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Transcript of McCNS Drive-Thru
Posterior Parietal Cortex A Model of Neural Components
and Their Functions By: Matthew, Marianne, Faris and Chelsey The Drive-Thru Intercom Input of Order Primary Motor Cortex General Manager Spinal Cord Basal Ganglia Secondary Motor Area and
Pre-Motor Cortex Line Cooks Cerebellum Order Modifications Prep Cooks Drive-Thru Window Attendant The premotor cortex is located anterior to the primary motor cortex (Schwerin, n.d.).
Majority of its output is to the primary motor cortex, with a smaller output to the brainstem and the spinal cord (Schwerin, n.d.).
This region receives input from the sensory association cortex as well as feedback from the basal ganglia ("Review of Clinical and Functional Neuroscience").
It is divided into the ventral and the dorsal areas (Nudo, 2008).
The secondary motor area is part of the premotor cortex that extends onto the medial side of the hemisphere (Schwerin, n.d.).
This brain centre sends output to the primary motor cortex, the basal ganglia, the thalamus, and the brainstem ("Review of Clinical and Functional Neuroscience").
The secondary motor area can be divided into two sub-divisions based on functional differences: the SMA proper and the pre-SMA (Nudo, 2008). Structure Order Transfer Thalamus Function Structure Function Damage/Dysfunctions Role in Speed Stacking Collection of nuclei found on both sides of the thalamus, below the cingulate gyrus and within the temporal lobe.
Composed of the striatum, globus pallidus, subthalamic nucleus and the substantia nigra
Striatum is composed of the caudate nucleus and the putamen
Caudate nucleus - Located behind the frontal lobe and curves back toward the occipital lobe This region plays an important role in planning, preparing and initiating the movements required to complete a speed stacking cycle.
The secondary motor area participates in sequencing function of motor skill learning; as speed stacking involves a very specific sequence that must be learned, it relies heavily on the SMA.
The SMA is also involved in coordinating two-handed movement and it is necessary to use coordinated bimanual movements in order to achieve an optimal speed stacking time.
Both the pre-SMA and SMA are involved in the process of learning to speed stack:
While the performer is learning the speed-stacking pattern, the pre-SMA will be more active.
When they perform a speed stack after having learned the pattern, the SMA will be more active. Role in Speed Stacking SMA lesions can produce a condition called abulia, a condition that severely inhibits the initiation of movement ("Review of Clinical and Functional Neuroscience").
SMA lesions may also result in deficits in bimanual coordination and difficulty producing rhythmic motions (Nudo, 2008).
Because of the role the pre-SMA plays in learning new motor sequences, the inactivation of the neurons of the pre-SMA causes deficits in learning (Sosnik, Polyakov, & Flash, 2009).
A case of abulia would prevent a performer from initiating the movement necessary to complete a speed stacking cycle.
Less extreme performance deficits resulting from SMA lesions could prevent the performer from effectively coordinating the movements of their two hands and cause them difficulty in finding a rhythmic movement pattern.
Damage to the pre-SMA, which plays a role in learning new motor sequences, would be detrimental to the performance of a novice who is in the process of learning how to speed stack. Damage/Dysfunctions Putamen - Located under and behind the front of the caudate nucleus
The globus pallidus is located just inside the putamen
Internal - One of two main output nuclei
External - Passes information to the subthalamic nucleus
Subthalamic nucleus is part of the diencephalon that is located below the thalamus
Substatia nigra is a nucleus located in the upper portions of the midbrain, below the thalamus
Composed of the pars compacta and the pars reticulata These motor areas play a significant role in the planning, preparation and initiation of voluntary movement (Nudo, 2008).
The premotor cortex is active in the planning stages of a voluntary movement.
The premotor cortex plays a role in guiding sensory movement, and controls the proximal trunk muscles of the body (Schwerin, n.d.).
The secondary motor area is involved in the sequencing function of motor skill learning and in coordinating movements involving both hands ("Review of Clinical and Functional Neuroscience").
Although the functions of the SMA & pre-SMA overlap, they are generally thought to be responsible for different functions in the motor learning process:
The SMA is more active during performance of pre-learned sequences.
