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Brain Neurons & BDNF · Acedra
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Brain Neurons & BDNF
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0:02
your brain is an amazing organ it's home to one of the most fascinating type of cells neurons neurons form vast networks of connections which work together to control the human body an incredibly form consciousness how does the brain form these networks and connections well today I'm gonna take you on a journey inside of a neuron and show you how one particular protein is involved in neuron function and development this protein is called B D and F or brain derived
0:40
neurotrophic factor it's part of a family of proteins called neurotrophins our neuro trophic factors also included in this family is nerve growth factor or ng F the first neurotrophins covered in this family BDNF is involved in many neurological functions such as neuron development neuron survival and synaptic plasticity so for BD enough to perform its functions it must first be released at the synapse and this is very similar to a neurotransmitter being released
1:20
it's released from a vesicle into the synaptic cleft and as you can see this is a post synapse and a pre synapse and as the growth factor is released it has to bind to a receptor now BDNF can bind to two different types of receptors first is the trek b receptor and the second is the p75 receptor now upon binding this produces very different effects on the nervous system in which trek B is responsible for neuron growth and survival and plasticity however the P 75 receptor is involved in
2:02
processes like apoptosis or programmed cell death now you may ask why would the nervous system want to kill off nerves or neurons and that's because for instance during development you begin with mourner you could ever need and you must prune off the unwanted or unneeded neurons interestingly the truck B receptor is involved in survival of developmental neurons so for instance as neurons are migrating the ones that will reach their innervation points first will receive
2:37
their trek B innervation from B D and F and they will survive so you can kind of get an idea of how these different binding of these different receptors leads to very different effects on the nervous system now I want to take a step back from molecular biology for a second and I would like you all to sometime perform this exercise now neurons are beautiful and they have these incredible dendritic arborizations and an arborisation means a tree like branch so especially in our northern climates we
3:16
have these trees without their leaves and if you go into the woods you can get an incredible representation of what it would be like to stand inside the brain and little use of your imagination and in this case a help from Photoshop I turned this tree into what I see underneath the microscope and if you compare it to this image here this is an upper Kinji fiber located in the cerebellum a structure on the back of your brain and these neurons have some of the most robust dendritic
3:49
arborizations they're absolutely beautiful now neurotrophins for instance are involved in the development of these arborizations and dendrites specifically dendritic spines so you can see from this image these little spines that are coming off the dendrites are the location of synaptic formation so the connections between neurons that's where neurotransmitters are signaled and neurons can communicate and BDNF is involved in the formation of these dendritic spines they kind of
4:25
resemble mushrooms and what really is happening here as a neuron fires and communicates it will then release BDNF back and forth and interestingly beating F can be transported either backwards from the post snaps to the previous naps called a retrograde signaling or anterograde similar to a neurotransmitter from the pre-snap to the postsynaptic saying hey bro I received your signal let's uh hang out and uh you know can continue to communicate and form a better relationship and as this happens it
5:03
strengthens these connections and not only does it begin to strengthen just the synapse it starts to form circuits and networks and this is the foundation of learning and memory so as you can see beating athis is crucial to the development and function and maintenance of the nervous system now you may have heard things like exercise is good for the brain well why is it good for the brain I mean it is good for a number of reasons but for one reason is that it can up
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regulate and maintain levels of neurotrophins such as B D and F so therefore it can enhance your ability to learn and have a healthy functioning nervous system and this brings me to my next point because BDNF is so important to neural function in the healthy nervous system it is also involved in disease pathology so in diseases like major depressive disorder or just depression stress is related to decreased neural activity and formation of synaptic connections and
6:14
therefore antidepressants can help restore you know maybe BDNF levels and there this is a theory behind this that exercise and antidepressants can help restore BDNF levels and therefore enhance neural activity and synaptic plasticity and diseases like schizophrenia there's also a correlation to abnormal expression levels of this protein so either too much or too little now I want to talk about one disease and specifically and that's Huntington's disease Huntington's is a movement
