motor system overview
TRANSCRIPT
VOLUNTARY MOTOR CONTROL
BRAIN VS. HEART
Hippocrates 460-377 BC, “Men ought to know that from the brain and from the brain only arise our pleasures, joys, laughter and jests, as well as our sorrows, pains, grieves and tears”.
Aristotle 384-322 B.C “the heart as the organ of thinking, of perception and feelings,”“brain could cool the passion of heart”
387 B.C. - Plato teaches at Athens. Believes brain is seat of mental process
BRAIN AS HOLLOW ORGAN: 335-280 BC HEROPHILUS
Ventricles are seat of human intelligence
GALEN 130-200 AD
177 - Galen lecture On the Brain
ANDREAS VESALIUS (1514-1564 CE)
DESCARTES, BRAIN AND MIND
1649 - Rene Descartes describes pineal as control center of body and mind
1664 - THOMAS WILLIS
1664 - Publishes Cerebri anatome (in Latin)
1681 - coins the term Neurology
BIOELECTRICITY
1791 - Luigi Galvani publishes work on electrical stimulation of frog nerves
1809 - Luigi Rolando uses galvanic current to stimulate cortex
PHRENOLOGY FRANZ JOSEPH GALL 1806
The theory of Gall and Spurzheim is ... an instance of a theory which, while essentially wrong, was just enough right to further scientific thought…Edwin Boring
1824 - MARIE-JEAN-PIERRE FLOURENS
1825 - JEAN-BAPTISTE BOUILLAUD
Presents cases of loss of speech after frontal lesions
PIERRE GRATIOLET
PHINEASE GAGE (1848)
On 13th Sept 1848 a
railroad worker hard
working, diligent,
reliable, responsible,
intelligent, good
humored, polite god
fearing, family oriented
foreman
Following an explosion
iron bar drove into
frontal lobe
1. He becomes unreliable and fails to come to work and when present he is "lazy."
2. He has no interest in going to church, constantly drinks alcohol, gambles, and "whores about."
3. He is accused of sexually molesting young children.
4. He ignores his wife and children and fails to meet his financial and family obligations.
5. He has lost his sense of humour.
6. He curses constantly and does so in inappropriate circumstances.
7. Died of status epilepticus in 1861
LOBAR LOCALIZATION
Paul Broca 1868
1861 - discusses cortical localization
1870, HITZIG AND FRITSCH
Electrically stimulated various parts of a dog's motor cortex.
They observed that depending on what part of the cortex they stimulated, a different part of the body contracted.
Then they found that if they destroyed this same small area of the cortex, the corresponding part of the body became paralyzed.
This is how it was discovered that every part of the body has a particular region of the primary motor cortex that controls its movement.
1870 - DAVID FERRIER
JOHN HUGHLINGS JACKSON Described seizure as
cerebral event not medulla on clinicopathological observation of head injury patients.
DISCOVERY OF NEURON
Ramony Cajal and Camillo Golgi 1906 Noble
BRODMANN’S AREA: 1909
1906 - SIR CHARLES SCOTT SHERRINGTON
1906 - Sir Charles Scott Sherrington publishes The Integrative Action of the Nervous system that describes the synapse and motor cortex
1957 - W. PENFIELD
CONTROL OF VOLUNTARY MOVEMENT
IdeaAssociation
cortexPremotor +
Motor cortex
Basal Ganglia
Lateral cerebellu
m
Movement
Intermediate Cerebellum
ExecutionPlanning
ORGANIZATION OF MOTOR SYSTEM
ORGANIZATION OF MOTOR NERVOUS SYSTEM
