Interbrain and Brainstem

Cerebral Cortex - The outermost layer of the brain
containing gray matter. Responsible for many "higherorder" functions like language and information
Cerebral Cortex
Layers of the Cerebrum
• Gray Matter
– Outer layer of the brain
– Composed of neuron cell bodies (site of nucleus)
– Includes regions of the brain involved in muscle control, sensory
perceptions, like seeing and hearing, memory, emotions, speech and
critical thinking/problem solving
Body of
Layers of the Cerebrum
• White Matter
– Contains mainly long, myelinated axons
– Involved in the relay of sensory information
from the rest of the body to the cerebral cortex
Myelin = fatty
outer covering of
Allows for faster
transmission of
Axon of
Limbic System
• set of evolutionary
primitive brain
• involved in emotions
and motivations, like the
ones related to survival
– fear, anger, sexual
• also involved in feeling
of pleasure
– eating and sex
Limbic System Structures
• Amygdala – linked to both fear
responses and pleasure. Anxiety,
autism, depression, post-traumatic
stress disorder, and phobias are
linked to abnormal functioning
• Hippocampus – sends memories
out to the appropriate part of the
brain for long-term storage and
retrieves them when needed.
– damage to hippocampus can
cause an inability to form new
Amygdala shrinks by more than 30% in
males upon castration – minimizes pleasure
Diencephalon – “Interbrain”
• Sits on top of the brain
• Enclosed by the cerebral
hemispheres; wellhidden brain region
• Made of three parts
– Thalamus
– Hypothalamus
– Epithalamus
• The relay station for sensory
impulses (switchboard)
• Transfers impulses to the
correct part of the cerebrum
for interpretation
• All incoming impulses get
sorted here first and
identified as pleasant or nonpleasant
• Under the thalamus
• Controls organs by maintaining
• Important autonomic nervous
system center
– Helps regulate body
– Controls water balance
– Regulates metabolism
The pituitary gland is attached to the
hypothalamus. It releases hormones
which affect growth, sexual
development, metabolism and
• Helps to regulate the
sleep/wake cycle by
releasing hormones like
melatonin from pineal gland
• Controls some parts of
emotions and mood
Brain Stem
• Attaches to the spinal cord;
primitive “rat brain”
• Controls automatic
behaviors necessary for
survival (breathing)
• Parts of the brain stem each
about an inch long
– Midbrain
– Pons
– Medulla oblongata
• Midbrain = Smallest region of
the brain which relays auditory
and visual information.
– Also controls eye movements,
like blinking
• Pons = “bridge” of the brainstem.
Controls Breathing.
• Medulla Oblongata = The lowest part of the brain
– Merges into the spinal cord
– Contains important control centers
Heart rate control
Blood pressure regulation
• contains ~70% of all the brain's
neurons; yet is only 10% of the
volume of the brain!
• contributes to precise timing of
skeletal muscle activity (i.e.
walking, running or standing on
your hands)
• controls our balance and
• Doesn’t function well under
influence of alcohol
• Works like ‘auto pilot’ –
monitors body position and
amount of tension in body parts
Cerebellum and other brain parts
Meninges = three
connective tissue
membranes covering
and protecting brain
Dura Mater: outermost meninges; tough and thick. Can restrict
movement of the brain within the skull. Protects the brain from
movements that may stretch and break brain blood vessels.
Central Nervous System Disorders
• Meningitis = inflammation of
meninges. Serious threat since
bacteria or viruses can spread to
• Concussion = injury is slight;
dizzy, see stars, or lose
consciousness briefly but no
permanent damage.
• Stroke = blood circulation to a
brain area is blocked from ruptured
blood vessel or blood clot.
More Brain Disorders
• Hemorrhage = bleeding from
ruptured blood vessels.
• Aneurysm = dilation, bulging or
ballooning out of part of the wall
of a vein or artery in the brain
– Can get larger over a lifetime
– Pushes on brain regions
causing symptoms like blurred
vision, stutter, etc.
– Can hemorrhage
What brain structures
can you see?