Getting to Know Itself

At this moment you are using your temporal lobe, the part of the brain involved in language comprehension and the area activated when you read an article like this. If, while reading it, an idea occurs to you and you pause to think about it, the rostrolateral part of the prefrontal cortex—an area specialized in introspective reasoning—will be activated. And if reading this text seems to be a memorable event, your hippocampus will take charge of storing it in your long-term memory among all the other events of daily life.

This example illustrates just how far the human brain has gotten in understanding itself. The study of the mind has entered that mature phase, and science is gradually making surprising findings that illustrate the brain’s complexity. The Annual General Meeting of the European Brain and Behavior Society, held in Barcelona last week [Sept. 17-20], provided evidence of the development of this scientific discipline. Researchers are managing to explain the physical mechanisms associated with mental function—something that seemed impossible just 20 years ago. It is hoped that this knowledge will be useful in treating diseases ranging from Alzheimer’s to depression.

The research presented revealed the sophisticated modular functioning of the human brain, an organ made up of very specialized regions that, although distinct, are integrated into a whole. The brain, though specialized, is tremendously plastic, and it is at the border between specialization and plasticity that experts see possibilities for intervention in neurological and mental disorders.

One of the most innovative instances of research illustrating the modularity of the brain was presented in Barcelona by professor Lawrence Weiskrantz of the University of Oxford. He has worked with patients afflicted by an unusual disorder occurring after they stare fixedly at an object. If they then close their eyes, the image remains on the retina for a few seconds. A normal person is aware of the existence of the first object that caused the later image—but some individuals are not conscious of what they saw a few seconds before. This surprising observation, reminiscent of the cases retold by Oliver Sacks in his books, indicates that the mechanism of consciousness is composed of different parts and is divisible.

Another subject neurobiologists are shedding light on is the great specialization of the brain and how each function resides in a specific region—or sometimes in several. Scientists at Leipzig’s Max Planck Institute of Cognitive Neuroscience detected a series of regions of the cortex involved in distinguishing between thoughts originating internally and those induced externally—a mechanism that obviously fails in schizophrenics.

The list of brain functions that have been anatomically located is growing longer. Habits reside in the dorsal striate, language comprehension in the temporal lobe, and a good part of the emotions are in the amygdala. The idea of physically locating mental functions, finding their material base, remains somewhat disturbing, because these functions have always been seen as having no material basis.

“It is only very recently that the mind has been considered a material entity subject to scientific study,” says Ignacio Morgado, professor of psychobiology at the Autonomous University of Barcelona and president of the meeting’s organizing committee. Morgado believes the field has reached this level of scientific maturity thanks to “the proliferation of new techniques for studying the brain, together with the necessary theoretical development, because the mind is so complicated that theory is needed to determine what and how to study it.”

One of the new techniques has been utilized by Catalonian researcher Joaquim Fuster, who works in the United States and who received an award at the meeting. He uses microelectrodes so fine that they can detect the electrical activity of a single neuron. With this technique it is possible to trace the learning process of a primate who is offered two boxes—one empty and one containing a peanut. The significance of the game is that, each time, the peanut is in a box that was previously empty, which implies the animal must remember what happened earlier.

Using the tests, Fuster discovered which neurons were activated in storing the information. Their electrical activity constituted a memory. These neurons were part of the short-term memory system. This type of study would be unimaginable without sophisticated technology.

The researchers hope that the accumulation of knowledge about the brain will allow them to treat illnesses such as autism, depression, Alzheimer’s, and Parkinson’s. Morgado believes that the plasticity of the brain itself opens a door to dealing with these diseases. The professor’s own lab has already worked for years with rats that, after developing brain lesions, were able to recover their memories when other parts of their brains were stimulated, thus enabling them to compensate for the damaged area. Activation of these mechanisms of plasticity might mean being able, if not to cure diseases like Alzheimer’s, at least to alleviate symptoms.

The relation between the conscious world and the unconscious is another fascinating subject. Some individuals insist they are blind, yet their behavior makes it clear that they can visually locate objects. Such people probably can see but are not conscious of it. This is a very practical finding, since the brain tends to convert memory into habits in order to make chores routine. Morgado criticizes the current model of teaching that “denigrates rote learning and the training of memory,” and says it works against the very nature of the mind.