Limbic system Flashcards
Define diencephalon.
-Thalamic structures: thalamus, hypothalamus, epithalamus and subthalamus
Label the following.
- Groups within the basal ganglia (terminology).. Define:
- Lentiform nucleus
- Striatum
- Corpus Striatum
- Lentiform nucleus :
> Putamen and globus pallidus - Striatum
> Caudate nucleus and putamen - Corpus Striatum
> Striatum and globus pallidus (OR caudate, globus, putamen)
What is the thalamus?
- Grey matter protruding into 3rd ventricle
- Receives nearly all sensory info on its way to cerebral cortex integrates info and directs to
- Motor involvement (mainly with basal ganglia and cerebellum)
- Involved in emotional and memory functions (works with limbic system)
What is the limbic system?
- A system of interconnected subcortical structures within the brain forming a ring around the corpus callosum.
-Associated with producing behavioural and emotional responses. - OLD
5 Fs and limbic system.
- Feeling
- Fighting
- Fleeing
- Feeding
- Physical act of love
List Functions of the limbic system (4 categories).
1- Emotions and drives - amygdala (Feelings, motivation etc.)
2- Homeostasis and motivation via hypothalamus (autonomic and neuroendocrine responses)
3- Olfaction - olfactory cortex
4- Memory formation via hippocampus (learning)
What are the parts of the limbic system?
1- Cingulate Gyrus
2- Fornix: connecting pathway between hippocampus and mammillary body
3- Hippocampus: Receives information from all sensory association areas.
4- Amygdala: Structure that provides an emotional component to experiences and memory.
5- Mammillary Body: (linked to hypothalamus)
6- Olfactory Bulb
7- Parts of the thalamus and the hypothalamus
8- Entorhinal cortex - Relays major cortical input from the medial entorhinal cortex (MEC) and the lateral entorhinal cortex (LEC) > Hippocampus
What is the function of the hypothalamus?
Where is it situated?
- Homeostasis
-Numerous nuclei that have afferent and efferent connections with widespread regions of the NS
> Releases factors acting on the pituitary gland
> produces ADH (supraoptic nucleus)
> Produces oxytocin (paraventricular) - Most ventral (anterior) part of diencephalon
> Lies beneath the thalamus and ventromedial to the subthalamic nucleus
Where is the fornix, what is its function?
- Arch shaped bundle of fibres, travels over the diencephalon
- Output of hippocampus
What is the function of mammillary bodies?
- Involved in memory formation
- Part of hypothalamus
Where is the hippocampus found, what is its function?
- Found in temporal lobe
- Essential in memory consolidation & learning
- Receives information from all sensory association areas
Where is the amygdala found? What is its function?
It is the main output to….. via……?
- Lies near temporal pole at the tip of the tail of the caudate nucleus.
- Provides an emotional component to experiences & memory, and the ability to recognise fear in others
> Has extensive connections with all cortical association areas allowing us to associate emotions to what we sense e.g. see - Main output to hypothalamus via stria terminalis
What is different about the olfactory system?
- No thalamic relay. Central projection of olfactory structures reach parts of the temporal lobe and amygdala without thalamic relay
- The olfactory nerve consists of numerous bipolar neurones, whose cell bodies do not form a ganglion
- Primary neurones are continually replaced: 30-120 days in mammals.
Describe the following olfactory deficits.
- Hyposmia
- Dysosmia
- Anosmia
- Hyposmia (reduced)
- Dysosmia (distorted)
- Anosmia (Complete)
