Early life impacts the brain’s biological and functional development, researchers find

A new study by a team of neuroscientists has found that learning and memory abilities may vary, depending on the nature of individual experiences in early life.

While the scientists used mice and rats for their research, lead author Professor Cristina Alberini said the implications of the work are vast, including environmental influences on mental health, the role of education, the significance of poverty, and the impact of social settings.

Benjamin Bessieres, a postdoctoral researcher based at New York University’s (NYU) Center for Neural Science agreed, noting that the results “also offer promise for potential therapeutic interventions”.

“By identifying critical time periods for brain development, they provide an indicator of when pharmaceutical, behavioural or other type of interventions may be most beneficial,” he added.

Very little is presently known about the mechanisms that underlie the development of learning and memory abilities. The study sought to shed new light on this process, studying the biological elements linked to episodic memories – those of specific events or experiences – in infants by using rats and mice.

In their experiments, the scientists tested whether and how different types of experiences mature learning and memory abilities.

In one experience, infant mice and rats were placed in a small compartment – a procedure paired with a mild foot shock (a commonly used method to test memory for a context). Their memory was tested by placing them back in these compartments; if they revealed a hesitation, it indicated that they had formed a memory of previously being in the compartment.

In a different type of experience, the infant mice and rats were exposed to novel objects in a given spatial configuration. Here, rodents that have a memory for this experience show more exploration toward a novel object location when presented with a combination of new and old locations, simply because they have a natural tendency to explore more new object locations. This reveals a memory of object location. Both types of experiences, context and object location, are stored by the same memory system.

Following the experiments, authors then asked two questions – does learning mature memory abilities and then does the maturation produced by one type of experience develop the entire memory system and all its abilities? Or is the maturation selective for the type of experience that the animal had?

The results showed that learning does mature memory abilities, and that the episodic experiences of the young mice and rats led to unique biological changes, specifically indicating maturation in the hippocampus – a region critical for episodic memory formation. This was true, however, only for the young animals.

In response to the second question, researchers found that the maturation produced by one type of experience (context) did not transfer to the other learning (object location) and vice versa, leading them to conclude that the maturation of learning and memory abilities is selective for the type of experiences encountered early in life.

“The infant brain,” the authors noted “employs distinct biological mechanisms to form and store episodic memories.”

Specific experiences in the early years, they added, make “a major contribution to individual differences in learning and memory abilities.”

“Although all individuals are exposed to general learning of facts, people, things, time, and spaces, and therefore must develop a wide range of abilities and competences processed by the hippocampal memory system, our data suggests that the individual history shapes the maturation of selective abilities.”

“Memory formation is important for thinking, future learning, planning, decision-making, problem-solving, reflecting, imagining, and the overall capacity to form a sense of self,” the authors note. “This means that what infants learn and experience is crucial for their later development.”

To read the study in full, please see here.