Mt 1 Flashcards
L1 - What is the Degrees of Freedom Problem
There are infinite movements which end up with the same result/movement
L1 - Factors that influence RT
- Stimulus Intensity
- # of Choices
- S-R Compatibility
- Response Complexity
L1 - What is Hick’s Law
RT increases by a similar amount each time the number of alternatives is doubled
L1 - What is S-R Compatibility
Degree of natural or learned correspondence between a stimulus and a response
Ex. Congruent vs. Incongruent
L1 - Factors that Influence Movement
- Speed-accuracy trade-off
- End-State Comfort Effect
- Motor Equivalence
L1 - What are the stages of RT/movement task?
- Foreperiod
- Reaction Time
- Movement Time
L2 - What are two ways to study motor control
- Behavioural
- Neurophysiology
L2 - What is the 3 Stage Model in Information Processing
- Stimulus Identification - receives information from senses
- Response Selection - decides on a plan of action
- Response Programming - organize and prepare a response
L2 - What are the limits and benefits to Behavioural Study of Motor Control
Benefits
- Subjects can do complicated paradigms
- Need to validate tasks for future use
- Inexpensive
- Studying behaviour
Limits
- Potentially don’t get a full picture of why things are happening
-Only get a observed description, but not how things are happening neurophysiologically
L2 - What are the benefits and limitations of using Neurophysiology to study Motor Control?
Benefits
- Much more descriptive picture as to why and how the brain is processing the movements
- Can use brain activity to explain processing
- Can see where in the brain there is activity during these paradigms
Limits
- Can be potentially very expensive
- May not tell you exactly what you are looking for if using the wrong machine
- Can potentially be hard to get readings on brain activity if not done properly
L2 - Describe what an EEG is and how it works + pros and cons
-Movement of ions inside, across, and outside neural cell membranes creates electrical currents in excitable tissue
-Electrical currents travel to scalp surface
-Measure electrical potentials with electrodes placed on scalp
-TR: ms
-SR: cm
Pros
-Easy to record
-Cheap
Cons
-signals are smeared before they reach the scalp
-limited to activity in brain cortex surface
L2 - Describe what an MEG is and how it works + pros and cons
-Electrical neural currents create magnetic fields
-Measurement of magnetic fields of the brain
-TR: ms
-SR: cm
Pros
-Clean signals
Cons
-Expensive
-Insensitive to radial currents
L2 - Describe what an fMRI is and how it works + pros and cons
-Studied brain function
-Measures changes in blood oxygen levels
-It is closely related to changes in neural activity
-TR: sec
-SR: mm
-Knowledge gained: activated areas
Pros
-3D - volume resolution
Cons
-Expensive
-Low temporal resolution, no straight forward analysis
L2 - Describe what PET is and how it works + pros and cons
-Injection of a radioactive solution, in which atoms emit positively charged electrons (positrons)
-Positrons interact with electrons in the blood to produce photons of electromagnetic radiation
-Scanner used to determine the location (and levels) of these photons in brain areas
-TR : ms
Pros
-Cleanest signals
Cons
-Training
-Expensive
L2 - Describe what TMS is and how it works + pros and cons
-Coil placed over target brain region
-Cognitive failures recorded
-Focused oscillating magnetic fields can activate or suppress neural activity across the skull
Pros
-Non-invasive
-Allows direct manipulation of neural activity
-Single pulses affected brain activity for only a few seconds
-Repeated pulses can change brain activity for weeks
Cons
-Sensation can be disturbing
-Spread of activation/inhibition
L3 - List Function of Soma
-Contains nucleus, cytoplasm, organelles, metabolic center
L3 - List Function of Dendrites
-Receives information
L3 - List Function of Axon
-Transmits information (0.1 to 3 meters long)
L3 - List Function of Myelin Sheath
-Covers the axon to increase transmission speed
L3 - List Function of Presynaptic Terminal
-Communication site
L3 - What are the functional components of a Neuron
-An input component (dendrites)
-An integration component (axon hillock)
-A transmission component (axon)
-An output component (synapse)
L3 - What are the different types of neurons
-Sensory neuron
-Motor neuron
-Local interneuron
-Projection interneuron
-Neuroendocrine cell
L3 - What is a sensory neuron
-Transmit sensory information from sensory organs and receptors to the CNS
-Leads into CNS
L3 - What is a motor neuron
