27 min

Cellular balance across the lifespan Lessons in Lifespan Health

    • Health & Fitness

Dion Dickman, associate professor of neuroscience and gerontology, joins George Shannon to discuss how the nervous system processes and stabilizes the transfer of information in healthy brains, aging brains and after injury or disease. 
Quotes from the episode:
On synaptic plasticity:
“Synapses are essential, fundamental units of nervous system function and plasticity is this remarkable ability to change. And throughout early development into maturation and even into old age, synapses just have this amazing resilience to change and adapt to different situations and injury disease, things like that. So synaptic plasticity is really the essence of what it means to grow and mature and change throughout life. Things like learning and memory all depend on changes in synaptic function and structure and it's really a key area of research for many of us.”
 On challenges to maintaining nervous system stability:
“You can imagine in the incredibly complex environment of your brain, where neurons are making synapses with thousands of other neurons, that itself is a big challenge to maintain stability. Sometimes I'm kind of amazed that we don't walk around like raving lunatics half the time and our brains remain stable. When you think of disorders of excitability or stability, things like seizures and various forms of defects in cognition ultimately come down to not being able to stabilize or maintain your neural circuit function. And this really just comes down to normal development that all of your nervous system has to stay stable and your synapses are the key substrates to maintain stability.” 
On the aging brain:
“.. a lot of studies are showing is that this cognitive decline that happens in aging really is ultimately due some sort of a maladaptive reduction in plasticity. And it's kind of amazing, but, young humans, our brains are remarkably plastic and resilient, and that resiliency and plasticity seems to degrade over time and into old age… We think as old age happens .. people's memories start to lapse, even in the absence of any disease, they're not quite as sharp. We think this all ultimately comes down to some limitations imposed on neuroplasticity and that's a major area of the research.
On studying diseases like schizophrenia, which cannot be seen in brain imaging:
“There are no good biomarkers for neuropsychiatric diseases like schizophrenia and bipolar and things like that. So, there are basically two ways to study these kinds of diseases. One is through behavior where you try to get animals to model behaviors that mimic neuropsychiatric diseases. There's some good work happening rodent systems. Although I find it to be honest, very difficult to know whether a mouse is showing the defect in social interaction, for example, that are characteristic of autism or schizophrenia for that matter. So the alternative instead is not to actually model the disease in drosophila or mice, but to take humans in which we can mine their genetics to find genes highly associated with the disease in humans and find out what the fundamental function of these genes are. And that's kind of the strategy that we take.
So we found about 30 genes now that when mutated in drosophila give rise to defects in this process of homeostatic plasticity at synapses, and the vast majority of these genes have links to human diseases that give rise to neuropsychiatric diseases like autism spectrum disorder, schizophrenia, seizure disorders and, bipolar disorder as well. And so I think by understanding the fundamental functions of individual genes, we can extrapolate what might be happening in humans when those genes aren't functioning properly.”
On the importance of sleep:
“…one of the most fascinating questions in neuroscience, or really science more generally is what is the function of sleep? What is the essential function of sleep and what role does synaptic homeostasis and disease play a role in sleep behavior? So, it's q

Dion Dickman, associate professor of neuroscience and gerontology, joins George Shannon to discuss how the nervous system processes and stabilizes the transfer of information in healthy brains, aging brains and after injury or disease. 
Quotes from the episode:
On synaptic plasticity:
“Synapses are essential, fundamental units of nervous system function and plasticity is this remarkable ability to change. And throughout early development into maturation and even into old age, synapses just have this amazing resilience to change and adapt to different situations and injury disease, things like that. So synaptic plasticity is really the essence of what it means to grow and mature and change throughout life. Things like learning and memory all depend on changes in synaptic function and structure and it's really a key area of research for many of us.”
 On challenges to maintaining nervous system stability:
“You can imagine in the incredibly complex environment of your brain, where neurons are making synapses with thousands of other neurons, that itself is a big challenge to maintain stability. Sometimes I'm kind of amazed that we don't walk around like raving lunatics half the time and our brains remain stable. When you think of disorders of excitability or stability, things like seizures and various forms of defects in cognition ultimately come down to not being able to stabilize or maintain your neural circuit function. And this really just comes down to normal development that all of your nervous system has to stay stable and your synapses are the key substrates to maintain stability.” 
On the aging brain:
“.. a lot of studies are showing is that this cognitive decline that happens in aging really is ultimately due some sort of a maladaptive reduction in plasticity. And it's kind of amazing, but, young humans, our brains are remarkably plastic and resilient, and that resiliency and plasticity seems to degrade over time and into old age… We think as old age happens .. people's memories start to lapse, even in the absence of any disease, they're not quite as sharp. We think this all ultimately comes down to some limitations imposed on neuroplasticity and that's a major area of the research.
On studying diseases like schizophrenia, which cannot be seen in brain imaging:
“There are no good biomarkers for neuropsychiatric diseases like schizophrenia and bipolar and things like that. So, there are basically two ways to study these kinds of diseases. One is through behavior where you try to get animals to model behaviors that mimic neuropsychiatric diseases. There's some good work happening rodent systems. Although I find it to be honest, very difficult to know whether a mouse is showing the defect in social interaction, for example, that are characteristic of autism or schizophrenia for that matter. So the alternative instead is not to actually model the disease in drosophila or mice, but to take humans in which we can mine their genetics to find genes highly associated with the disease in humans and find out what the fundamental function of these genes are. And that's kind of the strategy that we take.
So we found about 30 genes now that when mutated in drosophila give rise to defects in this process of homeostatic plasticity at synapses, and the vast majority of these genes have links to human diseases that give rise to neuropsychiatric diseases like autism spectrum disorder, schizophrenia, seizure disorders and, bipolar disorder as well. And so I think by understanding the fundamental functions of individual genes, we can extrapolate what might be happening in humans when those genes aren't functioning properly.”
On the importance of sleep:
“…one of the most fascinating questions in neuroscience, or really science more generally is what is the function of sleep? What is the essential function of sleep and what role does synaptic homeostasis and disease play a role in sleep behavior? So, it's q

27 min

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