Ah, here we go, quote from the study:

Importantly, the right anterior insula is strongly related with affective empathy

Disclaimer: not a shrink and I generally believe most "social" sciences are unworthy of the title, but I really do like to read

They cite studies that do fMRIs to test cognitive vs affective empathy; more recent trends in psychology/neurology tend toward defining more than two kinds of empathy; most often using cognitive, affective/emotional, and compassionate.

• Cognitive empathy: detecting and analyzing the emotional state of another
• Affective/Emotional empathy: experiencing the emotional state of another or tying it to one's own experiences
• Compassionate empathy: a desire or drive to alleviate another's emotional distress

Compassion is a big-brain thing--as in it requires a bunch of the brain bits working together, instead of a couple areas firing up.