Researchers can tell how much you are struggling with a task or decision based on sensory input by looking at the activity of your brain’s insular cortex, according to a new study at Georgia State University.
For example, if you are driving down the road and suddenly see an object in front of you, you must decide what action to take, such as whether to slow down or go around the object. If the situation remains unclear and you are still unsure what to do — perhaps you are still trying to figure out if it is an animal or a box — then your insular cortex activity would fire up.
The findings shed light on the insular cortex’s role in perceptual decision-making, which up until now has remained a mystery.
The study involved 33 participants with normal or corrected-to-normal vision and normal neurological history. The subjects completed four perceptual-decision making tasks, in which the researchers manipulated the visual and audiovisual stimuli to create varying degrees of task difficulty.
Behavioral experiments were performed both inside and outside the MRI scanner. Outside the MRI scanner, participants were asked to indicate their decisions as quickly and accurately as possible with left and right mouse clicks for two given stimuli.
Inside the MRI scanner, participants were asked to perceive the presented stimuli, wait for a question mark to be displayed on the screen and then indicate their choice by pressing a response key on a button box.
The researchers also measured blood oxygen level dependent (BOLD) signals and examined the role of anterior insulae in easy and difficult perceptual decision-making.
In all four experimental tasks, researchers found that anterior insulae activity consistently increased with task difficulty.
For perception of facial expressions, for example, the anterior insulae was activated significantly more for blurred or “noisy” pictures compared to clear pictures. Researchers also found higher BOLD activity for difficult tasks compared to easier ones. The participants’ behavioral performance also changed when the sensory information was unclear.
“This study found the activity of the anterior insulae can predict how well the sensory information is perceived or what the difficulty level of the perceptual task is,” said Dr. Mukesh Dhamala, associate professor in the Department of Physics and Astronomy at Georgia State.
“This research is important because the anterior insulae, along with two nearby brain structures, make up the salience network, and when this network is impaired, it affects the ability to switch between tasks and make coherent thoughts.”
“Impairment in this network could possibly be linked to psychiatric illnesses, such as schizophrenia, dementia and autism, so it’s essential to learn more about how this brain area should be functioning.”
The findings are published in the journal Neuroscience.
Source: Georgia State University