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Transcript of PTA 217
Determining intelligence & personality
Producing & understanding language Cerebellum
Motor Coordination Thalamus
Executive Assistant Hypothalamus
Regulates body systems
Maintain homeostasis Limbic System
Controls emotion and learning Brainstem Midbrain
Visuomotor functions, visual reflexes, auditory relays, motor coordination Pons
Bridges the cerebral cortex with the medulla
Auditory and vestibular (balance), sensory and motor
Input-output of sensory and motor information to and from the CNS-PNS (Peripheral Nervous System)
peripheral parts are not encased in the vertebral column or skull Sensory System
Conveys information from the skin and musculoskeletal system to areas of the brain Autonomic System
Provides bidirectional communication between the brain and smooth muscle, cardiac muscle, and gland cells. wikipedia.com wikipedia.com Mayoclinic.com juliadovgy.com neuroskills.com Thought coordination Essential for: Heart Rate Breathing Sleep wake fotosearch.com clker.com wordpress.com columbia.edu columbia.edu Medulla
Connects the spinal cord to pons
Autonomic function (breathing, heart rate, etc.) columbia.edu Spinal Cord PNS mstrust.org.uk clipart.dk.co.uk alinenewton.com cytochemistry.net learninglab.co.uk Astrocytes
Found throughout CNS
Maintain neuronal signaling
Form Blood-Brain Barrier (BBB) histology.leeds.ac.uk Oligodendrocytes
Form a white coat known as the myelin sheath which insulate axons. course1.winona.edu Schwann Cells
Form a myelin sheath that insulates neurons
Act as phagocytes when PNS is inflamed. http://faculty.southwest.tn.edu Glial Cells
supporting cells for neurons 3 important cells Astrocytes - CNS
Oligodendrocytes - CNS
Schwann Cells - PNS Motor System
transmits information from the brain to skeletal muscles medical-dictionary.thefreedictionary.com editthis.info/psy3242/Hippocampus Hippocampus
Part of the Limbic System
Important for “verbalization” memory Dorsal Columns
Carry sensory information including discriminative touch and conscious proprioception. Uses a three-neuron relay
Primary or first-order neuron.
Secondary or second-order neuron.
Tertiary or third-order neuron. neuroanatomy.wisc.edu changepain-emodules.com Primary/First-order
Neurons transmits information from the receptors to the medulla.
Neuron's proximal axons enters spinal cord via the dorsal root.
Ascends in the ipsilateral dorsal column. Fasciculus Gracilis
Axons from the lower limb occupy the medial part of the dorsal column. Fasciculus Cuneatus
Axons from the upper limb occupy the lateral part of the dorsal column. Nucleus Gracilis
Cell bodies of the 2nd-order neuron.
Axons that rise in the fasciculus gracilis synapse with 2nd-order neuron in the nucleus gracilis of the medulla. Nucleus Cuneatus
Cell bodies of the 2nd-order neuron.
Axons that rise in the fasciculus cuneatus synapse with 2nd-order neuron in the nucleus cuneatus of the medulla. Secondary/2nd-order
Neurons transmits information from medulla to the thalamus.
Cell bodies are located in the nucleus gracilis and cuneatus as mentioned earlier. Medial Lemniscus
Transmits proprioceptive information from the spinal cord to the thalamus VPL
Nucleus of the thalamus where second-order neurons end. Tertiary/3rd-order
Neurons connect the thalamus to the sensory cortex.
Axons form part of the thalamocortical radiations.
Thalamocortical axons travel through the internal capsule. Somatosensory Pathways Anterolateral Columns
Contain axons that conveys discriminative pain and temperature information. jaaos.org studyblue.com Temperature Sensation
Warmth and cold are detected by specialized free nerve endings of small myelinated and unmyelinated neurons. mnmeditations.wordpress.com A Delta Fibers
Carry impulses produced by cooling. C Fibers
Carry information regarding heat Spinothalamic Tract
Conveys info from anterolateral spinal cord to the thalamus. bioon.com In the Spinothalamic Pathway of Temperature Sensation First order - neuron branches to spread vertically to adjacent segments of the spinal cord
Second order - then synapse occur in the secondary neurons in the dorsal horn , then ascend contralaterally to the VPL nucleus of the thalamus.
