Posts tagged: medial temporal lobe


Business Logo for Psychological and Neuropsychological IssuesThere is a century old debate in psychology regarding the method the brain employs to store memories.  A recent article in the Scientific American (February, 2013) contained an article that spoke to this very debate.  It attempts to revive the theory that the human brain stores memories in specific neurons.  Put another way, any memory encoded is programmed into a discrete cluster of neurons within the brain.  For example, the authors reported they discovered the exact brain cells that encoded the image of Jennifer Aniston (actress) in someone’s brain.  Quite impressive.  The competing theory is that the features of any memory are distributed across the brain.  Rather than being stored with Ms. Aniston in a particular area of the temporal lobe, this same area is conjectured to be the site where the location of each sense memory is stored.  For example, the name of Jennifer Aniston would be stored in the area of the brain that retains words, her face would be stored in a different area that stores faces, and her body type would be stored in an area that retains spatial details.  This retrieval strategy has similarities to the library card catalogue system.  The actual books (content) are not stored in the library cards, but rather the cards store the location where the content may be found.

This article is perhaps most notable for its contradictions than it is for presenting new ideas.  It is very seductive to believe there is an exact area of the brain that serves as a storage sight of each memory.  It corresponds to the way we store objects in our everyday life.  Nothing is easier or more attractive than to relate complicated processes to our everyday experience.  Contrary to this end, the authors (to their credit) admit that brain cells that fired to a picture of Jennifer Aniston also fired to a picture of another blond actress.  This tends to disprove their contention of discrete cellular representations of each memory.  Another objection advanced by the authors is that there is not enough brain cells to encode every new experience in the human brain.  Essentially, our brain would fill with memories until the bucket could hold no more.  The authors believe the solution to this contradiction is that a “typical person remembers no more than 10,000 concepts.”  Their notion of “concept” is problematic, even beyond their vague definition as to what defines a “concept.”  The notion that all information regarding objects and their relations should hover around 10,000 bits is difficult to accept.

The authors advance another contradiction as proof of their theory.  They cite the famous case of a man whose hippocampus was surgically destroyed.  The hippocampus is a medial temporal lobe structure where the authors believe all our memories are stored.  This unfortunate man could not encode new memories at all, but he enjoyed complete retention of all his old memories-until the time of the surgery.  This strongly contradicts the authors contention of exact cellular storage of each memory.  Given that the hippocampus was destroyed by a surgeon, this man should lose all his old memories as well.  He would literally become a tabula rasa; incapable of even drawing anything new upon the slate.

Even without a detailed knowledge of neuroscience, a critical reading of this article would alert the reader to fundamental problems.  In psychology it is called “internal consistency.”  This refers to a story having a logical progression that avoids contradictions.  The authors brought up the contradictions in order to dispel these arguments; long advanced by psychologists.  They tended to reframe the contradictions in an effort to prove their theory; rather breath new life into an old theory.  This is a perfectly normal error that bedevils all human thought.  Once humans formulate a goal, we will tend to gloss over the contradictions to obtain that goal.  It may be termed “messaging the data” to ensure that data proves the desired outcome.  Science is the bulwark protecting us from ourselves.  Always maintain a critical eye.  These authors have a bit of wool over theirs!

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