-Transmits motor impulses from the CNS to specific motor neurons
-Leads to muscles
L3 - What is a local interneuron
-Transmits signals between nearby neurons
-Helps integrate and process information in a localized area, facilitating communication between sensory and motor neurons
-Lead into other neurons in the same local region
L3 - What are projection interneurons
-Receive input from sensory neurons or other interneurons and transmit the information to distant targets within the CNS
-Are useful for longer distances
L3 - What portion of the spine has the most grey matter and why
-Sacral levels
-Less sensory fibres have joined the spinal cord therefore there is more grey matter
L3 - What is grey matter and white matter
-Grey matter is cell bodies
-White matter are axons
L3 - What side of the spine does sensory inflow enter the grey matter
-Dorsal horn (dorsal side)
L3 - What side of the spine does motor commands exit the spinal cord
-Ventral horn (ventral side)
L3 - How does the location of the neuron within the spinal cord relate to the muscle which is controlled
-Medial neurons in the grey matter deal with proximal muscles (shoulder & elbow) and axial muscles (trunk)
-Lateral neurons in the grey matter deal with distal muscles (wrists)
L3 - How does the segment of the spinal cord relate to where in the body the neurons will affect
-The higher in the spinal cord the neurons are, the higher the muscles are that are affected
L3 - What are the types of spinal cord neurons
Projection neurons
-ascend to the brain
Propriospinal neurons
-reach distant spinal segments
Motor neurons
-Exit the central nervous system to innervate muscles
Interneurons
-Project within their own adjacent spinal segments
L3 - What is membrane potential
Membrane potential: difference in net electrical charge on either side of the membrane
L3 - What is action potential
A short-lasting event in which the electrical membrane potential rapidly rises and falls
L3 - List and Describe Part A of Neuron firing
-The input signal is graded in amplitude and duration, proportional to the amplitude and duration of the stimulus
L3 - List and Describe Part B of Neuron firing
-The trigger zone integrates the input signal into a trigger action that produces action potentials that will be propagated along the axon. An action potential is generated only if the input signal is greater than a certain spike threshold. Once the input signal surpasses this threshold, any further increase in amplitude of the input signal increases the frequency with which the action potentials are generated, not their amplitude. The duration of the input signal determines the number of action potentials.
L3 - List and Describe Part C of Neuron firing
-Action potentials are all or none. Every action potential has a the same amplitude and duration. Since action potentials are conducted without fail along the full length of the axon to the synaptic terminals, the information in the signal is represented only by the frequency and number of spikes, not by the amplitude
L3 - List and Describe Part D of Neuron firing
-When the action potential reaches the synaptic terminal, the cells release a chemical neurotransmitter that serves as the output signal. The total number of action potentials in a given period of time determines exactly how much neurotransmitter will be released by the cell.
L3 - What diseases can change neuron firing and why
ALS/Lou Gehrig’s disease
-Degeneration of motor neurons
Multiple sclerosis
-Damage to myelin sheath
L3 - What are the 3 categories of movement
-Reflex
-Rhythmic
-Voluntary
L3 - List examples of reflex movements
-Coughing, blink, withdrawal, stretch reflex
L3 - List examples of rhythmic movements
-Chewing, breathing, locomotion
L3 - Explain what reflex movements are
- Stereotyped, fast-responding, involuntary
L3 - Explain what rhythmic movements are
-Driven by circuits in brain stem and spinal cord which can function autonomously but are influenced by higher centres
L3 - What does a sensory receptor (muscle spindle) do
-When muscle spindle is stretch, it increases firing rate of afferent neuron
-When slackened, decreases firing rate of afferent neuron
L3 - What is the order of monosynaptic reflex circuit
- Sensory signals
- Motor signals
- Muscle signals
L3 - What is the Hoffman reflex
L3 - Describe the Gain of System
High Gain
-Larger H reflex
Small Gain
-Smaller H reflex
L3 - What are the most common spinal cord injuries
Severing spinal cord
L3 - What are the 5 levels of SCI
A. Complete - No motor or sensory function is preserved in the sacral segments
