♥ Achy-breaky heart? Try touchy-feely brain! ♥

Written by Laura Smith

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As today is Valentine’s day, let’s get a bit touchy-feely. Whether you’re looking forward to a date with your significant other; planning to profess your feelings to a special someone; or hoping your soulmate will sweep you off your feet, you’d probably like to share a romantic caress. But what happens in the brain when we anticipate touching the one we desire? Using functional magnetic resonance imaging (fMRI), scientists in Italy set out to answer just that question. Isn’t that convenient!

fMRI uses the same principle as standard MRI: a large, very powerful electromagnet detects differences in the magnetic properties of different bodily tissues, and some fancy maths turns these signals into pictures. In fMRI, people in the scanner perform tasks, and scientists can locate brain areas where activity levels change in response to this.

In their fMRI study, published in the journal Frontiers in Behavioural Neuroscience, Ebisch and colleagues1 wanted to find out if how much someone loved their partner was reflected in their brain activity when they anticipated caressing them. Participants in the MRI scanner were instructed to affectionately touch either a ball or their partner’s hand, which were both placed close to them.  They received a “touch” or “do not touch” instruction 3 seconds after they were told which item to touch (the hand or the ball). Therefore, they would anticipate performing the touch each time, which would involve a change in brain activity.  The task was performed many times but, 67% of the time, participants were asked not to perform the touch.

Participants also completed the Passionate Love Scale (PLS)2: a 15-item questionnaire measuring the intensity of their desire for their partner from “extremely cool” to “extremely passionate”, so that the researchers could see whether it was related to the changes in brain activity.  There was such a relationship in the right posterior insula: an area of cortex believed to act as a processing-hub for information about the body’s current physiological state3.  Insula activity decreased during anticipation of touching but the more passionate the love, the less deactivation there was for anticipation of romantic but not non-romantic touching. So, when participants’ desire for their partners was higher, there was more neural response to anticipation of touching the partner versus the ball.  Additionally, insula activity increased when touches were actually performed, and significantly moreso for romantic versus non-romantic touches.

laurainsulaLocation of right posterior insula. Retrieved from Ebisch et al. (2014)1

The insula interacts with brain areas involved in bodily sensation4, in particular the somatosensory cortex.  This area’s activity in response to touch was previously shown to be influenced by anticipation of a reward5. Taking this into account, the researchers suggest that the posterior insula, via its connection with somatosensory cortex, may influence how we actually experience touches. As such, because desire for the partner was associated with less insula deactivation during anticipation of touching them, it may be that wanting to touch someone actually makes the experience of doing so all the more pleasant.

So spare a thought for your clever insula today, and have a happy Valentine’s day.

References

  1. Ebisch SJ, Ferri F & Gallese V. (2014). Touching moments: desire modulates the neural anticipation of active romantic caress.
  2. Hatfield E. & Sprecher S. (1986). Measuring passionate love in intimate relations. Adolescence, 9, 383-410.
  3. Augustine, JR. (1996). Circuitry and functional aspects of the insular lobe in primates including humans. Brain Res. Rev., 22, 229-244.
  4. Zweynert S, Pade JP, Wustenberg T et al. (2011). Motivational salience modulates hippocampal repetition suppression and functional connectivity in humans. Hum. Neurosci, 5, 144.
  5. Pleger B, Blankenburg F, Ruff C, Driver J & Dolan R. (2008). Reward facilitates tactile judgments and modulates hemodynamic responses in human primary somatosensory cortex. Neurophysiol., 39, A9.

Featured image by Alex Van

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