Read Online Healthy Brain, Happy Life by Wendy Suzuki - Free Book Online Page B
Authors: Wendy Suzuki
Ads: Link
the normal brain typically responds during a memory task.
It’s important to note that there are no pain receptors in the brain, so the microelectrodes we used for the recordings didn’t cause any discomfort, but they did allow us to record the brief electrical bursts of activity (called action potentials or spikes) that occur as an animal is learning or remembering something new. I basically trained animals to play video games focused on learning and memory and then recorded the activity of individual cells to figure out how the brain signals different aspects of the task and what happens to the pattern of brain activity when the brain remembers or forgets. I focused on one of the cortical brain areas in the medial temporal lobe, the entorhinal cortex, and characterized the patterns of neural activity in this area as animals performed a memory task. This was one of the only studies like this done in the entorhinal cortex. But I knew that there was much more left to understand relative to the physiological response properties of other key areas of the medial temporal lobe. That’s what I wanted to focus on in my own lab.
Those four years at NIH were intense and very valuable because they taught me the ins and outs of this powerful approach of behavioral neurophysiology, which I brought with me when I started my own neuroscience research lab in 1998. This is where things really got interesting in my career. I had at this point been studying memory for ten years. I was thrilled beyond belief to now be able to build my own research program focused on my scientific obsession—understanding what happens in the hippocampus when a new memory is first formed. My desire to learn this was inspired directly by the original description of patient H.M. He could appreciate the things around him in the present moment, but unlike us, he could not make that information stick in his brain longer than he could focus his attention on it. We knew that the ability to retain it depends on the hippocampus and surrounding cortical areas, but we had no idea what these cells do when a new memory is formed. That was the question that I wanted to investigate in my lab.
So as head of my own lab, the first decision I needed to make was what kind of information I was going to have the animals learn. It had to be something relatively simple, so they could do it easily, and be a task we knew was impaired by damage to the hippocampus and surrounding structures. I settled on something that required animals to associate particular visual cues (such as a picture of a dog or a house or a building) with a particular rewarded target to the north, south, east, or west on the computer monitor. We knew this form of learning, called associative learning, was a subcategory of declarative memory (in other words, it could be consciously learned and brought to mind), and there was good evidence that damage to the hippocampus and/or its surrounding brain structures caused significant impairment in learning these picture–target associations.
I set about teaching animals to learn multiple new associations each day, and when they could do the task very well, I introduced a thin electrode into their brain to record activity as they were in the process of learning.
Finally! I was going to be able to peer into the brain and see what happens in the hippocampus as we learn something new.
One reason people had not done this kind of experiment before is because it’s difficult to get animals to learn new associations. It turns out that the task that I chose was a good one; animals could learn multiple new associations in a given session. This was exactly what we needed to start looking at how new associations are signaled in the hippocampus.
Recording the activity of individual cells in the brain is a little like fishing. First, you set yourself up in a good part of the lake (or brain) where you think there will be some nice big fish (or brain cells), and then you wait. I
It’s important to note that there are no pain receptors in the brain, so the microelectrodes we used for the recordings didn’t cause any discomfort, but they did allow us to record the brief electrical bursts of activity (called action potentials or spikes) that occur as an animal is learning or remembering something new. I basically trained animals to play video games focused on learning and memory and then recorded the activity of individual cells to figure out how the brain signals different aspects of the task and what happens to the pattern of brain activity when the brain remembers or forgets. I focused on one of the cortical brain areas in the medial temporal lobe, the entorhinal cortex, and characterized the patterns of neural activity in this area as animals performed a memory task. This was one of the only studies like this done in the entorhinal cortex. But I knew that there was much more left to understand relative to the physiological response properties of other key areas of the medial temporal lobe. That’s what I wanted to focus on in my own lab.
Those four years at NIH were intense and very valuable because they taught me the ins and outs of this powerful approach of behavioral neurophysiology, which I brought with me when I started my own neuroscience research lab in 1998. This is where things really got interesting in my career. I had at this point been studying memory for ten years. I was thrilled beyond belief to now be able to build my own research program focused on my scientific obsession—understanding what happens in the hippocampus when a new memory is first formed. My desire to learn this was inspired directly by the original description of patient H.M. He could appreciate the things around him in the present moment, but unlike us, he could not make that information stick in his brain longer than he could focus his attention on it. We knew that the ability to retain it depends on the hippocampus and surrounding cortical areas, but we had no idea what these cells do when a new memory is formed. That was the question that I wanted to investigate in my lab.
So as head of my own lab, the first decision I needed to make was what kind of information I was going to have the animals learn. It had to be something relatively simple, so they could do it easily, and be a task we knew was impaired by damage to the hippocampus and surrounding structures. I settled on something that required animals to associate particular visual cues (such as a picture of a dog or a house or a building) with a particular rewarded target to the north, south, east, or west on the computer monitor. We knew this form of learning, called associative learning, was a subcategory of declarative memory (in other words, it could be consciously learned and brought to mind), and there was good evidence that damage to the hippocampus and/or its surrounding brain structures caused significant impairment in learning these picture–target associations.
I set about teaching animals to learn multiple new associations each day, and when they could do the task very well, I introduced a thin electrode into their brain to record activity as they were in the process of learning.
Finally! I was going to be able to peer into the brain and see what happens in the hippocampus as we learn something new.
One reason people had not done this kind of experiment before is because it’s difficult to get animals to learn new associations. It turns out that the task that I chose was a good one; animals could learn multiple new associations in a given session. This was exactly what we needed to start looking at how new associations are signaled in the hippocampus.
Recording the activity of individual cells in the brain is a little like fishing. First, you set yourself up in a good part of the lake (or brain) where you think there will be some nice big fish (or brain cells), and then you wait. I
Similar Books