The pre-SMA is more active during the process of learning a motor sequence (Sosnik, Polyakov, & Flash, 2009). General function is to enable learned motor acts by modifying motor programs that are initiated in the cortex
Takes input from the cortex, modifies it and returns it to the cortex via the thalamus
Indirect role in the motor system
Connects to the prefrontal cortex, premotor cortex and secondary motor area simultaneously
Forms the corto-basal ganglia motor loop
Inhibitory direct pathway - Facilitates motion
Inhibitory indirect pathway - Restricts motion
Determines and controls the movements to be generated
Encodes and stores a long-lasting representation of a learned skill Diseases affecting the basal ganglia act to disrupt the balance between the 2 major pathways
Results in involuntary movements or impaired movements
Parkinsons's Disease - Reduction of dopamine in the brain due to damage to the dopaminergic pathway from the substantia nigra to the striatum
Causes an increase in output signals from the basal ganglia to the thalamus
Results is tremors, rigidity, and akinesia
Huntington's Disease - A loss of specific striatal neurons
Results in a decrease of output signals from the basal ganglia to the thalamus
Causes hyperkineticity (opposite symptoms of Parkinson's) Activates the desired motor program to facilitate the correct movement
Restricts other motor programs so the correct movement is made
Modifies the motor program depending on the external environment
Stores a representation of the cup stacking process (after cup stacking is learned)
Effects of Basal ganglia diseases on cup stacking:
Limits the movement of the hands and arms
Athetosis and akinesia
Causes involuntary movements of the hands and arms
Tremors and chorea From your team here at the McCNS Drive-Thru:
Marianne, Matt, Chelsey and Faris :) Enjoy and Have a Great Day! Structure Paired, symmetrical structure located between the midbrain and the cerebral cortex
Forms the lateral walls of the third ventricle
Composed of multiple nuclei that receive input from numerous cortical and subcortical structures
Limbic nuclei Function "Gateway to the cortex"
Relays all sensory information (except olfaction) from the sensory neurons of the body to the motor cortex
Relays limbic information from the body to the motor cortex
Transmits output from the basal ganglia to the motor cortex
Processes all sensory information and determines which is sent to the cerebral cortex Damage/Dysfunctions Dejerine–Roussy syndrome
Occurs after a stroke causes a lesion of the thalamus
Causes a lack of sensation on one side of the body
Lack of sensation can evolve into chronic pain
Parkinson's and Hutchinson's Disease
Causes a breakdown in the nerve channels of the thalamus
Slows down or stops the transmission of sensory information Role in Speed Stacking Inputs all sensory, limbic, and motor information from the external and internal environment
Determines which sensory, limbic and motor information is transmitted to the cerebral cortex Structure Damage/Dysfunctions Function Role in Speed Stacking Located in the parietal lobe and within the postcentral gyrus, a structure around the middle of the brain
Includes all of the neural receptors and pathways for the transmission of sensory information
Greater amount of sensory fibers than motor fibers Separated into three cortices:
Primary somatosensory cortex - Receives all nerve signals for the sense of touch
Secondary somatosensory cortex - Receives nerve signals from the primary cortex
Somatosensory association cortex - Processes associations between different senses Receives and interprets sensory neurons related to touch
Receives signals from several types of nerve cells including mechanoreceptors, thermoreceptors and nociceptors
Involved in proprioception which is used to determine the body's location in space
Involves the hippocampus Damage to the primary somatosensory cortex causes:
Decreased sensory threshold
Inability to recognize the properties of tactile stimuli
Inability to identify objects by touch
Lesions to the secondary somatosensory cortex cause a decrease in sensory discrimination
Damage to the somatosensory association cortex can cause tactile agnosia
Ability to recognize objects but not feel them
Damage to the parietal lobe can affect the somatosensory cortex
Can cause the brain to ignore its nondominant hemisphere
Leads to paralysis of one side of the body Interprets signals sent from the hands regarding the size and shape of the cup
Determines the location of your body, the table, and the cups in the surrounding space
Dysfunction of the somatosensory cortex and speed stacking:
Inability to grasp the cups
Inability to perceive the location of the cups Contains a one-to-one representation of human skin called a homunculus
Based on degree of sensory innervation
Hands and face are most sensitive Structure - In Latin = means "little brain"
- Posterior and inferior to cerebrum.
- Three lobes:
a) Anterior Lobe - spinal cord
b) Posterior Lobe - cortex
c) Flocculondular Lobe - proprioception
(Martini et al., 2009) Function in Motor Control - Exchange of information from sensory and motor corticies about movement characteristics. - Integration, regulation, coordination of movement. - Regulates posture, precision and timing of movement. - Acts as an internal clock and calculates movement speed times to sequence motor commands. Function in Speed Stacking - Body, arm and wrist movements are coordinated by the cerebellum. - During learning, movement pattern sequence is translated into procedural memory for fast retrieval. - It marries your current position in the speed stacking sequence with the end goal. - It adjusts movement error i.e error in stacking or sequencing
(Dubac, 2002). Consequences of Damage - Motion is still possible, only coordination impaired. - Disorder in motor learning and fine motor control i.e discontinuous stacking. - Loss of movement precision.
