Transcript Learning Skill

Skilled Movement
Different exercises demand an array of different & (semi-?)
skilled movements
Different sports demand a huge array of different & highly
skilled movements
Specific sports skills are nothing more than highly
controlled specific physical movements with specific
demands:
precision . efficiency . repeatability
The more complex the sport, the greater demands for skill…
NEUROLOGICAL BASIS OF SKILL
Environmental stimuli – select behavior –
activate pre-motor – primary motor –
muscles
Some Important Parts of the Brain
Limbic (another very important) System of the Brain
The limbic system is
responsible for generating
our emotional feelings (pleasure,
frustration, anger) based on our
cognitive interpretation of our
environment
Basal Ganglia
is part of the limbic system
Putamem
Globus Pallidus
Caudate
Substantia
nigra
Ventral tegmental
area
Locus coeruleus
Kinesthetic Perception
Sensory areas of the brain receive input from nerve fibers
which originate from different types of receptors (touch,
visual, auditory, pain, taste).
Sensory nerves originating from Pacinian corpuscles in the
skin (mechanoreceptors) respond to touch.
Sensory nerves originating from proprioceptors
in the joints respond to “angle-specific pressure”
A-delta nerves originating from free nerve endings (Noci
receptors) respond to tissue damage.
Our sensory nerves inform our brain about our
physical environment
Primary (SI) and secondary
(SII) sensory cortex involved
with the localization of pain
Anterior portion of insular
is most likely concerned
with pain perception
All sensory information is relayed throughout different parts
of the brain and our conscious interpretation of the stimuli
generates a physical and emotional response which we “feel”:
body/joint position, body and/or limb movement, well-being,
nausea, pain …
happy, sad, frustration, disappointment, joy, ecstasy, anger …
Our CNS response to stimuli also includes (selective) changes
in the (autonomic) sympathetic and parasympathetic nerve
pathways; selective changes based on our interpretation of the
stimuli.
Skill Performance
Environmental stimulus
visual . auditory . kinesthetic .
Select skill from memory
hippocampus . cerebrum . cerebellum .
(conscious) (unconscious)
Initiate skill
frontal cortex . pre-motor cortex . motor cortex .
caudate . substantia nigra .
Perform skill
frontal cortex . pre-motor cortex . motor cortex .
basal ganglia . reticular formation .
Performance of a Skill
Analyze and activate memories of the array of
possible motor responses to the current
environmental stimuli.
Select appropriate motor response and activate the
pre-motor cortex to initiate the selected movement
patterns via the motor cortex.
Basal ganglia (esp. caudate nucleus and substantia
nigra) help coordinate activation of the appropriate
motor neurons.
Performance of a Skill
All sensory inputs are coordinated by reticular formation
and basal ganglia and transmitted to frontal cortex.
Sensory input is unconsciously compared to sensory
memory and adjustments are made “as-you-go”.
Simultaneously, conscious image of movement (based on
sensory input) is compared to conscious memory of what
we should look like while we do it and we make conscious
adjustments to mimic the conscious memory of the skill.
Integration of conscious and subconscious adjustments
based on conscious and subconscious memories of the
performance result in the actual performance.
Learning and memory play a very important
role in how we develop skills (and behaviors)
Memory, Learning & Behavior
The most basic connection between behavior and memory is
that we desire to perform behaviors which produce responses
that we want….if we can’t remember that a particular behavior
resulted in a desirable outcome, there is little chance we will
seek out to repeat the same behavior.
In addition, if a particular behavior results in an unpleasant
experience, there is a strong likelihood that we will avoid that
behavior.
On the other hand, if a behavior is not particularly pleasant, but
does result in a highly desirable outcome, there is a high
likelihood that the unpleasant behavior will be continued in
order to get the pleasant payoff.
Memory
A “memory” is not a discrete location in the brain made up of a
cluster of cells which are independent of other cells.
A “memory” is actually comprised of a “pattern” of nerve-cell
activities made up of interconnected nerve cells which are
scattered throughout the cerebral cortex. These cells are in
turn interconnected to all other brain cells.
Memory/Learning
We do not remember facts as discrete pieces of independent
information.
We have memories of “facts” only in association with other
memories.
We develop new memories only in association with existing
memories.
Memory/Learning
New memories are created by rearranging existing patterns of
activated nerve cells into new patterns of activity.
This process demands synthesis of new proteins in “some” nerve
cells to modify their ability to be activated by other nerves and
thereby create a new patterns of activation.
Learning
Parts of the brain
that are important
for learning.
Memory & Skill
Sensory memories of
physical movements
are stored as
patterns of neural
activity in the
cerebellum and are
developed in much
the same way as
factual memories.
Learning
Hippocampus coordinates and integrates all
incoming environmental stimuli with existing
memories that correspond to the stimuli so
we can identify (threats?) and act
accordingly;
activating ALL of them
– we then pay attention to those that we recognize
and are “important” to us
Learning
New memory is constructed
based on novel stimulus in
comparison to existing
memory.
“Strength” of the memory is
dependent on the frequency
and strength of the neural
activity.
How Does this Work?
The learning process demands synaptic
remodeling: the development of “new active”
synapses between existing nerves in order to
produce the new patterns of neural activity.
In order to do this a host of proteins that
stimulate nerve-growth must be produced and
maintained for many hours:
New Proteins: (synapsin I, synaptotagmin, syntaxin,
and integrins, among others);
Activate enzymes of the signal transduction
pathways: (Ca2+/calmodulin-dependent protein kinase
II, CaM-KII; mitogen-activated/extracellular signalregulated protein kinase, MAP-K/ERK I and II;
protein kinase C, PKC-δ);
Activate DNA-binding proteins (transcription
regulators): (cyclic AMP response element binding
protein - CREB, Brain-derived neurotrophic factor BDNF)
Inactive
Synapse
Synapse
Synaptic Remodeling
Active
Synapse
How Does this Work?
