The human instinct and obsession to explore, and discover in all ways, shaped the world we know. Humans have visited virtually every desolate face on the face of Earth, have lifted off the planet to walk on the moon, and continue to inspect the solar system and the limitless reaches of space beyond it. And yet the most unique, mysterious territories within our individual jurisdictions -- the brain -- largely remains uncharted. Indeed, it is probably one of the most facinating organs that our body has. It is estimated that in a lifetime a brain can store 1,000,000,000,000,000 -- a million billion or a trillion (?) 'bits' of information. A bit, ofcourse, is a computer lingo for 'binary digit' -- that is either 1 or 0 -- representing the minimum unit of information, the amount gained when a question is answered simply yes or no. There can be little arguement that we have taken huge strides, particularly in the last four decades, towards better knowledge of the basic structure of the brain and what must be the beginning of an understanding of how it works. This relative surge of success is attributable to the latest technology, now in vogue, to study the brain. The new era in brain research is dominated by machines that use radioactive tracers, magnetic resonance effects or faint electrical signals to map the activity of the living brain. There is also a talk about reaching inside brains to 'film' the trails of human thoughts and feelings. Modern imaging systems can track the activities of human brain in several ways. Perhaps the most recent in the line of visual pathways into the brain is positron-emission tomography, also known as the PET scan. The PET uses radioactivity to label blood, blood sugars, or other neuro-transmitters.

The tagged chemical is injected into volunteers while they lie in a scanner carrying out a mental task. As the subjects perform a variety of tasks, say seeing hearing, speaking and so on, PET enables researchers to locate and study the active regions of the organ on the screen.

Another technique -- the functional resonance imaging (functional MRI) looks even more promising. It uses a powerful magnetic field to align the tiny dipoles of atomic nuclei in the brain. The particles are then probed with carefully tuned radio pulses. At particular frequencies, these particles resonate, revealing the concentration of elements, such as hydrogen in different regions of the organ. This technique also helps in measuring the change in oxygen levels and hence the blood flow, that occur in cappilaries supplying blood to active brain regions.

A third imaging method is magneto-encephalography or MEG, which employs delicate superconducting sensors to pick up faint magnetic fields generated by active nerve-networks in the brain.

Researchers believe that MEG, especially when used along side with the traditional electroencephalography -- which monitors stronger electric fields in the brain -- will eventually prove to be a very poerful technique.

But is the future of brain research as bright as it seems? Not many agree. Critics have argued that the colourful brain scans that adorn many current research papers are used as 'concrete' evidence to support whatever theory the scientist holds. But the creation of every image also holds the possibility of scores of errors creeping in, they argue.