sensory motor processing in planning and execution of movement
TRANSCRIPT
Sensory-motor processing in planning and execution of movement
Subhadeep Dutta Gupta M.Phil Scholar
Department of Neurophysiology, NIMHANS
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Sea squirt (Ascidiacea)
Introduction
• Movement is an important feature of living organism.
• All interaction with the surrounding world is through motor
system.
• The motor system continues to develop through maturation
of neuronal circuitry and by learning through different motor
activities during the first 15 years of life.
Hierarchy of motor control:
• Background:
Jackson, (1889) : higher motor centers controlling simple movements.
William James, (1890) : voluntary movement is secondary to reflexive
actions, and involves anticipatory image.
C. Sherrington, (1906) : distinguished between upper & lower motor neurons.
Keele, (1968) : ordered nature of high level motor programs for feed- forward
control of movements.
3 levels in hierarchy of motor control:h Cerebral cortex:
-- primary motor & sensory cortex, premotor cortex, supplementary motor
cortex
-- mediated by Pyramidal system.
Brain Stem:
-- Extrapyramidal system.
Spinal cord:
-- ‘final common pathway’ modulated by higher centre.
-- executive centre for reflexes & pattern generation.
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Organization of the motor system:
Cerebral Cortex: Representation of the motor functions:
• J.H Jackson:
-- Specific part of the cortex has a causal role in movement.
• Fritsch, Hitzig, Ferrier:
-- Electrical stimulation at specific region of the cortex evoked
movements in contralateral body parts.
-- Lesion of that region caused loss of motor control of the specific
body part.
Cerebral Cortex: Sensory & Motor Homunculus:
Cytoarchitecture of motor cortex :
-- Primary motor cortex is agranular.
-- Layer IV (cell-packed granular layer) is very
thin or nearly absent.
-- Layer V (descending output layer) is thicker
& contains the giant Betz cells.
-- These neurons makes up around 30% of the
fibres in the cortico-spinal tract.
Betz cells of layer V
Organization of precentral motor area:
--Principles of Neural Science, 5th Edn
Internal Model:• Postulated neural process that simulates the response of the
motor system in order to estimate the outcome of a motor
command.
• The motor system makes use of internal models in order to
control the musculoskeletal system during rapid, skilled, motor
behaviour.
• Ex – Size Mass estimation-- Science, 269, 1880-1882 (1995).
Processing of sensory information in the cerebral cortex
--Principles of Neural Science, 5th Edn
Cross talk of association areas :
--Principles of Neural Science, 5th Edn
Motor & executive control
Emotional responses
• Parietal Association Cortex: -- key role in the visual guidance of motor behaviour.
-- spatial perception & cognition.
-- suited for such computation as it is connected with visual,
somatosensory & motor areas of cortex.
• Damage: -- Ideomotor apraxia
-- Impaired speech repetition
-- Personal neglect syndrome
‘Binding’
Conceptual representation of feature binding & representation:
Trends in Neurosciences, 2013(36)3
• Temporal Association Cortex:
-- Object recognition and semantic memory.
Inferotemporal neurons :
-- are sensitive to the shape, colour, and texture of an object.
-- insensitive to size and location of the objects.
-- activity is not influenced by the motor behaviour of the animal.
• Damage:
-- semantic dementia Visual object agnosia
Connection between prefrontal & motor cortex:
--Principles of Neural Science, 5th Edn
Emotional & cognitive processes in the PFC controls the motor behaviour
Primary Motor Cortex:
• Primary motor cortex neurons fire 5-100 msec before the onset of a
movement.
• Primary motor cortex encodes the force of a movement (Evarts et
al., 1968).file:///D:/Presentation%20on%20Movement/Videos/1.Force%20of%20movement.swf
• It encodes the direction of movement (Georgopoulas et al., 1982).
-- Many neurons are selective for a particular direction of movement. file:///D:/Presentation%20on%20Movement/Videos/2.Direction%20of%20movement.swf
• It encodes the extent of movement.
• It also encodes the speed of movement. file:///D:/Presentation%20on%20Movement/Videos/3.Speed%20of%20movement.swf
-- Bell shaped curve
• Premotor cortex neurons signal the preparation for movement
(Weinrich and Wise,1982). file:///D:/Presentation%20on%20Movement/Videos/4.Preparation%20of%20movement.swf
-- Motor- set neurons ‘Go’ signal.
• Premotor cortex is sensitive to the behavioural context of a
particular movement (Iacoboni et al., 2005).file:///D:/Presentation%20on%20Movement/Videos/5..Behavioral%20context.swf
• Premotor cortex signals correct and incorrect actions.
Premotor Cortex:
g• Premotor cortex neurons signal various sensory aspects
associated with particular motor acts.
-- Some neurons fire when a subject is performing a particular
action.
-- Same neuron fires selectively when the subject sees someone
performing a particular action.
-- It also fires selectively even without a visual or motor activity.
-- Concept of Mirror & Cannonical Neurons (Rizzolatti et al.,
1996)
Supplementary Motor Area:
• SMA is involved in the transformation of
kinematic to dynamic information.
