The goal of this experimental protocol is to investigate the neural correlates of immediate and long-term impact of explicit and implicit emotional control using functional magnetic resonance imaging. This protocol involves assessments of emotional ratings of pictures, and of the memory for these pictures as a result of inducing the goal to regulate emotion. Recording of brain imaging data is performed during the rating task.
The goal to control emotions is induced either explicitly by instructing the participants to control their emotions or implicitly by priming the participants with emotion control. Words embedded in a so-called scrambled sentence. Task analysis of brain imaging data targets activity in regions associated with basic emotion processing, such as the amygdala and brain regions involved in emotion control such as the prefrontal cortex, particularly lateral and medial regions.
The main advantage of this technique over existing methods like those mainly focusing on the immediate impact of emotional regulation and typically targeting deliberate emotional regulation, is that it allows assessments of both immediate and long-term impact of emotional regulation, as well as comparisons of automatic and deliberate emotional regulation induction. This method can help answer questions about opposing emotional biases such as those observing healthy aging where there is a positivity bias and depression. Where is a negativity bias, which seem to be associated with enhanced ability to automatically engage emotional regression strategies observing healthy aging as opposed to impair ability to engage emotional regression strategies observed in depression?
This protocol involves assessments of emotional ratings of pictures and of memory for these pictures. As a result of inducing the goal to regulate emotions, the goal to regulate is induced explicitly or implicitly, and the immediate and long-term impact is assessed relative to pictures presented during baseline blocks that precede the emotional regulation. Manipulations sets of pictures for emotional rating and memory tasks will need to be set up for this experiment using emotional and neutral pictures.
We suggest using images from the international effective picture system. Careful attention should be paid to balancing the emotional content of pictures across all study blocks, including those that are presented before and after the induction of emotion regulation and those used in the memory task to avoid confounding effects due to possible differences in these basic properties. For the rating task, we suggest that each picture be presented on the screen for four seconds, followed by a fixation cross for 12 seconds with a task to rate the subjective emotional experience triggered by the pictures.
If your equipment allows, use an eight point scale with one being neutral and eight being extremely negative. To avoid mood induction pictures should be pseudo randomized so that no more than three pictures of the same valence are consecutively presented. Next, set up the explicit and implicit emotion regulation manipulation paradigms.
The latter can be adapted from the scrambled sentence task, and we suggest designing a task for which subjects are instructed to construct 20 forward grammatically correct sentences from five word jumbles that have embedded words that will prime the participants to suppress their emotional response, such as restrain covered or withheld for the explicit condition. Also present 20 sentences, but containing only neutral terms, which do not induce emotion regulation, and then instruct participants to suppress their emotional experience and expression of emotional responses. When running subjects, either the explicit or implicit condition can be run first, but be sure to counterbalance the runs across subjects.
For example, for half of the subjects the order of task paradigms could be baseline emotion rating, block explicit induction of emotion regulation goal, explicit condition, emotion rating blocks, followed by another baseline emotion rating block, implicit induction of emotion regulation goal and implicit condition. Emotion rating blocks for the other half, the order of experimental blocks is switched. Finally, set up a memory retrieval task, which will be run outside the MRI machine one week after the emotion regulation runs.
This task should display an equal number of old images that were seen in the scanner and new pictures which have not been seen before, all presented in black and white to prevent ceiling performance. The task should be an old versus new decision based on whether subjects remember the pictures followed by a confidence rating of their responses on a three point scale, with one being low, two being medium, and three being high confidence. When the subject arrives, be sure to obtain written and informed consent from them, and in order to screen for MRI safety, make sure all metal he or she may be wearing is removed.
Also, warn the subject that many of the pictures that will be viewed depict distressing events and provide printed examples of representative pictures. Here are some representative images of what you'll see in the scanner. Some of them are of a disturbing or traumatic nature.
Next, the subject's current state of mind should be assessed to control for the effect of mood on the emotional experience and the ability to control emotions In conjunction with post scanning assessments. These initial evaluations can be used to screen for changes in mood as a result of the study participation prior to the scan. Inform the participant in detail of the scan procedures and give specific instructions for the behavioral task to avoid discomfort and to create increased familiarity with the task.
