PROPRIOCEPTION
SLT301 WEEK 2
ROSALIND ROGERS
Using a computer metaphor, inside our cortex, we
constantly ‘run a programme’ that creates an internal
model of where our body is, in real time.
This dynamic internal body map or schema captures an
accurate internal 3D representation of our body’s
dimensions, body mass –both at a macro and micro level
of detail.
It details our body posture and it’s positioning.
At a macro level we need to know
our body shape and place in
relation to our environment.
At a micro level, we need to know the
relationship of each part to another.
This may be where our fingers are to each other, or where our feet
are in relation to each other. It also includes small details.
For example, where our tongue position is in order to plan where to
begin to plan to produce a speech sound –is our tongue raised at
the back as for producing /k/ or is the tongue flattened out for
certain vowels? We need to know where our lips are in relation to
each other –open or closed- in order to bring a cup of tea safely to
our mouth.
How do we do this?
We process and interpret information from our
skeletal muscles and joints, which is using a
sense called proprioception –literally one’s own
perception of one’s body.
We also use other senses, where possible, to
build up and to check the accuracy of our
internal model.
We also use vision, touch and vestibular
information in order to make this internal model
as accurate as possible.
What makes the accuracy of this internal body model
so important?
In order to execute a movement correctly, you have to
work out a plan from your current body position.
So, starting to walk, do you need to stand up, change your
point of gravity, and where will you place your first step?
If your current body position is not accurately represented
in your CNS, then you will have to use a ‘trial and error’
approach to that motor action.
In summary, it is critically important for us as humans to
develop an accurate internal body representation, which
dynamically reflects real time changes in our body
position.
So, lets then explore proprioception
as the most essential sense for this
internal body model
As a sense, it does not give information
about our bodies when they are static.
However, any time that our muscles or
joints sense that our body or limb
position, or posture, has changed,
proprioceptive information is
communicated to our CNS.
What are the Receptors for Proprioception?
This has been introduced in Stage 4 of the Pathways and
Routes Unit, when we were looking at sensory feedback
from muscles and joints.
1.Muscle Spindles
2.Golgi Tendon Organs
3.Joint and Ligament receptors –Ruffini Endings
and Paciniform endings, also called Pacinian
corpuscles
What are the pathways for proprioception?
First need to draw out the difference between:
Subconscious proprioception; co-ordinates
basic postural control -POSTURE
Conscious proprioception: important for
complex motor activity which is cortically planned
and hence conscious; mainly in Dorsal Column
and to some extent Spino-Cervical KINAESTHESIA…movement
The conscious proprioception route from kinaesthesia
receptors travels in two general pathways
• Spinal Cord to Thalamus to Cerebral Cortex
• Spinal Cord to Cerebellum to Thalamus to Cortex.
The Dorsal Column Medial Lemniscal Tract (DCML) conveys
localised sensations of fine touch, vibration, two point discrimination,
and conscious proprioception from the skin and joints to the postcentral
gyrus of the cerebral cortex.
The Trigeminal Pathway carries somatosensory information from the
face, mouth, outer two thirds of the tongue and the dura mater covering
the brain. Conscious proprioceptive input travels along with discriminative
touch in the trigeminal lemniscus.
The Spinocerebellar Pathway
This pathway conveys unconscious proprioceptive information to the
cerebellum. It is an important tract because it allows us to make postural
adjustments when we are moving, without engaging our cortex.
Beyond the Pathways: What happens
at the Cortex?
Proprioception information is processed in three main
areas in the cortex:
1. The Motor Network, which is covered in the Motor
Control System notes in Stage 4 in the Pathways and
Routes Unit.
2. Somatosensory Cortex and the Specialised Parietal
system which is in the posterior parietal lobes and the
relevant association areas
3. Right Inferior Frontal to the Parietal Lobe network
HAPPENS IN PARALLEL!
Areas of the primary motor cortex are activated when
afferent muscle spindle information is being processed in the
parietal lobes.
1ST: the processing at the primary sensory area in
the somatosensory cortex.
2ND: the associative level where the incoming stimuli
is made sense of within that sensory system,
3RD: the integrative level, where the specific sensory
association areas exchange information within and across
the hemispheres.
This is in order to verify the accuracy of the internal
body model using all related senses’ information.
This is a video showing how children with proprioceptive challenges might
present
https://www.youtube.com/watch?v=b2iOliN3fAE
This is an excellent video presenting children with Sensory Processing
Disorder SPD
We will watch the intro and then from 5.27.
https://www.youtube.com/watch?v=D1G5ssZlVUw
https://www.youtube.com/watch?v=wvDi5B_7Cv0
What Proprioceptive pathway is not being tested in this typical
neuro exam?
Analyse these actions with respect to the use of this sense?
Scooter Board
https://www.youtube.com/watch?v=3plxeImXwyY
https://www.youtube.com/watch?v=Fg9X33
TNLkU
This is a 5 year old Ninja!
https://www.youtube.com/watch?v=tcQojvS
y_QM&t=415
This is the six year old Ninja!