1. Biological Psychology
….explaining human behavior through biology

2. Remember from class our list of the “biological events” that might be involved in (i.e., might help explain) human behavior?
Genetic make-up—the genetic inheritance we receive from our biological parents
Nervous system functioning
Hormones—endocrine system
Brain structure & function—the size and shape of different brain areas & how these different areas “work”

3. First, let’s review the function of the nervous system…one of the two communication systems within the body

4. The nervous system is made up of …
Central nervous system (CNS)—the brain & the spinal cord
Peripheral nervous system (PNS)—everything else. The PNS can be broken down into two sub-parts
Skeletal, somatic nervous system—skeletal muscles for voluntary movement
Autonomic nervous system—non-skeletal muscles found in organs, typically operate without voluntary control

5. Autonomic nervous system includes….

7. The CNS & PNS work together in executing behavior…
e.g., information from our senses (PNS) are sent to the brain (e.g., the “sound” of a teacher asking a question in class) and our brain (CNS) sends messages to tell our skeletal muscles (PNS) what to do (e.g., raise your hand because you have something to say!)

8. Messages are sent via…..
NEURONS!!!!

9. Neurons… …allow for communication within the body.
There are networks of neurons throughout the body—somewhere in the vicinity of 100 billion neurons throughout the body
No two neurons are exactly alike in size or shape. They range in length from a millimeter to several feet.

10. Neurons Soma (cell body) –contains cell nucleus
No two neurons are alike….
..but all have the same basic parts:
Soma (cell body) –contains cell nucleus
Dendrites—receive information from other neurons
Axon—transmits info from dendrites to other neurons
Terminal buttons—at the end of the axon—their job is to transmit info to the dendrites or cell body of next neuron

11. Neurons—Make sure you can label the different parts on the neuron on the next slide
(You can use your book if you need help--& ask in class if you need more help!)

13. Communication within neurons is electrical
Communication within neurons happens through the process of conduction
An electrical signal is sent down the length of the axon. This electrical signal is called an “action potential”
Some axons are myelinated (i.e., covered with a fatty tissue called the myelin sheath)—myelinated axons allow for quicker transmission of the electrical impulse.

14. Communication between neurons is chemical
When the electrical impulse reaches the terminal buttons, they release chemicals called neurotransmitters into the synapse.
These neurotransmitters connect with receptor sites (located mostly on the dendrites, but also some on the soma) of nearby neurons. The neurotransmitters “fit in” to these receptor sites like locks into keys

15. Communication between neurons is chemical
In this “lock & key” fashion, neurotransmitters unlock tiny channels at the receiving sites on nearby neurons, and electrically charged atoms enter the receiving neuron.
These electrically charged atoms—through altering the electrical charge of the receiving neuron—either excite or inhibit its readiness to fire an electrical impulse down it’s axon

16. Communication within neurons is electrical
Neurons fire when their electrical charge reaches what is called the threshold of excitation.
When this threshold is reached, they send an electrical charge or impulse down their axons. This electrical impulse is called (as I mentioned earlier) “an action potential.”

17. Communication between neurons is chemical and within neurons is electrical…
Through binding with receptor cells, neurotransmitters alter the likelihood of the receiving neurons reaching the threshold of excitation, thus they are either inhibitory (make the firing of the receiving neuron LESS likely) or excitatory (make the firing of the receiving neuron MORE likely).

18. Neurotransmitters…
…are chemicals that are released into the synapse by neurons.
These neurotransmitters are “taken back up” into the terminal buttons of neurons through the process of reuptake

19. Neurotransmitters…
..and the balance of neurotransmitters in the body have been implicated in a number of conditions that are very interesting to psychologists, such as depression or schizophrenia (a mental disorder in which an individual loses touch with reality and e.g., may hear voices or see things that aren’t there—called hallucinations)

20. Psychotropic drugs (drugs used to treat psychological conditions)
…work through altering neurotransmitter balances in the body

21. Psychotropic drugs
Agonists mimic the neurotransmitter by binding to the receptor sites just as the neurotransmitters do and having the same effect on the receiving neuron. Agonists are used when it is believed that there is not enough neurotransmitter
Antagonists BLOCK the neurotransmitter by binding to the receptor sites without affecting the receiving neuron in the same way. Because they “fill” the receptor sites, the neurotransmitters can’t bind to the neuron. Antagonists are used when it is believed that there is TOO much of the neurotransmitter in the body.

22. Psychotropic drugs
When there is TOO LITTLE neurotransmitter in the body, drugs may also help by blocking reuptake and thus increasing the amount of neurotransmitter that remains in the synapse
Prozac is an example of this sort of drug. Prozac falls in a class of drugs called SSRI’s (Selective Serotonin Reuptake Inhibitor) and by inhibiting reuptake of serotonin, they increase the levels of this neurotransmitter in the brain.

23. The two communication systems for your body are:
The nervous system (which we’ve just been discussing) AND
The endocrine system—Read the section in your textbook on the endocrine system on pp of your textbook

24. THE BRAIN

25. THE BRAIN
The cerebral cortex is a higher-level brain structure…it’s responsible for higher-level cognitive processes
The cerebral cortex covers the two hemispheres of the brain with wrinkled folds (sort of like a cauliflower)….these “wrinkles” increase the entire surface area of the cortex.
The cerebral cortex consists of 30 billion nerve cells and around 300 trillion synaptic connections!

26. The cerebral cortex
For convenience sake, each hemisphere of the brain is often subdivided into four different lobes—or four different geographic regions..
The cerebral cortex provides many functions for the body—some of these functions have been “localized” (i.e., the particular part of the cortex that carries the functions out have been identified) but it is important to realize that multiple areas of the brain work together for most complex human behaviors.

27. Functions of the cerebral cortex
Motor functions—the motor cortex is located at the rear of the frontal lobe.
Sensory functions—the sensory cortex is located in the front of the parietal lobe (right behind the motor cortex)
Note that each hemisphere of the brain controls and receives info from the OPPOSITE side of the body. So the command for moving your left arm originates from the motor cortex in your right hemisphere.

28. Functions of the cerebral cortex
Sensory functions (continued)
Information from the optic nerve is sent to the visual cortex located in the occipital lobe
Information from the sensory organs in our ears are sent to the auditory cortex located in the temporal lobes

29. Functions of the cerebral cortex
Associational functions—
Our brain does lots of organizing and interpretation of information. This organization and interpretation is accomplished by association areas in the brain
Association areas are believed to make up ¾ of the area of the brain
Association areas of the brain used for planning ahead are believed to be located in the frontal lobes of the brain

30. Functions of the cerebral cortex
Motor functions
Sensory functions
Associational functions
Language functions—Two important brain areas for language are:
Wernicke’s area—located in the left temporal lobe—important for our understanding of language
Broca’s area—located in the left frontal lobe—important for spoken language

31. A mnemonic (memory) device that you can use to remember some of the locations of these functions…
Frontal: forethought—thinking & planning ahead (associational areas)
Occipital: observing –vision (visual cortex)
Temporal: twanging –sound (auditory cortex)
Parietal: prickling—sensation (sensory cortex)