|
 Researchers designed a sound experiment to explore the brain’s
plasticity, or its ability to change and respond to new situations.
These changes influence how the brain reacts to stimuli and whether
the person is able to distinguish between safe or dangerous
circumstances, said lead author Rony Paz of the Weizmann Institute
of Science in Rehovot, Israel.
“Our study suggests that people with anxiety cannot discriminate, at
the most basic level, between stimuli that have an emotional content
and similar mundane or daily stimuli,” Paz said by email.
“This in turn might explain the anxious response that they exhibit
to scenarios that seem regular, normal or non-emotional to anyone
else – their brain cannot discriminate and responds as if it is the
anxious stimulus,” Paz added.
In the first part of the experiment, Paz and colleagues trained 28
volunteers with anxiety to associate three distinct tones with three
outcomes – money loss, money gain, or no consequences.
Then, in the second phase, researchers played 15 different tones and
asked participants to identify whether they had heard the sound
during the first part of the experiment.
The goal was to see if people could avoid over-generalizing a new
tone and mistaking it for a different sound they heard before.
But the people with anxiety were much more likely to make this
mistake than 16 healthy controls who previously participated in a
similar experiment, researchers report in the journal Current
Biology, March 3.
Researchers also compared magnetic resonance imaging (MRI) scans of
the anxious people to those of the healthy participants in the
previous experiment.
With anxiety, people had more activity visible in the amygdala, a
brain region tied to fear and anxiety, and also in primary sensory
regions of the brain, the study found.
The study is small, and more research involving more people is still
needed to understand how or whether anxiety may directly cause
shifts in how people perceive the world around them, Paz said.
It’s possible, however, that the inability to distinguish sounds may
extend to other senses, Paz added.
“Our world is comprised of simple features that build the complex
picture,” Paz said. “If we cannot discriminate these building blocks
or simple features, we would not be able to discriminate the big
picture.”
[to top of second column] |
The results also underscore that anxiety is a disease, not a
voluntary way of perceiving the world, said Dr. Damiaan Denys, a
psychiatry researcher at the University of Amsterdam who wasn’t
involved in the study.
“If you’re anxious, you’re hardly to blame,” Denys said by email.
“It is not a choice or a lack of free willpower.”
In an ideal world, people would want to have less generalization and
more ability to detect nuances differences in distinct situations,
said Dr. Amit Etkin, a psychiatry researcher at Stanford University
who wasn’t involved in the study.
The findings add to a growing body of evidence suggesting that
people with anxiety respond with fear to situations that only
partially resemble previous frightening encounters, Etkin said by
email.
“This paper goes a long way in providing a biological explanation
and shows how the bias towards over-generalization that is seen in
anxiety is evident even in how their brain encodes the perceptual
information itself,” Etkin added.
“More and more, I see over-generalization as a new and important
domain for understanding anxiety, which may furthermore offer us new
and different insights into how we might better treat these
patients,” Etkin said.
SOURCE: http://bit.ly/1pbrHXN
Current Biol 2016.
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