Third order - axons project from thalamus to the sensory cortex. Pain
Composed of both protective sensation and emotional response to it. drmayzels.com Spinothalamic Pain
& Spinolimbic Pain - Both occur in acute pain
- Both impulses convey fast and slow pain travel together in the anterolateral section of the spinal cord
- End paths become separate in the brain Pain Pathway Divergent Pathways
Transmit information to many parts in the brainstem and cerebrum.
Aching pain is a form of sensation that is conveyed via divergent pathways in the CNS. Spinomesencephalic
Carries nociceptive information to two areas: 1. Midbrain - the superior colliculus
2. Cerebral Aqueduct - the periaqueductal gray Spinoreticular Tract
Ascending neurons synapse in the brainstem reticular formation. Reticular Formation
Modulates attention, sleep/wake cycles, and arousal. www.thebrainwiki.com Spinolimbic Tract
Convey slow pain information to the medial and intralaminar nuclei in the thalamus
Axons project to the anterior cingulate cortex and the posterior insula. Spinolimbic projects to areas of cerebral cortex involved with: -emotions
-as well as to the
amygdala lburridge.pbworks.com Trigeminoreticulolimbic Pathway First neurons are the C fibers in the trigeminal nerve, which synapse in the reticular formation with ascending projection neurons.
These neurons project to the intralaminar nuclei.
The projections of the intralaminar nuclei are similar to the spinolimbic pathways, which projects to many areas of the cerebral cortex. Unconscious Tracts Bring unconscious proprioceptive and other movement related information to the cerebellum Spinocerebellar Tracts Information conveyed by these tracts is important for adjusting movements
It is used for unconscious adjustments to posture and movements.
Information is from proprioceptors, spinal interneurons, and descending motor pathways High-Fedelity Pathways
Somatotopically arranged information in the cerebellar cortex. 1. Posterior Spinocerebellar Pathway
2. Cuneocerebellar Pathway Posterior Spinocerebellar
Pathway Transmit information from the legs and the lower half of the body . First order neuron travels in the dorsal column to the thoracic or upper lumbar, then synapse in the area of the dorsal gray matter called nucleus dorsalis that extends vertically from spinal segments T1 to L2. Cuneocerebellar
Pathway Transmit information from the arms and the upper half of the body . The synapse between first- and second-order neurons occurs in the lateral cuneate nucleus, a nucleus in the medulla analogous.
Second-order neuron then enters ipsilateral inferior peduncle, and end in the cerebral cortex. Internal Feedback Tracts Monitor the activity of spinal interneurons and of descending motor signals from the cerebral cortex and brainstem.
Also convey info about the activity of spinal reflex circuits 1. Anterior Spinocerebellar Tract
2. Rostrospinocerebellar Tract Anterior Spinocerebellar
Tract Transmits information from the thoracolumbar spinal cord.
Tract begins in the lateral and ventral horns.
Axons ascend to the midbrain.
Leaving the midbrain, axons enter the cerebellum via superior cerebellar peduncle. Rostrospinocerebellar
Tract Transmits information from the cervical spinal cord.
Ascend to the ipsilateral cerebellum.
Enters the cerebellum via both the inferior and superior cerebellar peduncles. Two-types of Feedback biosingularity.com The Motor System The Motor System
will cover the following: bio2.rwth-aachen.de Medial Upper Motor Neuron Tracts -Signals lower motor neurons that innervate postural and girdle muscles. -These tracts are located in the medial white matter of the spinal cord. These tracts include Tectospinal Tract
Medial Corticospinal Tectospinal Tract - This tract arises from superior colliculus of the posterior midbrain.
- Superior colliculus processes visual, auditory, and somatic information
- Neural activity - superior colliculus stimulates neurons that activates LMNs in the cervical spinal cord to signal muscles that reflexively turn the head toward a sound or a visual stimulus. Medial Reticulospinal Tract - This tract begins in the pontince reticular information.
- It facilitates ipsilateral LMNs innervating postural muscles and limb extensors.