B. Incomplete - Sensory but not motor function is preserved below the neurological level and includes the sacral segments
C. Incomplete - Motor function is preserves below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3
D. Incomplete - Motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade of 3 or more
E. Normal - Motor and sensory function are normal
L4 - What is the function of the brain stem
-Concerned with sensation from and motor control of the head, neck and face
-Point of entry for several specialized senses (hearing, balance, taste)
-Mediate reflexes of autonomic nervous system (e.g. heart rate, digestion, respiratory rate, salivation, perspiration, pupillary, dilation, micturition, sexual arousal)
-Carries sensory and motor information to the other division
L4 - What is the Reticulospinal Pathway
-Individual axons project widely, coordinating different regions of the spinal cord
-In ventromedial cord, contact interneurons, long propriospinal cells, & some motor neurons
-Influence axial & proximal muscles
L4 - What are the divisions of the brain stem and what are their functions
- Medulla - Regulates blood pressure and respiration, receives input regarding taste, hearing and maintenance of balance & involved in control of neck and facial muscles
- Pons - Relays information about movement and sensation from the cerebral cortex to the cerebellum & involved in respiration, taste and sleep
- Midbrain - Forms linkage between parts of motor system (cerebellum, basal ganglia, and cerebral hemispheres)
L4 - What is premotor time & motor time
Premotor time
-“Central processing time” – information processing activity involved in preparation
Motor time
-Represents muscular processes - initial contractile activity required to overcome inertia
L4 - What is the tri-phasic muscle activation pattern
- First agonist burst (AG1)
-precedes movement onset
-burst amplitude and duration are dependent on movement amplitude
-burst amplitude reflects force - Antagonist burst (ANT)
-burst amplitude and timing influenced by movement extent and velocity
-early onsets with small, fast movements
-may represent braking - Second agonist burst (AG2)
-helps to “clamp” limb at target position
L4 - What is the process of startle leading to preplanned movements
-Startle activated midbrain reticular formation
-Movement program stored in midbrain reticular formation
-Program carried to appropriate muscles by reticulospinal tract
L5 - What makes up the Diencephalon
- Thalamus - integrates motor (and sensory) information
- Hypothalamus - homeostasis and reproduction
L5 - List the Direct Path of the Basal Ganglia to the Cortex
- striatum
- GPi (internal)
- thalamus
- cortex
L5 - List the Indirect Path of the Basal Ganglia to the Cortex
- striatum
- GPe (external)
- STN
- GPi
- thalamus
- cortex
L5 - What does the Basal Ganglia do?
-Selecting and maintaining purposeful motor activity while suppressing unwanted or useless movements
-Controls force production
-Fine tunes movements (like cerebellum)
-Involved in making movements smooth
-Autopilot for well-learned movements, timing and switching, planning , learning
-Helps monitor and coordinate slow, sustained contractions related to posture
L5 - Explain what the Direct path of the Basal Ganglia to the Cortex does
-Decrease inhibition of thalamus
-Leads to less inhibition of the thalamus, i.e. striatum inhibits GPi which in turn inhibits its normal (inhibitory) action on the thalamus, thus leading to greater excitation from the thalamus to the cortex
-Allows one to sustain actions or initiation of action
L5 - Explain what the Indirect path of the Basal Ganglia to the Cortex does
-Increase Inhibition of the thalamus
-Excites the GPi thereby increasing its inhibition of the thalamus
-Suppresses (unwanted) movements
L7 - What are common symptoms of damaged basal ganglia
- Tremors - involuntary oscillatory movements
- Athetosis - slow, writhing movements of the hand
- Chorea - abrupt movements of limb and facial muscles
- Ballism - violent, flailing movements
- Dystonia - persistent abnormal posture
L7 - List PD Symptoms
- Tremor, rigidity, akinesia, bradykinesia
-Gait disorders
-Dimentia
-Postural instability or impaired balance coordination
L7 - List PD Treatment
- L-Dopa: increased amount of dopamine
-Exercise
-Surgical interventions: eliminate neural circuits responsible for abnormal movement production
-Deep brain stimulation
L7 - Where is the Cerebellum located
-Located behind the brainstem and below the cerebral cortex (occipital lobe)
L7 - Where does the cerebellum input
- Spinal cord