After sufficient amounts of new growth
signals have been produced …
&
… they remain elevated long enough in the
“stimulus-memory specific” activated nerve
pathways:
… a new memory is formed
Learning & Memory
The new memory can now be activated
either through the “novel” stimulus or
through the associated memory.
We remember facts as pieces of “information” in
relation to other pieces of “information” which
in turn are related to other …
Learning & Memory
Because we construct and remember
“facts” in relation to other “facts” that in
turn are related to other “facts” …
The greater the number of interconnected
pathways that “intersect” the “new memory” –
the easier it is to recall the “new memory”
Put it all together and you get …
Analyze and activate memories of the
array of possible motor responses to
the current environmental stimuli.
Select appropriate motor response
and activate the pre-motor cortex to
initiate the selected movement
patterns via the motor cortex.
Basal ganglia (esp. caudate nucleus
and substantia nigra) help coordinate
activation of the appropriate motor
neurons.
All sensory inputs are coordinated by reticular formation
and basal ganglia and transmitted to frontal cortex.
Sensory input is unconsciously compared to sensory memory and adjustments are made “as-you-go”.
Simultaneously, conscious image of movement (based on sensory input) is compared to conscious
memory of what we should look like while we do it and we make conscious adjustments to mimic the
conscious memory of the skill.
Integration of conscious and subconscious adjustments based on conscious and subconscious
memories of the performance result in the actual performance.
So…
Skills such as running & cycling (and a whole lot more) are actually just
programmed memories that are activated by a variety of stimuli; such as:
got to catch the bus…
starters pistol goes off at the beginning of a race…
PE teacher tells you to run for a standardized test… and so on.
Physical exercise is important for learning as illustrated in the following slides…
But… how do things work when there is
no memory of a skill to recall???
Well… Here are some thoughts:
And some important brain areas that might relate…
Frontal lobe of cerebral cortex
- conscious thought
- voluntary initiation of movement
Basal ganglia: caudate nucleus, substantia nigra, putamen, globus pallidus, (and
the reticular formation)
- subconscious initiation of movement
- subconscious control of movement
- learning of habits
- part of limbic system
Limbic system: amygdala, hippocampus, hypothalmus, nucleus accumbens,
piriform cortex, olfactory tubercle, striatum, septum
- generation of emotional responses based on:
- integration of unconscious sensory input and
conscious interpretation of sensory input and conscious
interpretation of the appropriateness of the feelings
Neurotransmitter Release
Some Norepinephrine - Releasing Pathways
Hypothalmus
Hippocampus
Cerebral
Cortex
Locus
Coeruleus
Arousal
Amygdala
Cerebellum
Some Dopamine - Releasing
Pathways
Amygdala
Substantia Nigra
Caudate
Nucleus
Putamen
Globus Pallidus
Piriform Cortex
Striatum
Nucleus
Accumbens
Ventral
Tegmental
Area
Some Frontal
Cortex
Septum
Hypothalmus
Pituitary
What’s up with all this stuff about neurotransmitters?
…
What do they have to do with a lack of skill?
Well …
They affect membrane potentials and cell function …
Dopamine release into the nucleus accumbens by neurons
originating in the ventral tegmental area usually leads to
inhibition (Cl- influx = IPSP) and feelings of mild pleasure or
reduced anxiety and frustration…
Enhanced norepinephrine release by nerves originating in the
locus coeruleus leads to stimulation (usually Na+ influx = EPSP) of a
variety of brain areas associated with arousal (heightened
ability to focus), pleasure, and maybe even enhanced learning.
Norepinephrine (or the hormone; epinephrine) makes nerve cells easier to
be stimulated and dopamine makes cells harder to be stimulated.
Dopamine release into the caudate, globus pallidus, and putamen inhibits
the activation of motor pathways to prevent unwanted movement. When the
dopaminergic pathways are damaged and dopamine cannot be released,
Parkinson’s Disease is the result – a condition when motor pathways are not
properly inhibited; producing less-than-perfect motor control.
When too much epinephrine is present, inappropriate activation of the
motor pathways may occur, again, resulting in less-than-perfect motor
control.
Now consider a new-born… obviously there is no skill…
Imagine the mostly random arm, leg and head movements whenever there is
any stimulation (no selective inhibition by dopamine). Now imagine the
much faster random movements when excited (epinephrine effects); say,
when mommy or daddy are successfully entertaining the little thing.
It takes many months for the random arm movements to be refined into
grabbing and pointing movements and each time attempts are made,
conscious efforts to figure out how to control the movements also are made.
This self-discovery of more efficient movements eventually leads to an array
of somewhat efficient movements that are stored as motor memories and
integrated with the sensory memories of those movements.
These initial motor memories form the building blocks of various motor
skills such as standing, creeping, walking, and grabbing anything and
putting it in your mouth.
From the preceding, there is essentially a progression from:
Complete conscious control over movements as they are being discovered – a
time-consuming and inefficient process…
To
A combination of mostly conscious with some subconscious control as new
movement skills are developed on the basis of learned ones…
To
A combination of conscious and subconscious control as complex movement
skills are developed on the basis of learned complex skills…
To
A combination of subconscious control with some conscious control as
complex movement skills are refined…
In other words… learning of motor skills is a
constant dynamic process of continually
modifying learned motor memories in order to
develop more refined motor memories that are
easily recalled and efficiently executed.