The sense of touch: embodied simulation processes and empathy in Autism Spectrum Disorders

Autistism Spectrum Disorders are chronic developmental neurobiologic disorders,
which have onset in the first years of life. The most disabling and most
defining symptoms for autism are the social deficits, leading to life-long
handicaps in social functioning. There is no curative treatment for autism, and
the neural and cognitive mechanisms underlying the social deficits are poorly
understood.
A putative mechanism underlying social cognition is embodied simulation.
Neuroscientific models of embodied simulation propose that the same neural
structures involved in our own body-related experiences also contribute to the
understanding of the experiences and intentions of others. This idea is
supported by the discovery of the mirror neuron system (grounded in the
sensory-motor system) that creates a link between others and ourselves, since
it is involved in performing actions or experiencing emotions/sensations as
well as in observing someone else performing an action or experiencing an
emotion/sensation. Accordingly, the brain regions that have been implicated
most often in autism all have mirror/simulation capacities involved in social
cognition, not coincidentally impaired in autism. Hence a mirror
neuron-simulation theory for autism has been postulated, claiming that impaired
simulation processes, especially in the mirror neuron system, are at the root
of autism.
Recent studies also found support for the existence of a visuo-tactile
mirroring mechanism in the somatosensory cortices. This activated when one
experiences a touch as well as when one observes someone or something else
being touched. Furthermore, it was found that visuo-tactile synaesthesia (a
neurological condition in which the observation of another person being touched
leads to tactile sensations on one's own body) is related to hyperactivation of
this mechanism, and that this type of synaesthesia correlates with heightened
empathic abilities. These findings suggest an essential role of this mechanism
in social cognition (like empathic abilities), and in the social cognition
deficits that are defining for autism. However, a visuo-tactile mirroring
mechansism has not been investigated in autsim yet.

The present study aims at exploring a visuo-tactile mirroring mechanism in
patients with autism. Furthermore, the relationship between neural tactile
simulation processes, empathic abilities, and symptom severity in the social
domain will be investigated.
Based on the mirror neuron-simulation theory patients with autism are
hypothesized to show less activation in the visuo-tactile mirroring mechanism
during the observation of touch stimuli, compared with healthy control
participants, which would indicate dysfunctional embodied simulation processes.
An inverse correlation is predicted between activation in the visuo-tactile
mirroring mechanism during the observation of touch stimuli, and symptom
severity in the social domain. A correlation is predicted between activation in
the visuo-tactile mirroring mechanism during the observation of touch stimuli,
and empathic abilities.

Twenty high-functioning autistic patients (age 14-18 years) will undergo a
functional magnetic resonance imaging (fMRI) session, while watching short
video clips depicting a person being touched, or not. To compare the results of
the patients, 20 healthy control participants will undergo the same procedure.
An implicit attentional task requires the participants to watch specifically
whether the person in the video clip is being touched. Afterwards the
participants will be asked to answer some questions regarding the observed
video clips, and to respond a questionnaire estimating empathic abilities.

The duration of the fMRI scan session is 50 minutes. Responding the
questionnaire will take approximately 30 minutes. The study is not demanding or
aggravating for the participants. The used research methods are applied to a
very large scale in normal subjects and in subjects with various conditions
(including autism) without side-effects or unwanted effects, and will not
expose participants to any thinkable risk.