NeuroPhys Unit 1

• Dura Mater
• -2 layers of fibrous connective tissue
• Arachnoid Mater
• -Subdural space under the dura mater
• Pia Mater
• -Delicate, clings to the brain

• Protection
• Blood brain barrier
• -Glucose, amino acids, electrolytes, fats and fat-soluble molecules move freely
• -Toxins, wastes, etc. do not

Executive functions; high order functions

• Somatosensory
• Initial processing of tactile and proprioceptive info
• Comprehension of language (works with temporal lobe)
• Spatial orientation and perception (a secondary role)

• Primary auditory cortex (Wernicke's Area)
• Visual association cortex - Higher order processing of visual info
• Includes Hippocampus and Amygdala (learning and memory)

• Primary visual cortex
• Visual association cortex - high order processing of visual info (extends into temporal lobe)

• Cingulate Gyrus and structures connected make up the Limbic System
• Emotional responses
• Memory

• Gustatory (taste)
• Autonomic
• Pain
• Emotional responses (to pain?)
• Language?

• Receives info on body position and muscles tension and visual input
• Coordinated muscles; sends info to cerebral motor cortex
• Also sends stimulus to the midbrain and thus the spinal cord

• Anterior lobe: leg movement coordination
• Flocculonodular lobe: input from vestibular system; controls eye movements and postural adjustments to gravity
• Posterior lobe: voluntary movements

• Autonomic, endocrine, emotional and somatic functions
• Promotes homeostasis

• vital functions - regulates blood glucose, salivation, vomiting, sneezing, coughing, and cardiovascular and respiratory functions
• Most sensory and motor tracts run through this

relays info to/from Hippocampus

• Upper portion of limbic system
• Helps regulate emotions and pain
• Drives the body's conscious response to unpleasant experiences
• Involved in fear and prediction (and avoidance) of negative consequences

Gateway to cortex; relay for sensory input

• Secretes melatonin
• Role in sleep-wake cycle and sexual behavior

Visual reflexes, auditory relay, startle reflex, releases dopamine, limb flexion

Transmits nerves from medulla oblongata to cerebrum, cerebrum to the cerebellum, and peripheral nerves to higher functions

Made of corticospinal, corticobulbar, and corticopontine fibers traveling base of midbrain

• Receives afferents from retina and visual cortex
• Role in directing visual attention and eye movements

Link to auditory system - sends fibers to medial geniculate nucleus

• Generate CSF
• Contain Cerebral Aquaduct = narrow channel that connects 3rd and 4th ventricles

• Protects the CNS - absorbs impact of injury
• Supplies water, amino acids, ions and chemical messengers, nutrients and removes metabolites from brain
• Formed in ventricles in Choroid Plexus

• Group of nuclei that includes the Caudate Nucleus, Putamen, Globus Pallidus, and Substantia Nigra
• Initiation and coordination of movements

• Associated with prefrontal area
• Mostly involved in cognition

Motor functions of Basal Ganglia

• Inhibitory axons to thalamus
• Major output structure of Basal Ganglia

Recollective memory and relay for impulses coming from the amygdala and hippocampi to the thalamus

• Part of motor system
• Correlation center for optic and vestibular impulses relayed to the globus pallidus

• Contains dopaminergic neurons
• Involved in motor control

• Connects to hypothalamus
• Regulates endocrine activity, sexual behaviors, food and water intake, and fear and aggression responses

memory

relays info for vision to thalamus and then to Occipital lobe

relays auditory info to thalamus and then temporal lobe

connects hemispheres

• Fibers form sensorimotor cortex
• Initiate movement, skilled volitional movement, modulate ascending systems

• Project to spinal motor neurons
• Motor control; but over time, role has been replaced by Corticospinal tract

• Guide head movements - activate cervical spinal circuits that control neck and back muscles
• Keep us upright - extensors of legs

moves head in response to stimulus

• Pontine = leg extension (antigravity)
• Medullary = releases antigravity muscles to move

Carry touch and proprioception info to brain stem

Convey pain and temp to thalamus

• Primary (first order) neuron
• -Receptor to CNS (DRG or equivalent)
• Secondary (second order) neuron
• -One level of CNS to thalamus
• Tertiary (third order) neuron
• -Thalamus to cortex

Motor cortex and motor tracts that descend into the cord

Alpha motor neuron to muscle or autonomic motor

• Apathy and indifference
• Spoken language
• Poor problem solving
• Memory loss
• Personality changes
• Antisocial behavior
• Disinhibition
• Motor impairments

