neuro 500 -- cerebellum, diencephalon, cerebrum Flashcards
more folds in brain structure?
more surface area
more neural connections
one of the components associated with intelligence of mammal
cerebellum proportion of neurons of overall brain
“Although the cerebellum accounts for approximately 10% of the brain’s volume, it contains over 50% of the total number of neurons in the brain.”
cerebellum morphology/structure/function
-highly folded surface
-increases the surface area of its outer
grey matter, allowing for a greater
number of neurons
-it accounts for about a tenth of the brain
mass but contains about half of the neurons
-things that separate the cerebellum from the cerebrum:
-tentorium cerebelli
-transverse fissure
cerebellar vermis (worm)
Vermis: the central constricted part (the worm)
cerebellum “butterfly”
Hemispheres are the wings of the butterfly
cerebellum lobes
anterior lobe
posterior lobe
—-> these two govern subconscious mvt of
skeletal mm
FLOCCULONODULAR lobe
—-> involved in equilibrium
primary fissure
separates anterior/posteiror lobes
posterolateral fissure
separates posterior lobe from flocculonodular lobe
Cerebellar peduncles
-attach the cerebellum to the brain stem
-bundles of white matter
superior cerebellar peduncle
Superior
– cerebellum to red nuclei (midbrain) + thalamus
middle cerebellar peduncle
largest
- axons carry impulses for voluntary mvts from pontine nucleus to cerebellum
Functions of the cerebellum
-primary function of cerebellum is to evaluate how well movements initiated by the cerebrum are actually carried out
-if not carried out correctly, the cerebellum detects the discrepancy and sends feedback signals to the cerebral cortex
-the feedback signals help correct the errors, smooth the movements and coordinate complex sequences of skeletal muscle contractions
cerebellum vs posture
-also regulates posture and balance
damage to cerebellum and ATAXIA
-ataxia: loss of ability to coordinate muscle mvts
E.g. ataxia
Eg blindfolded and ataxia – can’t touch the tip of nose (can’t coordinate mvts with the proprioceptive info)
-changed speech pattern due to uncoordinated speech muscles
-staggering or abnormal walking gait
—> “ataxic gait”
alcohol vs cerebellum
-alcohol inhibits activity of cerebellum so drunks show signs of ataxia
ataxia vs degenerative diseases
-ataxia can also occur from
degenerative diseases (MS, Parkinson’s), trauma, brain tumours, genetic factors, meds side effects
diencephalon structures
Thalamus
Hypothalamus
Epithalamus
Thalamus 3 major functions
-relays almost all sensory input to cerebral cortex
-contributes to motor functions by transmitting information from cerebellum and basal nuclei to primary motor area of cerebral cortex
-also relays nerve impulses between different areas of the cerebrum and plays a role in the maintenance of consciousness
thalamus nuclei
1) Anterior nucleus
2) Medial nuclei
3) Lateral group
4) Ventral group (FIVE nuclei)
5) intralaminar nuclei
6) midline nucleus
7) reticular nucleus
intermediate mass of thalamus
(aka interthalamic adhesion)
-bridge of grey matter
-joins the right and left thalamus
-found in 70% of brains
—> found more often in females
Internal medullary lamina (of thalamus)
-divides the grey matter of each thalamus
-myelinated axons that enter and leave the various thalamic nuclei (y-shaped)
Internal capsule of thalamus
Internal capsule – thick band of white matter, lateral to the thalamus
three nuclei to remember for exams
vpn ventral posterior nucleus)
lgn (lateral geniculate nucleus)
mgn (medial geniculate nucleus)
4) Ventral group (FIVE nuclei)
ventral anterior nucleus
Ventral lateral nucleus
Ventral posterior nucleus
Lateral geniculate nucleus
Medial geniculate nucleus
hypothalamus
The hypothalamus controls many body activities and is one of the major regulators of homeostasis.
important functions of hypothalamus
-control of ANS
-production of hormones
-regulates emotional and behavioural patterns
-regulates eating and drinking
-control of body temperature
-regulates circadian rhythm
hypothalamus vs hormones
hypothalamus regulates production of hormones by anterior pituitary gland
hypothalamus and body temp
sweat/shiver
fever
hypothalamus and circadian rhythm
(including sleep)
24 hour (biological) clock
hypothalamus functions
-control of ANS
-control of body temperature
-regulates circadian rhythm
-regulates eating and drinking
-production of hormones
-regulates emotional and behavioural patterns
mammillary bodies are in
mamillary region
hypothalamus 4 regions
mamillary region
Tuberal region
Supraoptic region
Preoptic region
Epithalamus
-consists of pineal gland and habenular nuclei
pineal gland
-the pineal gland is part of the endocrine system because it secretes the hormone melatonin
habenular nuclei
-habenular nuclei are involved in olfaction,
especially emotional responses to odors
Basal nuclei (aka basal ganglia)
consists of 3 nuclei
—> deep within each cerebral hemisphere
the 3 nuclei of basal nuclei
Globus pallidus
Putamen
Caudate nucleus
Globus pallidus & Putamen form _______
Lentiform Nucleus
Corpus Striatum
CORPUS STRIATUM refers to the striated appearance of the internal capsule as it passes among the basal nuclei
Function of basal nuclei
-regulate initiation and termination of movements
-suppress unwanted mvts and regulate muscle tone
-control subconscious contractions of skeletal mm
-influence cortical function
(initiating and terminating cognitive processes like attention, memory and planning)
Dysfunction of circuits between basal nuclei and limbic system:
- Parkinson’s disease
- Obsessive-compulsive disorder
- Schizophrenia
- Chronic anxiety
Limbic system
-emotional brain
-plays a major role in a range of emotions
-involved in olfaction and memory
limbic system consists of
Limbic lobe
Dentate gyrus
Amygdala
Septal nuclei
Mammillary bodies
Anterior nucleus & medial nucleus
Olfactory bulbs
Fornix, stria terminalis, stria medullaris, medial forebrain bundle, mammillothalamic tract
Limbic lobe
-olfaction and memory
Dentate gyrus
-new memories, regulate happiness
Amygdala
-reward, fear, mating
Septal nuclei
-reward, reinforcement
Mammillary bodies
(of hypothalamus)
kluver bucy syndrome (FYI)
“Kluver-Bucy syndrome (KBS) is a rare neuropsychiatric disorder due to lesions affecting bilateral temporal lobes, especially the hippocampus and amygdala. It is characterized by hyperorality, hypermetamorphosis, hypersexuality, bulimia, placidity, visual agnosia, and amnesia.”
