Tickling and the Brain

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Tickling and the Brain
By Dr. Silvia Helena Cardoso
Please, see comments on each slide
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TicklingFascinating instance of the
Congenitally blind child
Normal child
Chimpanzee

• Connection between playfulness, laughter and
  social bonding
• Almost always produces laughter
• Tickling and laughter evolved in part to help us
  relate to others

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Anatomy of Tickling
(Area that registers touch)
Touch receptors
Tickling stimulates touch receptors in the skin.
These receptors, when stimulated carry
information in sensory neurons that goes to the
spinal cord. Then this information travels up to
the sensory cortex via the thalamus. The sensory
cortex is involved in processing information from
the skin.
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The big enigma of
Tickling

• We do not laugh when we tickle ourselves, only
  when other people tickle us.

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Why is it impossible to tickle ourselves?
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Cerebellum Brain region that helps to control
voluntary movement and balance
Predicts the sensory consequences of movements -
supplying the brain with information that reduces
the sensation of touch information.
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Charles Darwin 1809 -1882 For tickling to be
effective, you must not know the precise point of
stimulation in advance
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.
When you try to tickle yourself, your cerebellum
sends to your somatosensory cortex precise
information on the position of the tickling
target and therefore what sensation to expect.
.
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Robotic arm
Subject tickling himself. He couldnt make
himself laugh.
Experiment using robotic arms to tickle people.
It is as effective as real people in provoking
laughter.
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Touchs area
fMRI
Part of the brain that registers touch
fMRI detected more neuronal activity in
somatosensory cortex, when people were tickled
than when they tickled themselves.
To compare brain activity when a subject's hand
was tickled by an experimenter or by himself.
Somatosensory cortex helps interpret external
stimuli registered by nerve endings that sense
touch.