(October 21, 2015) Findings
Help Explain How the Brain Pays Attention to What’s Important & How Neural
Circuits May be “Broken” in Attention-Deficit Disorders
Researchers at NYU Langone Medical Center say they have
added to evidence that a shell-shaped region in the center of the mammalian
brain, known as the thalamic reticular nucleus, or TRN, is likely responsible
for the ability to routinely and seamlessly multitask.
The process, they suggest, is done by individual TRN neurons
that act like a “switchboard,” continuously filtering sensory information and
shifting more or less attention onto one sense—like sight—while relatively
blocking out distracting information from other senses, including sound.
In their research in mice, described in the journal Nature
online October 21, the investigators showed that TRN neurons, which have been
previously implicated in the dampening of brain signals in people, were also
less active when the mice were led to focus on—and respond to—a visual flash of
light to get a milk reward.
In contrast, when the mice were made to pay attention to a
sound and ignore the flash of light, researchers say TRN neurons that
controlled vision were more active, suppressing the visual signals in order to
pay more attention to the sound. Earlier research by the same team of
scientists showed that different TRN neurons controlled specific senses.
“Our latest research findings support a newly emerging model
of how the brain focuses attention on a particular task, using neurons in the
thalamic reticular nucleus as a switchboard to control the amount of
information the brain receives, limiting and filtering out sensory information
that we don’t want to pay attention to,” says senior study investigator and
neuroscientist Michael Halassa, MD, PhD.