BRAIN FUNCTION
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Embryology – 3-4
Weeks
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Embryology – 4 Weeks - understand
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Embryology – 5
Weeks
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Same organization as
newborn’s
Embryology – 11
Weeks
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A Child’s Brain
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Predict
•
•
•
•
Are there just a few brain neurotransmitters?
Are there over 5?
Are there over 10?
Are there over 100?
– Why would you guess that number?
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Brain Neurotransmitters - example
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Figure
9-19: The diffuse modulatory systems modulate brain function
1. Derived from amino acid
aspartate
glutamate (Glu)
γ-aminobutyric acid (GABA)
glycine (Gly)
4. Polypeptides (or
neuropeptides):
bombesin
gastrin releasing peptide
(GRP)
2. Biogenic amines
acetylcholine (Ach)
42 Brain
Neurotran
s-mitters –
examples
…and
counting!
3. Monoamines
-from phenylalanine and
tyrosine:
dopamine (DA)
norepinephrine or
noradrenaline (NE)
epinephrine or adrenaline
(Epi)
-from tryptophan:
serotonin (5hydroxytryptamine, 5HT)
melatonin (Mel)
-from histidine:
histamine (H)
Gastrins
gastrin
cholecystokinin (CCK)
Neurohypophyseals
vasopressin
oxytocin
neurophysin I
neurophysin II
Neuropeptide Y
neuropeptide Y (NY)
pancreatic polypeptide (PP)
peptide YY (PYY)
Opioids
corticotropin
(adrenocorticotropic hormone,
ACTH)
Beta-lipotropin
dynorphin
endorphin
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enkephaline
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leumorphin
4. cont’d Polypeptides (or
neuropeptides):
Secretins
secretin
motilin
glucagon
vasoactive intestinal peptide
(VIP)
growth hormone-releasing
factor (GRF)
Somatostatins
somatostatin
Tachykinins
neurokinin A
neurokinin B
neuropeptide A
neuropeptide gamma
substance P
Other neurotransmitters
nitric oxide (NO) no receptor
carbon monoxide (CO)
anandamide
Homunculus – distorted human shape - know what it is
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Primary Motor Cortex
Primary Sensory Cortex
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Sensory Homunculus – know what it is
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Motor Homunculus
– know what it is
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Adult Brain – know technical terms!
1. Forebrain (prosencephalon)
• Cerebrum (telencephalon)
• Thalamus, hypothalamus
(diencephalon)
2. Midbrain (mesencephalon)
3. Hindbrain (rhombencephalon)
• Cerebellum & pons
(metencephalon)
• Medulla oblongata
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(myelencephalon)
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Telencephalon (Cerebrum) - understand
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Diencephalon (Thalamus & Hypothalamus) understand
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Mesencephalon understand
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Metencephalon
(Pons) - understand
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Metencephalon
(Cerebellum) understand
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Myelencephalon
(Medulla Oblongata) understand
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The Ventricles of the Brain – know this!
–Hollow areas within the brain
•Connect to spinal canal and
space around the brain
–Cerebrospinal fluid circulates
around the brain, down through
the ventricles, and into the
spinal cord.
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The Ventricles of the Brain - understand
– Lateral ventricles
• Separated by the septum pallucidum (“transparent
wall”)
• Connects to third ventricle by the interventricular
foramen
– Third ventricle
• Connects to fourth ventricle by the cerebral
aqueduct
– Fourth ventricle
• Connects to the subarachnoid space and spinal
canal
– Cerebrospinal fluid circulates down through the
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ventricles and into
theHall,
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Ventricles of the Brain – find them!
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Ventricles of the Brain – find them!
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Cerebrospinal Fluid – know this!
– Composition
• Clear, colorless, watery
• Contains proteins, glucose, urea, salts
• Contains some white blood cells
– Functions
• “Floats” the brain
• Medium of transport
– Should be clear, colorless to slightly
yellowish, without red blood cells
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Problems Associated with CSF
–Hydrocephalus
–Meningitis
–Headaches
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Hydrocephalus
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Blood-Brain Barrier (BBB) - know
– Endothelial cells of capillaries form tight
junctions
• Lipid-soluble compounds diffuse across
• Water-soluble compounds are actively transported
across
– Differential rates of passage of certain materials
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The Parts of the Brain - review
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Cerebrum – Gray & White Matter – know this!