• Loss of sensation
• Cant comprehend language
• Hemi-neglect = more common with right lesion
• Perceptual deficits

• Comprehension of language
• Auditory issues
• Learning and memory
• Lowest threshold for seizure activity

visual impairments

• Emotional impairments
• -Recognizing danger
• -Expression of emotions
• Memory

• Coordination
• Balance
• Vestibular issues

Death of brain cells due to lack of oxygen resulting from blocked or ruptured vessels (hemorrhagic or ischemic)

• Transient Ischemic Attack (TIA)
• Short term blockage of blood flow
• Damage isn't permanent; symptoms last less then 24 hrs
• Warning for a risk for major CVA

• Result of rupture of weakened blood vessels in brain
• Includes Aneurysm (ballooning of blood vessels) and Arteriovenous Malformation (AVM; abnormally formed blood vessels)

• Bleeding within the brain tissue
• Life threatening
• Causes
• hypertension
• arteriovenous malformations
• head traumas

• Bleeding in space between Pia Mater and Arachnoid membrane
• Causes
• Head trauma most common
• Cerebral aneurysms, Arteriovenous Malformation, and Hypertension

• Blockage of blood vessel supplying blood to brain
• Cerebral Thrombosis
• -Blood clot that develops at the site of the vessel
• Cerebral Embolism
• -Blood clot the develops at larger arteries and travel to blood vessels of the brain

• Sudden one sided weakness (limbs and facial droop)
• Visual Changes
• Confusion
• Sensory changes
• Trouble producing language or comprehending speech
• Headache
• Balance problems

• FAST
• Face
• Arms
• Speech
• Time

• Full communication
• Left sided weakness/dysfunction
• Impaired judgement
• Denial
• Impulsiveness
• Impaired attention
• Inappropriate socialization/behavior
• Problems with non-verbal communication
• May be seen as uncooperative, unmotivated, overly dependent
• Spatial perceptual deficits
• Left neglect
• Left inattention

• Aphasia (loss of ability to speak or interpret written or spoken word)
• Difficulty swallowing
• Slow movements
• Decreased initiation of/cautious movements
• Lack of motor planning or proper use of items (Apraxia)
• Rarely have right neglect or inattention

• Responsible for relaying sensation, motor signals, and spatial sense
• Symptoms
• Hearing noises
• Feeling ear pressure on opposite side
• Pain in opposite side of body (most common)

• Due to Posteriolateral Thalamus CVA
• Exhibit tendency to push away from the noninvolved side

• Midbrain
• Visual reflexes
• Auditory relay
• Startle reflex
• Releases dopamine
• Limb flexion
• Pons
• Transmits nerves from medulla and cerebrum, and from cerebrum to the cerebellum
• Medulla
• Sends ascending impulses through the brain stem and to higher functions
• Controls heart rate
• Vasomotor control
• Respiratory center

• No/limited response to stimulus
• May have spontaneous body movements
• Cause: Reticular Activating System

*Due to increased ICP

• Headaches
• Nausea
• Drowsiness
• Seizures
• -Blocked or abnormal electrical signals

*Depends on lobe/structures impacted

• Paralysis
• Memory and cognitive disorders
• Speech disorders
• Ataxia, dysarthria, apraxia
• Hormonal changes
• Etc.

• Fatigue
• Memory and cognitive changes
• Seizures

• Most common primary brain tumor
• Arise from meninges

• Symptoms/side effects
• Weakness in limbs
• Personality change
• Low vision problems
• Depends on location

• Inflammation in meninges of brain and spinal cord
• Infection in fluid surrounding brain and spinal cord
• CSF becomes thickened; causes blockage of ventricles
• Can lead to hydrocephalus or encephalitis

• Causes
• Viral infection
• Bacterial infection
• Chemical irritation
• Drug allergies
• Fungi

• Inflammation of the brain
• Usually occurs in first year of life; most severe in young and elderly

• Transmission
• Saliva
• Nasal discharge
• Feces
• Respiratory secretions
• Throat secretions

• Causes
• Viral infection most common
• Bacterial infection

Imbalance between how much CSF is produced, how much is absorbed into blood stream, and abnormal flow from brain to SC

• Contributing factors
• Congenital
• Lesions or tumors
• CNS infections
• Bleeding in brain from stroke or head injury
• Other traumatic injury to brain

• Shunt replacement 
• -Insertion of a catheter into the 3rd ventricle
• Pleural, peritoneal, or atrial drainage

