Neurons and Neurotransmitters

1. Psychology 001Introduction to PsychologyChristopher Gade, PhDOffice: 621 HeafeyOffice hours: F 3-6 and by apt. Email: gadecj@gmail.com Class WF 7:00-8:30

2. Neuronsand Neurotransmitters

3. Why do we need to knowabout this stuff? • In order to understand human behavior, psychologists often look to the brain. In order to understand the brain, you need to understand the parts that it’s made up of, and how those parts work. • Car Example • Knowing this will help us understand what’s going on (on the cellular level) when something wrong happens to an individual (e.g. depression, schizophrenia, etc). • Car Example Continued

4. The Neuron • Neurons are nerve cells that receive and transmit information throughout the body and brain. • The human body has roughly 80-100 billion neurons in it by adulthood. • Located throughout our body with the majority of them being located in the brain. • Come in a number of different sizes and are utilized in a number of different ways.

6. How Do We Know About this? Answer: Staining

7. What a Neuron Looks Like • Cell body: contains the nucleus of the cell. Consider this as the brain of the neuron.

8. Dendrites: widely branching structures that receive transmissions (via neurotransmitters) from other neurons.

9. Axon: a single, long, thin, straight fiber which branches near its tip. Once a neuron is activated, a neural impulse is sent down this part of the neuron into the terminal branches.

10. Terminal Branches (AKA terminal buttons): the ends of the axon that branch out and are responsible for the release of the neurotransmitter that is needed for the communication with other neurons.

11. The Supporting Staff • Glia Cells – cells that support neurons by • Removing waste • Insulating neurons (protection and mylenation) • Synchronizing activity

13. Neural Communication The action potential is an all-or-none signal that is sent along the neuron. It does not fade over time or distance. When an action potential reaches the axon endings it initiates the release of neurotransmitters into the synapse. • Synapse: the space between the axon’s terminal button and the dendrite of the subsequent neuron.

14. How Does the Action Potential Occur?... Most of the time. • Once enough of the dendrites of a neuron have been “activated” by neurotransmitters, a change in the electrical charge of the neuron begins in the axon hillock. • This charge is then sent down the axon of the cell in order to tell the terminal branches of that cell to release a neurotransmitter. • In other words, neurotransmitters are needed for a cell to fire, so the more synapses in a neuron, the more likely it will fire.

16. Once a neurotransmitter has been released into the synapse, three things can occur to them. • Activation: the neurotransmitters can temporarily cling to the dendrites of another neuron, and influence this neuron based on the type of neurotransmitter that was released. • Reuptake: the axon terminal can eventually “suck back” the neurotransmitter that it released (recycling at its best) • Diffusion/Metabolized: the neurotransmitter can be broken down, washed away, or used up by other cells and enzymes that are located in the synapse.

17. Neurotransmitter Examples Dopamine (DA) • Important for motor functioning – Parkinson’s disease involves selective deterioration of the region in the brain that produces DA • Implicated in ‘reward’/positive emotional sensation, motivation • High levels of DA are associated with schizophrenia Serotonin (5-HT) • Implicated in psychological wellness/mood, SSRIs are effective treatment for depression • Affects hunger, sleep cycles, and arousal