The Brain in Health and Disease

Rationale

Most Physics curricula spend a significant amount of time exploring electricity. This usually involves an extensive study of electrostatics and current flow. Often, the teaching of these topics lacks specific relevancy even though our modern society is heavily dependent on electrical energy to power devices. It is difficult to give the students the experiential knowledge and comprehension that is inherent in the study of physical Newtonian Mechanics. There always seems to be a disconnect with the study of electricity because of the lack of tangibility and relevancy for the students. Certainly, electricity is pervasive around us, but students do not have a "physical" sense of its presence. I currently utilize static electricity to try to present my students with the physical nature of electricity by letting them feel the shock of the Van de Graff generator and less dramatic examples. Later, we explore the properties of current with batteries and light bulbs. The students can see that the light bulb is lit when properly connected to the battery and they are able to understand the applicability of electricity but I sense that there is a lack of appreciation for the generation of electrical currents and its relevance.

In this seminar, "The Brain in Health and Disease," I recognize the powerful relevancy for my students that the brain itself functions by generating electrical impulses! These electrical impulses are created by interactions of chemical ion gradients that create electric potentials that are utilized by specific brain cells, called neurons (Figure 1), to generate a signal. An "all or none" signal, known as an action potential, which is propagated along the neuron's membrane, has the special property of continual regeneration and consequently being constant over distance. The signal is sent along the length of the neuron where it meets a synapse, which is a gap between neurons. There, the signal is converted into a chemical message, carried by a chemical called a neurotransmitter, that then stimulates the next neuron and allows movement of messages throughout the body, and if the conditions are favorable the process is continued. These synaptic connections are believed to store the information that we know as memory!

When the brain is functioning normally we are relatively oblivious to these incredible processes; however, there are cases when exchange of electrical activity does not occur normally in the brain. One example is a seizure. My students are aware of the existence of seizures and usually know someone who has had one, since they are more common in children, but they do not know that seizures are the result of electrical activity in the brain gone awry. Seizures actually result when the electrical signals in the brain become synchronized! This is surprising, because it turns out that the brain must maintain a chaotic pattern of signals for brain health. I recently received a patent for a Radio-Frequency powered vagus nerve stimulator to help minimize epileptic seizures and will demonstrate my device and explain how introducing an intermittent electrical impulse into the brain can reduce the frequency of epileptic seizures.

I believe that this unit will provide relevance to the study of electricity, explain biochemical generation of a signal using ions, reinforce the significance of electric potential, motivate electrical-physical models of neuronal membranes, introduce mathematical models of systems, explore the implications of abnormal electrical activity, and stimulate appreciation for the scientific pursuit of knowledge acquisition. My intention in this unit is to concentrate on the specific functioning of a single neuronal axon and then to utilize that knowledge to comprehend the electrical malfunction of a group of neurons. I am confident that this will stimulate my students to relate their understanding of chemistry to electrical phenomenon, apply the combination of complex electrical elements to develop mathematical equations for membrane potentials, which can then be solved, and appreciate the impressive "normal" electrical functioning of their own brain. This curriculum unit will explore how a signal is transmitted along a neuron and as the unit develops I will create labs that will reinforce the knowledge of electrical signal generation and transmission. Lastly, we will explore the ramifications of a disorder of signal functioning that manifests in epileptic seizures.