Neuromotor Basis for Motor Control PDF

Neuromotor Basis for Motor Control Dianne L. Salvaleon Neuromotor Basis for Motor Control Page 1 of 45  Why did the brain refuse to take a bath? Neuromotor Basis for...

Neuromotor Basis for Motor Control Dianne L. Salvaleon Neuromotor Basis for Motor Control Page 1 of 45  Why did the brain refuse to take a bath? Neuromotor Basis for Motor Control Page 2 of 45  It didn't want to be brainwashed. Neuromotor Basis for Motor Control Page 3 of 45  Topics for Learning 01 02 Neuron Central Nervous System Why do we need to look into the neurophysiologic basis of the neural activity with voluntary movement? A basic understanding of the physiology underlying the control of voluntary movement gives the practitioner - you, a more comprehensive appreciation and awareness of the capabilities and limitations of the people we work with. Neuromotor Basis for Motor Control Page 4 of 45  The Neuron aka nerve cell basic component of the nervous system provides the means for receiving and sending information through the entire nervous system. The Neuron Basic component of the nervous system is the nerve cell. There are billions of neurons in our body and they vary in sizes. Neurons provides the means for receiving and sending information through the entire nervous system. Neuromotor Basis for Motor Control Page 5 of 45  Myelin Sheath Nucleus speeds up transmission of The regulates homeostasis of the neuron neural signal along the axon Neuron Dendrites receives information from other neurons Axon Terminals Axon provides signal transmission (nerve fiber) sends information relay station for from the neurons neurotransmitters the number of dendrites per neuron can be none to thousands a nerve has 1 axon Neuromotor Basis for Motor Control Page 6 of 45  Types and Functions of Neurons Sensory Neurons sends neural impulses to CNS receives information from sensory receptors some are UNIPOLAR, but mostly pseudounipolar: are sensory neurons with cell bodies located in spinal and cranial nerve ganglia Unipolar: a neuron in which only one process, called a neurite, extends from the cell body. The neurite then branches to form dendritic and axonal processes pseudo unipolar Sensory neurons with cell bodies in the dorsal root ganglia of the vertebrate spinal cord are pseudo-unipolar: one branch projects to the periphery (to sensory receptors in the skin, joints, and muscle), the other to the spinal cord. are sensory neurons with cell bodies located in spinal and cranial nerve ganglia Neuromotor Basis for Motor Control Page 7 of 45  Types and Functions of Neurons Motor Neurons sends neural impulse from the CNS to skeletal muscles Two types: Alpha Motor Neurons have large cell body; axon terminals connect with skeletal muscles; responsible to initiating extrafusal muscle fiber contractions Gamma Motor Neurons have a small cell body; supply a portion of the skeletal muscle called intrafusal muscle fiber; allow individual to judge the position of their muscles Alpha: They innervate extrafusal muscle fibers of skeletal muscle and are directly responsible for initiating their contraction Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors). They detect the amount and rate of change in length of a muscle.[1 It is by the sensory information from gamma motor neurons and beta motor neurons that an individual is able to judge the position of their muscles. Neuromotor Basis for Motor Control Page 8 of 45  Types and Functions of Neurons Interneurons specialized neurons which originate and terminate in the brain or spinal cord "in between" they relay information from axons from the brain to motor neurons and axons from sensory beves and the spinal nerves travelling to the brain Neuromotor Basis for Motor Control Page 9 of 45  Central forms the center of activity for the integration and organization of the sensory Nervous and motor information in the control of movement System 01 Brain Cerebrum, Cerebellum, Brainstem 02 Spinal Cord Sensory Neural Pathways, Motor Neural Pathways, Motor Unit THE CENTRAL NERVOUS SYSTEM “command center” for human behavior forms the center of activity for the integration and organization of the sensory and motor information in the control of movement we will concentrate on those portions most directly related to the motor control associated with learning and performing the types of motor skills that are the focus of this book Neuromotor Basis for Motor Control Page 10 of 45  BRAIN cerebrum, diencephalon, cerebellum, and brainstem: directly involved in control of movement let's watch the video, keep pay attention to the location of the lobes of cerebrum, the other parts and function of the brain Neuromotor Basis for Motor Control Page 11 of 45  The Cerebrum frontal lobe: control of voluntary movement occipital lobe: important in visual perception temporal lobe: memory, abstract thought, and judgment parietal lobe: control of perception and the integration of sensory information * interacting with the premotor cortex, primary motor cortex, and SMA before and during movement important cortical area involved in the control of