For those of you who don’t know, I study psychology at university and throughout the past
few years I’ve studied fascinating topics like forensics, the brain and developmental
psychology. Although my degree involves a lot more statistics and brain terminology than I
would prefer, I have really enjoyed learning about these areas of psychology.
This year I did a module about cases in Clinical Neuropsychology. I quite liked this module
and I found myself looking forward the lectures, for those of you who have been to
university you might understand how rare that is. I went away from each lecture having
learnt something new about what our bodies and minds are capable of so, I thought I would
try and explain a few of these cases since my exams are coming up and I need to understand
these a bit better. But also, because these cases are thought-provoking and make us
question what we think is possible in our bodies and minds.
The first is Phantom Limbs, this is when someone has sensations of a limb that is no longer
there perhaps due to an amputation. These sensations can include pressure and pain and
can sometimes be quite unpleasant. But why does this happen? There are a few reasons,
some argue that this is just a memory of the limb or that the nerve endings are still active
despite the limb being absent. A psychologist called Melzack introduced his theory of the
neuromatrix which suggested that we are born with a matrix that gives us a sense of having
a whole body. Included in this is the ability to feel our limbs and body and where they are in
relation to us, this can also be called body schema. While some suggest that we are born
with this internal body awareness others argue that this is something we learn and develop
as we grow up.
People who are born without limbs can also experience phantom sensations, but how can
the body miss something it never had? Unless we are born with our body schema as
Melzack suggested. I found phantom sensations very interesting as it had never occurred to
me how my brain knows that I have all my limbs. This case can help us question how we
make sense of our bodies and what happens when we no longer have a limb. The research
into phantom sensations is extensive and ongoing and this can help with treatments for
these sensations.
The next case is Alien Hand Syndrome (AHS). A peculiar instance where someone may feel
as if they are not in control of their limb, they might feel like someone else is controlling
their movements. This might sound familiar if you’ve heard of Dr Strangelove, although this
is a fictional example this is exactly what alien hand syndrome is. Fortunately, this is very
rare, so the likelihood of not being in control of your hands is very slim. Why does this
happen? The research shows that specific areas of the brain have been associated with AHS
this includes lesions to the medial frontal lobe (where your forehead is), the bridge between
the two hemispheres of your brain and a condition called cortical basal degeneration which
causes nerve cells to die over time.
What does this tell us about free will? A famous experiment by Libet in 1983 found that
there was neural activity in the brain around 1 second (in brain terms this is a long time!)
before a person got the idea to move which suggests that our brain know what we are
about to do before we even think of doing it. In a follow up experiment by Brass and
Haggard (2007) they investigated what would happen if you started to make an action but
stopped at the last second.
They found that the medial frontal lobe area was used for this,and this is the area associated w AHS. Overall, this suggests when the ability to stop actions
is damaged this is when we might have uncontrollable movement. This shows how clever
our brains really are and how each tiny part is needed for a function.
The final case is Out of Body Experiences (OBEs). Which as the name suggests is when you
feel like you are outside of your physical body. This can be related to certain neurological
and psychiatric disorders but is not restricted to them as around 10% of OBEs can occur in
the healthy population too. So, if you find yourself to be outside looking down on your body,
there’s nothing to worry about. Why does this happen? A study by Blanke et al (2004)
focused 6 patients who had OBEs, they reported quite vivid and detailed experiences. When
overlapping the brain lesions of these patients, they found they all had one place in
common- The Temporo-Parietal Junction.
So, if we are capable of being outside our own bodies, where does our consciousness reside
and are we able to change where our consciousness is? There are many studies on induced
OBEs which suggest that we can feel as if our consciousness elsewhere if there is a
correlation of visual and tactile information. Furthermore, people were able to feel as if they
were in a humanoid fake body! The implications of this are huge as it could be used as
treatment in body dysmorphia and other instances where it might be beneficial for people
to feel like they are in a different body than their own.
I hope you enjoyed reading about these cases as much as I enjoyed learning about them.
There is so much more to say about each of these cases and what I’ve written is only a
miniscule part of the current research. I’ve provided some references below for further
reading.
Some of these cases from the module were taken from the book ‘The Man Who Mistook His
Wife For A Hat’ by neurologist Oliver Sacks-
https://web.arch.virginia.edu/arch5420/docs/reading/sackspdf/sacksvl.pdf
Blanke, O., Landis, T., Spinelli, L., & Seeck, M. (2004). Out‐of‐body experience and autoscopy
of neurological origin. Brain
Libet, B. et al. (1983).Time of conscious intention to act in relation to onset of cerebral
activity (readiness potential)
Melzack R. Pain and the neuromatrix in the brain. J Dent Educ. 2001.
Comments