October 23, 2007

Stroop Task and The Anterior Cingulate

Stroop TaskTry to read (name) the colors in which the words are written and not the words themselves. See how you stumble and fumble. Beg your pardon, everyone stumbles at this seemingly minuscule task. This test is aimed to make you fumble. This testing procedure, called the Stroop Task, actually tests the conflict between the lower and higher areas in our brain. Here, lower and higher mean hierarchically (functionally, evolution-wise) lower and higher respectively and NOT anatomically.

In my previous article, 'Right is Might', I discussed about how the left and right cortex did their chores in their own unique ways. Now, the part of the brain that is involved in this conflict, lies midway between the two cortices, called the anterior cingulate cortex. This little area of the brain connects the two cortices so that information can flow bidirectionally, between the two hemispheres. We are pretty adept in understanding the SMS (short messaging service) text jargons from mobile phones, even though the words are misspelled; can see continuous motion pictures, even though they are actually shown at 48 frames per second. This highlights our instinctive ability to decipher them easily. On the other hand, naming colors (not merely seeing them) is more resource intensive and is taken care of by higher brain areas. Thus in a task like this, where two threads of activity occur simultaneously (reading the texts and naming the ink in which they are written) an interference or conflict is produced. And hence the slowing down. It can be compared to bottlenecking due to multitasking in computer systems. In fact, it is through the anterior cingulate, system buses from both upper and lower functional areas, in addition to, right and left cortex (anatomically) pass.

The anterior cingulate not only decides the bone of contention but also determines error related negativity (ERN). That is it somewhat functions like a "differential operational amplifier" of electronics, in which the output signal is the difference between input signals . By doing this, it may be able to instruct the motor system which task is to be given precedence. It also acts as seat of emotion. For example, in (lactating) women her baby's cry will elicit strong emotions on her. This has been studied by fMRI (functional Magnetic Resonance Imaging). It may also explain the fact that women are more socially sensitive.
Post a Comment