voluntary movement especially important in the integration of movement preparation and execution processes by interacting with the premotor cortex, primary motor cortex, and SMA before and during movement Neuromotor Basis for Motor Control Page 12 of 45  The Cerebrum Neuromotor Basis for Motor Control Page 13 of 45  control of voluntary control of perception and the integration of sensory information movement control of visual and auditory The selective attention; visually tracking a moving target; and grasping. Cerebrum important in visual perception memory, abstract thought, and judgment frontal lobe: control of voluntary movement occipital lobe: important in visual perception temporal lobe: memory, abstract thought, and judgment parietal lobe: control of perception and the integration of sensory information * interacting with the premotor cortex, primary motor cortex, and SMA before and during movement important cortical area involved in the control of voluntary movement especially important in the integration of movement preparation and execution processes by interacting with the premotor cortex, primary motor cortex, and SMA before and during movement Neuromotor Basis for Motor Control Page 14 of 45  Sagittal section of the Brain Neuromotor Basis for Motor Control Page 15 of 45  The Cerebrum Neuromotor Basis for Motor Control Page 16 of 45  The Sensory Cortex receives sensory information 01 from sensory nerves sensory-specific areas exist 02 for vision, taste, speech, and body, etc sensory cortex: Specific types of sensory information are transmitted via the sensory nerves to the area of the cortex that receives that type of information. Note in figure 4.4 that sensory-specific areas exist for vision, taste, speech, and body (for example, the somatic sensory area receives pain, temperature, and pressure sensory information). Neuromotor Basis for Motor Control Page 17 of 45  The where the brain “associates,” or connects together the integration Association area01 of various types of sensory information as well as the sensory information from various parts of the body connect with other cortex areas in ways that allow for the interaction 02 between perceptual and higher- order cognitive functions association areas: lie adjacent to each specific sensory area in the parietal, temporal, and occipital lobes; describe these areas because it is there where the brain “associates,” or connects together, information from the several different sensory cortex areas connecting together involves the integration of various types of sensory information as well as the sensory information from various parts of the body connect with other cortex areas in ways that allow for the interaction between perceptual and higher-order cognitive functions, such as would occur in a choice reaction time situation where each choice alternative has a different probability of being the correct choice Neuromotor Basis for Motor Control Page 18 of 45  The Primary Motor Cortex 01 critical for movement initiation coordination of movements for 02 fine motor skills involved in the control and 03 learning of postural coordination primary motor cortex: contains motor neurons that send axons to specific skeletal muscles throughout the body. critical for movement initiation and the coordination of movements for fine motor skills involved in the control and learning of postural coordination Neuromotor Basis for Motor Control Page 19 of 45  The Pre-Motor Area controls the organization of movements before they are 01 initiated and rhythmic coordination during movement key role in the planning of eye 02 movements and orienting visual- spatial attention premotor area: controls the organization of movements before they are initiated and rhythmic coordination during movement, thus enabling the transitioning between movements for a skill that involves sequential movement key role in the planning of eye movements and orienting visual-spatial attention Neuromotor Basis for Motor Control Page 20 of 45  The Supplementary 01 essential role in the control of sequential movements Motor Area (SMA) preparation and organization of 02 movement play a role in modifying the continuous, bilateral, multijoint 03 movements associated with variable rate pedaling supplementary motor area (SMA): essential role in the control of sequential movements preparation and organization of movement play a role, together with other brain regions, in modifying the continuous, bilateral, multijoint movements associated with variable rate pedaling Neuromotor Basis for Motor Control Page 21 of 45  receive neural information from roles in the control of movement, 01 the cerebral cortex and the especially in the planning and initiation of movement the control brainstem 03 of antagonist muscles during neural information from the basal movement, and the control of 02 ganglia goes primarily to the force brainstem The Basal Ganglia Video: Basal Ganglia: Neuroanatomy Video Lab - Brain Dissections basal ganglia: buried within the cerebral hemispheres consisting of a group of subcortical nuclei which are: the caudate nucleus, the putamen, the