- Both the reticulospinal and tectospinal neurons are influenced by cerebral cortex, forming corticoreticulospinal and corticotectospinal pathways. Medial Vestibulospinal Tract - Medial vestibular nuclei receive information about head movement and position from the vestibular apparatus (figure below), located in the inner ear.
-Axons of these tracts are projected bilaterally to cervical and thoracic levels and affect activity in LMNs controlling neck and upper back muscles. medical-dictionary.thefreedictionary.com Lateral Vestibulospinal Tract - The lateral vestibular nucleus responds to gravity information from the vestibular apparatus.
-Axons of these tracts are projected ipsilaterally and to facilitates LMNs to extensors while inhibiting LMNs to flexors.
-When a person is upright, the tracts are continuously active to maintain the center of gravity over the base of support responding to the slightest destabilization. - The medial & lateral Tracts with their functions
- Upper Motor Neuron (UMN) lesion signs/symptoms
- Lower Motor Neuron (LMN) lesion signs/symptoms
- Progression of information during a reflex Medial Corticospinal Tract -The tracts descend directly from cerebral cortex through internal capsule and the anterior branstem.
- Axons synapse only in the cervical and the thoracic cord (does not reach the lower spinal cord) and convey information to LMNs that control neck, shoulder, and trunk muscles. Lateral Upper Motor
Neuron Tracts - Signal LMNs that innervate distally located muscles used for fine movement.
- Tracts control limbs fine movements and limb flexion descend in the lateral spinal cord and synapse with laterally located motor neuron pools in the ventral horn The lateral tracts that descend into the spinal cord are: Lateral Corticospinal
Lateral Reticulospinal Lateral Corticospinal Tract - This tract arises in the supplementary motor, premotor, and primary motor cerebral cortex.
- It's unique contribution is fractionation of movements, the ability to activate individual muscles indepedently of other muscles.
- Fractionation is essential for normal movement of the hands. Rubrospinal Tract - It originates in the red nucleus of the midbrain.
- Descend through pons, medulla, and spinal cord then synapse with LMNs primarily innervating upper limb flexor muscles. Lateral (Medullary) Reticulospinal Tract - The tract originates in the lateral reticular formation and descends bilaterally.
- This tract facilitates flexor muscle motor neurons and inhibits extensor motor neurons.
- The rubrospinal and lateral reticulospinal tracts both receive input from cerebral cortex. Corticobulbar Tracts - Arises in the motor areas of the cerebral cortex, then project to cranial nerve nuclei in the brainstem.
- It facilitates LMNs innervating the muscles of the face, tongue, pharynx, larynx, and the sternocleidomastoid & trapezius. Motor Neuron Lesions Lesion - an area of damage or dysfunction; a pathologic that be structural or functional. UMN lesions signs/symptoms
LMN lesions signs/symptoms Common locations of neuron lesions UMN Lesions
signs/symptoms LMN Lesions
Loss of reflexes
Loss of fractionation of movement
Muscle hyperstiffness Paresis - Partial loss of voluntary contraction
- Prevalent in post-stroke, spinal cord injury, and spina bifida. Abnormal Reflexes Babinski's sign - extension of the great toe, often accompanied by fanning of the other toes. Muscle Stretch Hyperreflexia - absence of the moderating influence of UMNs into LMNs causes excessive muscle contraction when muscle spindles are stretched. Clonus - Involuntary, rhythmic, repeating muscle contractions. Clasp-knife response -resistance drops at a specific point in the ROM when a paretic muscle os slowly and passively tautened. Muscle Hyperstiffness - Excessive resistance to muscle stretch. Muscle stiffness is caused by:
Overactive neural input to the muscles Hyperstiffness - is a resistance to both active and passive muscle stretch. Paralysis - Complete loss of voluntary contraction. Atrophy - Loss of muscle bulk hughston.com Fibrillations - Rapid, un-synchronized , and irregular contraction of muscle fibers. Progression of information
during a reflex Reflex - an involuntary response to an external stimulus (see fig. 1). **Clinically, reflexes provides crucial details about the peripheral and spinal circuits, and the level of background excitation in the spinal cord. Figure 1: Reflex tutorvista.com Spinal Region Reflexes -Requires sensory receptors, primary afferents, connections between primary afferents & LMNs, and muscles. - Can operate without brain input; however, normally signals from the brain influences spinal reflexes by adjusting the background level of neural activity in the spinal cord. Two reflexes involved in this section - Stretch Reflexes
- Cutaneous Reflexes Stretch Reflexes - Muscle contraction elicited by stretch of the spindle. Two-types of
stretch reflex 1. Phasic - muscle contraction in response to quick stretch.
