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A Book Commentary on Synaptic Self

fquadri's picture

            What makes you you? Despite that fact that everyone’s nervous system looks the same more or less, how does the brain shape the self and the personality of an individual? Many philosophers, psychologists, writers, and theologians have pondered upon the question. However, has a scientist ever given thought to that question? Joseph LeDoux, a neuroscientist and professor at New York University, has thought about it. Not only has he thought about it, but in his book, Synapitc Self, he offers us an answer, “Your ‘self,’ the essence of who you are, reflects patterns of interconnectivity between neurons in your brain” (p 2). The answer lies in the brain, specifically gaps that connect neurons: synapses.

            Synapses are gaps that connect neurons and allow them to communicate with each other via synaptic transmission. Synapses help determine how information is processed within the nervous system. Since they “determine the pattern of interconnectivity between neurons”, their activity is reflected through personality and the self (hence the term, “synaptic self”). LeDoux discusses how genes, environment, and learning can contribute to the construction of a brain and the wiring of synapses during development. Even though development stops, synapses still have the ability to change. These synaptic changes are what allow one person to be distinct from another – this is the emergence of an individual personality. LeDoux supports this claim with array of neurobiological information and focuses significantly on memory processing. LeDoux describes memory as “a reconstruction of facts and experiences on the basis that they were stored” (p 97). Memory is important in relation to synapses and the self because that’s how experiences are recorded in the brain through methods like cognitive learning and emotional associations. LeDoux discussed many smaller issues in the bigger context of synaptic magic. Two examples of the smaller issues are 1) his notions as the brain as a trilogy and 2) the importance of the unconscious’s work with memory on the personality.

            The brain as a trilogy was an interesting concept for me. LeDoux mentions that the brain is a trilogy and consists of three major portions of personality: cognition (thought process), motivation (neural activity that guides us toward a goal), and emotion (process that determines the value of a stimulus). The three are independent of each other but can work together to shape the self. For example, an emotional response can arise from cognitive thinking and an emotional action can trigger a specific motivation.  I saw this idea as something that one could build off of the bipartite brain that was discussed in class. The idea of the bipartite brain divides the brain into the conscious and unconscious and discusses how the two work together in order for the nervous system to function. Here, the trilogy sort of presents a tripartite brain, where cognition, motivation, and emotion, despite being separate features of the brain, overlap and work together in order to construct a unique self.  

             In the past, people would associate the self and personality to one’s consciousness. Granted, the consciousness plays a part in one’s personality, but it does not act alone, and LeDoux stresses that unconsciousness deserves more credit than it has received in the past. The unconscious is very important to creating and maintaining personality and one example is through memory. LeDoux discusses how Alzheimer’s disease and other damages to the hippocampus can affect memory loss. The kind of memory loss affected in these situations only involves explicit memory. Explicit memory is impacted by consciousness. Implicit memory, memory that is not associated with awareness, is retained. Even though people with hippocampus damage cannot remember what they ate for breakfast, there are still able to carry out actions that do not involve conscious memory such as walking or playing an instrument. Therefore, thanks to unconscious memory, a segment of personality is still intact despite severe explicit memory loss. This small topic LeDoux mentioned, in conjunction with the book’s overall theme that synapses shape our personality, had my own brain enjoy a short time travel back to the early days of the semester. 

            “Does brain equal behavior?” I remember how we discussed whether or not brain equals behavior and whether or not the brain was separate from the mind. We talked about Rene Descartes’ and Emily Dickinson’s views on the matter. Descartes believed that the brain and mind were two separate entities. Dickinson on the other hand believed that the brain and the mind were the same thing. Some people in the class, agreed with Descartes, some with Dickinson, and some just weren’t sure. I was one of the ones who agreed with Descartes but with time, I started leaning towards Dickinson’s view. This book sealed the deal for me that Dickinson’s view is correct. Brain does indeed equal behavior.

            Behavior is constituted as the sum of actions, emotions, drives, creativity, agency, and the self.  So behavior encompasses our complete personality, hence the brain encompasses our complete personality as well. Personality and the self are defined by experiences and new experiences can bring changes to the personality and to the self. Due to the brain’s plasticity, neural and synaptic activity can also change with new experiences. With that in mind LeDoux says that, “when connections change, personality, too, can change” (p 307). Therefore, when connections are damaged, a portion of personality is lost. This goes back to the example I drew out about damage to the hippocampus and how explicit memory is affected. Because of the interruptions of connections, the consciousness is unable to create memory. Is there a way for some disconnections to be connected again and restore the complete personality? LeDoux touches on the subject when he states that “an important challenge for the field of neuroscience is to figure out how to manipulate the brain in a way that patients with mental disorders can…try to put the self’s synapses back together” (p 307). The idea is great for such treatments, but it also lead me to think: Can we alter our synapses to change our personalities…willingly, in the realm of our consciousness? I believe so. Whether it’s cocaine (causes a temporary effect) or anger management (intended for a long term effect), many people use drugs and therapy to alter their personalities.

            Synaptic Self reinstates how our brains shape us into we are. I believe LeDoux says it the best on page 303, “We all have the same brain systems, and the number of neurons in each brain system is mor or less the same in eacho of us… the particular way those neurons are connected is distinct, and that uniqueness, in short, is what makes us who are are” Brains function through synaptic transmission. Synapses are influenced by experiences. Our “selves” and personality are also influenced by experiences. Hence we are our reflections of the synaptic activity that is taking place within us.



LeDoux, Joseph. Synaptic Self How Our Brains Become Who We Are. New York: Viking Adult, 2002.



Paul Grobstein's picture

synaptic self and beyond

" we are our reflections of the synaptic activity that is taking place within us"

But, also, as you imply, we can influence the synaptic activity; its a loop.