1. Chapter 2: Biology, Neurons, and Brain Imagery

2. Case Study
SM: The No-Fear Woman

3. Why is learning to play an instrument good for the brain?

4. Introduction
At birth have extra supply of nerve cells; stabilizes in adolescence
200,000 will die every day of your adult life
you will end up with 98% of your supply by the time you’re 70

5. Neurons
Individual cells in nervous system that receive, integrate, & transmit info

6. Parts of the Neuron
1. Soma: is the cell body, which contains the nucleus.
2. Dendrites: (Greek for tree)
branching extensions that receive incoming messages and conduct messages toward the cell body.

7. Parts of A Neuron
3. Axon: extension of a neuron which takes messages from the soma to other neurons, muscles or glands
Longest part of the neuron
4. Myelin Sheath: white fatty substance around axons; allows faster transmission speeds of signals
Multiple sclerosis leads to deterioration
Slows communication to muscles – loss of muscle control

8. How does a neuron communicate?
Resting Potential: neuron is in its normal, resting state
Ions within the cell give the axon a small negative charge, fluid outside is positive charged
When the cell body becomes excited, triggers a cascade of events (like setting a little fuse on fire and keeps going until it blows up)
Action potential: temporarily reverses the charge (positive) and causes an electrical signal to race along the axon. (200 mph)
Happens when sense receptors feel something
Chain reaction along axon to end

9. Your turn! Draw and label a neuron in your notes

10. How does a neuron communicate?
Refractory Period – neuron pumps the positively charged sodium ions back outside (pausing to recharge)

11. How Does A Neuron Communicate?
Some signals are excitatory – (pushing on accelerator); some are inhibitory (pushing on brakes)
If excitatory signals exceed maximum intensity (threshold) it will trigger an action potential
All or none principle: it fires or it doesn’t (doesn’t differ in intensity)
Whole cycle takes less than 1/100th of a second

12. Neuron Communication With Other Neurons
In order for one neuron to communicate with another it must pass a junction or gap called the synapse between the axon which is sending the signal and the dendrite which is receiving the signal.
At the ends of the axon, the terminal buttons release neurotransmitters: which are chemical messengers that bind together neurons and influence whether another neural impulse will take place.

13. Neural communication Reuptake- regulates amount of NT
Drugs affect neural communication at the synapse
Antidepressants often act as reuptake initiators and helps regulate
Insomnia is regulated by serotonin

14. Neuron Communication

15. Glial Cells
Glial Cells: provide structural support, nourishment and insulation of neurons, maintains chemical environment
Helps in forming new synapses
New research suggests may be crucial in part of the process of learning
Form a myelin sheath-fatty insulation around some axons in brain and spinal cord
Helps speed up neural impulses
Multiple sclerosis is a disease in which the myelin sheath degenerates-leads to loss of muscle control

16. Review: Can you name them all?

17. Schizophrenia, Parkinson’s disease
Neurotransmitters
Normal Function:
Produces sensations of pleasure and reward; used by CNS neurons in voluntary movement
Dopamine
Serotonin
Norepinephrine
Problems with Imbalance:
Schizophrenia, Parkinson’s disease
Acetylcholine
GABA
Substances that Affect:
Cocaine, amphetamines, Ritalin, alcohol
Glutamine
Endorphins
Copyright © Allyn & Bacon 2007

18. Depression, certain anxiety disorders, obsessive- compulsive disorder
Neurotransmitters
Normal Function:
Regulates sleep and dreaming, mood, pain, aggression, appetite and sexual behavior
Dopamine
Serotonin
Norepinephrine
Problems with Imbalance:
Depression, certain anxiety disorders, obsessive- compulsive disorder
Acetylcholine
GABA
Glutamine
Substances that Affect:
Prozac, hallucinogenics (e.g. LSD)
Endorphins
Copyright © Allyn & Bacon 2007

19. High blood pressure, depression
Neurotransmitters
Normal Function:
Controls heart rate, sleep, sexual responsiveness, stress, vigilance and appetite
Dopamine
Serotonin
Norepinephrine
Problems with Imbalance:
High blood pressure, depression
Acetylcholine
GABA
Substances that Affect:
Tricyclic antidepressants, beta blockers
Glutamine
Endorphins
Copyright © Allyn & Bacon 2007