2. Tonic - muscle contraction in response to a stimulus that last longer and is maintained. Cutaneous Reflex - Also elicit reflexive movements. Withdrawal reflex - usually occurs in response to a painful cutaneous stimulus, muscles are activated to move the body part away from the stimulation. www.youtube.com/watch?v=RLe9koPfVoo www.youtube.com/watch?v=F871bBWS4oY Autonomic Nervous
System Autonomic Nervous
System Maintain homeostasis by regulating to activity of internal organs, glands, and vasculature.
Regulates body's circulation, respiration, digestion, metabolism, secretions, body temperature, and reproduction. Efferent Pathways Afferent Pathways Information from visceral receptors enters the CNS by two routes: 1. Spinal cord via the dorsal roots.
2. Brainstem via cranial nerves 1. Sympathetic System
2. Parasympathetic System Autonomic effectors use a two-neuron pathways, with the 2 neurons synapse in a peripheral ganglion.
classified in two types Peripheral Nervous
System Spinal Region Sympathetic Nervous
System The preganglionic motor neurons of the sympathetic system arise in the spinal cord. They pass into sympathetic ganglia which are organized into two chains that run parallel to and on either side of the spinal cord. Sympathetic System
Functions i. Maintains optimal blood supply to body
ii. Body Temperature and Blood to Muscle, increase metabolism of Cells
iii. Pupil Dilation, HR/Contractility
iv. GI system decrease blood
v. Contracts sphincters
vi. “Fear” – Fight or Flight Parasympathetic Nervous System The main nerves of the parasympathetic system is the tenth cranial nerve, the vagus nerve. It originate in the medulla oblongata. Other preganglionic parasympathetic neurons also extend from the brain as well as from the lower tip of the spinal cord. Parasympathetic System Functions i. Energy Conservation and Storage
ii. Slows HR, Bronchiocontricts
iii. Increased GI activity
iv. No innervation to limbs or body wall
v. Sacral Spine
-Emptying of bowel and bladder
-Erection of sexual organs becomehealthynow.com drugline.org Autonomic Control Centers Limbic System - autonomic response due to emotion
Hypothalamus - Main visceral sensory and Cranial Nerves
Solitary Nucleus - master controller of homeostasisMedulla - heart rate and blood vessels
Pons - respiration Pathology of the Autonomic System Spinal Cord level that each of the following is lost 1. Bowel, bladder, & genital fxn
2. Temp regulation and BP control
3. Heart rate, BP control, and respiration Brainstem Lesions Interfere with descending control of blood pressure, heart rate, and respiration.
Also affect crania nerve nuclei, interferring with constriction of the pupil, production of tears, salivation, or regulation of thoracic and abdominal viscera. Spinal Region
Lesions Complete lesions above the lumbar (L1-above) obstruct voluntary control of the following: 1. Bladder,
2. Bowel, &
3. Genital Function Spinal Region
Lesions Complete lesions above the midthoracic (T6-above) isolate much of the cord from control by the brain, jeopardizing homeostasis by interfering with BP regulation and temperature control. Autonomic Dysreflexia Also called as mass reflex, is an excessive activity of the sympathetic nervous system, elicited by noxious stimuli below the lesion. Occurs in spinal cord injured patients at T6 or higher. Autonomic Dysreflexia health-pic.com Autonomic Dysreflexia
SIGNS/SYMPTOMS becoming clammy
disorientation Autonomic Dysreflexia
INTERVENTIONS •Sit patient up – why? To minimize increased blood pressure affects on brain•Remove stimuli•Check Vitals•Call 911 parentsexpert.com Nerve Plexuses Cervical Plexus
Sacral Plexus Cervical Plexus - Sensory posterior scalp to the clavicle
- Innervates the anterior neck muscles and diaphragm http://www.frca.co.uk
Phrenic Nerve: ONLY motor supply and main sensory nerve for the diaphragm. Brachial Plexus - Branches into radial, axillary, ulnar, median and musculocutaneaous nerves
- Innervates entire upper limb wikipedia.com C1-C4 C5-T1 Lumbar Plexus - Innervates skin and muscles
- Anterior and medial thigh, medial leg and foot
- Sciatic Nerve branches from this plexus www.nysora.com L1-L4 Sacral Plexus - Can be part of Lumbosacral Plexus
- Injury typically due to fall
most of the leg and foot
Peroneal Peripheral anesthesiauniverse.net The Basal Ganglia & Cerebellum 3 areas of the cerebellum and their function 1. Vestibulocerebellum
