Tag Archives: memory

Genes Behind Humankind’s Big Brain

Scientists have pinpointed three genes that may have played a pivotal role in an important milestone in human evolution: the striking increase in brain size that facilitated cognitive advances that helped define what it means to be human. These genes, found only in people, appeared between 3 and 4 million years ago, just prior to a period when the fossil record demonstrates a dramatic brain enlargement in ancestral species in the human lineage, researchers said. The three nearly identical genes, as well as a fourth nonfunctional one, are called NOTCH2NL genes, arising from a gene family dating back hundreds of millions of years and heavily involved in embryonic development. 

The NOTCH2NL genes are particularly active in the reservoir of neural stem cells of the cerebral cortex, the brain’s outer layer responsible for the highest mental functions such as cognition, language, memory, reasoning and consciousness. The genes were found to delay development of cortical stem cells into neurons in the embryo, leading to the production of a higher number of mature nerve cells in this brain region.

The cerebral cortex defines to a large extent what we are as a species and who we are as individuals. Understanding how it emerged in evolution is a fascinating question, touching at the basic origins of mankind,” said developmental neurobiologist Pierre Vanderhaeghen of Université Libre de Bruxelles and VIB/KULeuven in Belgium.

It is the ultimate evolutionary question and it is thrilling to work in this area of research,” added biomolecular engineer David Haussler, scientific director of the University of California, Santa Cruz Genomics Institute and a Howard Hughes Medical Institute investigator.

Source: https://www.reuters.com/


Learning How To Create And Keep Memories

Drug manufacturers are looking at ways to alleviate memory loss, one of the most distressing symptoms of diseases such as Alzheimer’s. Professor George Kemenes from the Sussex University (UK) intends to show how such drugs could work.


The goal is to identify brain molecules that are crucial for the building up and maintenance of long-term memory,’ he says. ‘We aim to find ways to manipulate these molecules to enable us to control functions and improve the speed at which animals learn, or help them remember for longer periods of time. This would then link into drug development for humans.’

Pond snails are ideal for this kind of study because they share important characteristics with humans. These include the basic molecular mechanisms that control long-term memory and learning. These mechanisms involve the activation or suppression of a protein, CREB, which is key to the formation of long-term memory. CREB is present in species ranging from molluscs and flies to rats and humans.

Memory responses can be tested with classic Pavlovian experiments. Snails exposed to the smell of pear drops followed by food still respond weeks later to the smell by moving their mouth parts in anticipation of food. This ‘flashbulbmemory is created by just one exposure to the two stimuli. The snails have a memory associating the smell of pear drops with the arrival of food – a learned and remembered response.

In a similar test, a snail is exposed to a mildly unpleasant stimulus by touching its head with a paintbrush (snails don’t like being tickled) before food is introduced. It takes much longer for the snail to associate an unpleasant stimulus with the arrival of food. Recently, George has succeeded in inhibiting the quickly learned memory and improving the weaker, more slowly-acquired memory at molecular level.

Working in collaboration with colleagues at the University, key findings include the discovery that amyloid peptides, substances that are thought to underlie Alzheimer’s disease in humans, also cause memory loss in snails. Another finding is that age-related memory loss in snails can be prevented by treatment with a small peptide known as PACAP.

Source: http://www.sussex.ac.uk/