DO NOW
• What is the neurotransmitter involved in the
use of cocaine?
• How does cocaine affect the way this
neurotransmitter?
(hint: check Mouse Party handout)
Quick Review:
Synapses, neurotransmitters & neurons…oh my!
Neuron
Synapse
Neurotransmitters
• Cells of the nervous
system that transmit
electric and chemical
signals
• Tiny gap where 2 or
more neurons
connect, (pass info)
• Chemicals in the
endings of nerve cells
that send information
across synapse
What are Some Neurotransmitters made up of?
Dopamine
Motor Functions
Too much – Schizophrenia (theory)
Too little – Parkinson's and other
movement diseases
Acetylcholine
Attention and R.E.M. Sleep Inducer
Too little: muscle weakness
Endorphin
Relieve pain, Natural form of morphine
Serotonin
chemical that helps maintain a "happy
feeling," helps with sleep, anxiety,
depression
GABA
gamma-aminobutyric acid
amino acid that helps induce relaxation
and sleep, builds muscle tone.
It balances the brain by inhibiting overexcitation
What have we learned?
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Sensory Neurons:
Travel from body to brain
Motor Neurons:
Travel from brain to body
Interneurons:
Connect sensory and motor neurons
Neurotransmitters:
Chemicals in the endings of nerve cells that send information across
synapse
Central Nervous System:
Brain and Spinal Cord
Peripheral Nervous System:
Sensory neurons, motor neurons, sensory organs
What are reflexes?
•A reflex is an involuntary or automatic,
action that your body does in response to
something - without you even having to think
about it.
• Reflexes are processed in the spinal cord and not
the brain
• Reflexes protect the body before the brain knows
what’s going on
• Reflexes protect your body from things
that can harm it.
• For example, if you put your hand on a
hot stove, a reflex causes you to
immediately remove your hand before a
"Hey, this is hot!" message even gets to
your brain
• Blinking when something flies toward
your eyes or raising your arm if a ball is
thrown your way. Even coughing and
sneezing are reflexes. They clear the
airways of irritating things
Reflex Arc
Activity:
The pupil reflex
Common Reflexes
Babinski
(foot)
Rooting
(sucking)
Moro
(startle)
Pupillary
(eyes – constriction
Or dilation)
Tonic
(fencing)
Galant
(leaning against
side of spine
that is stroked)
Babinski on Infant
Babinski Reflex
• Babinski's reflex occurs when the big toe
moves toward the top of the foot and the
other toes fan out after the sole of the foot
has been firmly stroked.
• This reflex, or sign, is normal in younger
children, but abnormal after the age of 2
• The presence of a Babinski's reflex after age 2
is a sign of damage to the nerve paths
connecting the spinal cord and the brain
Babinski Explanation
Moro
Moro Reflex
• Arms will rapidly fan out as if startled.
• It is normally present in all infants/newborns
up to 4 or 5 months of age
• Absence indicates a profound disorder of the
motor system.
• Persistence of the Moro response beyond 4 or
5 months of age is noted only in infants with
severe neurological defects
• It is believed to be the only unlearned fear in
human newborns
Moro Reflex in baby kitten too
Tonic (Fencers) Reflex
• known as the “fencing reflex" because of the
characteristic position of the infant's arms
and head, which resembles that of a trained
fencer.
• Beyond the first months of life may indicate
that the child has developmental delays, at
which point the reflex is atypical or abnormal.
For example, in children with cerebral palsy
the reflexes may persist and even be more
pronounced.
Tonic
Knee Jerk (Patellar) Reflex
Causes of Abnormal Knee Jerk Response
• Hyperactive (knee jerks too much): ALS, brain
tumor, stroke, liver disease, hypocalcemia (low
calcium), hypomagnesemia (low magnesium),
hypothermia, multiple sclerosis, preeclampsia,
spinal cord lesion and tetanus.
• Hypoactive (knee doesn't jerk enough):
botulism, nerve inflammation, peripheral
neuropathy, polio, untreated syphillis,
diabetes, alcoholism, arthritis, etc.
What have we learned about
reflexes?
• Types of reflexes: Knee Jerk, Babinski, Moro, Fencers (Tonic)
• Primitive reflexes in adulthood often sign of neurological
disease
• Absence of reflexes in infancy – neurologicial problem
• Normal reflexes protect us.
• Reflexes use interneurons – not sensory or motor neurons.
Reading
Knee Jerk or (DTR) reflex
• The reflex that the doctor checks by tapping
your knee is called the patellar, or knee-jerk,
reflex. It is also known as a deep tendon reflex
(DTR) This tap stretches the tendon and
the muscle in the thigh that connects to it.
• A message then gets sent to the spinal cord
that the muscle has been stretched. The spinal
cord very quickly sends a message back to the
muscle telling it to contract. The contraction
of the muscle causes your lower leg to kick
out.
Do Now: Awakenings – final day
• In reality, Dr. Sacks was conducting a double blind study
with 50% of the group on the L-Dopa and the rest on a
placebo. When Dr. Sacks saw the respons, he
immediately put the entire group on the drug. The
family members had to sign approvals releasing the
hospital from responsibility. Do you think this was
ethical? Why/Why not?
• Even though Dr. “Sayer” was the doctor and Leonard
was the patient – do you think he learned anything
from Leonard. Do you think it would’ve been better for
the patients to remain in their frozen states rather than
giving them back life for only a summer?
Headaches
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Vascular Headaches: Migraines
Muscle Headaches: Cluster, Tension
Worst Headache of your life! – aneurism
Seizures: Grand Mal, Petit Mal, Absence
• Types of reflexes: Knee Jerk, Babinski, Moro,
Fencers (Tonic)
• Primitive reflexes in adulthood often sign of
neurological disease
• Normal adult reflexes protect us.
Dr. Oliver Sacks
In 1966 Dr. Sacks began working as a consulting neurologist
for Beth Abraham Hospital in the Bronx, a chronic care
hospital where he encountered an extraordinary group of
patients, many of whom had spent decades in strange,
frozen states, like human statues, unable to initiate
movement. He recognized these patients as survivors of
the great pandemic of sleepy sickness that had swept the
world from 1916 to 1927, and treated them with a thenexperimental drug, L-dopa, which enabled them to come
back to life.
They became the subjects of his book Awakenings, which
later inspired a play by Harold Pinter ("A Kind of Alaska")
and the Oscar-nominated feature film ("Awakenings") with
Robert De Niro and Robin Williams. Dr. Sacks is a NYT
bestselling author and award winning Neurologist. You can
reach him at
This film is based on a true story
Do you remember?
• Why do we have reflexes?
• Describe two reflexes you have now
• Describe one reflex you don’t have anymore
and why