substantia nigra, and the globus pallidus receive neural information from the cerebral cortex and the brainstem neural information from the basal ganglia goes primarily to the brainstem play critical roles in the control of movement, especially in the planning and initiation of movement, the control of antagonist muscles during movement, and the control of force Neuromotor Basis for Motor Control Page 22 of 45  thalamus relay station; receives and integrates most of the sensory neural inputs from the spinal cord and brain stem and then passing them through to the cerebral cortex plays an important role in the control of attention, mood, and the perception of pain The Diencephalon The diencephalon. two groups of nuclei, the thalamus and hypothalamus Thalamus serves an important function as a relay station, receiving and integrating most of the sensory neural inputs from the spinal cord and brain stem and then passing them through to the cerebral cortex plays an important role in the control of attention, mood, and the perception of pain Neuromotor Basis for Motor Control Page 23 of 45  hypothalamus critical brain center for the control of the endocrine system and the regulation of body homeostasis, including temperature, hunger, thirst, and physiological responses to stress. The Diencephalon hypothalamus critical brain center for the control of the endocrine system and the regulation of body homeostasis, including temperature, hunger, thirst, and physiological responses to stress. Neuromotor Basis for Motor Control Page 24 of 45  When does it rain brains? Neuromotor Basis for Motor Control Page 25 of 45  During a brain storm Neuromotor Basis for Motor Control Page 26 of 45  The Cerebellum Neuromotor Basis for Motor Control Page 27 of 45  plays a key role in the execution of The 01 smooth and accurate movements Cerebellum functions as a type of movement 02 error detection and correction system active in the control of other movement activities such as those 03 requiring eye-hand coordination, movement timing, force control, and posture control involved in the learning of motor 04 skills coordinates and plans voluntary 05 muscular skill plays a key role in the execution of smooth and accurate movements functions as a type of movement error detection and correction system as it receives a copy of signals about an intended movement sent from the motor cortex to the muscles and compares the motor information with the sensory information it receives from sensory nerves that connect to the cerebellum This comparison functions in a way that signals to the muscles any needed adjustments to movements already in progress, thus assuring achievement of the intended movement’s goal active in the control of other movement activities such as those requiring eye-hand coordination, movement timing, force control, and posture control involved in the learning of motor skills as it interacts with areas of the cerebral cortex Coordinates and plans voluntary muscular skill Maintains balance Monitors feedback from ongoing movements and initiates corrective actions Maintains muscle tone Neuromotor Basis for Motor Control Page 28 of 45 Helps with synchronization of limb movement Neuromotor Basis for Motor Control Page 29 of 45  The 06 Maintains balance Cerebellum Monitors feedback from ongoing 07 movements and initiates corrective actions 08 Maintains muscle tone Helps with synchronization of limb 09 movement Maintains balance Monitors feedback from ongoing movements and initiates corrective actions Maintains muscle tone Helps with synchronization of limb movement Neuromotor Basis for Motor Control Page 30 of 45  appears to be involved in the control of body functions such as chewing, swallowing, pons salivating, and breathing. may also play a role in the control of balance serves as a regulatory agent for various medulla internal physiologic processes functions as a site where the corticospinal tracts of the sensory and motor neural pathways cross over reticular primary role in the control of movement is as an integrator of sensory and motor formation neural impulses appears to have access to all sensory information and can exert direct The influence on the CNS to modify activity brainstem Pons: acts as a bridge between the cerebral cortex and cerebellum appears to be involved in the control of body functions such as chewing, swallowing, salivating, and breathing. may also play a role in the control of balance medulla: extension of the spinal cord and serves as a regulatory agent for various internal physiologic processes, such as respiration, in which it interacts with the pons, and heartbeat functions as a site where the corticospinal tracts of the sensory and motor neural pathways cross over the body midline and merge on their way to the cerebellum and cerebral cortex reticular formation: primary role in the control of movement is as an integrator of sensory and motor neural impulses appears to have access to all sensory information and can exert direct influence on the CNS to modify activity of the CNS either by inhibiting or increasing that activity, which in turn