Indian scientists have discovered the genetic switch that turns on human memory.  Inside the embryo brain, an intricate interplay between bulk of the precursor brain cells where the switch – a gene called Lhx2 – is on with a handful of cells where the switch is off, leads to the formation of hippocampus, which stores memory.

In adult brain, the Lhx2 gene is switched on in all cells. But, in some of the embryo cells, the gene is turned off.  The “off and on” combination results into a complex molecular mechanism leading to growth and development of hippocampus.

Hippocampus is a part of the forebrain, which has an essential role in the creation of new memories about experienced events.

Carried out by scientists at the Tata Institute of Fundamental Research (TIFR) in Mumbai, the research also gives a new insight into functioning of some of the primary tasks of the brain including vision, hear, smell and learning.  “Switching on the Lhx2 gene is responsible for formation of cerebral cortex whose functions includes memory, attention, perception, thought, language, and consciousness,” Dr Shubha Tole, the team leader at TIFR told Deccan Herald.

The research has been published in Friday’s issue of Science and its importance can be understood from the fact that the Science paper actually is an unusual combination of two independent works by TIFR and the University of California, Irvine separately.  “It’s not collaboration but our independent research. We arrive at the same conclusion despite working halfway across the world. Then the journal directed us to tell this fascinating story together,” she insisted.  Mental disorders like autism, epilepsy, mental retardation and schizophrenia are believed to have been triggered by things that happened during the brain’s developmental phase.

“Better understanding of the brain’s development at the embryonic stage may provide a clue or two to other researchers on how to deal with these disorders better,” said Dr Tole.  The study shows how the signals stimulating the growth and development of hippocampus – the memory maker in the brain – are controlled in the embryonic brain. Using stem cells of transgenic mice, the TIFR team identified the source of these signals and the major genetic switch that restricts their production to correct region of the developing brain. 

The US team reported the same findings using a special type of mice in which certain genes have been knocked off. Though the research has been carried out in mice, results can be extended to humans as well.