Why do we cry? (Part 2)

The crying was associated with a sorrowful facial expression, sobbing body movements, and a voice inflected with sadness. These physical manifestations ended with the termi- nation of stimulation and the patient described feeling sad, but could not express the trigger for the sadness or crying. Results were consistent and reproducible.

I have previously wondered why we cry, from a biological perspective. When I went looking for reasons, I found a paucity of actual evidence. However, in a link from a recent report on sticking electrodes in people I found a study that was able to induce crying. Causing a person to cry by electrically stimulating a part of the brain is about as good as you can get, right? Then you have causal evidence that that region is intimately involved in that behavior.

To recap, when an epileptic patient needs surgery, an electrode will often be stuck in the brain in order to localize the source of the seizures. Scientists are always thrilled about this because it’s next to impossible to get an electrode in a human brain otherwise, and how else are we to study human-specific behavior? So they get into these operations and zap portions of the patient’s brain to see what it does – and what qualitative feelings the patient experiences.

One recent such zapping managed to reliably produce crying in a patient – and not just crying, but crying with a feeling of sadness. This isn’t like what I had reported previously, where crying was the result of very deep areas that may not be directly linked to ’emotion’. The area of the brain they were stimulating was the ‘left posterior orbito-frontal gyrus’, which is a region of orbitofrontal cortex and looks to me like it may overlay the ventromedial (or perhaps ventrolateral) prefrontal cortex? This area has strong connections with amygdala and hypothalamus, as well as other reward-related areas.

So activation of this area of orbitofrontal cortex is sufficient to induce crying and sadness. But is the crying directly caused by this stimulation? Or is it indirectly induced by the feeling of intense sadness? I’ll admit to being pretty interested in what the pathway is here, and then: what is the pathway that causes this area to activate?

Also, three cheers for the surgeon whose job it was to repeatedly and remorselessly cause this patient to cry and feel intense sadness!

References

Burghardt T, Basha MM, Fuerst D, & Mittal S (2013). Crying with sorrow evoked by electrocortical stimulation. Epileptic disorders : international epilepsy journal with videotape, 15 (1), 72-5 PMID: 23531727

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One thought on “Why do we cry? (Part 2)

  1. Pingback: this is why some people cry excessively.

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