Understanding how the human brain works remains one of the most elusive achievements for scientists over the years. While previous studies have revealed some of the basic mechanisms of this all-important organ, the specifics regarding how the brain operates are yet to be determined.
In a study featured in the journal Neuron, researchers from New York University have sought to explore how regions of the brain, which are associated with various memory types, can help determine how people pay attention in novel situations.
"We've long understood there are different types of memories, but what these findings reveal are how different kinds of memories can drive our attention in the future," lead author Elizabeth Goldfarb of NYU's psychology department, said.
Basic Types Of Memories
For their research, Goldfarb and her colleagues focused their analysis on episodic and habitual memories, two of the most basic memory types that people experience.
Episodic memories refer to the recollections of people involving contextual details of certain life events, such as being able to remember the layout of a room and where specific objects can be located.
Meanwhile, habitual memories tend to be reflexive in nature. They are often triggered when people carry out their daily activities.
For example, a driver who is used to taking a right turn at a stop sign every day on his way to work may habitually take the same right turn instead of a left despite not going to work on that particular instance.
A previous study has suggested that various types of memories were influenced by different parts of the brain. Episodic memories were believed to be determined by the hippocampus, while habitual memories were triggered by the striatum.
Scientists have also tried to explain how a person's attention during new situations is directed by memories formed by these neurological processes.
To find out how this phenomenon works, Goldfarb and her team carried out several experiments designed to identify how episodic and habitual memories can impact a person's future attention. This was done by monitoring the brain activity of study participants using functional magnetic resonance imaging (fMRI).
The team tested the participants' episodic memories through a "contextual cueing" in which each person is asked to look for a rotating letter "T" that was mixed among several other distracting images on a computer monitor. When they are able to locate the target, the participants were told to press a button.
Throughout these experiments, these individuals were not aware that some of the monitors were showing the same images repeatedly. The researchers believe this would allow the participants' memory of the familiar context to help them focus on finding the letter "T".
The results revealed that the attention of the participants that was guided by familiar context was associated with an activity in the hippocampus of the brain.
Goldfarb and her team tested the habitual memories of the participants through several experiments that utilized a "stimulus-response" mechanism of the brain.
This time around, the letter "T" and the distracting images were shown in a different color compared to the first set to experiments. The color of the onscreen objects served as the stimulus.
As the experiments went on, the participants discovered that, when they spot the color, they are to search for the letter "T" in a particular portion of the monitor and make the necessary response to the stimulus.
The team found that the participants' striatum was most active during this set of experiments, suggesting that this region of the brain helps guide a person's attention.
Goldfarb pointed out that the participants performed well when they were given contextual cues or habitual cues, despite remaining unaware that they were already creating episodic and habitual memories. This suggests that memory influences a person's attention.
She added that each memory type can help determine the future behavior of people, as shown in their experiments.
Photo: Denise Mattox | Flickr