- Brainstem
- Cerebral cortex
L7 - Where does the cerebellum output
- Primarily motor regions of brain stem and cerebral cortex (via the thalamus)
L7 - What is the function of the cerebellum
-Handles a lot of information
-Contains >50% of the brains neurons (only constitutes 10% of there total brain volume)
-Talks to both sensory and motor cortical areas
-Neurons project ipsilaterally
L8 - What is the function of the frontal lobe
-Contains the motor cortex
-Planning, reasoning, movement (map of body), some aspects of speech
L8 - What is the function of the occipital lobe
-Seat of the visual cortex
-Deals with visual information
L8 - What is the function of the parietal lobe
-Handles skin based proprioceptive information (heat, cold, pressure & pain)
-Works closely with the motor areas
L8 - What is the function of the temporal lobe
-Speech, hearing, language
L8 - What are the 4 types of input to the somatosensory cortex (and cerebellum)
- Touch
- Pain
- Temperature
- Proprioceptive Input
L8 - What are the directions of orientation in the cortex
- Rostral is front of brain vs caudal is back of brain
-Dorsal it top of brain vs ventral is bottom of brain
L8 - What are the section planes of orientation in cortex
-Horizontal plane cuts into top and bottom of skull
-Coronal plane cuts skull into front and back
-Sagittal plane cuts skull into left and right
L8 - What are the sensations of touch
-Detect gentle contact of the skin and its position
-Recognize vibration and determine its frequency and altitude
-Resolve spatial detail by touch (texture, spacing of two points touched simultaneously)
-Recognize the shape of objects grasped in the hand
L8 - What are the 5 sensory mechanoreceptors that are sensitive to touch and what mechanical stimulus activates them?
- Hair receptors: position changes of hairs
2.Meissner’s Corpuscles: stroking, fluttering - Merkel Cells: pressure, texture
- Pacinian Corpuscles: vibration
- Ruffini Endings: stretch of the skin
L8 - What are the locations of the touch sensory mechanoreceptors
-Meissner’s Corpuscles and Merkel Cells: superficial layers of skin
-Pacinian Corpuscles and Ruffini Endings: deep subcutaneous tissue, large in size, less in terms of absolute number compared to superficial receptors
L8 - What is proprioception
-Sense of body position and orientation in space
L8 - What are the 3 sensation of proprioception
- Sense of Position and Movement in the limbs
- Sense of Force (effort and heaviness)
- Sense of Timing of muscular contractions
L8 - Where are the sensory mechanoreceptors of the proprioceptive input found
-Joints: sensitive to extreme joint angles
-Tendons: Golgi tendon organs detect tension/force
-Skin: Somatosensory receptors detect position of limbs (specifically the fingers)
-Muscles: Muscle spindles detect limb position and movement
L8 - What are the 4 somatosensory maps in S1
3a: proprioceptive input
3b: skin (touch)
1: skin (touch)
2. combination of input
L8 - List types of mechanoreceptors found within muscle spindles
-Bag fibres
-Chain fibres
L8 - What is the difference between primary afferent and secondary afferent
-Primary afferents are muscle fibres that detect change when muscles are stretched, and give information on how fast and how much the muscle is stretching, called a phasic response
-Secondary afferents also give information about how the muscle is stretching, but more focused on muscle position due to only focusing on static mechanoreceptors, called a tonic response
L8 - Explain open-loop control
-Once a movement has started, it cannot be altered throughout the movement
-Ex. a punch cannot be changed in direction while a target dodges it
-No role (time) for feedback
L8 - What are the ingredients of Open-loop control
-Desired state, controller, command, actuator
L8 - Explain closed-loop control
-A feedback system constantly monitors its own progress and adjusts it control accordingly
-Ex. we constantly are monitoring out balance using our inner ears, vision and proprioception
-Role (time) for feedback
L9 - What are the two visual pathways
- Cortical pathway
- Midbrain pathway
L9 - What is the difference between Perception vs. Action
Visual Perception (Perception)
-Process that subserve the recognition and identification of objects and events and their relations
-Provides foundation for visual-cognitive processes
Visual-Motor Control (Action)
-Complex processes that subserve the control of movement or action
L9 - Which system is the what system?
Cortical system
-enables organism to identify a stimulus
L9 - Which system is the where system?