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disorder it is a autosomal dominant disease that leads to the death of neurons in an area of the brain called the striatum it's located in the basal ganglia and it's involved in coordination of movement now the huntingtin protein itself is involved in absolutely incredible cellular function called axonal transport and what I didn't talk about earlier when I was explaining how BDNF bind so it's a track B receptor those signals are like a relay and there's a passing of molecules
7:26
down that leads to transcription of new genes and for new genes to be made that has to be activated by DNA located in the nucleus and in neurons that nucleus is or cell body in soma is located very far away from the synaptic terminals so we have these amazing motor proteins called dining and kinesin and they literally walk along the lengths of the axon carrying cargo and as you can see in this illustration here those are the vesicles and the yellow proteins are the
8:04
motor proteins so as B D and F is bound to its receptor it's endocytosed in these vesicles and traffic all the way back to the nucleus now that Huntington protein is involved in these motor proteins and it in Huntington's it is mutated and therefore it renders it dysfunctional and actual transport becomes aberrant therefore these neurotrophins aport signals are disrupted leading to death in these neurons now this brings me to my research so here at Northern Michigan
8:42
University our research lab supervised by dr. Eric autumn researches the relationship between muscle synthesize brain derived neurotrophic factor and its relationship to motor neurons so yes BDNF is not only synthesized in neurons it is also made in the muscle tissue and we are trying to elucidate if there's an involvement between neuro trophic signaling retrograde axonal transport so the motor proteins carrying information from our vesicles from the dendrites back to the nucleus and
9:21
diseases like spinal Balder muscular atrophy and amyotrophic lateral sclerosis or ALS ALS is a motor neuron disease it is the disease that Stephen Hawking the famed theoretical physicists who recently passed away suffered from the majority of his life in his wheelchair is an absolutely debilitating disease and we really do not understand this disease very well at all there are no treatments that can prolong life at this point and the interesting thing is 90% of its spontaneous so there are
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cellular mechanisms that are going wrong and our research lab is trying to elucidate if this mechanism is involved
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so before we go today I want to share one message with you and that's why I think having a greater understanding of neural function is very important now aside from neuroscience I have one other passion and that's playing guitar I'm an absolute guitar fanatic and my advisor will tell you that I have a guitar problem and I don't think it's a problem unless I'm trying to meet a deadline like finish my thesis on time however I do have a problem as a guitarist and
10:42
that's because I didn't learn music at a young age and as I began to play guitar I was bad I was absolutely horrible and I probably drove everybody nuts because I had no foundation of rhythm and timing or any understanding of melodic and harmonic relationships in over the years I got a little bit better I suddenly realized to be a good or great guitar player you first have to be a great musician and in grad school so around like five six years ago I was able to take a few music
11:19
courses specifically sight singing an auditory training and this is a course where you learn how to not only understand timing and rhythm you sing sheet music and you understand the foundations of harmony and melody and pick up how to understand intervals of music I didn't think I was going to be able to become very good at this and it was really hard it was honestly one of the hardest classes I ever took in grad school even on top of these neuroscience and advanced molecular biology courses
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it is incredibly hard to be able to hear different pitches of music and tell you the intervals like a perfect fifth or a major third and it was during this time where I was studying neuroscience so I was studying these neurotrophins and how neural networks are formed and finally at one point I realized that oh my gosh I'm making progress I'm also understanding how the brain learns information how it actually functions and this information together helped me begin to make progress because
12:29
I started to realize how I learned the best and as students you may have heard this before you need to learn how you learn the best and it is intuitive however it's also hard because sometimes it doesn't seem like you're making any progress but if you understand how these networks are forming how neural signaling works and how synapses are strengthening and forming new networks it can be extremely beneficial for your progress and I look at it as you are expanding these neural
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networks and it can take a long time and a lot of hard work but eventually you're able to tap into them and as you tap into them in a way you're able to increase your perception of reality and your cognitive enhancement I truly feel that a greater awareness an understanding of brain function can be a powerful tool to help you succeed at great things thank you [Applause]
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