influences skeletal muscle activity. Neuromotor Basis for Motor Control Page 31 of 45  The limbic system frontal and temporal lobes of the cerebral cortex, the thalamus and hypothalamus, and the nerve fibers that interconnect these parts and other CNS structures system plays important roles in the learning of motor skills as well as in the control of emotions and several visceral behaviors The limbic system: consists of parts of the frontal and temporal lobes of the cerebral cortex, the thalamus and hypothalamus, and the nerve fibers that interconnect these parts and other CNS structures. This system plays important roles in the learning of motor skills as well as in the control of emotions and several visceral behaviors Visceral: instinctive Visceral processing involves automatic, prewired, emotional responses: rapid judgments of good or bad Neuromotor Basis for Motor Control Page 32 of 45  Review. "Servier - Drawing Brain sagittal section - no labels" by Servier Medical Art, license: CC BY Neuromotor Basis for Motor Control Page 33 of 45  The Spinal Cord a complex system that interacts with a variety of systems and is critically involved in motor control processes. Neuromotor Basis for Motor Control Page 34 of 45  Spinal Cord dorsal contains cells involved in the horns transmission of sensory information ventral contains alpha motor neuron cell bodies horns whose axons terminate on skeletal muscle interneurons located in the ventral horn renshaw inhibit the amount of neural activity of cells alpha motor neurons Spinal cord composition white matter: composed of bundles of axons. These axons are coated with myelin, a mixture of proteins and lipids, that helps conduct nerve signals and protect the axons. White matter conducts, processes, and send nerve signals up and down the spinal cord. gray matter: H-shaped central portion of the cord consists primarily of cell bodies and axons of neurons that reside in the spinal cord. allows it to process information and release new information through axon signaling found in the white matter. vital to motor control: Two pairs of “horns” protrude from the gray matter. The posterior pair of horns, known as the dorsal horns, contains cells involved in the transmission of sensory information. dorsal horn :Sensory neurons from the various sensory receptors in the body synapse on the DH neurons. anterior pair of horns, known as the ventral horns, contains alpha motor neuron cell bodies whose axons terminate on skeletal muscle spinal cord contains alpha motor neurons and sensory neurons, as well as interneurons Neuromotor Basis for Motor Control Page 35 of 45 Renshaw cells (composed of interneurons located in the ventral horn. They influence the neural activity of alpha motor neurons by inhibiting the amount of activity, sometimes turning off the activity so that the neurons can fire again in a short period of time Neuromotor Basis for Motor Control Page 36 of 45  sensory ascending pass through the spinal cord and brainstem to connect with the various neural tracts: sensory areas of the cerebral cortex and cerebellum. pathways 01 first neuron in the chain synapses with a sensory neuron outside the spinal cord. Dorsal column: transmits proprioception, touch and pressure information 02 Anterolateral system: transmit pain and temperature and some touch and pressure information tracts enter the thalamus, where they 03 synapse with another sensory neuron to continue to the cerebral cortex ascending tracts: pass through the spinal cord and brainstem to connect with the various sensory areas of the cerebral cortex and cerebellum. contain sequences of two or three neurons The first neuron in the chain synapses with a sensory neuron outside the spinal cord. (depending on type of sensory receptors) Two ascending tracts: the sensory cortex transmit sensory information important for the control of voluntary movement. 1) Dorsal column: transmits proprioception, touch and pressure information 2) Anterolateral system: transmit pain and temperature and some touch and pressure information. The tracts enter the thalamus, where they synapse with another sensory neuron to continue to the cerebral cortex Neuromotor Basis for Motor Control Page 37 of 45  motor descending tracts motor pathways that descend from the brain through the spinal cord neural Pyramidal corticospinal tract pathways tracts originates in various parts of the cerebral cortex and projects axons to the spinal cord 60% come from primary motor cortex cross over to the opposite side of the body at the medulla in the brainstem and continue down the lateral column of the spinal cord. Transmit information primarily involved in the control of movements associated with the performance of fine motor skills Motor neural pathways Descending tracts: motor pathways that descend from the brain through the spinal cord. (pyramidal tracts or extrapyramidal tracts) Pyramidal tracts (aka corticospinal tract): originates in various parts of the cerebral cortex and projects axons to the spinal cord. 60% of the pathways come from primary motor cortex Most of the fibers from this tract cross