Download Neuron

Neuroscience and Behavior
T/F: We only use 10% of our brains: Lucy
It’s all about the body!
crash course
Neural Communication
Neuron – a nerve cell; “building block” of the
nervous system
Icons of Science
Neuroanatomy
(include glial cells)
Khan Academy, stop @ 3:30
Neuroanatomy
• Synapse – the junction (space) between
the axon of one neuron and the dendrite
of another
• Neurotransmitter – chemicals that
carry messages across the synapse from
one neuron to another
How a Neuron Fires
Khan: stop @ 4:45
• an electrochemical process
– Electrical inside the neuron; chemical
outside the neuron
(neurotransmitters).
• called an action potential
• an “all or nothing” process
– like a gun
– greater intensity of stimulus does not
equal faster/more intense firing;
greater stimulus can mean more
neurons firing or more frequent
firing
Action Potential
1. Resting Potential - the neuron is ready to
fire
2. Reaches its threshold , then fires based on
the all-or-none response
3. Polarization  Depolarization
a) opens up portals in axon letting in
positive ions (Sodium) which mix with
negative ions (Potassium) that are
already inside the axon
b) process continues down axon to the axon
terminal
4. Terminal buttons convert electrical charge
into chemical response (neurotransmitter)
and sends message to next neuron, across
the synapse
Action Potential
The Role of Neurotransmitters
•Excitatory - neurotransmitter effect
that makes it more likely that the
receiving neuron will generate an action
potential or “fire”
•Inhibitory - neurotransmitter effect
that makes it less likely that the
receiving neuron will generate an action
potential or “fire”
SPECIFIC
NEUROTRANSMITTERS
Acetylcholine (ACh)
• vital role in movement
and memory
• too much – muscle
contractions,
convulsions
– some spider venoms
cause floods of ACh
• too little – immobility,
extreme lethargy
– Botulin causes paralysis
by blocking its release
• Undersupply of ACh has
been linked to
Alzheimer’s disease
Dopamine
• deals with
movement, learning,
attention & emotion
• lack of dopamine has
been linked to
Parkinson’s Disease
• too much has been
linked to
Schizophrenia
Serotonin
• involved in mood
control, hunger, sleep /
arousal
• lack of serotonin has
been linked to clinical
depression (Prozac and
other antidepressants
raise serotonin levels)
Endorphins
• “endogenous
morphine”
• involved in pain
control
• most addictive drugs
work with
endorphins
Neurotransmission Drugs
• Agonists - mimics / blocks reuptake / excites
• Antagonists - prevents release / blocks /
inhibits
Types of Neurons
Khan;start @ 4:50
• Efferent (Motor) Neurons
– info to body parts for movement
• Interneurons
– info within central nervous
system
• Afferent (Sensory)
Neurons
– info to CNS from body parts
• Remember… S.A.M.E.
A Neural Chain
A Neural Chain
A Neural Chain
A Neural Chain
The Nervous System
crash course
Khan
Central Nervous System
• brain and
spinal cord
• CNS
Peripheral Nervous System
• all nerves that are
not encased in bone
• everything but the
brain and spinal cord
• divided into two
categories
– somatic
– autonomic
Somatic Nervous System
• controls voluntary
muscle movement
• uses motor
(efferent) neurons
Autonomic Nervous System
• controls the
automatic functions
of the body
• divided into two
categories
– sympathetic
– parasympathetic
Sympathetic Nervous System
• “Fight or Flight”
response
• automatically
accelerates heart
rate, breathing,
dilates pupils, slows
down digestion
Parasympathetic Nervous System
• automatically calms
the body down after
a stressful event
• heart rate and
breathing slow down,
pupils constrict, and
digestion speeds up
• think, “parachute”
Reflexes
• normally, afferent
neurons  spine  brain
& brain sends orders for
movement  efferent
neurons
• some reactions occur
when sensory neurons
reach just the spinal cord
& spinal cord sends
orders
brain rap
Neural Networks
fact or fiction?
crash course: brain
• interconnected neurons
• regular connections or
routes of communication for
different tasks, processes,
etc.
