A novel educational module to teach neural circuits for college and high school students: NGSS-neurons, genetics, and selective stimulations

Abstract

This report introduces various approaches to target defined neural pathways for stimulation and to address the effect of particular neural circuits on behavior in a model animal, the fruit fly ( ). The objective of this Drosophila melanogaster novel educational module described can be used to explain and address principle concepts in neurobiology for high school and college level students. A goal of neurobiology is to show how neural circuit activity controls corresponding behavior in animals. The fruit fly model system provides powerful genetic tools, such as the UAS-Gal4 system, to manipulate expression of non-native proteins in various populations of defined neurons: glutamergic, serotonergic, GABAergic, and cholinergic. The exhibited behaviors in the examples we provide allows teachers and students to address questions from behaviors to details at a cellular level. We provided example sets of data, obtained in a research lab, as well as ideas on ways to present data for participants and instructors. The optogenetic tool, channelrhodpsin 2 (ChR2), is employed to increase the activity of each population of neurons in a spatiotemporal controlled manner in behaving larvae and adult flies. Various behavioral assays are used to observe the effect of a specific neuron population activation on crawling behavior in larvae and climbing behavior in adult flies. Participants using this module become acquainted with the actions of different neurotransmitters in the nervous system. A pre-and postassessment survey on the content is provided for teachers, as templates, to address learning of content and concepts.

Revisiting Mendel: use of a Behavioral Assay to Examine Inheritance of Traits in Drosophila

“…There are many online web sources available to distinguish males and female Drosophila. One can consult an educational module with details on this content which is provided as open source (Majeed et al, 2017). 3.…”

“…There are many variations in genetic crosses which can be made for this module. The ones we choose to highlight are those that express light sensitive proteins in body wall muscles or motor neurons, as these crosses produce easily observed behaviors in the following generations which will express the gene to make the light sensitive proteins (Majeed et al, 2017). 2.…”

The Effects of Chloride Flux on Drosophila Heart Rate

“…The visceral organs were removed, keeping the heart tube intact. This dissection technique was previously used to directly assess light-sensitive ion channels and pumps as well as pharmacological agents on the heart of Drosophila larvae [58,59,60,61,62,63,64]. Pinning of the animal on its back after dissection was used to directly apply the LED lights on the caudal aspect of the heart and to allow for the exchange of the bathing saline to one containing serotonin in later steps of the procedure.…”

Hyperpolarization by activation of halorhodopsin results in enhanced synaptic transmission: Neuromuscular junction and CNS circuit

“…In brief, the preparations were “fileted” along the mid-dorsal longitudinal axis and pinned flat. Excitatory postsynaptic potentials (EPSPs) were evoked by exposing the dissected preparations with blue light (470nm wavelength, LEDsupply, LXML-PB01-0040) or yellow-lime light (567.5 nM wavelength, LEDsupply, LXML-PM02-0000) from a high intensity LED that was focused on the specimen through a 10x ocular objective while the EPSPs were measured [ 53 , 57 ]. Intracellular recordings from muscle 6 were made with microelectrodes filled with 3M KCl having a resistance of 30–60 MΩ.…”

“…The larval Drosophila neuromuscular junction (NMJ) serves as a model preparation to address synaptic function and plasticity [ 47 – 51 ]. A sensory-CNS-motor neuron circuit in the larval system also provides a measure of central synaptic function which is readily related to behavior in the intact animal [ 14 , 52 , 53 ]. These two models were used in this study to address the consequences in manipulating the activity profile of defined neurons and the developmental impacts on the formation of neural circuits.…”