CORTICAL MOTOR AREAS
FUNCTIONAL ORGANIZATION OF THE PRIMARY MOTOR CORTEX
THE MAJOR INPUTS TO THE MOTOR CORTEX IN MONKEYS
MOTOR CORTEX AFFERENT
CORTICOSPINAL TRACT
CONVERGENCE OF MOTOR CONTROL ON THE ANTERIOR MOTOR NEURON
EXPERIMENTAL APPARATUS DEVELOPED TO RECORD THE ACTIVITY OF SINGLE NEURONS IN AWAKE PRIMATES TRAINED TO PERFORM SPECIFIC MOVEMENTS : ED EVARTS 1960
DIRECT CORTICOSPINAL CONTROL OF MOTOR NEURONS IS NECESSARY FOR FINE CONTROL OF THE DIGITS
MOTOR CORTICAL CELL FIRING WITH FORCE GENERATED
CORTICOMOTONEURONAL (CM) CELL IS ACTIVE DEPENDS ON THE MOTOR TASK
ACTIVITY IN INDIVIDUAL NEURONS OF THE PRIMARY MOTOR CORTEX IS RELATED TO MUSCLE FORCE AND DIRECTION OF MOVEMENT
SPIKE TRIGGERED AVERAGING 1970
DIRECTIONAL TUNING OF AN UPPER MOTOR NEURON IN THE PRIMARY MOTOR CORTEX
DIFFERENT AREAS OF CORTEX ARE ACTIVATED DURING SIMPLE, COMPLEX, AND IMAGINED SEQUENCES OF FINGER MOVEMENTS (XENON PET)
CELL ACTIVITY IN THE MOTOR CORTEX DEPENDS ON WHETHER A SEQUENCE OF MOVEMENTS IS GUIDED BY VISUAL CUES OR BY PRIOR TRAINING
A SET-RELATED NEURON IN THE DORSAL PREMOTOR AREA BECOMES ACTIVE WHILE THE MONKEY PREPARES TO MAKE A MOVEMENT TO THE LEFT
THE VISUOMOTOR TRANSFORMATIONS REQUIRED FOR REACHING AND GRASPING INVOLVE TWO DIFFERENT PATHWAYS
Individual neurons in the ventral premotor area fire during specific hand actions only
A. ACTIVITY IN THE NEURON AS THE MONKEY OBSERVES ANOTHER MONKEY MAKE A PRECISION GROUP.B. ACTIVITY IN THE SAME NEURON AS THE MONKEY OBSERVES THE HUMAN EXPERIMENTER MAKE THE PRECISION GRIP.C. ACTIVITY IN THE SAME NEURON AS THE MONKEY ITSELF PERFORMS A PRECISION GRIP. (FROM RIZZOLOTTI ET AL 1996.)
Mirror Neurons
DIFFERENT AREAS OF CORTEX ARE ACTIVATED DURING SIMPLE, COMPLEX, AND IMAGINED SEQUENCES OF FINGER MOVEMENTS (XENON PET)
THE SOMATOTOPIC ORGANIZATION OF THE MOTOR CORTEX IS PLASTIC
AS A MOVEMENT BECOMES MORE PRACTICED, IT IS REPRESENTED MORE EXTENSIVELY IN PRIMARY MOTOR CORTEX
SUMMARY Primary Motor Cortex:
Codes force and direction of movement Spinal motor neuron are directly under control for
precise movement. Dorsal Premotor Cortex
Movement related neuron encodes sensorimotor transformation for visual and sensory cue
Fire before movement Ventral Premotor Cortex
Encodes learned motor act fire before movement
All cortical neurons are adaptable and plastic
RUBROSPINAL TRACT
MODULATION OF MOVEMENT BY THE BASAL GANGLIA
MOTOR COMPONENTS OF THE HUMAN BASAL GANGLIA
ANATOMICAL ORGANIZATION OF BASAL GANGLIA INPUT
OUTPUT OF BASAL GANGLIA
DISINHIBITION IN THE DIRECT AND INDIRECT PATHWAYS THROUGH THE BASAL GANGLIA
ORGANIZATION OF CEREBELLUM
INPUT OF CEREBELLUM
CEREBELLAR OUTPUT
VESTIBULOCEREBELLUM
NEOCEREBELLUM
THE SPINOCEREBELLUM CONTAINS TWO SOMATOTOPIC NEURAL MAPS OF THE BODY
MOTOR MODULATION BY THE CEREBROCEREBELLUM
CEREBELLAR PATHWAY
SPINAL MOTOR NEURON
SPINAL CORD: GREY MATTER
MOTOR UNIT
NEUROMUSCULAR JUNCTION
MECHANISM OF MUSCLE CONTRACTION
MUSCLE SPINDLE
STRETCH REFLEX
MUSCLE STRETCH REFLEXES
GOLGI TENDON ORGAN
GOLGI TENDON ORGAN
FEEDBACK INHIBITION: GOLGI TENDON ORGAN
ALPHA AND GAMMA MOTOR NEURONS ARE COACTIVATED DURING VOLUNTARY MOVEMENTS
SPINAL ANIMAL
SENSORY FEEDBACK FOR WALKING
LOCOMOTOR CENTER IN CAT
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