Working memory, which is able to store a small amount of information for a short period of time, works even after damage to the hippocampus and other brain structures important to memory, US researchers say in The Journal of Neuroscience.
Working memory is the brain’s ability to store a small amount of information (such as the location of an object) in an active, readily available form – usually for a few seconds. Unlike working memory, potentially unlimited amounts of information are stored in long-term memory and can be retained for any length of time.
Professor Larry Squire and colleagues from the San Diego School of Medicine studied four patients with memory impairment associated with damage to the temporal lobes of the brain – the region containing the hippocampus, a structure necessary for the functioning of long-term memory.
The participants of the study were to find out about the arrangement of items on the table, and then recreate this arrangement on another table. When the task involved three or fewer items, patients with brain injuries did as well as healthy individuals, and had no problem memorizing the position of the items in relation to each other.
Unfortunately, when more information had to be memorized for four or more items, the working memory capacity was exceeded and patients had problems with the task.
According to the authors of the study, their discovery proves a definitive separation between working and long-term memory processes in the brain, even when it comes to spatial memory. (PAP)