• Group of rare disorders that develop in some people with cancer
• Rare
• Can affect any organ or tissue; nervous system itself is a common site
• Caused by typical cancers
• -Occur when the cancer fighting agents of the immune system attack nerve cells

• Treat the cancer
• Suppress immune response causing the neurological signs
• Medication 
• Immunosuppression by intravenous immune globulin
• Plasmapheresis
• -Remove plasma containing unwanted antibodies

• Mild
• Loss of consciousness for less than 30 minutes
• Severe
• Loss of consciousness longer than 30 minutes as well as loss of memory
• Irreversible brain damage

• Penetrating (open)
• Bullet or shrapnel
• Stab wound
• Skull fragment

• Closed
• Blow to head
• Falls
• Car accidents

• Epidural
• Damage to middle meningeal artery by a fracture to the temporal bone
• Subdural
• Damage to veins between cortex and dural sinuses from falls or car crashes
• Intracerebral
• Results from merging of contusions

Damage to impact site and opposite side of brain as well

• Damage throughout brain due to rotational/shearing effects
• Influx of calcium
• Cytoskeletal collapse disrupts transmissions
• Axon swells and breaks
• Distal axon degenerates

Primarily affects basal ganglia, superior cerebellar peduncle, corpus callosum, and midbrain

• Primary tissue damage from injury itself
• Secondary due to chemical process response of brain to injury 
• -Impaired regulation of cerebral blood flow
• --Increased lactic acid, membrane permeability, and edema
• -Impaired metabolism

Chronic depolarization due to reduced K+ channel activity in blood vessels

• Balance between delivery and consumption of cerebral oxygen can indicate severity of injury
• Critical threshold of oxygen pressure before neurons begin to die
• -15-10mm Hg PtO2

• Massive release of excitatory amino acid neurotransmitters
• Glutamate
• -Affects neurons, astrocytes, and causes overstimulation of glutamate receptors
• --Release of Ca²⁺, Na⁺, and K⁺
• --Breakdown of blood brain barrier
• --Increased metabolic demand

• Dangerous in a closed brain injury
• Pressure prevents blood flow and oxygen from getting to brain

• Sensory only
• Smell
• Lesions cause loss of smell (anosmia) or taste
• Test with Pocket smell test or other familiar aromas

• Sensory only
• Vision
• Test with standard vision tests
• Pathology often results in blindness

• Compromise the decussating fibers from both nasal hemiretinas
• Loss of peripheral vision in both eyes = Bitemporal Hemianopia

Affects the fibers of the ipsilateral nasal hemiretina

• Half of the ganglion cell axons projecting to the LGN decussate in the optic chiasm
• Loss of input from contralateral visual fields of both eyes (homonymous hemianopia)

Loss of contralateral visual fields in both eyes (homonymous hemianopia)

• Fibers of the optic radiation are considerably more spread out than those of the optic tract
• Damage normally only occurs to a portion of the geniculocalcarine tracts

• Eye and eyelid movement
• -Superior rectus, inferior rectus, medial rectus, inferior oblique, levator palpebrae superioris
• Autonomic - parasympathetic (pupillary constrictor)

• Compressive lesions are peripheral; usually dilate the pupil
• Ischemic lesions affect central portion of nerve and don't dilate
• If completely paralyzed, eyes will deviate to lateral
• Ptosis: eyelid droop

• Look for ptosis
• Test extraocular range of motion (H pattern)
• Test pupillary constriction with the light reflex

• Motor only
• Moves eye downwards and outward (superior oblique muscle)

• Sensory and motor
• 3 branches
• Ophthalmic
• Motor - eyeball, tear gland
• Sensory - eye lining, brow forehead
• Maxillary
• Motor - muscles of temple
• Sensory - side of forehead, cheek, mouth membranes, lower eyelid
• Mandibular 
• Motor - chewing muscles, salivary glands, anterior 2/3 of tongue
• Sensory - teeth and gums of jaw, external ear, temple, tongue (not taste)

• Anesthesia to half of the face
• Inflammation of cornea
• Chewing muscles paralyzed

• Touch cornea with cotton wisp
• Immediate closure of both eyelids should occur

• Tough face with a piece of cotton and a safety pin
• Positive test if impaired or absent sensation or inability to differentiate

• Patient performs mandibular protrusion, retrusion, and lateral deviation
• Positive test if impaired ability to move mandible through the specific motions

