Limbic system Flashcards
Name the structures part of the limbic lobe
Cingulate gyrus Hippocampus Insula Parahippocampal gyrus Septal nucleus
Name the structures in the subcortical nuclei
Habenula Amygdala Reticular formation Mamillary bodies Nuclear accumbens Olfactory bulb Hypothalamus Occipitofrontal cortex Tegmentum (thalamus?)
what makes up the hippocampal formation
what is its function
hippocampus , subiculum ,dentate gyrus
memory emotion
Describe the Papez circuit
Cingulate Parahippocampal gyrus entorhinal cortex Hippocampus Fornix hypothalamis Mamillary bodies Ant nuclei of thalamus Cingulate cortex
Describe the amydala
CNS response to certain stimuli- autonomic, hormonal, behaviour, feeding
- Inputs- visual system, auditory, somatosensory, olfactory, ventral striatum, hyp and brainstem
What is the amygdala the centre of
Fear and aggression
What are the inputs to the amygdala
Visual Auditory Visceral Brainstorm (reticular formation) Cerebral cortex Olfactory system Thalamus
What are the outputs from the amygdala
Stria medularis ( to hypothalamus) And central amygdalofugal pathway
What is Kluver Bucy syndrome
Large bilateral amygdala damage= loss of emotion, docility, oral tendencies, hyper sexual behaviour
What are the afferent and efferent memory pathways
Afferent- perforant
Sensory info- entorhinal cortex- dentate gyrus
Efferent- fornix
Pre-commisural = septum
Post-comisural = cingulate gyrus, mammillary bodies
And anterior thalamic nucleus
What regulates he papez circuit
Orbitofrontal Cortex- prevents over/under emotion
What are the outputs of the papez circuit
Neuroendocrine from hypothalamus
Neural via reticular formation
Cranial nerves and hypothalamus
What are the main functions of the limbic system
Emotion and
memory
Describe how info travels in the hippocampus
- Info enters hippocampus in gap between subiculum and dentate gyrus-perforant path
- Entorhinal axons synapse on cells in the dentate gyrus
- Dentate neurones send axons to CA3 (mossy fibres)
- CA3 sends axons (Schaeffer collaterals) to CA1
- Sends fibres to subiculum
- Subiculum responsible for hippocampus output
- Can send axons directly to hyp and mam bodies via fornix or back to entorhinal cortex–> sensory cortex
- Continuous pathway that begins in sensory cortex, traverses hippocampus and returns to sensory cortex
Describe the relations of the entorhinal cortex and subiculum
Subiculum at base of hippocampus
Continous with entorhinal cortex (part of parahippocampal gyrus)
