Dosophila Larval Orn Experiment

In previous studies, Frank and Byram’s article suggest that taste and smell interactions are dependent on taste and odor. In their experiments, they gave subjects strawberry

Doctor Linqun Luo is a professor here at Stanford and currently teaches neurobiology and does research as the principal investigator in the Luo Lab as a member of the Howard Hughes Medical Institute. His primary research area is the human brain focusing on neural circuits and how they function, how precise are the connections, how they develop. To this end his lab is using fly and mouse models to study their various circuits, centering mainly on the olfactory, and exploring the early development of neural networks in mammals (Luo Lab Bio). In order to write this commentary on the topic “How do neurons connect with each other”, I have chosen two pieces to read. The first, from Science magazine, outlines the main issues, goals, and paths the world is taking to understand to understand neuroscience including the research being done to answer the question in his topic. The second paper, from Cell Press, is a much more technical paper which outlines one of the pathways Luo isolated in the olfactory cortex of mice and how their neurons may connect.

problem: Do Tobacco Hornworms have a sense of smell and if so, is it strong enough to lead them to a stimulus?

Precise control over the routes taken by growing neurons is tightly controlled (Steward, 1989). In the brain extracellular cues play an important part prompting attractive or repulsive behaviours in cell migration. In addition, they are necessary for cell adhesion, axon guidance and branching (Erskine & Herrera, 2007). For neurons that navigate over long distances, axons can be guided by chemoattractants that draw axonal navigation in its direction or chemorepellents that deter axonal growth in its region.

While sitting in the living room, as the fresh smell of popcorn wafts into the room, one might find themselves drawn to the kitchen, only realizing they have drifted from the couch to the kitchen and face buried in the popcorn. A tiny nematode, known as C. elegans, too, finds this smell irresistible and has developed a physiological mechanism, known as chemotaxis, the ability to detect and respond to their external environment. And this physiological mechanism is important to C. Elegans because they use it for their way of survival, to find food, avoid noxious conditions, develop

The entire experiment was conducted on an adult cockroach, Periplaneta americana, which was anesthetized using CO2 followed by an exposure of the ventral nerve cord using the method outlined in the PNB 3263WQ Laboratory Manual (Moiseff, 2016). Exposure to sound stimulation began with a spontaneous recording which was used as baseline for the obtained firing rate, followed by Auditory stimulation at 200 Hz, 400 Hz, 600 Hz and Ultrasonic pest repellent (UPR, which emits a sound frequency of 25,000 Hz). Eight trials were performed per sound frequency with 10 second rest between each trial and 1-minute rest allowed between frequency change. (Fig.1). the length of each stimulation lasted for 250 msec. eight specimens were used in the experiment

The larvae of Drosophila melanogaster are documented as being more sensitive than adults, the traditional model.

The odor must pass through the epithelial cells located in each nasal cavity by means of a large inhalation of air through the nose. Once the odor passes through the epithelium, it must pass through the mucous from the cilia by odorant-binding proteins. When the g-protein is activated it triggers a converted form of adenylate cyclase into cAMP which opens ion channels allowing calcium and sodium ions to enter the cell. This process turns the odor into a neural signal the brain can then interpret. Once this signal is created, the axons of olfactory neurons carry the stimuli to the olfactory bulb and then to the primary olfactory cortex within the temporal lobe. This process can take just a few seconds through the rapid firing of synapses within the receptors. The processing of an odor leads to a reaction depending on the type of scent being processed. Olfaction is just one of the five special senses that make up how stimuli is perceived on a daily basis (Amerman,

Introduction: The Drosophila experiment was to demonstrate independent assortment through mendelian genetics. Gregor Mendel’s second law of independent assortment states, when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together (Dictionary.com). Drosphilia is a great way to test inheritance because life cycle is very short, approximately 10-14 days and it produces a large amount of offspring. The phenotypes that are being examined are eye color and wing shape/size. The wild type flies were red eyes and long wings.

