Basic questions Flashcards
(96 cards)
1
Q
Traumatic Brain Injury
A
“injury from an external trauma to the head; when the head suddenly and send violently hits an object or when an object pierces the skull”
- can result in physical, cognitive, emotional and behavioural changes
2
Q
motivation
A
Processes that initiate and sustain goal-directed activity
- Goal directed behaviour eg. Deciding on a goal, Planning, Executing a plan, Evaluation of the plan
3
Q
amygdala
A
generates feelings and interprets facial expressions, body language and social signals
essential for social behaviour and important for emotional learning
4
Q
Social-Behaviour Circuit
A
recognise social disapproval, regulates self control, filters and selects relevant information from irrelevant and directs visual attention, taking in cues
ventral prefrontal cortex, head of caudate nucleus, substantia nigra reticularis, thalamus
5
Q
Emotion loop
A
integrates emotions with the roles of other loops and is partly responsible for the perception and experience of emotion
essential function of the Emotion Loop is seeking rewards
6
Q
what is consciousness?
A
Consciousness is having subjective experiences. It is a state of awareness of the self and the environment
- Consider the level of consciousness
- Also influenced by altered states
- Consider content of consciousness
7
Q
What are the neurotransmitters associated with consciousness?
A
seratonin - arousal level
norepinephrine - attention
acetylcholine - selection of object attention
dopamine - motivation
8
Q
what is the type of attention?
A
- Orienting- the ability to locate specific sensory information from among many stimuli
- Divided - the ability to attend to two or more things simultaneously
- Selective - the ability to attend to important information and ignore distractions
- Sustained - the ability to continue an activity over time
- Switching - the abukity to change from one task to another successfully
9
Q
short term memory
A
- maintains goal-relevant information for a short time
- essential for language, problem solving, mental navigation, and reasoning
mental multitasking requires working memory and is central to cognition
10
Q
declarative LONG term memory
A
- refers to recollections (memories) that can be easily verbalised/ declared
a. EPISODIC: episodic memory is the collection of specific personal events
b. SEMANTIC: common knowledge eg. names of countries
Declarative memory has 3 stages -
1. encoding - process information into a memory representation.
2. consolidation - stabilises memories.
3. retrieval - ability to find and accurately recall memories
11
Q
procedural LONG TERM memory
A
refers to recall of skills and habits
Practice is required to store procedural memories. Once the skill or habit is learned, less attention is required when performing the task
12
Q
memory loss
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AMNESIA > loss of DECLARATIVE memory
- most common causes - head injurysevere illness, dementia etc.
- Retrograde amnesia is the loss of memories for events that occurred before the trauma/ disease
- Anterograde amnesia is the loss of memories for events following the trauma/ disease
13
Q
dysarthria
A
difficulties executing the muscle movements for speech
14
Q
aphasia
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refers to difficulties with processing verbal or written language
15
Q
somatosensation
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Proprioception (sense of oneself) - information from the musculoskeletal system
Exteroception (sense of external world) - information from the skin
- interactions with environment
Interoception - information from internal organs
16
Q
Somatosensory receptors in skin/joint/muscle include an assortment of specialised receptors that only respond to specific stimulus:
A
Mechanoreceptors = are sensitive to physical distortion such as touch, pressure, stretch or vibration
Nocireceptors = are sensitive to pain
Thermoreceptors = are sensitive to change in temperature
Chemoreceptors = sensitive to chemical changes in the body
17
Q
sensory receptors in musculoskeletal system
A
muscle spindles
golgi tendon organs
joint receptors
18
Q
muscle spindles
A
- Muscle spindles are the sensory receptors/ organs (mechanoreceptors) within the skeletal muscle belly
- numerous intrafusal muscle fibers comprise a muscle spindle
- respond to muscle stretch
proprioception
19
Q
golgi tendon organs
A
- Golgi Tendon Organs are found in tendons near the musculotendinous junction
GTO’s detect force/ muscle tension generated during muscle contraction
20
Q
joint receptors
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respond to mechanical deformation of joint capsules and ligaments
21
Q
sensory nerve fibres
