Limbic System I Flashcards
What does the limbic system control?
Mood, emotion, feelings, motivation and memory
Why is the limbic sytem difficult to study?
- anatomically interconnected
- physiological it’s hard to measure limbic system output
What are the 5 pathwways of the limbic system?
- Fornix
- MMT
- Stria terminalis
- Medial forebrain bundle
- Dorsal longitudinal fasiculus
Fornix pathway
Hippocampus to mammilary bodies and septal nuclei
MMT
Mammilary bodies to anterior nucleus of the thalamus
Stria terminalis
Amydala to the septal nuclei
Fornix and stria terminalis lie close together
Medial forebrain bundle
Midbrain through the hypothalmus to the forebrain
Dorsal longitudinal fasiculus
Hypothalmus to the brainstem and spinal cord
The limbic system receives innervation from what types of axons?
Monaminergic and cholinergic
Where is NE stored?
NE is stored in the locus ceruleus in the dorsal pons
Where is 5HT stored?
In the Raphe nuclei in the midbrain, pons and medulla
NE and 5HT are important for what basal funcitons?
sleep and wake cycles
attention and arousal
Where is dopamine made and stored?
The VTA in the MIDBRAIN.
DA travels through themedial forebrain bundle to reach the nucleus acccumbens, medial prefrontal cortex, amygdala and septal nuceli
What causes drug addiction?
Cocaine and amphetamines both increase DA in the synaptic cleft leading to a HIGH.
A lesion of the VTA/nucleus accumbens/septal nuclei would do what?
It would DECREASE drug seeking behaviors because there would be LESS dopamine.
Blocking DA receptors is a way of decreasing drug seeking behaviors….this also makes you feel naseous and sick.
Where is ACh made?
Nucleus bassilus and the septal nucleus
Both project to the forebrain and hippocampus
What nucleus is commonly lost in Alzheimers?
The nucleus basalis. This leads to memory defects.
What is the role of the amydala?
Processes memory and emotional responses.
Plays a role in fear conditioning.
A lesion of the amygdala causes what deficits?
Leads to decreased conditioning–don’t associate a connection between “shock” and “tone”.
If there is a conditioned fear resonse it is lost!
How are the prefrontal cortex and the amygdala connected?
The prefrontal cortex inhibits the amygdala which activates the hypothalamus and leads to an emotional response.
What is prefrontal lobe syndrome?
Discovered becasue of Phinneus Gage!
He was a nice man but then suffered damage to his prefrontal lobe and became a weiner face. He had no emotional conrol, poor social judegmeent and impaired goal directed behavior.
What are hte DLPFC and the OFC?
Dorsolateral PFC is responsible for working memory.
The orbitofrontal cortex connects to the amygdala.
The hippocampus plays a role in what type of memory?
Explicit or declarative moemroy!
Semantic- memory of words/facts
episodic- memory of events, experiences
What type of memory is the hippocmampus NOT involved in?
Implicit memory (procedural/nondeclarative)
NOT needed for motor skills.
What is anterograde amnesia?
No NEW memories
What is temporally graded amnesia?
Childhood memories- strongest
Memories before surgery- weakest