20. Certain muscular disorders, Alzheimer’s disease
Neurotransmitters
Normal Function:
Primary transmitter used by neurons carrying messages from CNS; involved in some kinds of learning and memory
Dopamine
Serotonin
Norepinephrine
Problems with Imbalance:
Certain muscular disorders, Alzheimer’s disease
Acetylcholine
GABA
Substances that Affect:
Nicotine, botulism toxin, curare, atropine
Glutamine
Endorphins
Copyright © Allyn & Bacon 2007

21. Most prevalent inhibitory neurotransmitter in neurons of CNS
Neurotransmitters
Normal Function:
Most prevalent inhibitory neurotransmitter in neurons of CNS
Dopamine
Serotonin
Norepinephrine
Problems with Imbalance:
Anxiety, epilepsy
Acetylcholine
GABA
Substances that Affect:
Barbiturates, tranquilizers (e.g. Valium, Librium), alcohol
Glutamine
Endorphins
Copyright © Allyn & Bacon 2007

22. Brain damage after stroke
Neurotransmitters
Dopamine
Normal Function:
Primary excitatory neurotransmitter in CNS; involved in learning and memory
Serotonin
Norepinephrine
Acetylcholine
Problems with Imbalance:
Brain damage after stroke
GABA
Substances that Affect:
PCP (“angel dust”)
Glutamine
Endorphins
Copyright © Allyn & Bacon 2007

23. Pleasurable sensations and control of pain
Neurotransmitters
Dopamine
Normal Function:
Pleasurable sensations and control of pain
Serotonin
Norepinephrine
Problems with Imbalance:
Lowered levels resulting from opiate addiction
Acetylcholine
GABA
Substances that Affect:
Opiates: opium, heroin, morphine, methadone
Glutamine
Endorphins
Copyright © Allyn & Bacon 2007

24. Neural communication
Agonists excite neurons by mimicking natural neurotransmitters or blocking their reuptake to keep more of them in your system
Antagonists inhibit neural impulses by blocking receptor sites or diminishing their release
One reason it is difficult to design pharmaceutical drugs is that we have a blood brain barrier: which is a membrane that only lets certain chemicals pass through
Parkinson’s suffer from a lack of dopamine, but dopamine can’t cross the barrier, therefore we can’t give them dopamine
L-Dopa must be used (kind of like synthetic dopamine) because it can cross the barrier

26. Nervous system
Reflexes: (automatic responses) are a good example of how the spinal cord works; brain not involved in simple reflexes
Simple spinal pathways only involve 2 neurons
sensory neuron
motor neuron
communication through an interneuron
ex. knee-jerk
ex. hand on a hot stove

27. Figure 2.9 A simple reflex Myers: Psychology, Eighth Edition Copyright © 2007 by Worth Publishers

28. Nervous system
if you become paralyzed from a spinal cord injury these reflexes still work; depending on type of damage
Brain involved in voluntary movements; how paralysis occurs with spinal injury, the higher the greater extent of damage.

29. Nervous system
Peripheral Nervous System: the sensory and motor neurons that connect the CNS to the rest of the body
nerve- bundled axons of motor and sensory neurons
We have 3 types of neurons
1) sensory neurons- afferent -carry info. from sense receptors toward the Brain
2) motor neurons-efferent- carry information away from the Brain to the muscles, organs, and glands
3) interneurons- the go-between-most of the neurons in the brain and spinal cord. Relay messages from sensory neurons to other interneurons or to motor neurons, sometimes in complex pathways.

30. Nervous system Peripheral Nervous System – has many branches
1) Somatic nervous system
controls voluntary movements of skeletal muscles
communications link with the outside world
sensory and motor components
2) Autonomic nervous system
controls the glands and muscles of our internal organs
operates without us thinking about it
heartbeat, breathing, digestion, etc.
broken down into 2 divisions; even while sleeping and unconscious

31. Autonomic Nervous system
3) Sympathetic nervous system
arouses the body to deal with stressful situations
slows digestion, raises heartbeat and blood sugar, dilates your arteries, etc.
prepares for “fight or flight”
4) Parasympathetic nervous system
calms the body to bring it back into homeostasis
decreases heartbeat, lowers blood sugar, etc.