(Samuel, 2011). - Overestimation of movement; slow acceleration and braking. - e.g Drunk person trying to touch his/her nose
(Dubac, 2002). Structure Prefrontal Cortex: -Anterior most part of frontal lobe.
-It can be divided up into three divisions:
a) Orbitofrontal cortex
b) Lateral prefrontal cortex
c) Ventromedial cortex
(Martini, Timmons, & Tallitsch, 2009) Posterior Parietal Cortex: -Located in the parietal lobe.
-It has two sub-divisions:
a) Superior parietal lobule.
b) Inferior parietal lobule.
- Lies within close proximity to the somatosensory cortex
(Martini et al., 2009) Function Prefrontal Cortex: Posterior Parietal Cortex: - Highest level in the motor control hierarchy.
- Assesses decisions before choosing a motor command.
- Houses active, working memory.
(Michael, 2012) - Plays a role in VOLUNTARY movement.
- Assesses the context in which voluntary movements are made.
- Gathers somatosensory, proprioceptive and visual input = body position and target position.
- Generates internal movement models and send them to the pre-motor and primary motor cortex. Role in Speed Stacking Prefrontal Cortex: Posterior Parietal Cortex: - It will determine the most efficient way to transition from one sequence to another.
- When learning the speed-stacking sequence, the prefrontal cortex assists in working memory.
- Decides course of action during stacking. - Gathers information about the following:
* Cup size
* Cup texture
* Cup weight
-It helps distinguish the number of cups when they are stacked and unstacked.
-Based on this information it helps plan movement. Consequences of Damage Prefrontal Cortex: Posterior Parietal Cortex: - Difficulty in planning sequence of movement.
- Performer is unable to understand movement goal.
- Slow, purposeless stacking. - Apraxia
One form causes patients to make gestures spontaneously
Another form causes patients to have difficulty performing movements, even though they can describe them perfectly
- Uncoordinated cup stacking and incorrect movement patterns
The somatosensory, proprioceptive and visual stimuli will be inaccurately interpreted, causing a lack of information about the body and target positions. Structure Thin region located along the precentral gyrus, on the posterior side of the frontal lobe (1)
Connected with motor neurons of the spinal cord
Contains complete representation of skeletal and orofacial musculature
The model of this representation is called the homunculus
This model maps out the control of movement for the body parts (3) Function The location of efferent neural pathways which lead from the brain to the spinal cord and the muscles (2)
Generates neural impulses that control the movement of our limbs (2)
Divided into left and right hemispheres
Control opposite sides of the body Dysfunction/Damage Results in a lack of accuracy and/or speed of movements (3)
Affects ability to move parts of body independently (3)
Damage via a stroke or head injury can cause paralysis (3)
If left hemisphere is damaged, right side of body becomes paralyzed Role in Speed Stacking Transmits signals down the spinal cord to the limbs/muscles to be activated
Used to accurately and quickly stack the cups
Damage and Speed stacking:
Inhibits speed stacking movements
Lack of accuracy in movements (3)
Paralysis - loss of movement of one side of the body (3) Structure Composed of 31 segments (4)
Split into 4 regions: cervical region, thoracic region, lumbar region and sacral region (4)
Each controls a different part of the body
Specific components make up the vertebrae of the spinal cord
Central canal, grey matter, ventral and dorsal root, spinal ganglion and the spinal nerves (1,2)
Protected by 3 layers of tissue called meninges (3)
Dura mater, arachnoid mater and pia mater Function Transmits and receives efferent and afferent messages to and from the brain and body (4)
Initiates and coordinates reflexes of the limbs
Connects various organs, tissues and muscles with the brain Dysfunctions/Damage Loss of movement and feeling (4)
Depends on where the damage is located
Does not have to be severely damaged for this to occur
Can cause temporary or permanent loss of movement and feeling
Severe cases of damage causing paralysis: paraplegia (two limbs) and quadriplegia (four limbs) (4) Role in Speed Stacking Plays a very important role in speed stacking
Responsible for movement of fingers, hands, wrists, arms, shoulders, head (4)
Responsible for stability and breathing (4)
Damage and Speed Stacking:
Damage to any vertebrae from the C1-T1 can cause a loss of movement or feeling in the above structures (4) References (1) Dubuc, B. (2002, January). The motor cortex.
