Functional connectivity in brain regions during negative emotion generation

1. BackgroundSpontaneous responses to various endogenous and exogenous emotional stimuli play a substantial role in human daily life. In fact, in addition to external factors, internal thoughts, feelings or sensations may drastically affect the physiological bases of emotional responses. Several experimental, behavioral and physiological studies have been previously conducted to address the involved brain networks may be activated during negative emotional tasks. In the present study, we aimed to extract related functional network activatedduring negative emotion generation using fMRI images. 2. Method A total of thirty healthy adults were recruited for the experiment. The designed task consists of 6 functionalruns with 18 randomized trials for each run. Therefore, each participant completed 108 trials in total. There are two types of images in experiment (aversive and neutral) which were shown to participants in two conditions, namely Look Negative and Look Neutral. To identify brain regions that support the generation of emotional responses, ICA analysis was used, which is a useful method for decomposing activation during complex cognitive tasks in which multiple operations occur simultaneously After appropriate preprocessingstage, spatial ICA conducted using GIFT Toolbox for fMRI data in order to extract task related component. The number of independent components estimated using MDL criteria was 20 and one of the components was correlated with Look Negative> Look Neutral contrast using MLR method. 3. Results Responding naturally to negative stimuli during the task recruited brain regions involved in both emotional and sensory processing including the amygdala, Anterior insula, Superior temporal gyrus, middle occipital gyrus, ventral striatum, and ventromedial Prefrontal Cortex (vmPFC). 4. Conclusions Mentioned network demonstrates a certain kind of functional connectivity strengthened during emotiongeneration. Amygdala and ventral striatum are responsible for perception of stimuli and learning which cues are associated with appropriate responses, respectively. As well as this, vmPFC integrates evaluations of relevant stimuli made by amygdala striatum, and other brain regions. This area tracks also the positive or negative valuation of stimuli. All the related regions activate during the task and our final results show that their activities correlate with each other, which means that increasing activity in one region leads to a rise inactivity in other regions.