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LARGE diameter fibres - course touch, pressure, vibration, fine/light touch (tactile discrimination), proprioception
SMALL diameter fibres - pain and temperature large diameter fibres transmit signals faster where small fibres are slower
22
Q
receptive fields
A
each receptor monitors a specific area known as the receptive field
receptive field of a sensory neuron is the cutaneous (skin) area
LARGE fields = LOW sensitivity
SMALL fields = HIGH sensitivity
receptive fields tend to be smaller distally (thus denser) and larger proximally (less dense)
23
Q
primary sensory neurons
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somatosensory information from the bodies skin, muscles, joint capsules, and viscera are conveyed by dorsal root ganglion neurons of the spinal cord
24
Q
primary somatosensory cortex
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Primary somatosensory cortex is located in the post-central gyrus
Nerve fibres carrying proprioception information go to area 3
Nerve fibres carrying texture/ size/ shape information go to areas 1 & 2
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secondary somatosensory cortex
the secondary somatosensory cortex (area 40) is in the lower parietal lobe
stores and retains sensory info
this area receives connections from the primary sensory cortex
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three types of ascending tracts bringing in somatic information to brain
conscious relay
divergent relay
nonconscious relay
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conscious relay tracts
- transmit information about the location and type of stimulus with high fidelity
-high level of, and accurate details
- allows discrimination of information
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dorsal column medial leminiscus tracts
○ 1st order neuron:
-enters and ascends in dorsal column of spinal cord
-some collaterals head off in spinal cord
○ 2nd order neuron :
- cell bodies located in nucleus gracilis or cuneatus (in dorsal medulla)
- axons cross the midline (decussate) then ascend to the thalamus
○ 3rd order neuron:
- cell bodies located in the Thalamus send their axons to the cortex via the Internal Capsule
- synapse to cells in the primary somatosensory cortex corresponding to the body area they originated from
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spinothalamic tract
transmits info about FAST PAIN, and TEMPERATURE
○ 1st order neuron:
- brings information into the posterior horn (grey matter) of the spinal cord
○ 2nd order neuron:
- have cell body in posterior grey area of the spinal cord
- axons of secondary neurons cross the midline and ascend from the spinal cord to the thalamus (anteriolaterally)
○ 3rd order neuron:
- have cell bodies in the Thalamus
axons project from the Thalamus to the cerebral cortex
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Divergent Tracts
- transmission of slow pain
- information is transmitted to many locations in the brainstem and cortex
- is not localised, input is involved in arousal, attentional, motivational, sleep/ wake and reflexive functions
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Nonconscious (unconscious) relay Tracts
- transmits unconscious movement-related information to the cerebellum
- unconscious proprioceptive information, as well as sensory information from muscles, joints and ligaments
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visual pathway
neural visual pathway = optic tract travelling from eye to relay nuclei in thalamus (lateral geniculate)
primary visual cortex activate neurones that help discriminate shape, size and texture of objects
information is transferred also to secondary visual cortex - analysed for information on colour and motion
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muscles moving the eyeball
Eyeball will be moved by:
○ Superior rectus - pull eye up
○ Inferior rectus - pull eye down
○ Medial rectus - move pupil medially (horizontal)
○ Lateral rectus - -move pupil laterally (horizontal)
2 oblique muscles- posterior half of eyeball
○ Superior oblique
○ Inferior oblique
Nerve supply:
SO= CNIV, LR= CNVI, rest = CNIIO
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internal structures of the eye
FIBROUS layer
- sclera and cornea
VASCULAR layer
- choroid
- ciliary body muscles and suspensory ligaments
- iris - pupillary dilator/ constrictor muscle
NEURAL layer
- fovea, retina, photoreceptors and other neural cells
35
neural structures for taste
receptor cells in the papillae
cranial nerves VII, IX and X synapse in the Solitary nucleus in the brainstem
Synapse in the ventral posteromedial thalamus
Terminates in the Gustatory Cortex
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what is the loss of taste?
