Limbic system Flashcards
Describe the pathway of the olfactory system
- olfactory bulb (mitral cells)
- olfactory tract (splits into 2 stria: medial and lateral)
- piriform and orbitofrontal cortex
connections to brainstem promote autonomic responses
What are the functions of the limbic system?
- maintanance of homeostasis via activation of visceral effector mechanisms, modulation of pituitary hormone release and initiation of feeding and drinking
- agonistic (defence and attack) behavior
- sexual and reproductive behavior
- memory
Describe the papez circuit.
Diagram
Hippocampus
Main connections:
- Afferent: _________
- Efferent: _________
Function: __________
Clinical: ____________,________
Main connections:
- Afferent: Perforant pathway
- Efferent: fimbria/fornix
Function: Memory and learning
Clinical: Alzheimer’s disease, epilepsy
Give 3 clinical presentations of Alzheimer’s.
- cortical atrophy enlargement of ventricles and shrinkage of brain
- plaques
- tangles
Describe the progression of Alzheimer’s.
Early:
- hippocampus and entorhinal cortex -
- short-term memory problems
Moderate:
- parietal lobe
- dressing apraxia
Late:
- frontal lobe
- loss of executive skills
Amygdala
Main connections:
- Afferent: _________, _________, _________, ________ Efferent: ____ _________
Functions: __________ __________
Clinical: _____-_______ _______
Main connections:
- Afferent: olfactory corteex, septum, temporal neocortex, hippocampus, brainstem
- Efferent: STRIA TERMINALIS
Function: fear and anxiety fight or flight
Clinical: Kluver-Bucy syndrome
Give the symptoms of Kluver-Bucy syndrome
Described in monkeys by bilateral temporal lobectomy
- hyperporality
- loss of fear
- visual agnosia
- hypersexuality
Which structures are shown experimentally to be associated with aggression?
- hypothalamus
- brainstem
- amygdala
5-HT in raphe nuclei (serotonin main neurotransmitter)
Septal nuclei
Main connections:
- Afferent: _________, _________, _________, ________ Efferent: ________, _________, ___________
Functions: __________ &; _______
Main connections:
- Afferent: amygdala, olfactory tract, hippocampus, brainstem
- Efferent: stria medularis thalami, hippocampus, hypothalamus
Functions: reinforcement &; reward
Describe the mesolimbic pathway (Dopamine)
Diagram
How do Opioids, nicotine, amphetamines, ethanol and cocaine affect the mesolimbic pathway?
Opioids, nicotine, amphetamines, ethanol and cocaine all increase DA release in nucleus accumbens. Stimulate midbrain neurons, promote DA release or inhibit DA reuptake,