3. Cerebrocerebellum Vestibulocerebellum Vestibulo = inner ear - Influences eye movement and postural muscles.
- Head and neck postural control with visual inputs
- Regulates equilibrium Spinocerebellum Spino = spinal cord - Influences gross limb movement.
- Ambulation and postural Cerebrocerebellum Cerebro = cerebral cortex - Influences fine, distal and voluntary motor movements.
- Regulates reaching and grasping actions. 3 types of Ataxia 1. Trunk Ataxia
2. Limb Ataxia
3. Gait Ataxia Trunk Ataxia Gait Ataxia Limb Ataxia Ataxia - voluntary, normal-strength, jerky, and inaccurate movements that are not associated with hyper-stiffness. Lesions of the vestibulocerebellum - Gaze control in peripheral vision
*typically causes nystagmus (rapid eye movement) - Head and Neck postural control with visual inputs
*head positioning Lesions of the cerebrocerebellum Controls: fine, distal, and voluntary motor movements Dysfunctions:
*Gait and limb Ataxia
*Action tremor Lesions of the Spinocerebellum Gait and Trunk Ataxia
* WBO's - wide based support
* Wavering forward line of progression
* Look intoxicated cueflash.com Basal Ganglia http://webspace.ship.edu/ - Regulates motor planning
*muscle contraction and force
*Multi-joint and sequencing of movement - No direct connections with LMN's
- Uses the neurotransmitter: DOPAMINE
*Enhances or inhibits quality of movement waiting.com The Brainstem 3 parts of the brainstem and its function 1. Medulla
3. Midbrain Medulla Pons Midbrain Reticular Activating System *Awareness of self and surroundings
* Alertness, sleep, and attention -Sleep/Wake cycle control Regulates consciousness andrewwales.blogspot.com/ 4 D's of the Brainstem Dysfunction - Dysarthria
- Dysmetria from inferior to superior - The most inferior part of the brainstem It coordinates:
* Cardiovascular and Respiratory Control
* Head movement with eye movement
* Swallowing - Maintenance of Vital Signs dreveterinary.com - midsection of the Brainstem - "Bridge" between the cerebellum hemispheres - Sensory Analysis and involved in cranial nerves V-VII "Process motor information and relays information to the cerebellum" Upper portion of the Brainstem - Involved with Basal Ganglia
- Pain Control
- Auditory Information "Relay information from cerebral cortex to cerebellum and spinal cord" The Cerebral Cortex - The 5 areas of the cortex and their functions
- Wernicke’s and Broca’s Areas and their functions www.brainhealthandpuzzles.com/ 5 Areas of Cerebral Cortex 1. Primary Sensory
2. Sensory Association
3. Motor Planning
4. Primary Motor
5. Association Cortex Primary Sensory Cortex Sensory Association
Cortex - Preparation of movement components Motor Planning Cortex Primary Motor Cortex - Execute the movements Association Cortex - Controls behavior, interprets sensation, and processes emotions and memories. - Tells the brain details pure sensory information sciencedefined.wordpress.com/ -Identifies the sensory stimulation to the name of something. ex. clear, fresh, soft liquid, and cold you feel when you wash your face is called water. http://thebrain.mcgill.ca/ http://www.dana.org/ http://www.indiana.edu/ Wernicke's Area - Comprehension of spoken language - Subregion of the left parietotemporal cortex. http://www.agefotostock.com/ Broca's Area - Instructions for language output. - located in the left frontal lobe http://www.mm-theory.com/ THE END ;-)