More than one mechanism may underlie memory and learning

The brain seems to form some memories as sequences of events, rather than by coordinated firing of interconnected neurons.

Neuroscience dogma has long held that memories are formed when networks of neurons in the brain fire all at once, strengthening the connections between them. But this may not always be the case.

Jeffrey Magee at the Howard Hughes Medical Institute in Ashburn, Virginia, and his colleagues recorded neuronal activity in the hippocampus — the area of the brain that controls memory — in mice running on a treadmill. The team found that brain-activity patterns associated with forming memories of a place occurred over several seconds, rather than milliseconds, as previously thought. 

The finding suggests that the brain uses a different, as-yet-unknown mechanism to store memories of chunks of time — effectively a new type of learning. This could allow animals to store an entire sequence of events, or to better learn important information, such as the location of a reward, the scientists say.