Researchers wanted to test if the color of paper effects test scores. They used two groups, group one tested with standard white paper, and group two took the test on green paper. They then compared the mean scores between the two groups. What is the dependent variable? What is the independent variable? Is this an experiment or quasi-experiment? What kind of grouping was used? What was each group? Was there a control? Was there a placebo?

An experiment was run to see if there is a difference in short term memory between men and women. A group of 20 men are asked to memorize and then recall a list of numbers, the list starts at 3 number and moves all the way up to 10. The same is done for the group of women. The mean of the correctly recalled numbers is used to compare. What is the dependent variable? What is the independent variable? Is this an experiment or quasi-experiment? What kind of grouping was used? What was each group? Was there a control? Was there a placebo?

A researcher wanted to test the effects of caffeine on recall of studied material. A group of 30 people were given either a sugar pill or a pill of 200 mg of caffeine and asked to study some math problems. After one day they were tested on the material. Each person was then given which ever pill they did not receive the first time and retested. The difference between the two recall sessions were compared. What is the dependent variable? What is the independent variable? Is this an experiment or quasi-experiment? What kind of grouping was used? What was each group? Was there a control? Was there a placebo?

A researcher wants to study whether caffeine can aid people in studying for an exam. Design a basic way to research this question using each level of analysis we discussed (Case study, naturalistic observation, the survey, correlation, and experiment). For the experiment identify the dependent variable, independent variable, style of grouping, groups and any control or placebos used.

The Biology of Behavior

Goals Understand the various biological elements that produce behavior Be able to describe the basic structure of the nervous system the physiological processes that allow it to perform its job Understand some of the theories about how neurons encode, process and retrive information, and how they change over time

Outline Overview of the biological processes that effect behavior The structure of the neuron The physiology of neuron action How neurons communicate and form networks The parasympathetic and central nervous systems

Neural and Hormonal Systems

The Structure of the Neuron

Action Potential The action potential is often called a “wave” but it is not a physical wave, but an exchange of ions at key points along the axon.

Diffusion Principle Diffuse Proximity High ConcentrationLow Concentration

There are more positive charges outside and more negative charges inside The cell membrane Is an insulator

Sodium-Potassium Pump “Active” Diffusion, The Sodium-Potassium pump changes the concentration gradient, pumping positive ions out creating a net negative charge When “fired’ the channels open and the higher concentration of positive ions out side the cell flood in changing the charge to positive Once the signal moves on the pumps reset the electrical charge pushing positive ions outside the cell again.

The value for the resting membrane potential

Stages of Neuronal Firing

Firing speed The signal is not like electricity down a wire, its significantly slower It is based around diffusion changes at set locations Transfer speed is increased because of the myelin sheath

Myelin Sheath Unmyelinated axons propagate like a wave, much slower. The sheath allows the signal to make rapid jumps. Schwann cells myelinate the peripheral nervus system, olgiodendrocytes myleniate the central nervous system.

Myelin Sheath Myelin is a characteristic of vertebrates, though similar structures have also evolved in invertebrates. Demyelination can occur in a range of disorders, usually autoimmune. Multiple sclerosis is one example. Causes a break down of the nervous systems ability to signal

Firing Threshold Neurons either fire, or don’t fire. It is an “all-or-nothing” deal. The triggering event is communication from other cells The cell that fires then has to communicate to cells further down the network Inter-neuronal communication is not electrical but chemical The communication occurs in the slight gaps between the termination of the axon on the dendrite inputs of the next cell This gap is called the synaptic cleft (junction or gap as well)

The Synapse

Neurotrasmitters Neurotransmitters are chemicals used to send a signal across the synaptic gap.

Neural Communication

Neurotransmitters Some Neurotransmitters and Their Functions NeurotransmitterFunctionProblems Caused by Imbalances Serotonin Affects mood, hunger, sleep, and arousal Undersupply linked to depression; some antidepressant drugs raise serotonin levels Dopamine Influences movement, learning, attention, and emotion Oversupply linked to schizophrenia; undersupply linked to tremors and decreased mobility in Parkinson’s disease and ADHD Acetylcholine (ACh) Enables muscle action, learning, and memory ACh-producing neurons deteriorate as Alzheimer’s disease progresses Norepinephrine Helps control alertness and arousal Undersupply can depress mood and cause ADHD-like attention problems GABA gamma- aminobutyric acid A major inhibitory neurotransmitter Undersupply linked to seizures, tremors, and insomnia Glutamate A major excitatory neurotransmitter; involved in memory Oversupply can overstimulate the brain, producing migraines or seizures; this is why some people avoid MSG (monosodium glutamate) in food

Serotonin pathways Networks of neurons that communicate with serotonin help regulate mood. Networks of neurons that communicate with dopamine are involved in focusing attention, movement, and learning. Dopamine pathways

Information Coding Information is encoded, and processed in networks not individual cells The connections between neurons change in response to stimulation Connections change through expansion or pruning of dendrite branches, or changes in number of activate receptors

Neural Networks OutputInputProcessing Layer Ideal Output

Neural Networks In practice most neurons are going to have multiple inputs and outputs in gigantic networks The overarching rule in network structure is Hebb’s Law “Cells that fire together wire together”

Reward prediction example If the reward never comes there is a dip in the firing pattern of the dopamine cells. Dopamine cells fire after an unexpected reward. If there is a predictor that occurs before the reward, the cells that signal the prediction cause the dopamine cells to fire (Hebb’s Law).

Divisions of the Nervous System

CNS vs. PNS The Central Nervous System (CNS), the brain and spinal cord, is the body’s decisionmaker. The Peripheral Nervous System (PNS), gathers information from the body and sends CNS decisions out to the body.

Types of Neurons Sensory Neurons: convey information into the CNS from the body's tissue and sensory receptors. Motor Neurons: Carry instructions out from the CNS to the body’s tissue Interneurons: Process information between the sensory and motor neurons, these are located in the spinal cord and the brain

The Peripheral Nervous System

The Autonomic Nervous System The sympathetic NS arouses (fight-or-flight) The parasympathetic NS calms (rest and digest)