Welcome to Yuzaki Lab
    Yuzaki Lab's (Department of Neurophysiology, Keio University School of Medicine) research theme is to elucidate "how neural activity and environmental changes induce memory and learning,、, 、and how they change the neural network itself ."。For details please Click here.
Past News
Journal Club
We await the participation of motivated indivisuals。We will vigorously nurture young researchers who will lead the future of basic science.。
   Interested in the Master course?Click here.
   Interested in the PhD course?Click here.
   Contact usClick here.

Interview by "e le c te ric"

e le c te ric

SPECIAL FEATURE "Exploring the Mechanisms of Memory, Recall, and Forgetting."

Revealing the Material Processes of Memory Mechanisms in the Brain - Synaptic Plasticity Forms Memory

In what mechanisms in the brain、do we recall memories、and forget?。There is a long history of memory research seeking the engrams (traces) of those memories in the brain。Memory is stored as plasticity (or flexibility, changeability) of synapses, the junction of nerve cells in the brain:.、.。Depending on the duration of the memory、Short- and medium-term memory as functional changes in synaptic transmission efficacy、Longer-term memories are thought to be stored as changes in the synaptic connections themselves, respectively。
Also、it's been studied that different brain regions are involved depending on the content of the memory。For example, It is almost certain that the cerebellum is primarily responsible for motor memory (procedural memory) 、and the hippocampus and cerebral cortex for episodic memory 、.。However、Many of the detailed mechanisms are yet unknown。Dr. Michisuke Yuzaki, Professor of Keio University School of Medicine, Department of Physiology (Neurophysiology), talks about the current state of memory research in the brain. 。


From Psychosomatic Medicine to Neurophysiology

I、entered medical school because I was fascinated by psychosomatic medicine, which approaches physical illness from the mental aspect。As the saying goes、,、sickness comes from the mind, and the mind can lead to lowered immunity and illness.。If that's the case、unless you approach the illness from the mental side、I thought that even if the physical illness is cured, it would come back.。
As I studied psychosomatic medicine in my own way after entering medical school、and as I learned that psychosomatic medicine was mainly based on zazen, meditation, and autonomous training methods, at that time、I began to feel frustrated with the way the mind was treated as a black box。Although I was very interested in psychiatry、I became concerned about the gap、psychoanalysis and psychotherapy and empirical diagnostic and treatment methods in other medical fields。

In search of the engram of memory

there、Material Foundations of the Mind、That feeling that you want to study the brain itself has entered a strong will of neurophysiological research。I wanted to elucidate the mechanism of memory。Connected via a joint every single nerve cell which is said to be the brain several hundred billion and is referred to as the hundreds of thousands of synapses from thousands、Convey information by converting the chemical signal into an electrical signal。When the activity of nerve cells is changed for a certain period of time、Efficiency of information transmission will occur a phenomenon that to change in the long term "synaptic plasticity" in the synapse。That synapses not only information transfer、That we apparatus to create a memory engram by synaptic plasticity。
There are various levels in the brain of research、Synaptic plasticity、Cell - it hits the underlying processes of memory in the circuit level。The brain regions synaptic plasticity occurs、In individual level、It will lead to a variety such as the movement of memory and episodic memory storage phenomenon。
It continued and repeated the same pain、Although hyperalgesia will occur even after the cause of real pain disappeared、This is the "memory of pain" by synaptic plasticity in the pain pathway。Post-traumatic stress disorder that occurs after the Gulf war and catastrophe (PTSD) even cells - in the circuit level has occurred synaptic plasticity abnormal。Even as the foundation for a variety of psychiatric disorders and developmental disorders cells - it has been considered synaptic plasticity disorders at the circuit level。

2 types of brain plasticity: short- and medium-term memory and long-term memory

The underlying synaptic plasticity engram memory formation is caused by two mechanisms。One is the change of the wiring itself of nerve cells by the increase or decrease of synaptic connections。Long time ago、It was thought to not be new synapses in the brain after mature。However、Changes in synaptic form in the brain of live animals by innovation techniques for visualizing、Synapses form it has become apparent in recent years continue to change throughout life。
the other one is、Although synapses form is not changed、It is when the efficiency of synaptic transmission is functional change。
In any animal species memory、Depending on the duration、It is divided into short and medium-term memory and long-term memory。The time axis is slightly different depending on the animal species、Each in humans corresponds to the second to time units and day to yearly。The former functional changes in synaptic efficacy、The latter is becoming clear that stored as changes in synaptic itself。


In the short and medium-term memory is、There are two types。Made strong functional binding of the synaptic、That information is easily transmitted long-term potentiation (LTP:Long-term Potentiation)と、Weakened functional binding of the synaptic、That information is less likely to be transmitted long-term depression (LTD:Long-term Depression)です。Both are one of the entities of the short-term and medium-term storage at the individual level。When I would say simplified、LTP at the time to remember、You will be considered to have been used is LTD is when you forget that you remember was。Interestingly、There is exactly the reverse in the cerebellar circuit、LTD When you remember、Has been with the LTP is used when forget。Code is the same thing in the sense that storage be different information、Even statues in statues、It will be considered to be the same from the viewpoint of formation of engram。
The LTP and LTD occurs mechanism、Long, but controversy has lasted、It is now believed to increase or decrease the number of glutamate receptors on the postsynaptic is mainly determined。If it kept the state in which glutamate receptors increases the LTP、State in which the receptor has decreased is the LTD。
In our laboratory、We aim to elucidate the LTP and LTD of the mechanism responsible for this kind of short and medium-term memory。In addition it also promoted research on the morphological plasticity of synapses responsible for long-term memory。To begin with、I want to tell you an example of the research results of the functional plasticity of synaptic transmission。
But I would like to talk a schematic、It contains the story of some molecular mechanisms。future、In order to connect, such as in the treatment and drug discovery, such as memory impairment and mental illness、Please bear with me just a little bit because it is necessary to elucidate the detailed molecular mechanism。 <2016.03>


Page: 1 2 3 4