10 - The Limbic System Flashcards
Blood supply to the limbic system
Anterior and Posterior Cerebral Artery
tip of the temporal lobe & orbital cortex may be supplied by MCA
Function of the limbic system
Pleasure pain, learning and memory
Anterior Cingulate Cortex
Activated during pain/depression
Caudal anterior cingulate
Quality of pain
Rostral anterior cingulate
What actions you do to deal with the pain
Parabrachial nucleus to the
Amygdala
ACC and Insula
Unpleasantness of pain
Cingulotomy
Cutting through the cingulate gyrus to disrupt fibres passing rostro-caudally through it
Reduces emotional stress of pain
Orbitofrontal cortex
How to behave to a threat
how to avoid pain
What can cause OCD
Prolonged pressure to make impossible decisions - which orbitofrontal cortex modulates
Posterior Cingulate Cortex
Involved in the emotional significance of memories e.g activated when memories about family/friends
Parahippocampal gyrus
Acquisition of new memories
Hippocampus
Needed to store memories
Spatial map = anchors to a time and place
Damage of hippocampus
Anterograde amnesia
inability to transfer memories from STM to LTM
Describe Papez’s loop
Cingulate cortex -> parahippocampal gyrus –> hyppocampus –> along fornix –> Mammilary bodies –> Anterior thalamus –> Cingulate cortex
Damage to Papez’s loop
Recollective memory - deficits in recall of memory
Function of mammillary bodies
Contain olfactory cues that link to memories of places
What condition did HM suffer from initially
Epilepsy
What occurred in the surgery HM had
disconnected temporal lobes
lost parahippocampal cortex, hippocampus and amygdala
What was the outcome of HM’s surgery
Severe anterograde amnesia and mild retrograde amnesia
Kluver Bucy Syndrome Symptoms
Oral tendencies
Inc sexual behaviour
Hypermetamorphosis
Loss all sense of fear
Cause of kluver bucy syndrome
Bilateral removal of amygdala
Amygdala function
Activates the flight or flight response of the sympathetic NS
Stimulates fear and anxiety
What tract do the effects of the amygdala flow down
Reticulospinal tract
Damage to the amygdala
Unable to judge fearful expressions
Misinterpretation of hazardous events - excess risk
Decreases ability to recognise emotion and makes it harder to empathise with them
What pathway is the accumbens nuclei part of
Mesolimbic dopamine pathway
Function of accumbens
Initiation and termination of behaviours that trigger reward pathways (e.g chewing and swallowing)
How can you help with addictive behaviours
By blocking dopamine receptors in the accumbens
