I Can't Feel Anything...

...and I can't describe it, either.


from Jackson, Meltzoff, & Decety (2005)

The Neurocritic has just noticed a new neuroimaging paper on empathy in individuals with alexithimia, which is an inability to describe one's own feelings. Coincidentally, Dr. Richard G. Petty has just posted on the topic, and I will quote from his description and send you over there for more information on the clinical syndrome.

The Harvard psychiatrist Peter Sifneos originally coined the term in 1972 to describe people who had extreme difficulty in emotional cognition. The word “alexithymia” literally means “no words for mood.” People with this problem lacked the ability to understanding, processing or describing their feelings verbally. As a result, most people who have the problem are largely unaware of their own feelings or what they signify. As a result they only rarely talk about their emotions or their emotional preferences, and they are largely unable to use their feelings or imagination to focus and fuel their drives and motivations.

People with alexithymia seem unable to fantasize and many report multiple somatic symptoms. However, alexithymia is also associated with a number of other complaints, such as hypertension, irritable bowel syndrome, substance use disorders, and some anxiety disorders. Their speech is often concrete, mundane and closely tied to external events. So they will describe physical symptoms rather than emotions, and don’t understand that their bodily sensations are signals of emotional distress.

Alexithymia lies on spectrum... For some people it is little more than an inability to get in touch with their emotions. But at the other end of the spectrum are a number of illnesses in which alexithymia may occur, including schizoid personality disorder, posttraumatic stress disorder, anorexia nervosa or Asperger's syndrome. It is also much more common in victims of trauma.

In the fMRI paper of Moriguchi and colleagues, the warm and fuzzy and trendy topic of empathy for other people's pain was under study, this time in individuals with alexithimia. The question here was whether a lack of knowledge of one's own emotional experiences would be associated with a lack of empathy for another's pain. Hence the ouch!-inducing photos in the figure above, which were contrasted with similar but non-owie pictures.

Moriguchi Y, Decety J, Ohnishi T, Maeda M, Mori T, Nemoto K, Matsuda H, Komaki G. (2006). Empathy and Judging Other's Pain: An fMRI Study of Alexithymia. Cereb Cortex. Dec 5 [Epub ahead of print].

Because awareness of emotional states in the self is a prerequisite to recognizing such states in others, alexithymia (ALEX), difficulty in identifying and expressing one's own emotional states, should involve impairment in empathy. Using functional magnetic resonance imaging (fMRI), we compared an ALEX group (n = 16) and a non-alexithymia (non-ALEX) group (n = 14) for their regional hemodynamic responses to the visual perception of pictures depicting human hands and feet in painful situations. Subjective pain ratings of the pictures and empathy-related psychological scores were also compared between the 2 groups. The ALEX group showed less cerebral activation in the left dorsolateral prefrontal cortex (DLPFC), the dorsal pons, the cerebellum, and the left caudal anterior cingulate cortex (ACC) within the pain matrix. The ALEX group showed greater activation in the right insula and inferior frontal gyrus. Furthermore, alexithymic participants scored lower on the pain ratings and on the scores related to mature empathy. In conclusion, the hypofunction in the DLPFC, brain stem, cerebellum, and ACC and the lower pain-rating and empathy-related scores in ALEX are related to cognitive impairments, particularly executive and regulatory aspects, of emotional processing and support the importance of self-awareness in empathy.

So what does all that mean? What is the significance of brain activation differences between the alexithymic and the control participants?

First, let's look at the empathy scores and pain ratings of the two groups. Before the experiment, Japanese versions of the emotional empathy scale (EES), the interpersonal reactivity index (IRI), and the stress coping inventory (SCI) were administered to all participants. During the experiment, each picture was shown for 2 s, followed by a 4-point pain-rating scale (no pain, a little pain, moderate pain, and worst possible pain). To no one's surprise,

Alexithymic participants showed lower pain ratings than non-alexithymics, indicating that they attributed lower levels of pain to the people depicted in the painful situation pictures. They scored lower on the IRI scales assessing "perspective taking" and "empathic concern," suggesting that they were less able to take the perspective of another and had less empathy. On the EES, alexithymics scored less on "warmth." Alexithymics scored lower on the SCI scales of "cognitive," "problem solving," and "positive reappraisal," indicating that they were less likely to use these approaches to manage emotional stimuli. On the other hand, alexithymics had significantly higher "personal distress" scores on the IRI.

What about the fMRI results?


from Moriguchi et al. (2006)

The top panel shows regions that were less active in alexithimics than controls, and include the left dorsolateral prefrontal cortex, the caudal anterior cingulate cortex, the dorsal pons (in the brainstem), and the cerebellum. The bottom panel shows regions that were more active in alexithimics, and include the anterior insula, the posterior insula, and the inferior frontal gyrus (all in the right hemisphere). Huh. The insula. More active for people lacking empathy. The insula has been shown previously to be associated with empathy for pain (e.g., Saarela et al., 2006; Singer et al., 2006). Hmm...what do the authors have to say about this?

Anterior insula:

Hemodynamic increases in the prelimbic area and decreases in the prefrontal cortex were reported in response to sadness, although these 2 areas demonstrated the inverse correlation as a person recovered from a depressive state (Mayberg et al. 1999). If an individual engages less cognitive processing for the painful pictures, the suppression of activation in the anterior insula would be decreased. The ALEX group, which has more impairment in cognitive aspects, may have had more activation in the anterior insula compared with the non-alexithymics as a result of decreased suppression.

Got that? Posterior insula:

...the dorsal posterior insula involves the primary (not metarepresentational) interoceptive representation of the inputs of physiological condition from all tissues of the body, including pain, temperature, itch, sensual touch, muscular and visceral sensations, vasomotor activity, hunger, thirst, and "air hunger." Thus, the posterior insula is related to lower level representation of the physical state. Considering that neural activity in this region positively correlated with the personal distress scale and negatively with cognition-related stress coping scales, the result of stronger activity in the posterior insula in the ALEX group indicates that individuals with ALEX might be stuck in lower level representation of one's own physical state.

The alexithimics attributed lower levels of pain to the people depicted in the owie pictures, yet they have more activity in an area that represents physical states. Fine, there is a disconnect between bodily sensations and emotion, but then they go on to say,

The posterior insula is associated with personal distress (self-oriented response), whereas the anterior insula is associated with empathy (other oriented emotional responses).

But, but... isn't empathy just what they're lacking? Have we learned anything useful from this study? I suppose the alexithimic individuals did show less activation than controls in other "empathy for pain" areas (namely the anterior cingulate). And there's more to read on impairments in self-awareness and theory of mind in these same individuals (Moriguchi, Ohnishi, et al., 2006).

References

Jackson PL, Meltzoff AN, Decety J. (2005). How do we perceive the pain of others? A window into the neural processes involved in empathy. Neuroimage 24: 771–779.

Moriguchi Y, Ohnishi T, Lane RD, Maeda M, Mori T, Nemoto K, Matsuda H, Komaki G. (2006). Impaired self-awareness and theory of mind: an fMRI study of mentalizing in alexithymia. Neuroimage 32: 1472-82.

Saarela MV, Hlushchuk Y, Williams AC, Schurmann M, Kalso E, Hari R. (2006). The Compassionate Brain: Humans Detect Intensity of Pain from Another's Face. Cereb Cortex 2006 Feb 22; [Epub ahead of print].

Singer T, Seymour B, O'doherty JP, Stephan KE, Dolan RJ, Frith CD. (2006). Empathic neural responses are modulated by the perceived fairness of others. Nature 439:466-9.