• body/brain “learns”
networks over time
• “muscle memory” in sports
(“practice makes
permanent”)
• answer
Ways to Study the Brain
• Case Studies /
Clinical Observation
– Accidents (i.e. –
Phinneas Gage)
– Diseases / Disorders
Invasive Exploration
• Lesion - a natural
or man-made
destruction of
brain tissue
• Electrical Probing
• Psychosurgery
Less Invasive Methods
• Electroencephalogram
(EEG)
• Computerized Axial
Tomography (CAT Scan /
CT Scan)
• Magnetic Resonance
Imaging (MRI)
• Positron Emission
Tomography (PET)
• Functional MRI (fMRI)
The Brain
Pinky & the Brain
• made up of…
– neurons
– glial cells (or glia support neural cells
by insulating them,
removing waste, etc.)
– connective tissues
– cerebrospinal fluid
• can be divided into
three major
sections: hindbrain,
midbrain, forebrain
"Playdough" brain
Brain Structures
brain mneumonics
• Be familiar with
functions/roles.
• Location / ability to
label might be
helpful, but not
required.
Brainstem
• Pons - involved in sleep,
arousal, facial recognition
• Medulla Oblongata
 located just above the spinal
cord
 involved in the control of heart
rate, blood pressure,
respiration.
• Reticular Formation - arousal
and ability to focus attention
Cerebellum
• coordinates voluntary
muscle movements
• balance/coordination
• injury = difficulty
walking, keeping
balance, shaking hands,
etc.
Thalamus
switchboard example
• Receives sensory
information and
sends them to
appropriate areas
of forebrain.
• Like a
switchboard.
• Everything but
smell.
Limbic System
#24
• EMOTIONAL
CONTROL CENTER
of the brain.
• Made up of
Hypothalamus,
Amygdala and
Hippocampus.
Hypothalamus
• Pea sized in brain,
but plays a not so
pea sized role.
• Body temperature
• Hunger
• Thirst
• Sexual Arousal
(libido)
• Endocrine System
Hippocampus and Amygdala
• Hippocampus is
involved in
forming new
memories.
• Amygdala is vital
for our basic
emotions.
Cerebral Cortex
• Top layer of our
brain.
• Contains wrinkles
called fissures.
• The fissures
increase surface
area of our brain.
• Laid out it would be
about the size of a
large pizza.
Hemispheres
• Divided into a left and
right hemisphere.
• Contralateral
controlled- left
controls right side of
body and vice versa.
• Brain Lateralization.
Split-Brain Patients
• Corpus Collosum
attaches the two
hemispheres of
cerebral cortex.
•
right & left sides working together?
• When removed
(usually b/c of
severe seizures) you
have a split-brain
patient.
#5
Areas of the Cerebral Cortex
• Divided into eight
lobes, four in each
hemisphere (frontal,
parietal, occipital and
temporal).
• Any area not dealing
with our senses or
muscle movements are
called association
areas.
Frontal Lobe
• Deals with planning,
maintaining emotional
control and abstract
thought.
• Contains Broca’s
Area.
• Broca’s Aphasia.
• Contains Motor
Cortex.
Parietal Lobes
• Located at the top
of our head.
• Contains the somatosensory cortex.
• Rest are association
areas (intelligence!).
Occipital Lobes
• In the back of our
head.
• Handles visual input
from eyes.
• Right half of each
retina goes to left
occipital lobe and
vice versa.
Temporal Lobes
• Process sound
sensed by ears.
• Not lateralized.
• Contains Wernicke’s
area.
• Wernicke’s Aphasia.
Brain Plasticity
#7
• ability of our brains
to form new
connections (repair
itself) after being
damaged
• the younger you are,
the more “plastic”
your brain is
The Endocrine System
a system of glands that secrete
hormones into the bloodstream
similar to nervous system, except
hormones work a lot slower than
neurotransmitters
Hormones
Neurotransmitters
Endocrine System
• System of glands
that secrete
hormones.
• Controlled by the
hypothalamus.
• Ovaries and Testes.
• Adrenal Gland
• Epinephrine-energy
boast (adrenaline)
So what’s the REAL significance of
this chapter??
• hold your stomach!