The Dynamic Brain

 

Image by Molly Magnell

Image by Molly Magnell

In the film Lucy, a student asks his professor “… what would happen if … somebody unlocked one hundred percent of the cerebral capacity?”  While the professor replies “I don’t know,” the informed reader of this article might scoff and respond: “Dude, that myth is absurd.”  The myth in question is the so-called “ten percent myth,” which claims that one has access to only ten percent of their brain at any given time.  Other popular films like the 2011 thriller Limitless are also built upon this shaky foundation.  The myth in itself is banal.  It seems like every time this myth resurfaces, a slew of neuroscientists and other people who know what they are talking about scramble to refute it, and at this point no Frontiers reader will be surprised to learn that it is indefensible.  However, an interesting question is: how much of our brain do we need to think, and how does information processing actually happen?  The Miller Lab at MIT’s Picower Institute of Learning and Memory tackled these problems, and their results turn more than just the ten percent myth on its head.

The lab trained monkeys to indicate using specific arm motions whether a light was red or green or whether it was moving right or left.  While the monkey performed the tasks, researchers recorded activity from its brain in six different locations using 108 electrodes implanted in its brain.  To make sense of their data, Miller and colleagues categorized the different kinds of information the monkey would need to process.  First would be “cue” information, when the monkey sees the stimulus, followed by recognition of the “task.”  When the monkey made its decision, its brain would be processing both “color” and “motion” information.  Finally, researchers added a “choice” category that would represent information when the monkey chose that could not be explained by processing of color or motion.

The traditional model of how the brain works posits that different areas in the brain control different kinds of functions.  Based on this, one may expect one area of the brain to activate when the monkey looks at the stimulus and other areas to light up when it is considering its answer and, finally, moving its arm.  However, the researchers saw something surprising: almost all measured areas activated during processing of all kinds of information!  In particular, researchers suggested that the monkeys’ choices arose from an “integration of opposite flows of sensory and task information.”  In other words, instead of considering cortical processes as a river in which activity in one area leads to a response somewhere downstream, it may be more helpful to envision the brain as an ocean, in which every new ripple changes the pattern of the waves.

Practically, Picower’s results could have profound impacts on the way we see the brain, especially in how we treat mental disorders such as depression.  Pharmacological treatment of depression typically targets the amygdala, whose dysfunction is thought to be a primary cause of depression.  However, the research indicates that we may be too focused with our treatment, ignoring other parts of the brain that play almost an equally important role.  Dr. Miller said it best in an interview with MIT News:  “One main concern about noninvasive brain stimulation is how to do that if the cortex is a patchwork of highly specialized structures,” Miller says.“This shows you can actually use things like noninvasive techniques to boost signaling in a whole bunch of areas simultaneously, and you don’t need to worry so much about targeting one specific area.”  The challenge for future generations of neuroscientists is to find order in our dynamic, chaotic brain.

This result may be another blow to the “ten percent” dead horse, but it has another, unexpected casualty – the traditional way the brain is viewed and taught.  Students in classes like Introduction to Psychology or AP Psychology traditionally learn to associate a part of the brain with a specific function.  For example,the occipital lobe is for vision and the temporal lobe is for hearing.  This, at first glance, seems logical.  “It makes sense that certain parts of the brain are specialized for certain kinds of functions,” says Washington University in St. Louis junior Emily Wen, “after all, the brain isn’t a big pile of mush.”  She has a point – the concept that each part of the brain is primarily responsible for a sense or function is very didactically convenient, exhibiting a crisp, logical causality.  However, nature did not evolve to make things easier for us, and it seems like the picture is much blurrier than we would like.

 



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Alex Chen can be reached at alex.b.chen@email.wustl.edu


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