ANS without Amygdala
Reflexive in nature
Continuous monitoring of body’s internal environment via baroreceptors and osmoreceptors and making appropriate adjustments
Amygdaloid control of ANS
Mediated by instinct
Utilises prior experiences to modulate ANS activity
Lesion of the Amygdala
Kluver-Bucy syndrome
- lack of fear and anger in previously wild animals
- docility
- changes in feeding behaviour
- hypersexuality
- excessive oral curiosity
- visual agnosia
