Hooked on opioids?
July 27th 2008 21:09
Signature Tune
Extracted from the Los Angeles Times: by IRVING BIEDERMAN
The human eye makes three fixations a second on the world around it, and not at random. Our gaze is drawn to items we suspect have something new to tell us — posters, signs, windows, vistas, busy streets. Confined to a featureless physician's examination room, we desperately seek a magazine, lest we be reduced to counting the holes in the ceiling tiles. Cornered at a party in a banal conversation, we seek to freshen our drink.
Without new information to assimilate, we experience a highly unpleasant state. Boredom. Conversely, at one time or another, each of us has felt the joy of information-absorption — the conversation that lasts late into the night, the awe at a magnificent vista.
Cognitive neuroscience — the science that seeks to explain how mind emerges from brain — is beginning to unravel how this all works. At the University of Southern California, my students and I use brain scanning to specifically investigate the neuroscience behind the infovore phenomenon.
The explanation involves opioids, one of many neurotransmitters — which are molecules that the neurons in our brain release to activate or inhibit other neighboring neurons. The effect of opioids is pleasurable. The same neural receptors are involved in the high we get from opiate drugs, such as heroin or morphine.
In the past, these opioids were believed to exist primarily in the spinal cord and lower brain centers, where they reduced the sensation of pain. But more recently, a gradient of opioid receptors was discovered in a region of the cerebral cortex, humans' enormous outer brain layer that is largely responsible for perception and cognition.
In the areas of the cortex that initially receive visual or auditory information, opioids are sparse. But in "association areas," where the sensory information triggers memory and taps into previous knowledge, there is a high density of opioid receptors. So the more a new piece of information tickles that part of your brain where you interpret the scene or conversation, the bigger the opioid hit.
Staring at a blank wall will produce few, if any, mental associations, and thus standing in a corner is punishment. Looking at a random mass of objects will produce strong activation only in the initial stages, where there is little opioid activity to be had.
Gaze at something that leads to a novel interpretation, however, and that will spur higher levels of associative activity in opioid-dense areas. We are thus thrilled when new insights tap into what we have previously learned. We seek ways to feed our opioid desires; we are willing to endure the line at the movie theater in anticipation of the pleasure within. We pay more for a room with a view or a cup of coffee at a Parisian sidewalk cafe.
But if we get more opioids from making connections to our memories and knowledge, why do we then prefer the new? The first time our brains take in a new perception — a scene, a movie, a literary passage — there's a high level of activity in which a few neurons are strongly activated but the vast majority are only moderately or weakly activated. The strongly activated neurons inhibit the weak — so there's a net reduction of activity and less opioid pleasure when our brain is exposed to the same information again. (Don't feel sorry for the inhibited neurons, the losers in this instance of neural Darwinism. They are now freed up to code other experiences.)
No wonder we can't resist carrying a BlackBerry 24/7. Who knows what goodies it will deliver? A breaking news item. A piece of gossip. An e-mail from a long-ago girlfriend. Another wirelessly and instan-taneously delivered opioid hit.
Who is Irving Biederman?
Biederman directs the Image Understanding Laboratory at the University of Southern California, where he is a professor in the departments of psychology and computer science and the neuroscience program. This article originally appeared in the Los Angeles Times.
| 60 |
| Vote |
Add To: 
subscribe to this blog
Comment by tlcorbin
Comment by katyzzz
Photography Tips
MS Paint Art