Experience-based Brain and Biological Development Accomplishments

CIFAR researchers describe how the offspring of rat mothers who had been brushed daily or been given more complex living environments during pregnancy exhibited enhanced brain development and better capacity to recover from brain injury. The extra tactile stimulation is thought to help mothers produce special growth factors, which pass through the placenta to the unborn offspring. These growth factors lead to the production of new connections in the brain that are thought to underlie the enhanced functions.

• A collaborative project in the program led to the discovery that a mother’s behaviour can cause lasting changes in the way her offspring’s genes are expressed. They compared baby rats who received less licking from their mothers with those who received more. They found that infants who received more licking were more stress resistant as adults. Researchers also found that rat pups of attentive mothers expressed a stress-regulation gene differently in their brains, which caused them to produce lower levels of stress hormones and explained their greater coping ability.
• EBBD members are beginning to identify specific genes that influence neurobiological development. A “foraging gene” found in some fruit flies, for instance, is also important to memory. Communication between nerve cells in the brain is determined by signaling pathways that involve binding of chemical neurotransmitters and their specialized receptor molecules. Glutamine is one such neurotransmittor. An EBBD researcher has demonstrated that genes regulating glutaminergic receptors also affect critical brain development periods in mice.
• A CIFAR researcher discovered that infants only 4 months old can use visual clues to recognize when a speaker switches from one language to another. Babies from unilingual and bilingual households who watched a silent video of a person reading aloud showed increased attention when the speaker switched from English to French, or vice versa. Only children from bilingual households still had this ability at the age of 8 months.