over to the opposite side of the body at the medulla in the brainstem and continue down the lateral column of the spinal cord. Transmit information primarily involved in the control of movements associated with the performance of fine motor skills. NOTE: since pyramidal tract crossover in the brainstem, the muscle on each side of the body are controlled by the opposite cerebral hemisphere. Neuromotor Basis for Motor Control Page 38 of 45  motor neural extrapyramidal tracts pathways brainstem pathways have their cell bodies in the brainstem with axons descending into the spinal cord involved in postural control as well as in facilitation and inhibition of muscles involved in the flexion and extension of hands and fingers. Extrapyramidal tract (brainstem pathways): have their cell bodies in the brainstem with axons descending into the spinal cord. This neural pathways are involved in postural control as well as in facilitation and inhibition of muscles involved in the flexion and extension of hands and fingers. They are responsible for the unconscious, reflexive or responsive control of musculature, eg muscle tone, balance, posture and locomotion Extrapyramidal tracts are chiefly found in the reticular formation of the pons and medulla, and target lower motor neurons in the spinal cord that are involved in reflexes, locomotion, complex movements, and postural control Neuromotor Basis for Motor Control Page 39 of 45  The motor unit 01 Defined as the alpha motor neuron and all the muscles it innervates. functional unit of motor control for the 02 innervation of the muscles involved in a movement from the nerve fiber to the muscle fibers number of muscle fiber varies greatly 03 example: fine motor movements: small number of muscle fibers per unit The motor unit ultimate end of the transmission of motor neural information Defined as the alpha motor neuron and all the muscles it innervates, the motor unit serves as the functional unit of motor control for the innervation of the muscles involved in a movement from the nerve fiber to the muscle fibers so that appropriate muscle contraction can occur. The number of muscle fiber varies greatly. In general, muscles involved in the control of fine motor movement, such as the muscles of the eye and larynx, have the smallest number of muscle fibers for each motor unit. Which in some cases if on per fiber. On the other hand, large skeletal muscles, such as those involved in the control of posture and gross motor skills have the largest number of muscle fibers per motor unit with as many as 700 muscle fiber innervated by one motor unit. Neuromotor Basis for Motor Control Page 40 of 45  Motor unit recruitment The number of muscle fibers active at any one time influences the amount of force the muscle can exert recruitment-specific process by beginning with the smallest (weakest) motor units to largest (powerful) motor units Motor unit recruitment The number of muscle fibers active at any one time influences the amount of force the muscle can exert increase the amount of force exerted by a muscle the number of motor neurons activated increases. This follows a recruitment-specific process by beginning with the smallest (weakest) motor units to largest (powerful) motor units Neuromotor Basis for Motor Control Page 41 of 45  THE NEURAL 01 begins with a cognitively derived intent CONTROL OF 02 for movement implementation, CNS structures, sensory-perceptual system VOLUNTARY components and the peripheral nervous system must coordinate MOVEMENT 03 This interaction occurs both hierarchically and in parallel THE NEURAL CONTROL OF VOLUNTARY MOVEMENT Performing a motor skill typically begins with a cognitively derived intent that is based on the dictates of the situation or needs of the person. The movement implementation of this intent requires numerous neurophysiologic events that involve the cooperative interaction of many CNS structures in addition to sensory- perceptual system components and the peripheral nervous system. This interaction occurs both hierarchically and in parallel Neuromotor Basis for Motor Control Page 42 of 45  THE NEURAL CONTROL OF VOLUNTARY MOVEMENT THE NEURAL CONTROL OF VOLUNTARY MOVEMENT Although the organizational diagram in the figure presents a hierarchical model of structures, many of the functions of the structures described in the table are carried out in parallel, which means they occur at the same time rather than as a sequence of events. Neuromotor Basis for Motor Control Page 43 of 45  THE NEURAL CONTROL OF VOLUNTARY MOVEMENT THE NEURAL CONTROL OF VOLUNTARY MOVEMENT One of the notable features of the figure is its depiction of the wide distribution of brain structures involved from the initial intent to perform a skill until the neural innervation of the muscles associated with producing the movements needed to perform the skill. Clearly, a complex array of neural activities underlies the performance of seemingly simple behavioral activities Neuromotor Basis for Motor Control Page 44 of 45  Summary 01 02 03 Brain Spinal Cord Neural Control Neuromotor Basis for Motor Control Page 45 of 45