Midbrain system
-enables organism to localize and orient to stimulus in space
L9 - What is the ventral stream and what does concern
-Visual processing for formation of perceptual and cognitive representations
-Location/movement
L9 - What is the dorsal stream and what does it concern
-Visual processing for the on-line control of goal-directed actions
-Colour/shape
L9 - Where is the site of damage with visual agnosia and which patient is effected
-DF has damage in the ventral pathway, meaning they can physically understand how to do a task, but cannot see the object or make out what it is, which proves that their perception is impaired
L9 - Where is the site of damage with optic ataxia and which patient is effected
-RV has damage in the dorsal pathway, meaning they can see the object in front of them, but cannot physically perform the task which proved their action is impaired
L10 - What are saccades
-Rapid, ballistic, eye movements
-Initiated voluntarily or reflexively
-High velocity (600-700 degrees/sec)
L12.1 - What input does the PPC receive?
-Somatosensory
-Visual cortex
-Auditory cortex
-Hippocampus
L12.1 - What is the function of the PPC?
-Visuomotor integration
-Selective attention
-Spatial perception
L12.1 - What input does S1 and V1 receive?
-Single sensory modality: visual or somatosensory input
L12.1 - What output does S1 and V1 perform?
-Unimodal association area: integrate information for a single sensory modality
-Multimodal association area: integrate information from more than one sensory modality
L12.1 - What happens when the Primary Sensory Areas are damaged?
-Blindness, deafness, lack of tactile (proprioceptive) sensibility
L12.1 - What happens when the Multimodal Association Areas are damaged?
-We receive sensory information, but cannot use it to perform more complex tasks
L12.1 - What is neglect syndrome
-Damage to the right posterior parietal cortex, leads to a deficit in spatial perception, deficit in self-image, deficit in external world on the left, also can lead to left-side paralysis
L12.1 - What is personal neglect syndrome
-Does not see/recognize the left side of the body e.g., disown body parts (leg or arm)
L12.1 - What is spatial neglect syndrome: extrapersonal
-Neglect extends into external space
L12.1 - What is spatial neglect syndrome: representational
-Cannot access and recall images associated with the left side of the body
L12.1 - What are the effects of damage to the Left PPC
-Aphasia: disorder of language
-Apraxia: impaired performance of learned motor responses, even though muscles still function properly, no loss of motivation, and no sensory loss
L12.1 - What is ideo-motor apraxia?
-Inability to carry out simple motor activity in response to verbal command
L12.1 - What is Ideational apraxia
-Impairment in carrying out a sequence of movements that are components of a behavioural script, while being able to carry out each one alone
L12.1 - How would you examine cerebral lateralization?
-You would sever the corpus callosum or split brain. This allows to see the effects of left side ppc
L12.2 - What are bimanual movements?
-Having two limbs perform an action at the same time
L12.2 - What is executive control
-Retrieves a motor program from memory
-Implements plan on cortical motor strip
-Detail of plan might refer to changes in motor units, muscles, joints, etc.
L14 - What is the role of the frontal lobe
-Contains the motor cortex
-Responsible for planning, reasoning, movement (map of the body), some aspects of speech
L14 - What is the role of the occipital lobe
-Seat of the visual cortex
-Deals with visual information
L14 - Where does the primary motor cortex receive information?
-Primary somatosensory cortex
-Premotor areas
-Posterior parietal area 5
-BG and cerebellum via the thalamus
L14 - What are primary motor cortex motor commands
-Signal sent from motor cortex to the periphery
-Goes through the signal cord before it reaches the muscles (via motor neurons)
-Can be modified/fine tuned by other parts of the brain
L14 - What are the outputs of the primary motor cortex?
-Spinal cord via Corticospinal Neurons - Pyramidal Tract
-Brainstem
-Basal Ganglia
-Cerebellum
-Thalamus
L14 - What are the motor planning areas of the premotor cortex?
-Supplementary motor area
-Cingulate Motor area
-Lateral Ventral Premotor area
-Lateral Dorsal Premotor area
L14 - What are the inputs to the premotor cortex
-Posterior Parietal Area 5 and 7
-Prefrontal areas
-Premotor areas
-Basal ganglia and cerebellum via the thalamus
L14 - What are the outputs of the premotor cortex
-Primary motor cortex
-Other premotor areas
-Thalamus
-Basal ganglia
-Cerebellum
-Brainstem
-Spinal cord vis Corticospinal Neurons
–Motor neurons
–Interneurons
L14 - What are the Premotor and M1 cortex responsibilities
-Fine control of the fingers
-Intact motor cortex, animals can use individual finger control to retrieve a food morsel from a small well
-Damage to the contralateral motor cortex leads to whole hand grasps, and loss of individual finger control.