– Outer layer – cerebral cortex
• Gray matter
– Inner portion
• White matter
• Masses of gray matter – cerebral
nuclei
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Cerebrum – Gray & White Matter – know
basic arrangement
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Cerebral Nuclei – understand
– Collections of cell bodies (gray matter)
– Mostly control the movement of skeletal
muscles
– Examples
• Caudate = “tail”
–Provides general pattern & rhythm for
walking
–Maintains arm & leg movements
• Amygdaloid = “almond-shaped”
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Gyri & Sulci – know this!
Pia mater
intact on left
hemisphere
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Homunculus – know what it is
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Primary Motor Cortex
Primary Sensory Cortex
Limbic System
– Functional unit (not anatomical)
– Emotional part of the brain
• Feelings of fear, loss, love, rage, etc.
– Includes parts of several anatomical
structures
• Cerebrum
• Hypothalamus
• Thalamus
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Limbic System – know major structures
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Hypothalamus – review
– Initiates primal drives
• Hunger, thirst, sex, rage, etc.
• Controls autonomic nervous system
–“fight or flight” sympathetic
response.
– Controls pituitary gland (“master gland”
of endocrine system)
• Infundibulum (“funnel”) funnels
secretions to the pituitary gland
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Hypothalamus – review
–Location – under thalamus
–Structure
•Clusters of nerve cell bodies
–Autonomic centers
•Infundibulum
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Thalamus – review
– Functions as a relay station between
the body and the cerebral cortex
• Inform us of our emotional state
• Relay information concerned with
motor requirements & actions
• Integrate visual and auditory
reflexes
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The Thalamus – know basic location
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Epithalamus
–Location
•Above thalamus
–Contains the pineal body
•Secretes melatonin
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II. Midbrain
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Midbrain – know this!
– Relay station
– Tracts of motor and sensory neurons
– Contains nuclei
• Substantia nigra secretes dopamine
–Modifies muscle tone & motor
activity
–Parkinson’s disease
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Midbrain – know basic location
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III. Hindbrain
Cerebellum, Pons, & Medulla
Oblongata
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Cerebellum, Pons, Medulla Oblongata – know
basic locations
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Medulla Oblongata – know this!
Continuation of spinal cord
Functions
• Maintains wakefulness and alertness
• Contains reflex centers
–Cardiac center, vasomotor center,
respiratory rythmicity center
–Other nonvital centers
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Neural Imaging 1: EEG – know what it is
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EEG
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Applications of EEC Feedback - example
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Neural Imaging – 2: Brain CT Scan – know what it is
• Developed in 1970s (Nobel prize 1979)
• Noninvasive; a radio-opaque contrast dye is usually injected
intravenously
• CAT (or CT) scanning is a process that combines many 2dimensional x-ray images to generate cross-sections or 3dimensional images of internal organs and body structures
(including the brain).
• Doing a CAT scan involves putting the subject in a special,
donut-shaped x-ray machine that moves around the person
and takes many x-rays. Then, a computer combines the 2dimensional x-ray images to make the cross-sections or 3dimensional images.
• CAT scans of the brain can detect brain damage and also
highlight local changes in cerebral blood flow (a measure of
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brain activity) as the subjects
perform
a task.
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Brain CT Scan
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Neural Imaging – 3: Brain MRI
• Magnetic Resonance Imaging: Magnetic resonance imaging utilizes radiowaves.
– Radiowaves have far less energy than x-rays
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MRI – know what it is
• A MRI scanner has a large
and very strong magnet.
• A radio wave antenna is
used to send radio wave
signals to the body and then
receive signals back.
• These returning signals are
converted into pictures by a
computer attached to the
scanner.
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•
This image set is comparing a young individual (left) with an athletic male
in his 80's (center) and with a person of similar age having Alzheimer's
Disease (right),
all imaged
at the same level.
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MRI Images: Multiple Scelerosis - example
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Normal Brain MRI: Playing the piano - example
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Neural Imaging –SPECT/PET
SPECT/PET (single photon/positron emission computed
tomography)
• When radiolabeled compounds are injected in tracer amounts,
their photon emissions can be detected much like x-rays in CT.
• The images made represent the
accumulation of the labeled
compound. The compound may
reflect, for example, blood flow,
oxygen or glucose metabolism,
or dopamine transporter concentration.
• Often these images are shown with a
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color scale.
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PET scan of the brain for Alzheimer's disease
These PET scan images show normal brain activity (left) and reduced brain activity caused
by Alzheimer's disease (right). The diminishing of the intense white and yellow areas in
the image on the right indicates mild
Alzheimer's
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green colors showing decreased brainPrentice
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