For a smell to be perceived it must be an odorant, a molecule that can be smelled. These odorants then go up into the nostrils and into the nasal cavity. Most are filtered by the cilia, or nose hairs. The ones that make it all the way up to olfactory receptor cells dissolve into the mucus coating the olfactory mucosa. Each receptor cell can detect only one type of scent. After each specific receptor is triggered, the potential travels down the axon to the olfactory bulb which contains neural junctions called the glomerulus. Then the action potential travels to thru the glomerulus to another nerve cell a mitral cell. It relays information to the brain. Once in the brain it can go one of two ways. It can take the subcortical route which goes

It is really interesting that the analysis of fat body sequencing has pointed to thems related to nervous system plasticity in PFD group. In natural conditions the foraging onset is characterized by a neuronal plasticity and anatomical changes in the mushroom bodies, which are essential for learning connected to foraging (Coss et al., 1980; Brandon & Coss, 1982; Withers et al., 1993). Recent studies showed a communication between hypothalamic neurons and adipose tissue in mice through insulin and leptin, controlling the energy balance of fat and consequently hunger or satiety (Dodd et al., 2015). Furthermore, a number of insects’ octopaminergic neurons are involved in nutritional signals transmission from peripheral organs, such as the fat body, to the brain (Roeder, 1999). Although the themes related to neuronal and synaptic plasticity have been found in the fat body, this result may indicate a synergistic expression between this organ and the brain. This result certainly needs a thorough study, but to our best knowledge it is the first time that the themes axon

The first major finding was that locust tactile hairs fall under two physiological categories, high-threshold and low-threshold hairs. High-threshold hair afferents respond rapidly to stimulus but adapt after a short period of excitation and require a larger degree of stimulus. In contrast, low-threshold hair afferents respond a low degree of stimulus and adapt at a slower rate, allowing the hairs to transmit information for as long as the stimulus is present. The second major finding was that both types of hair are directionally sensitive, meaning that certain directionality stimulates the hairs more than others. These findings did not completely answer the original question but provided key insights bringing researchers closer to

C. elegans is an attractive model system having behavioural plasticity towards various stimuli. The organism can learn and perceive the clues to maintain as both short term and long term memory as well as imprinted memory. Imprinting is a type of epigenetic learning which gather an internal exposition of an event and occurs without any previous experience that has a reference in the brain. In C. elegans olfactory imprinting occurs through AWC sensory neurons and AIY interneurons. Sra-11, a G-protein coupled seven transmembrane receptor expressed in AIY interneurons is essential for the formation of olfactory imprinting. Olfactory learning in the nematodes also shares AWC and AIY interneurons through CREB and its downstream pathways. Here we

The experiment was done on Sarophaga Crassipalpis, a species that enters a period of developmental/reproductive inactivity called diapause to avoid unfavorable environmental conditions, regulated by neuroendocrine system in insects. The experiment was performed under both nondiapause and diapause conditions. During the rearing stage, nondiapause conditions for the flesh fly pupae were put under long day conditions of 15 hours light and 9 hours dark in 25 degree Celsius temperatures. Diapause conditions were under short day conditions of 12 hours light and 12 hours dark at that same temperature. Resulting offspring were same light conditions at 20 degrees Celsius.

There are olfactory and visual cues which are important in pollination behaviour of attracting the flies towards the flower (Beaman, 1988). Olfactory cues is a condition described by which the flies attract to the flower by the odour. The unisexual flowers of Rafflesia attracting flies from the genera Lucilia and chrysomya by the bad odour like a ‘rotten flesh’ producing by the flower (Patiño et al., 2002). Bad odours also being described as the chemical mimicry through which the pollinator is trick by the flower by olfactory cues. The phenomenon is widely observed on unrelated plant lineages for example in angiosperm, splachnaceae and phallaceae (Urru et al., 2011). Targeted insects are mainly flies and beetles. Flower of Rafflesia will emit the bad odour which strongly attractive to the duped insects. Dung insects duped by flowers affects an oviposition substrate, to which flies attracted and noticed ovipositing in the flower. Oviposition requires the involvement of olfactory, taste and mechanosensory input to be produced. The combination of this three signals will missing the flower. The odour will produced the olfactory signals which act as the main attraction to the pollinator. Bad odour mainly focus on targeting gravid females by the imitation of the oviposition substrates but gravid males also seeking for opportunities to mate that might attracted and have a chance to rewarded with