Transcript Major Brain Structures and Functions

Major Brain
Structures
and Functions
Warning!
• The brain is not neatly organized into structures
that correspond to specific behaviors
• Most behavior involves neural activity in many
brain parts
• Here we are generalizing! The brain is not as
simple as we will make it sound!
The Brainstem: Oldest part of the
brain; Present in all mammals; Hidden
underneath cerebrum
Brain Stem
daf
Your brainstem is
also your crossover
point: most nerves to
and from each side of
the brain connect
with the body’s
opposite side
place where spinal
cord begins to swell;
life support center:
breathing, heart rate,
blood pressure
“netlike”; runs from the
spinal cord to the
thalamus; arousal; alerts
higher parts of the brain;
neurons with serotonin and
norepinephrine are found
here (help us respond
based on state of arousal)
Pons: “bridge”
between cerebral
cortex and medulla;
involved in
coordination of
movement, sleep,
arousal, facial
expressions
Thalamus and Cerebellum
Thalamus: 2 egg
shaped structures;
sensory switchboard;
receives info from all
senses (except smell)
and routes them to
higher brain regions;
“gateway” to the
cortex; also involved
in sleep (helps us
tune out during deep
sleep)
baseball sized; “little brain”;
judgment of time,
discrimination of sounds and
textures; coordinates voluntary
movement; balance;
coordination; memories of
skills; certain reflexes
Why not smell? Smell is an “old”
sense; It goes to the olfactory cortex
and then the thalamus
Midbrain: In between brain stem
and limbic system
smallest “region”;
acts as a relay
station for
auditory and
visual
information;
control of body
movement;
degeneration of
dopamine
neurons here
causes
Parkinson’s; one
of the areas where
pain is registered
Limbic System: “border” between
brain’s older and newer parts
“below”; reward
center: hunger,
thirst, body
temperature,
sexual behavior;
monitors blood
chemistry;
motivation;
biological
rhythms
part of endocrine system;
master gland; works with
hypothalamus to secrete
certain hormones
lima bean sized;
“almond”;
influence fear
and aggression;
processing of
emotional
memories
“sea horse: new
memories;
learning
Cerebrum: Two Large Hemispheres; 85%
of the brain’s weight
• Cerebral Cortex: “bark”; thin layer of interconnected neural
cells that cover the hemispheres; contains more than 300
trillion synapses
• The more complex the animal, the larger the cerebral cortex
• What’s underneath? Filled with the axons that connect the
cortex to the brain’s other regions
• Divided into lobes based upon fissures or folds
• Brain’s two halves are connected by the corpus callosum
(band of neural tissue that connects the two halves of the
brain)
Corpus Callosum
What’s in the Cerebral Cortex?
• Specialized cortexes control sensory functions
(movement, sight, hearing, touch, etc)
• Other areas are known as association areas
– Areas of the cerebral cortex that are not involved
in primary motor or sensory functions
– Involved in higher mental functioning (learning,
remembering, thinking, speaking, etc)
Association Areas
Frontal Lobes
• Executive control center: coordinates messages from all of the
lobes
• Association Areas: judgment, planning, processing of new
memories, personality
• Cortex: Prefrontal cortex – goal directed behavior, control of
impulses, metacognition (thinking about thinking), attention
Motor Cortex
• In the back of the frontal lobe
– Arc –shaped from ear to ear (like a headband!)
• Controls voluntary movements
• Body areas that require precise control (fingers,
mouth) take up more space in the motor cortex
Parietal Lobes
• Association Areas:
mathematical and
spatial reasoning
(larger and unusually
shaped in Einstein's
brain)
• Cortex: Sensory Cortex
– front of parietal lobe;
registers and processes
touch, taste, pain, skin
temperature
(Somato)Sensory and Motor Cortex
Temporal Lobes
• Balance, equilibrium;
right side allows us to
recognize faces
• Auditory cortex:
processes auditory
information
Occipital Lobes
• Visual Cortex: Processes visual information
Language
• Broca’s Area: controls language expression
– Usually in the left frontal lobe
– Directs muscle movement involved in speech
• Wernicke’s Area: controls language reception
– Usually in the left temporal lobe
– Involved in language comprehension and expression
– “Mother is always her working her work to get her better,
but when she’s looking the two boys looking the other
part. She’s working another time”
• Aphasia: impairment of language
Language
Brain (Neural) Plasticity
• The brain’s ability to modify itself after some
types of damage
• Severed neurons do not usually regenerate
• Instead, the brain’s neural tissue can
reorganize itself
• One brain area can take on functions not
normally “assigned” to that area
• Brain’s are most plastic when we are young