Please note! This essay has been submitted by a student.
Dr. Wei Ming Yu presented a seminar on neuroscience which was targeted towards the inner ear of rats. In his research, he experimented with the inner ear of rats to understand the reaction response with vibrations that correlated to the amplitudes and the threshold of what the rats heard. Dr. Ming Yu started off by explaining different parts of the inner ear. The cochlea is the inner part of the ear that is responsible for turning vibrations into neural signals. Inside the cochlea there are little hair cells which are responsible for converting the neural signals into neural messages. In basic terms, these vibrations are turned into words for us humans or signals for rats. There are outer hair cells that are receptors of the signal and inner hair cells that are receptors of the actual signal which gets amplified and sends us a message. SGNs, spiral ganglion neurons, are connected to hair cells in the cochlea which connect to the cochlear nucleus and serve as the afferent arm of the peripheral auditory pathway. The SGNs develop unique features that allow them to transmit signals from hair cells faithfully and rapidly. When action potential increases in the ganglion, the amplitude increases and when action potential decreases in the ganglion the amplitude decreases. The spiral ganglion neurons need to form ribbons which connect to the ribbon synapse where glutamate releases from the hair cells onto the SGNs and results in sound input. In a regular mammal, the cMaF is found only in the inner ear. Dr. Ming Yu’s main study was to take a mutant, the cMaFCKO, and implant it into a rat to understand how the auditory reaction responses. He recorded at ranges of decibels to determine the threshold. The mutants have abnormal auditory responses. 16 kHz most frequency a mouse can hear. 22.6 kHz resulted in impaired hearing, they had an increase in hearing threshold and the cochlea from the mutant and control were grossly normal. The pre- synaptic ribbon contains a Ribeye, a major protein component, which is part of a dense structure which is associated with presynaptic active zones at sensory synapses in the retina, lateral line, and inner ear organs. These proteins are an organelle that coordinates rapid and sustainable vesicle release to enable hearing and balance. Then Dr. Ming Yu went ahead and explained if the defect of the mutant was based on a molecular level. He mentioned that about 500 genes became misregulated: 256 genes were upregulated and 227 genes were downregulated. Furthermore, he mentioned they couldn’t further process these genes to understand the make-up of each because they didn’t have funds and machines to do so and there was a lot of them. But with the information that they did have he concluded that there was a lot of lost signals. The voltage- clamp recordings shot the cMaFCKO neurons which decreased voltage- dependent outward potassium currents. The potassium current/ channels are found in all animal cells which open and close due to the changes in the transmembrane potential. These channels allow rapid and selective flow of potassium ions across the cell membranes and this generates electrical signals in cells. He explained if potassium current/ channel which are open than the resting potential becomes negative and firing the action potential takes time. In his study, current- clamp recordings showed spontaneous firing and repetitive firing following stimulus- evoked action potential in cMaFCKO neurons. Dr. Ming Yu at last explained if the mutant failed to express potassium channels to sharpen their response and he answered yes. He added that there was a decrease in potassium channels and that there should be a very precise signal that needs to go through the hair cells in order to send a signal precisely.
My thoughts of this seminar were mostly all over the place. Dr. Ming Yu’s idea adding a mutant into the inner ear of a rat allowed for us to understand the reaction response with vibrations that correlated to the amplitudes and the threshold of what the rats heard. He concluded by telling us that the potassium channels in the ear were not present which resulted in a delay in signals. After attending and listening to this seminar I learned that potassium channels for both humans and animals are important for sending signals through the inner ear through hair cells which allows for us to balance and receive neural messages. Dr. Ming Yu and his teammates worked together and found that 500 genes were being misregulated with the mutant. With this information, they could have gone further into research to understand the makeup of each gene but since they didn’t have the funding or the machines this was impossible. Furthermore, Dr. Ming Yu explained that this would have been impossible regardless since there were so many genes to research. If they could do more research with these genes and go into the details of the gene makeup they could have distinguished the differences from the control and the mutant. Although this seminar was very eye opening for me, I didn’t understand what was going on at some points because this is not a field of my studies. This also isn’t much of something that I get interested about. The topic that Dr. Ming Yu was presenting was more based on the inner ear which had to do with the brain, the neurochemistry part of neuroscience. I feel like if the topic was more subjected to psychology I would be less interested since I have a weak understanding of the topic but also because I am not so good at it. All in all, I took some time of my own to research a little bit more about the topic and understand some of these features and subtopics that Dr. Ming Yu presented. I wonder if it would be possible to do these experiments on other animals and control them for a couple of months to see how this research correlates with their daily lives and if they can adapt to their surroundings with this mutant. Overall, to me, this was a very interesting seminar.