Eric Kandel
AbdulSamad Olagunju / November 25, 2021
7 min read
Welcome to another blog post!
Quote of the Post:
"There was little in my early life to indicate that an interest in biology would become the passion of my academic career. In fact, there was little to suggest I would have an academic career." - Eric Kandel
You wake up. What do you have to get done today? Thoughts scramble in your mind, as you try to figure out what your mom told you about the dishes yesterday. Your mind sorts through your experiences from the past week, and you know that you must brush your teeth, wash the dishes, and then rush to class before 8:15 am.
How can you gather all of these events from the past? How can a collection of cells produce coherent thoughts in a human being? How can we remember events like the first time we rode a bicycle—so vividly? Memory is a powerful mechanism. Eric Kandel is one of the men who opened our eyes to how this mechanism works. Not completely, but enough that his research won him a Nobel Prize.
In this series of blog posts, I will talk about the book he wrote about his life, In Search of Memory, The Emergence of a New Science of Mind. I felt like the novel was well written and gave a lot of insight into how scientists came up with the foundations for neuroscience.
The book begins with a discussion of Kandel’s life as a young boy, growing up in Austria and escaping to the United States before World War II. One can only imagine how it would be like to grow up in a city that hates your very nature, with people who call for the destruction of your people. To hear him explain how a culturally refined city such as Vienna was captivated and twisted by Nazism is shocking and saddening. Kandel makes use of a quote by a German playwright named Carl Zuckmayer to great effect,
“It was as if: Hades had opened its gates and vomited forth the basest, most despicable, most horrible demons. In the course of my life I had seen something of untrammeled human insights of horror or panic. I had taken part in a dozen battles in the First World War, had experienced barrages, gassings, going over the top. I had witnessed the turmoil of the postwar era, the crushing uprisings, street battles, meeting hall brawls. I was present among the bystanders during the Hitler Putsch in 1923 in Munich. I saw the early period of Nazi rule in Berlin. But none of this was comparable to those days in Vienna. What was unleashed upon Vienna had nothing to do with [the] seizure of power in Germany…. What was unleashed upon Vienna was a torrent of envy, jealousy, bitterness, blind, malignant craving for revenge. All better instincts were silenced…only the torpid masses had been unchained…. It was the witch’s Sabbath of the mob. All that makes for human dignity was buried.”
Thankfully, Kandel escapes what surely would have been a brutal life in concentration camps, and he makes his way to America.
Kandel becomes a star student and athlete, majoring in European history and literature at Harvard. He marries and decides to change his career path after being enamored by science. Kandel's interest is captivated by the world of psychoanalysis. I feel like science is more fascinating when you are delving into a field in which the answers are not yet evident. Psychoanalysis of that time must have felt like the wild west. I mean, just take a look at some of the ideas Freud had! Although Freud's ideas may seem strange to us today, Freud made the most of the empirical data he collected from his patients. He was a beacon for young scientists at this time, and his methods seemed futuristic and cutting edge. This draws in Kandel, and he decides to become a psychoanalyst. He enters medical school, learning about the mysteries of axons, the thalamus, and the central nervous system.
Kandel weaves the stories outlining the most important findings in neuroscience research in the past century. We learn about why Hodgkin and Huxley chose the axon of the squid, Freud’s model of psychoanalysis, Cajal’s visualization of the nerve cell, and Sherrington’s research into reflexes and inhibitory neurons. It is enlightening when you learn about why scientists performed the experiments they did and why they came to the conclusions they came to. The book is great because Kandel is such an expert in the history of this field, and he is able to explain the developments in neuroscience so clearly and succinctly.
Kandel himself begins the practical application of his knowledge of biology, working in laboratories and learning from experiments.
For example, in one experiment Kandel and his research partner placed electrodes on the brains of the cats. They then gave them LSD and serotonin. Kandel then measured the electrical signals of the cat’s visual cortex. What is the visual cortex? It is a region of your brain near the back of your head, and it is responsible for some of the processing of the visual signals that come into your eyes. Anyways, he measured the visual cortex in order to see if it could help him understand why LSD causes vivid hallucinations. He discovered that LSD and serotonin have the same action, inhibiting the transfer of signals between neurons via their synapses (space between two neurons). Kandel then performs some research into Aplysia slugs. This research reveals his research methodology, showing how you can gain new knowledge from the study of simple organisms. By reducing your problem and simulating it in a more simplistic environment, you can glean a lot of new information. Aplysia slugs have relatively simple nervous systems, with some nerve cells that can be easily identified. It is easier to measure the synaptic potential (you can think about it like the strength of a signal between two neurons) and map neural connections in Aplysia slugs. Now, the important question, what did Kandel learn about biology from Aplysia slugs?
He used the slugs to study learning and the effect of behavior modification on neural systems. Depending on the stimuli you receive from your environment, you will respond differently, and the connections in your brain reflect this. For example, you may not pay attention to the sound of the air conditioning in your house, as you are used to the sound. This a sign of habituation, but what I want you to take away from this example is that you learn to pay more or less attention to things in your environment depending on they affect you. Kandel wished to know how changes in your behavior were reflected in the physical changes in your central nervous system.
Kandel explains that “to simulate habituation, I would apply repeated, weak electrical pulses to this neural pathway. To simulate sensitization, I would stimulate a second neural pathway very strongly, one or more times, and see how it affected the target cell’s response to weak stimulation of the first pathway. Finally, to simulate classical conditioning, I would pair the strong stimulus to the second pathway with the weak stimulus to the first pathway in such a way that the strong stimulus would always follow and be associated with the weak stimulus.”
Kandel learns that different forms of learning affect synaptic plasticity in different ways. The terms homosynaptic depression and hetero-synaptic facilitation/depression are coined by Kandel. He studies how neurons change how they communicate depending on the kind of electrical stimulation they receive. He learns that the strength of synapses quickly responds to the environmental stimuli we receive. Kandel also discusses how Aplysia experiments are performed leisurely due to the lack of damage caused by the electrodes, and how this allowed him to easily run his 5–10-hour experiments. These little stories bring more life to the research he is performing and added a lot of enjoyment to his book.
I think we can stop here for now. Subscribe if you want to learn more about Kandel and his achievements!
Thanks for reading!
