Smell goes brainy

After reading Patrick Susskind’s ‘Perfume’, famed auteur Stanley Kubrick remarked that the book was ‘unfilmable’. On his part, Susskind, too, didn’t seem too keen to pursue the celluloid muse for his international best-seller, which was set in stinking suburbs of Paris in the 18th century, and centred around an orphan who has no smell of his own, but has the most astounding olfactory sense himself.

Jean-Baptiste Grenouille uses his nose to create the world’s finest perfumes. Eventually, however, the psychologically scarred perfumer takes a devilish turn as he tries to preserve scents in the search for the ultimate perfume.

Kubrick’s reservations probably stemmed from the immense difficulties involved in fleshing out the ephemeral world of scents and essences, and plumbing the mysteries of olfaction, which is one of our oldest sense.

It joins us way down the evolutionary ladder to all kinds of creepies and crawlies visually blind but nasally empowered. How mysterious this sense is has been revealed recently by a breakthrough reported by researchers from the University of Auckland, New Zealand, and the Sahlgrenska Academy in Sweden.

The scientists found a brand new type of brain cell that continuously regenerates in humans. This pool of “resting cells” migrates to brain areas involved with smell, to create new nerve cells.

To be fair, the ‘new neural nose system’ was known from earlier research done on mice and rats. But in keeping with the old dogma of the static brain, it was believed humans lacked it - scientists mistakenly believed that brain cells once lost could never be regenerated or re-grown.

Then came research by Fred Gage and his colleagues that showed the amazing plasticity of the brain, which responded to exercise, especially running, by sending out bursts of new neurones. In a sense, the present research ought to have been a no-brainer: because nasal neurones, which are the only brain cells directly exposed to the environment are constantly morphing and changing.

That it has taken so long to break the old hypothesis only shows how entrenched and resistant are old paradigms even in science. The international team of scientists showed the new class of stem cells rest in certain areas of the brain, just beneath large fluid-filled chambers called ventricles.

But then they needed to work out how they got to the right part of the brain. In many non-human species, it was known that a tube filled with brain fluid enabled these cells to travel to the olfactory bulb - the region of the brain that registers smells - turning into nerve cells as they went.

Using several techniques, including a powerful electron microscope, the team identified the tube, and showed it contained stem cells as well as cells which were gradually turning into nerve cells as they travelled along. The researchers said the addition of new nerve cells in the olfactory bulb in humans helped the system respond to different stimuli throughout a person’s life.

Other experts said the new findings, which were published in the journal ‘Science’, opened up the potential for research into repairing brains in conditions such as Alzheimer’s disease.