A new study suggests that as our brains age, groups of connections that co-ordinate brain activity during memory tasks become smaller and more numerous, indicating reduced cohesion. Elizabeth Davison of Princeton University, USA, and colleagues describe a novel method to characterize the brain dynamics of individuals and assess how brains change with age.
The researchers used a brain imaging technique, functional magnetic resonance imaging (fMRI), to record healthy participants’ brain activity during memory tasks, attention tasks, and at rest. They modeled each person’s brain as a network composed of brain regions and the connections between them, and compared coordinated brain activity between tasks and between individuals.
They found that the number of synchronous groups of connections was highly specific to each individual, and was consistent regardless of whether a person was using memory, directing attention, or resting.
On memory tasks, the researchers found that the degree of cohesive brain activity was strongly correlated with age. While young participants had a few large synchronous groups that linked almost the entire brain in coordinated activity, older participants had progressively more, smaller groups of connections, indicating loss of cohesive brain activity — even in the absence of memory impairment.
Future work will investigate how to use individual brain signatures to differentiate between healthily aging brains and brains with age-related impairments.
Research Article: Davison EN, Turner BO, Schlesinger KJ, Miller MB, Grafton ST, Bassett DS, et al. (2016) Individual Differences in Dynamic Functional Brain Connectivity across the Human Lifespan. PLoS Comput Biol 12(11): e1005178. doi:10.1371/journal.pcbi.1005178
Image Credit: Davison et al., 2016