L14 - What is the connection between the SMA and PreSMA
-SMA projects to M1
-PreSMA projects to the SMA
-Strong connections between SMAs of each hemisphere
L14 - How is the SMA connected to Bimanual movements
-SMA neurons respond much more during bimanual movements than during movements of either hand
L14 - What is active during sequential tasks, example: rapid serial actions
-See activation in SMA and PreSMA - even when just imagining
L14 - Is PreSMA more active in learning a new sequence? Or more active in an already learned sequence
-Learning a new sequence
L14 - Is the SMA more active in learning a new sequence? Or more active in an already learned sequence
-In an already learned sequence
L14 - Is the M1 more active in learning a new sequence? Or more active in an already learned sequence
-In an already learned sequence
L14 - What motor area is involved in learning and retrieving movement sequences (for all body parts)
-The SMA
L14 - What is the order for internal generated movements
- Prefrontal cortex + basal ganglia
- SMA
- Primary motor cortex
L14 - What is the order for externally generated movements
- Parietal cortex + cerebellum
- Premotor area
- Primary motor cortex
L14 - When is the dorsal premotor area active
- During movement preparation
L14 - When is the ventral premotor area active
- During specific hand actions (i.e., shaping of hand to stimulus)
L14 - When is the SMA involved in movement
-Bimanual movement
-Sequential tasks
-Internally generated movements
L14 - When are lateral premotor areas involved in movement
-Externally generated movements
-Movement preparation (Dorsal premotor)
-Shaping the hand (Ventral premotor)
L15 - Where is the cerebellum located
-Occipital lobe
-Behind the brainstem below the cerebral cortex
L15 - What inputs information into the cerebellum
-Spinal cord
-Brainstem
-Cerebral cortex
L15 - Where does the cerebellum output information
-Primarily motor regions of the brain stem and cerebral cortex
L15 - What is the spinocerebellum
-Receives sensory information from the spinal cord
-Important for posture, locomotion and gaze
-Chronic alcohol abusers destroy this area
L15 - What is the vestibulocerebellum
-Equilibrium & stability
-Balance and eye movements
L15 - What is the neocerebellum
-Does not receive input from spinal cord
-But gets heavy projections from cortex
-Involved in planning and mental rehearsal of complex movements, as well as assessment of movement errors
L15 - What is the role of the cerebellum in movement
-Locus of TIME, POSTURE, MOTOR LEARNING
-Learned activity is cerebellar
-Plays a large role in prediction
L15 - What occurs when there is damage to the cerebellum
-Disrupts spatial accuracy and temporal coordination
-Impairs balance
-Reduces muscle tone
-Impairs motor learning and other cognitive functions
–Does not alter strength of muscle contraction
–Does not alter thresholds
L15 - List symptoms of cerebellum dysfunction
- Hypotonia: abnormally low muscle tone
2: Ataxia: abnormalities in execution of voluntary movements - Intention tremor: this occurs during a voluntary limb movement, most often at the end of the movement when attempting to stop the movement by using the antagonist muscle
L20 - What is the vestibular system responsible for?
-Regulating balance and posture
-Adjusting the bodies orientation in space
-Detects linear and angular acceleration of the head
L20 - What are the planes of movement in the head
-Yaw - z-axis
-Roll - x-axis
-Pitch - y-axis
L20 - What is the vestibular apparatus composed of
-Bony labyrinth, which has membranous labyrinth inside
L20 - Where does the vestibular system receive input
-Vestibular nerve
L20 - What are 5 sensory organs
-Semicircular ducts
-The vestibule
-
L20 - What type of receptors are hair cells
-Mechanoreceptors
L15 - What is the sensory system
-Receive information from the world or from the body
L15 - What is the motor system
-To move us around and manipulate objects
L17 - What are the two types of memory
-Declarative memory: conscious recall of facts, events, people & objects
-Procedural memory: unconscious recall of motor & perceptual skills
L17 - How do we acquire procedural memory
-The brain needs to solve the following computational problems:
1) Movement consequences of a motor command (forward model)
2) Motor commands needed to achieve a desired movement trajectory (inverse model)
–Internal model
-direction of movement
-force of movement