Also, give the participant abbreviated practice runs for both the emotion rating and the scrambled sentence task. Now bring the subject into the scanning room and instruct him or her to lie. Sue Pine on the scanning bed, provide ear protection as well as isolation headphones for communication during the scan.
Additional cushioning for the head should be placed to ensure comfort during the scan and minimize movement. Also, the non-adhesive side of a length of tape may be wrapped lightly around the participant's forehead to further minimize head movement to assess automatic implicit psychophysiological responses to emotional and neutral pictures In addition to the explicit ratings, skin conductance responses can also be recorded During the FMRI scanning. Position the subject's right hand comfortably on the response box and place an emergency stop button nearby so that the subject may indicate any urgent need to stop the scanner.
Make sure that the subject can see the screen projection clearly for stimulus presentation and that the response buttons work properly before sending him or her into the scanner. BO now acquire a high resolution T one weighted structural image such as an SPGR or MP rage. In this study, we acquire a 3D MP rage anatomical series with a TR of 1600 milliseconds, a TE of 3.82 milliseconds, 112 slices, and one by one by one millimeter vs.
Next, set up your functional runs. To allow full brain coverage, we suggest using an echo planar sequence to acquire 28 axial slices with a voxel size four by four by four millimeters, a TR of 2000 milliseconds, a TE of 40 milliseconds, a 256 field of view, a 90 degree flip angle, and 64 by 64 matrix size. Inform the subject that the functional imaging is about to begin and remind him or her of the tasks.
First, run your baseline image rating task. Now run the first goal manipulation condition being either the implicit or explicit emotion regulation induction task followed by the image rating task. Next, run another baseline.
Then the second condition followed by an image rating task. When scanning is complete, help the subject out of the scanner and perform post scanning assessments to again, assess the subject's current state of mind. Finally, have the participant return one week later.
For the memory retrieval task, we suggest running this protocol for about 24 subjects so that group level analysis can be performed. Remember to counterbalance the order of implicit and explicit paradigms across subjects. Once collected, data can be analyzed using any FMRI processing software package, such as statistical parametric mapping, commonly known as SPM.
Our lab uses this in combination with in-house mat. Lab-based tools pre-processing should involve typical steps, quality assurance, image alignment, motion correction, co-registration, normalization, and spatial smoothing with an eight millimeter kernel. When using SPM, the general linear model is implemented to assess the fit of the data recorded for each condition of interest to a predetermined hemodynamic response function.
Alternatively, the data from each condition can be selectively average to view the raw FMR signal associated with each condition, with no predetermined assumptions about the shape of the hemodynamic response function. In this case, differences in response can be assessed on a time point by time, point basis. Contrast of interest then reveal the percent signal change compared to pre stimulus, baseline, and differences between one condition when compared to another condition.
Individual and group level statistical analysis can be performed involving comparisons of brain activity according to various factors including emotional valence and emotion regulation manipulation. Here we see a coronal view of a functional map overlaid onto a structural image showing areas with decreased activity as a result of emotion response manipulation based on group statistics, inducement of the emotion regulation goal was associated with reduced activity in the amygdala. The color bar indicates the gradient of TValue of the activation map.
The bar graph illustrates percent signal changes in response to emotional and neutral pictures before and after the induction of the ER goal. As can be seen during baseline, amygdala activity was higher for emotional compared to neutral pictures. This difference disappeared after the induction of the goal to regulate emotions.
Here we also see increased activity in brain regions associated with cognitive control and emotion regulation, including lateral and medial prefrontal cortex. Once again, the color bar indicates the gradient of T values and the bar graph illustrates percent signal changes in response to the two valences of pictures before and after the induction of the emotion response goal. As the top bar graph shows in the control regions activity to emotional pictures increased as a result of inducing the goal to regulate emotions.
While attending this procedure, it is important to properly balance the stimulus properties across the pre and post manipulation runs, and he avoid possible confounding effects. It is also important to make sure that participants understand the task instructions. After watching this video, you should have a good understanding of how to manipulate the goal to regulate emotions both explicitly and implicitly, and how to assess the immediate and long-term effects of these emotional regulation strategies.