Retrieved from http://thebrain.mcgill.ca/flash/d/d_06/d_06_cr/d_06_cr_mou/d_06_cr_mou.html
(2) Schwerin. (n.d.). Brain connection: The anatomy of movement.
Retrieved from http://brainconnection.positscience.com/topics/?main=anat/motor-anat
(3) Brown. (2012). Neuroscience: Motor systems primary motor cortex.
Retrieved from http://www.acbrown.com/neuro/Lectures/Motr/NrMotrPrmr.htm References (1) QA International. (2012). Visual dictionary online: Structure of the spinal cord.
Retrieved from http://visual.merriam-webster.com/human-being/anatomy/nervous-system/structure-spinal-cord.php
(2) McCaffrey, P. (2008). Chapter 8: The spinal cord, spinal nerves, and autonomic nervous system.
Retrieved from http://www.csuchico.edu/~pmccaffrey/syllabi/CMSD 320/362unit8.html
(3) Algonquin College. (2012). Anatomy and physiology resource site.
Retrieved from http://lyceum.algonquincollege.com/lts/AandPResources/module7-5.htm
(4) Spinal cord 101. (n.d.).
Retrieved from http://spinalinjury.net/html/_anatomy_of_a_spinal_cord.html ("The posterior parietal") (Sonsik, Polyakov, & Flash, 2009) (Nudo, 2008) References
Algonquin College. (2012). Anatomy and physiology resource site. Retrieved October 17, 2012 from http://lyceum.algonquincollege.com/lts/AandPResources/module7-5.htm
Brown, A. (2012). Neuroscience: Motor systems primary motor cortex. Retrieved October 17, 2012 from http://www.acbrown.com/neuro/Lectures/Motr/NrMotrPrmr.htm
Clarence, S. (1995). Basal ganglia components and pathways. Retrieved October 18, 2012, from http://www.hitl.washington.edu/publications/prothero/node51.html
Dayan, E., & Cohen, L.G. (2011). Neuroplasticity subserving motor skill learning. Neuron, 72(3), 443-454.
Doyon, J., Bellec, P. et al. (2008). Contributions of the basal ganglia and functionally related brain structures to motor learning. Behavioural Brain Research, 199(2009), 61-75
Dubuc. B. (2002). The brain from top to bottom: Making a voluntary movement. Retrieved October 17, 2012, from http://www.thebrain.mcgill.ca/flash/a/a_06/a_06_cr/a_06_cr_mou/a_06_cr_mou.html
McCaffrey, P. (2008). Chapter 8: The spinal cord, spinal nerves, and autonomic nervous system. Retrieved October 17, 2012 from http://www.csuchico.edu/~pmccaffrey/syllabi/CMSD 320/362unit8.html
Nudo, R.J. (2008). Neurophysiology of motor skill learning. In J.H. Byrne (1st ed.), Concise learning and memory: the editor’s selection (pp. 527-546). Slovenia: Elsevier.
Primary somatosensory and motor cortex. Retrieved October 18, 2012, from http://www.ualberta.ca/~kejones/pubs/M1S1Cortex.pdf
QA International. (2012). Visual dictionary online: Structure of the spinal cord. Retrieved October 17, 2012, from http://visual.merriam-webster.com/human-being/anatomy/nervous-system/structure-spinal-cord.php
Review of Clinical and Functional Neuroscience Web site. (2006). Retrieved October 17, 2012, from https://www.dartmouth.edu/~rswenson/NeuroSci/index.html
Schwerin, D. (n.d.). Brain connection: The anatomy of movement. Retrieved October 17, 2012 from http://brainconnection.positscience.com/topics/?main=anat/motor-anat
Sosnik, R., Polyakov, F., & Flash, T. (2009). Motor sequences. In L. Squire, New Encyclopedia of Neuroscience (pp 1047-1056). Slovenia: Elsevier. Spinal cord 101. (n.d.). Retrieved October 17, 2012 from http://spinalinjury.net/html/_anatomy_of_a_spinal_cord.html
Note: Prezi does not allow for italicisation or indenting so the above is not in correct APA format. (Dubuc, 2002). (Review of Clinical and Functional Neuroscience, 2006) (Primary somatosensory and motor cortex, 2006) (Review of Clinical and Functional Neuroscience, 2006) (Nudo, 2008) (Review of Clinical and Functional Neuroscience, 2006) (Doyon et al., 2008) (Clarence, 1995) (Dubuc, 2002) (Clarence, 1995) (Doyon et al., 2008) (Clarence, 1995) (Review of Clinical and Functional Neuroscience, 2006) (Review of Clinical and Functional Neuroscience, 2006) (Wiki) (Clarence, 1995) (2)