According to a recently published study, Psychophysiology This study sheds light on the relationship between anxiety and brain function, with a particular focus on how anxiety affects the brain’s cognitive control networks. Findings suggest that major anxiety disorders are associated with reduced activity in specific brain regions, which may act as neural markers of anxiety symptoms.
Anxiety is characterized by irrational fear and feelings of helplessness and affects millions of people worldwide. Mild anxiety can be beneficial as it encourages you to be more aware of your surroundings, but severe anxiety can lead to debilitating illnesses called anxiety disorders. These disorders interfere with daily functioning and are often accompanied by other mental health problems, most commonly depression.
Understanding the neural mechanisms behind anxiety disorders is essential to developing effective treatments. Previous studies have shown that anxiety may be associated with changes in brain activity, particularly in the frontal cortex, but these findings have not been consistent. Some studies report decreased neural activity, whereas others report increased activity or changes in functional connectivity in the brain. This study aimed to clarify these inconsistencies by focusing on individuals with anxiety but no depression and identifying the impact of anxiety on brain function.
The researchers recruited 366 participants from Huazhong University of Science and Technology in Wuhan, China, between September 2020 and May 2023. Participants were screened using the Hospital Anxiety and Depression Scale (HADS) to ensure they had normal levels of depression, and were then classified into three groups based on their anxiety levels: healthy controls, individuals with mild anxiety, and individuals with severe anxiety.
To measure brain activity, the study used a technique called functional near-infrared spectroscopy (fNIRS). This non-invasive method uses light to monitor changes in blood oxygen levels in the brain, indirectly measuring neural activity. Participants performed a verbal fluency task (VFT), in which they generated words based on given prompts, which is known to activate brain regions involved in cognitive control.
The study found significant differences in brain activity between the groups. Specifically, there was a negative correlation between anxiety severity and activation in the right dorsolateral prefrontal cortex (rDLPFC) and left frontal eye field (lFEF). In other words, people with higher anxiety levels showed lower activity in these regions during the VFT.
Severely anxious participants showed significantly lower activation in the rDLPFC compared to healthy controls. Mean oxyhemoglobin (oxy-Hb) levels, an indicator of brain activity, were 0.047 in the severely anxious group compared to 0.896 in the control group. Similar results were seen in the lFEF, where mean oxyhemoglobin levels were -1.255 in the severely anxious group compared to 0.601 in the control group.
The findings suggest that reduced activity in these brain regions may be a neural marker of major anxiety disorders. The cognitive control network, including the rDLPFC and lFEF, is essential for regulating thoughts and emotions. Dysfunction in this network may contribute to symptoms of anxiety, such as being unable to control unrealistic worries. These results are consistent with previous studies linking anxiety to impaired cognitive control but provide more precise evidence by dissociating anxiety from depression.
The findings highlight the importance of targeting specific brain regions in the treatment of anxiety disorders. Understanding the neural mechanisms underlying anxiety can help researchers develop more effective interventions. Future studies should incorporate more comprehensive measures of anxiety and depression, such as the Hamilton Depression Scale and Beck Depression Rating Scale, to validate these results.
An important limitation to note is the focus on the frontal and temporal lobes. The fNIRS technique used in this study does not measure activity in deeper brain regions such as the amygdala, which are known to be involved in anxiety. Future studies should aim to include these regions to provide a more complete picture of the neural mechanisms underlying anxiety disorders.
“Anxiety without depression is associated with dysfunction of the cognitive control network (CNN): an fNIRS study” authors are Qinqin Zhao, Zheng Wang, Caihong Yang, Han Chen, Yan Zhang, Irum Zeb, Pu Wang, Huifen Wu, Qiang Xiao, Fang Xu, Yueran Bian, Nian Xiang, and Min Qiu.
