Download The Brain and the Neuron (1)

Bell Activity
• http://www.npr.org/blogs/thetwoway/2013/08/30/217178528/dont-call-it-amind-meld-human-brains-connect-viainternet
• Predict how this study will help people in the
future.
• Why does a psychologist need to know about
the brain?
Phineas Gage
September 13, 1848
• Railroad worker who had a spike fly through
his skull due to an explosion. (Frontal Lobe)
• Most famous case in neuroscience.
• Personality changed after the accident.
• http://www.youtube.com/watch?v=5B2pQkq
M6nc
Lesions
• Removal or destruction of some part of the
brain.
• Can be natural or experimentally caused.
• Frontal Lobotomy
Neuron
Types of Neurons
• Sensory Neurons:
– Neurons that carry information from the sensory
receptors to the brain and spinal cord.
• Motor Neurons:
– Neurons that carry outgoing information from the
brain and spinal cord to the muscles and glands.
• Interneurons:
– Neurons within the brain and spinal cord that
communicate and intervene between sensory and
motor neurons.
Dendrites
• The extension of the neuron that receives
messages and conduct impulses toward the
cell body.
Axon
• The extension of the neuron. The part of the
neuron where messages pass to other
neurons or to muscles or glands. Neural
impulse is called the action potential.
Myelin Sheath
• A layer of fatty tissue around the axon. This
increases the speed of neural impulses and
they pass from one node to the next.
Reflex Arc
• Communication goes directly from interneurons in spinal cord
to motor neurons to move (reflexively) at the same time the
info is going to the brain to be perceived
Neural Networks
• Clusters of neurons that form a network of
cells
• The learn together as a team
The Synapse
• Synapse (synaptic cleft): gap between
dendrites of one neuron and axon of another
• Receptor sites: parts of dendrite which receive
neurotransmitters
• Neurotransmitters:
chemical substances
involved in sending
neural impulses
Resting potential
Neural Impulse: electrochemical
firing of a nerve cell
• Resting potential: electric potential when
neuron not firing (-70 millivolts)
• Depolarization: neuron reduces resting potential
by becoming positively charged
• Action Potential: neuron fires when it reaches
+30-40 millivolts
• Repolarization: internal charge becomes more
negative
• Refractory period: phase after firing an
impulse, neuron will not fire
• All-or-none principle: neuron will fire or not fire,
no in-between
• Threshold: level of stimulation required to
trigger a neural impulse (excitatory – inhibitory
= threshold)
How neurons are like toilets
• All-or-none principle: Toilet either flushes or it
does not.
• Resting potential: Water in the toilet is waiting
to fire.
• Threshold: Toilet will only flush correctly once
you push it past a critical point.
Neurons like toliets?
• Refectory period: Once you flush the toilet
you have to wait a little bit for it to flush again.
• Action potential: The water flowing down the
pipe.
Substances that Affect
Neurotransmitters
• Agonist: similar to the neurotransmitters,
mimics its effects
• Antagonist: inhibits the release of
neurotransmitters by sending neuron, or
blocks receptor site for NT on receiving
neuron
Neurotransmitters
• Acetylcholine (ACh)
Function: Muscle contractions,
learning, memory
EXCITATORY (sometimes inhibitory)
Malfunctions: Alzheimer’s Disease
Neurotransmitters
• Dopamine (DA)
Function: Voluntary movement,
sensations of pleasure & reward
Malfunctions: Too little  Parkinson’s,
Too much --> Schizophrenia
Neurotransmitters
• Serotonin
Function: Mood, appetite, sleep,
impulsivity, concentration
Malfunctions: Depression,
Eating Disorders
Neurotransmitters
• Norepinephrine
Function: Alertness, arousal,
mood, heart rate/appetite
Inhibitory & excitatory
Malfunctions: Depression
• GABA (most prevalent inhibitory NT)
Function: Decrease anxiety, sleep, reduce
seizures
Malfunctions: Anxiety disorders,
tremors, insomnia
• Glutamate (main excitatory NT)
Function: Memory & learning
Malfunctions: Migraines, seizures, addictions
• Endorphins
Function: Pain control
Malfunctions: None