Pronounced jaw jerk reflex when mandible is tapped at a downward angle

• Motor only
• Lateral rectus

• Sensory and motor
• Controls most facial expressions
• Secretion of tears and saliva (all glands of head except parotid)
• Sensory for ear and tympanic membrane
• Special sensory - taste, anterior two thirds of tongue
• Bell's Palsy - often is self-correcting

• Wrinkle forehead and compare the two sides
• Shut eyelids and try to pry both open; compare
• Smile and compare both sides
• Purse lips or whistle

Pt is asked to distinguish between sweet and salty placed on the anterior portion of the tongue

• Sensory only
• Hearing and balance
• Aspirin, streptomycin and quinine can damage auditory nerve and cause bilateral hearing loss
• Compression due to blood causes temporary deafness; permanent deafness results from acute compression

• Distance from ear where patient can hear a ticking watch
• Positive by inability to hear at 18-24 inches or a significant bilateral difference

• Vibrating tuning fork is placed on the mastoid process, and then quickly around the ear hold
• Sound should be louder next to the ear hole

• Vibrating tuning fork placed against the middle of forehead
• Sound should be equally audible in both ears

• Sensory and motor
• Posterior 1/3 of tongue and pharynx
• Motor to Stylopharyngess muscle and parotid gland
• Taste and swallowing
• Sensory for internal surface of tympanic membrane and carotid body
• Injury causes loss of sour and bitter taste and impaired swallowing

• Tough pharynx with a tongue depressor
• Lack of gagging may be a positive sign

• See if patient can taste, especially sour and bitter, on posterior 1/3 of tongue
• Also inability to feel tongue depressor touch back of throat

• Sensory and motor
• Muscles of pharynx/larynx
• Parasympathetic motor to neck, thorax, abdomen
• Sensory from pharynx/larynx/viscera

Clinical presentation is hoarseness, difficulty swallowing

• Positive if unable to feel or lack of gagging when a depressor touches the pharynx
• If absent; uvula will deviate from lesion or not elevate if bilateral

• Motor 
• Some laryngeal muscles and some muscles of back and neck
• Hyperactivity causes torticollis

Positive if Inability to shrug shoulders against resistance or turn head back to center against resistance

• Motor only
• Positive test if pt can't fully protrude tongue or tongue deviates to the week side
• Test speech - have patient repeat a phrase with lots of r's in it or say la la la

• Cortical branches
• Personality changes
• -Flat, impulsive, confused, inactive, perseverative, cognitive probs
• -Contralateral Hemiplegia and sensory loss
• Deep branches
• Motor dysfunction

• Optic tract - homonymous hemianopia
• Sensorimotor cortex - contralateral hemiplegia and sensory loss
• Dominant/Left Hemisphere - language impairment, apraxia, cautious
• Nondominant Hemisphere - spatial relationships, neglect, nonverbal communication, distracted, poor judgement, impulsive
• Deep branches - contralateral hemiplegia affecting extremities and face equally

• Midbrain branches
• Contralateral hemiparesis
• Eye movement paresis/paralysis - double vision 
• Cortical blindness
• Deep branches
• Thalamic syndrome - severe pain, contralateral hemisensory loss, flaccid hemiparesis
• Hippocampus - declarative memory

• Damage = TIA
• Atherosclerosis is one of the main risk factors for ischemic CVA
• Contralateral weakness and/or sensory disturbance, ipsilateral blindness, and dysphasia, aphasia, or speech apraxia
• Cognitive impairment and decline

• Supply structures in the cerebrum
• Damages
• Hemiplegia on contralateral side
• Contralateral hemihypesthesia
• Homonymous hemianopia

• Supplies brainstem
• Damage - complete occlusion is death

Diminished/lack of oxygen to brain

• Symptoms
• Loss of consciousness or coma
• Persistent vegetative state
• Resemble TBI

• Short term memory loss
• -Hippocampus is very sensitive to lack of oxygen
• Poor executive functions
• -judgement making, reasoning, and processing info
• -impulsive and indecisive
• -lack ability to concentrate or focus on more than one task

• Weak point in blood vessel in brain
• Can rupture

• Causes
• Trauma
• Infection
• Hardening of arteries
• Congenital (most)

• Prior to rupture may do lumbar puncture
• May do nothing
• May clip or remove it
• May insert coils to block it off

• abnormal collection of blood vessels
• Lack the tiny capillaries
• Blood does not go to the tissues but is pumped through the shunt and back to the heart without ever giving nutrients to the tissues
• Risk of rupture and a stroke