• SMA responds to sequences of movements
and to mental rehearsal of sequences of
movements (Roland et al., 1980). file:///D:/Presentation%20on%20Movement/Videos/6.Mental%20rehearsal.swf
Descending pathways that mediate motor functions:
--Fundamental Neuroscience; 3rd Edn
Corticospinal system:
The Malleable Motor Map:
-- Annu. Rev. Neurosci. 2000. 23:393–415
Phantom Limb & Mirror Therapy:
Amputated Limb
Intact Limb
Motor control centers in the brain stem:
The major brain stem nuclei sending fibers to the spinal cord.--The Central Nervous System,4th Edn
h• Hans Kuypers classification:
Medial Brain stem pathway
-- Vestibulospinal tract
-- Reticulospinal tract
-- Tectospinal tract
Lateral Brain stem pathway
-- Rubrospinal tract
Experimental evidence:
Transection of the direct pathway in Rhesus monkeys (with intact Indirect pathways):
difficulty in using the distal parts of their limbs.
unable to reach toward & pick up food with their fingers
they used the entire arm to sweep the food toward
them.-- Lawrence & Kuypers, 1968
--Principles of Neural Science, 5th Edn
Motor control at Spinal level: Reflex:
-- Automatic, stereotyped movement in response to stimulation of
peripheral receptors.
-- integrated by centrally generated motor commands into complex
adaptive movements.
Central pattern generator:
• Neural network within CNS that give rise to rhythmic
motor activity independent of sensory inputs.
• Ex- Motor behavior such as respiration, walking, feeding,
swimming, flying.
• Studied extensively in lampreys, snails, leeches, flies,
frogs, chicks etc.
EMG Recording in Lobster:
KKKKKk
k
HHHHHHHHHH
-- The Journal of Neuroscience, 1987, 7(7), 2097-2112.
Lateral Pyloric Neurons (LP)
Pyloric Neurons (PY)
Pyloric Dilator Neurons (PD)
Lateral Ventricular Nerve (lvn)
Generation of Fictive locomotion:HHHHH
HHHHHHH
hHHHHHHHHHH
-- J Neurophysiol 82:2029-2038, 1999.
Mechanism of swimming in lamprey:
Glutamate The membrane depolarizes
Na+ and Ca2+ flow into the cell through the NMDA receptors
Ca2+ activates K+ channels
K+ flows out of the cell
The membrane hyperpolarizes
Ca2+ stops flowing into the cell
K+ channels close
The membrane depolarizes, and the cycle repeats.-- Neurosci. Lett. 89, 31–35., 1987
Rhythmic activity in a spinal interneuron
Sensorimotor integration in movement disorders:
Parkinson’s Disease:
• Classical view:
• -- dysfunction of the basal ganglia-motor cortex
circuits.
• BG involved in:
• somatosensory discrimination
• visual perception
• spatial working memory -- Curr Opin Neurobiol 1997; 7:157-63.
• When external, visual or auditory cues are
provided, substantially improvement of specific
features of Parkinsonian bradykinesia was noted.
• Deficient internal cueing mechanism to
discharge successive stages of a movement
sequence ????
-- Mov Disord 2000; 15: 879-83.
Stroke:
• Sudden focal neurological deficit due to a
cerebrovascular abnormality.
• Decreased plasticity in affected region while an
increase of sensorimotor integration process
happens in non-affected regions.
• Restraint of the intact limb over an extended
period, in combination with a large number of
repetitions of task-specific training of the
affected limb.
Positive outcome
-- Lancet Neurol 2008; 7: 33-40.
Scheme of interaction between different motor centers
-- Fundamental Neuroscience; 3rdEdn
Bibliography:• Principles of Neural Science, 5th Edition, Eric Kandel.
• Fundamental Neuroscience, 3rd Edition, Larry Squire
• Neuroscience, 3rd Edition, Dale Purves
• The Central Nervous System, 4th Edition, Per Brodal
• Neuroscience, 3rd Edition, Mark Bear
• Modulation of the lobster pyloric rhythm by the peptide proctolin, The Journal of
Neuroscience, 1987, 7(7), 2097-2112.
• The mammalian central pattern generator for locomotion, Brain Research Reviews,
2009 (62) 45-56.
• Interaction Between Disinhibited Bursting and Fictive Locomotor Patterns in the
Rat Isolated Spinal Cord, J Neurophysiol ,1999, (82) 2029-2038.
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Neurosci., 2000. (23)393–415.
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ganglia. Curr Opin Neurobiol 1997; 7: 157-63.
• Marchese R, Diverio M, Zucchi F, Lentino C, Abbruzzese G. The role of sensory
cues in the rehabilitation of Parkinsonian patients: a comparison of two physical
therap. Mov Disord 2000; 15: 879-83.
• Wolf SL, Winstein CJ, Miller JP, Thompson PA, Taub E, Uswatte G, et al. Retention
of upper limb function in stroke survivors who have received constraint-induced
movement therapy: the EXCITE randomised trial. Lancet Neurol 2008; 7: 33-40.
• D.M. Wolpert, Z. Ghahramani and M.I. Jordon. An internal model for sensorimotor
integration. Science, 269, 1880-1882 (1995).
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generating network for locomotion in lamprey. Neurosci. Lett. 89, 31–35.
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March 2013, Vol. 36, No. 3.
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“All mankind can do is to move things… whether whispering a syllable or felling a forest.”
--Sir Charles Scott Sherrington
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Thank You !!!!