Cajal, Kandel, and Schacter

We recently read a stunning, moving memoir by L. Annette Binder about her mother’s slow decline and memory loss due to Alzheimer’s. It’s called Child of Earth and Starry Heaven and, in a word, it’s a powerful book. We highly recommend it. Binder is a terrific writer and her awards are ample proof of that.

Along the way, as Binder seeks to learn more about the disease, she brings up three notable scientists of the brain and memory that we think deserve more attention—Santiago Ramón y Cajal, Eric Kandel, and Daniel Schacter.

Photo credit: Photo by Aakash Dhage on Unsplash

Santiago Ramón y Cajal

A neuroscientist, pathologist, and histologist, Cajal lived from 1852 to 1934. He was born in northern Spain and his father would take him on walks through graveyards looking for bones to sketch (according to this brief documentary on YouTube.) Ramón y Cajal was a medical officer in the army and then followed his father’s footsteps by becoming a doctor and anatomy instructor.

Along with Camillo Golgi, Ramón y Cajal received the Nobel Prize in Physiology or Medicine in 1906. He pioneered microscopic structure of the brain. Hundreds of his drawings illustrate the “arborization” of brain cells that are still in use for educational and training purposes. (His drawings of nerve structures, in fact, look very much like trees.)

Cajal's most significant contribution was his rigorous defense of the neuron doctrine, the principle that the brain is composed of individual cells (neurons) that are discrete units, rather than a continuous, interconnected network. He also showed that neurons communicate with each other at junctions called synapses, where nerve impulses are transmitted from one cell to another. 

Ramón y Cajal generated meticulous depictions of neural structures and their connectivity and provided detail descriptions of cell types, including one named after him, the interstitial cell of Cajal. He is widely considered the father of modern neuroscience.

Eric Kandel

A recipient of the Novel Prize in Physiology or Medicine in 200, Eric Kandel’s big breakthrough came in 1970 while he was at New York University studying a marine snail with a simple nervous system. He found that as the snail learned, chemical signals changed the structure of the connections between cells.

From this article in Columbia Magazine from 2006, we learned that Kandel studied the snail’s withdrawal reflex that protects sensitive gills when the foot-long gastropod is under threat. Kandel’s lab modeled simple forms of learning with a series of benign touches and electrical shocks. As the snail’s giant neurons were stimulated in the right pattern, they began to “learn.” In other words, they responded to stimuli in predictable ways. Kandel’s work showed how synapses--the connections between specific neurons—strengthened or weakened under the right conditions.

Kandel is the author and co-editor of Principles of Neural Science, which was first published in 1981. The original edition was 468 pages. The sixth edition was published in 2021 and is 1,646 pages.

(That’s a lot of principles.)

Daniel Schacter

A professor of psychology at Harvard University, Daniel Schacter learned that memory is a constructive process, not a perfect recording. In other words, it’s prone to errors and distortions. Schacter used neuroimaging to show that memory failures are often linked to the same brain mechanisms used for successfully remembering the past and for simulating future events by flexibly combining past experiences. Memory is not a literal retrieval of the past but is built by combining elements of past experiences.

In fact, Schacter wrote a widely-renowned book called The Seven Sins of Memory.

What are the seven?

The seven common ways that memory malfunctions include transience (forgetting over time), absent-mindedness (lapses due to lack of attention), blocking (inability to retrieve information), misattribution (wrong source for a memory), suggestibility (false memories from outside influence), bias (distorting memories by current knowledge), and persistence (intrusive, unwanted memories.)

Are they “sins” as such? Not really. They are by-products of the memory’s adaptive, functional processes.

(Are all of your memories real? Are you sure? Check out this fascinating video.)

In short, says Schacter, “memory is not a simple replay. The bits of information that we recover from the past are often influenced by our knowledge, beliefs and feelings.”

So, thank you L. Annette Binder for reminding us of the contributions from these three notable scientists!

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