Chapter 4

3. What changes in brain activity occur as a person goes to sleep, and how do we measure these changes?
As a person drifts off to sleep they go through 4 stages from being in a light sleep in stage 1, to a deep sleep in stage 4. The brain activity slows from stage 1 to stage 4. These changes can be measured by an EEG (electroencephalogram).

5. What is addiction, and what brain processes play a central role in it?
Addiction is when the body has to have a certain substance to stay normal and not go through withdrawal.
The insula becomes active when viewing images of the drugs the person is addicted to and is the main cause of addiction.

Chapter 3 questions

1.       The difference between genotype and phenotype. The genotype is the genetic makeup of a person.  The phenotype is the physical attributes of the person, or the genes that are expressed. 

2.       Distinctions among motor neurons, sensory neurons, and interneurons.  Sensory neurons send signals to the brain through the spinal cord that comprehend the senses around a person. Motor neurons come from the brain to the muscles to move. Interneurons are neurons that communicate with each other in the brain.

3.       What is dopamine and what function does it serve?  Dopamine serves as motor function and also lets us experience pleasure when activated.

4.       The amygdala and what it does.  The amygdale associates things with positive or negative emotions. It also incorporates memory to activate emotions.

5.       How learning may be represented in the brain. When two neurons fire at the same time they form a strong synapse. The more synapses you have the more you know/ learn. This is how we think and have memories.  The hippocampus stores memories but is continually overwritten as we forget and remember new things. 

6.       What are monozygotic and dizygotic twins and how can we compare them to determine whether some behavior is partly caused by genetic factors.  Monozygotic twins are commonly named “identical twins” because they look identical because they are made from the same egg and sperm but it was split in two.  Dizygotic twins are also called “fraternal twins” because they aren’t identical and were created by two different sperm and egg cells.  There are many experiments involving mono and dizygotic twins.  If you separate the identical twins at birth but they turn out similar than their personality is primarily caused by nature, however if they act differently, then their personality is primarily caused by nurture. Fraternal twins are genetically no more alike than two regular siblings but you can still use experiments to see if they are  manipulated by nurture more than nature.

7.       What is the difference between axons and dendrites and what functions do they serve in neurons. The dendrites receive the signals with its branchlike appendages from nearby neurons and deliver it to the cell body of the neuron.  The axons take that signal and transmit it over long distances with its myelin sheath. Because of axons and dendrites our body can give and signals of stimuli to and from our CNS.

8.       Describe the resting potential and the action potential.  What ion movements occur during the action potential? Resting potential is when a neuron is not being activated, it is an ongoing state of negativity.  However when a neuron is stimulated the neuron goes into action potential and chemicals are released from terminal buttons. The two main types of ions in producing a stimulus are Sodium and Potassium.    

9.       How do neurotransmitters allow one neuron to communicate with another? Neurons do not touch each other, instead they send neurotransmitters from one axon to a dendrite across a synaptic cleft. These neurotransmitters are stored in vesicles that fuse with the presynaptic membrane one activated by action potentials.  Then the neurotransmitters bind to the postsynaptic receptors of the dendrite. 

10.   List the four lobes that form each brain hemisphere, and describe the areas of the cortex that process seeing, hearing, touch, and movement. The four lobes of the brain are the Frontal Lobe, Parietal Lobe, Occipital Lobe, and Temporal Lobe.  The Temporal lobe processes hearing, the Occipital lobe processes sight, the Parietal Lobe processes touch, and the Parietal Lobe processes movement.