1. Chapter 2 The Biological Basis of Behavior

2. Introduction
The brain is the control center of everything that we say and do!
Complex organ
Billons of cells
Overlapping pathways and networks
Plasticity= ability to adapt to new environmental conditions
Psychobiology= biological bases of behavior and mental processes

3. Introduction Neuroscience= study of the brain and nervous system
Neuropsychologists= study brain’s influence on behavior

4. Neurons Aka nerve cells Body contains approximately 100 billion
Varies widely in size and shape
Specialized to receive and transmit information

6. Neuron Types
Sensory neurons= carry messages from sense organs to the spinal cord or brain
Motor neurons= carry messages from the spinal cord or the brain to the muscles and glands
Interneurons= carry messages from one neuron to another
Glial cells= hold neurons in place, provide nourishment, remove waste, prevent harmful substances to passing into the brain

7. The Neural Impulse Yes-no, on-off electrochemical impulses
Ions= electrically charged particles
Resting Potential = electrical charge across a neuron membrane
Excess (+) ions on outside, (--) on the inside
Neural Impulse= the firing of a nerve cell
Polarization= a resting neuron; (--) on inside
Depolarization= inflow of (+) sodium ions
sets off a chain reaction

9. The Neural Impulse (cont)
Threshold of Excitation= the level the impulse must exceed to cause a neuron to fire
All-or-none law= the neuron will fire or it won’t
Absolute refractory period= time after a neuron has fired that it WILL NOT fire not matter what the impulse

10. The Synapse Neurons are NOT connected
Tiny space between called synaptic space
Terminal button= end of axon branch
Synaptic Vesicles = tiny sacs in terminal button that release chemicals into the synapse
Neurotransmitters= chemicals release by the synaptic vesicles

11. Neuron Toilet Worksheet

13. **review chart on page 54**
Neurotransmitters
Acetylcholine (Ach)= acts where neurons meet skeletal muscles
Role in arousal, attention, memory, & motivation
Linked to Alzheimer’s disease
Dopamine= assoc. with voluntary movement, learning, memory & emotions
Parkinson’s disease
Serotonin= “mood molecule” (sets emotional tone)
Half empty or half full
Endorphins= turn down neurons that transmit pain messages to the brain.
**review chart on page 54**

14. Neurotransmitters Imbalances have been linked to mental illness
Schizophrenia (over abundance of dopamine)
Depression (undersupply of serotonin & norepinephrine)

16. Nervous System Organization
Includes the brain and the spinal cord
Contains 90 % of the body’s neurons
Peripheral Nervous System= division of the nervous system that connects the CNS to the rest of the body

17. The Brain (cont.)

20. The Brain (cont.)
Cerebellum= sense of balance and coordinating body’s actions

21. The Limbic System
The Limbic System is a doughnut-shaped system of neural structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and drives for food and sex. It includes the hippocampus, amygdala, and hypothalamus.
Preview Question 6: What are the functions of limbic system structures?

22. Amygdala
The Amygdala [ah-MIG- dah-la] consists of two lima bean-sized neural clusters linked to the emotions of fear and anger.

23. Hypothalamus
The Hypothalamus lies below (hypo) the thalamus. It directs several maintenance activities like eating, drinking, body temperature, and control of emotions. It helps govern the endocrine system via the pituitary gland.

24. The Brain (cont.) Midbrain= important for hearing and sight
Pain is registered here (one of many)
Thalamus= “relay station” for incoming messages from the sense receptors (except for smell)
Reticular Formation= ALERT system; network of neurons
Pons- regulate sleep wake cycles
Medulla= regulates respiration, heart rate, blood pressure