Empathy, Defending, and Functional Connectivity While Witnessing Social Exclusion

Peers are present for most bullying episodes. Peers who witness bullying can play an important role in either stopping or perpetuating the behaviour. Defending can greatly benefit victimized peers. Empathy is strongly associated with defending. Yet, less is known about defenders' neural response to witnessing social distress, and how this response may relate to the link between empathy and defending. Forty-six first-year undergraduate students (M_age = 17.7; 37 women), with varied history of peer defending, underwent fMRI scanning while witnessing a depiction of social exclusion. Functional connectivity analysis was performed across brain regions that are involved in cognitive empathy, empathetic distress, and compassion. History of defending was positively associated with functional connectivity (Exclusion > Inclusion) between the left orbitofrontal cortex (OFC) - medial prefrontal cortex (MPFC), and right OFC - left and right amygdalae. Defending was negatively associated with functional connectivity between the left OFC - anterior cingulate cortex. The relationship between history of defending and empathy (specifically, empathetic perspective taking) was moderated by functional connectivity of the right OFC - left amygdala. These findings suggest that coactivation of brain regions involved in compassionate emotion regulation and empathetic distress play a role in the relationship between empathy and peer defending.

Functional connectivity across social inclusion and exclusion is related to peer victimization and depressive symptoms in young adults

BACKGROUND

Peer victimization is associated with increased risk for depression, as well as increased neural response to social exclusion in the anterior cingulate cortex (ACC) and the amygdala. Altered functional connectivity (FxC) of fronto-limbic circuitry is associated with risk for various affective disorders. The present study examined the relationship between fronto-limbic FxC during social exclusion, prior peer victimization experience and depressive symptoms.

METHODS

Three mutually exclusive groups were formed: peer victimized (with a history of peer victimization), defenders (history of defending peers), and controls (no prior peer victimization experience) (n = 15/group; M_age = 17.7 years). Functional Magnetic Resonance Imaging data were collected while participants completed the Cyberball paradigm (simulating the experience of social exclusion). FxC between the Medial Prefrontal Cortex (MPFC), ACC, right insula and left amygdala, was compared between groups and examined in relation to depressive symptoms.

RESULTS

Prior peer victimization experience was associated with differences in fronto-limbic FxC across social inclusion and exclusion. Defenders displayed distinct shifts in FxC across the transition from being included to excluded. Peer victimized individuals exhibited a unique pattern of amygdala-specific FxC during inclusive interaction with peers, and in the continuous FxC across inclusion and exclusion. FxC of the MPFC-amygdala across inclusion and exclusion moderated the relationship between peer victimization and depressive symptoms.

LIMITATIONS

Small sample size and cross-sectional design limit interpretation of the findings.

CONCLUSIONS

Peer victimized individuals who exhibit continuous positive FxC of the MPFC-left amygdala across inclusion and exclusion may be at greater risk for depressive symptoms.

Unique brain regions involved in positive versus negative emotional modulation of pain

Background and aims

Research has shown that negative emotions increase perceived pain whereas positive emotions reduce pain. Here we aim to investigate the neural mechanisms underlying this phenomenon.

Methods

While undergoing functional magnetic resonance imaging of the brain, 20 healthy adult females were presented with negative, neutral, and positive emotion-evoking visual stimuli in combination with the presentation of a noxious thermal stimulus to the hand. Participants rated the intensity and unpleasantness of the noxious thermal stimulus during each of the valence conditions. General linear model analyses were performed on the imaging data for each valence condition and specific contrasts were run.

Results

Significant differences were detected for the emotional modulation of pain (EMP) between the positive and negative conditions. Unique to the positive condition, there was increased activity in the inferior parietal, parahippocampal/perirhinal, precuneus/superior parietal, and the prefrontal cortices. Unique to the negative condition, there was increased activity in anterior and posterior cingulate and angular gyrus.

Conclusions

Positive and negative EMP appear to involve different brain regions.

Implications

Although there is some overlap in the brain regions involved in the positive and negative EMP, brain regions unique to each condition are identified and, moreover, the regions identified are involved in internal and external focus, respectively, pointing to a potential mechanism underlying this phenomenon.

Generating facial expressions of disgust activates neurons in the thoracic spinal cord: a spinal fMRI study

Facial expressions of disgust, which involve movement of the levator labii muscles on the nose, allow an organism to restrict the intake of potentially aversive stimuli by constricting the air cavities in the nostrils and reducing the speed of air intake. In the current research, we used fMRI of the thoracic spinal cord to measure neural activity related to (1) the contraction of the intercostal muscles that modulate the velocity of air intake and (2) the sensory feedback associated with this contraction. Thirteen participants completed two spinal fMRI runs in which the thoracic segments of the spinal cord were measured. Each five-minute 40-second run consisted of three 60-second blocks in which participants repeatedly generated a disgusted facial expression or a non-emotional expression consisting of repeated stretching of the lips (which did not involve the nasal cavity). Forty-second rest blocks were interleaved between each expression block. The results demonstrated that generating emotional expressions of disgust produces significantly more activity than producing non-emotional facial expressions. This activity occurred in both ventral (motoric) and dorsal (sensory) regions of the upper segments of the thoracic spinal cord and demonstrates a link between the generation of facial expressions and embodied emotional responses.

A neural correlate of visceral emotional responses: evidence from fMRI of the thoracic spinal cord

Functional magnetic resonance imaging (fMRI) of thoracic spinal cord neurons was used to examine the neural correlates of visceral emotional responses. Participants completed four spinal fMRI runs involving passive viewing (i.e. no movement) and motoric responses to negative or neutral images. Negative images, particularly in the movement condition, elicited robust activity in motoric nuclei, indicating 'action preparedness'. These images also enhanced activity in autonomic and sensory nuclei, thus providing a clear neural representation of visceral responses to emotional stimuli.

Functional MRI of the thoracic spinal cord during vibration sensation

PURPOSE

To demonstrate that it is possible to acquire accurate functional magnetic resonance images from thoracic spinal cord neurons.

MATERIALS AND METHODS

The lower thoracic spinal dermatomes (T7-T11) on the right side of the body were mechanically stimulated by vibration for 15 participants. Neuronal responses to vibration sensation were measured in the thoracic spinal cord using a HASTE sequence on a 3 Tesla MRI system.

RESULTS

Signal increases were observed in the corresponding lower thoracic spinal cord segments ipsilateral to the side of stimulation in the dorsal aspect of the spinal cord.

CONCLUSION

This is the first study to provide proof of principle that functional imaging of the entire thoracic spinal cord is possible, by detecting neuronal activity in the thoracic spinal cord during sensory stimulation using spinal fMRI.