AGEUSIA
- influence food choices, sensory stimuli act as triggers, loss of taste may reduce appetite
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disorders of olfaction
Loss of smell = anosmia
Decreased sensitivity to odorants = hyposoma or olfactory hypesthesia
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neural structures with olfaction
sniffing brings air through nasal passages > some of this air passes over thin sheet of cells (olfactory epithelium) sitting high in the nasal cavity > olfactory epithelium exudes thin coat of mucus
odorance dissolve into the mucus > within mucus reach olfactory receptor cells olfactory receptor have an unmyelinated axon - when the olfactory axons group together this is the olfactory nerve
39
vestibular pathways
Simple pathway - information travels from receptors via processing to cortex provides
Perceptions of head orientation
multiple pathways reflect large role in balance and control of movement
40
Symptoms/ signs of vestibular dysfunction
Vertigo = conscious illusion of the world/ or themselves spinning or moving, feel as though swaying or tilting
Nystagmus = rapid, rhythmic repetitive oscillatory involuntary eye movements
Oscillopsia = lack of gaze stabilisation makes vision 'jumpy'/ blurry
Lateropulsion = gait leaning or turning to one side (usually fall towards side of peripheral lesion)
Gait ataxia = clumsy, poorly controlled voluntary movements
Nausea/ Vomiting/ sweating
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four basic types of eye movement
- Saccades - rapid, ballistic movements - abruptly change point of fixation
- Smooth Pursuit - slower, tracking movements
- Vergence - aligns both eyes fovea with objects at varying distances
- Vestibulo-ocular - stabilize the eyes relative to the external world
42
vestibular ocular reflex
Role:
- to stabilise visual images on the retina (gaze stability) during head movements
- ACTIVATED BY (VESTIBULAR INPUT) HEAD MOVEMENTS
Mechanism:
- as head turns, signals from the SC canals are relayed to the vestibular nuclei and onward along the pathway to exert extraoccular muscle control
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semicircular canals
- 3 fluid filled rings arranged perpendicular to each other
- Role: respond to rotational acceleration/ deceleration of the head (change in velocity)
- The Crista Ampullaris is the sensory organ within the semicircular canals
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Hair Cells within the Vestibular Labyrinth
- Tranduction: converting, tilt, acceleration, and velocity into neural signals
- Mechanical deformation of stereocilia and the kinocilium causes depolarisation of hair cell
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Why is the vestibular system important?
Provides conscious perception of:
- head orientation/ position relative to gravity
- sense of 'movement' acceleration/ deceleration of the body
Has an essential role in two areas of motor function:
- postural control - postural adjustments
- control of eye movements - gave stabilisations
role in autonomic function and consciousness
46
meniere's disease
- affects the whole labyrinth - usually from increased endolymph in membranous labyrinth
- intermittent hearing loss/ changes (including tinnitus) as well as symptoms related to vestibular system - vertigo etc.
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hearing impairments
Otis media (with effusion)
middle ear infection (with fluid/ swelling)
Otosclerosis
fusion of the ossicles due to abnormal bony overgrowth
Presbycusis
the loss of high-frequency hearing with age
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conductive hearing loss
disorders of the external ear (eg. canal blocked by cerumen/wax) or middle ear - sound air wave not able to transmit to the inner ear
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Sensorineural Hearing Loss
disorders of the inner ear (haircells included), cochlear nerve or central connection
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auditory function in CNS
primary auditory cortex is the site of conscious awareness of the intensity of sounds
secondary auditory cortex - compares sounds with memories of other sounds, then categorises the sounds as language, music or noise
Wernicke's area is where comprehension of spoken language occurs - left temporal lobe
51
CONSCIOUS HEARING
cochlear nerve transmits to:
music to medial geniculate body
light to lateral geniculate body
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UNCONSCIOUS pathways
To the SUPERIOR COLLICULUS brainstem (midbrain) - orient to sound
To the RETICULAR FORMATION brainstem (medulla, pons, midbrain - arouse to sound
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converting sounds to neural signals
sound waves strike eardrum
ossicles move and cause vibration of membrane > movement of fluid in upper chamber
vibration of basilar membrane and hair cells
hair cells depolarise
activate cochlear nerve
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basal ganglia - structure
Basal Ganglia is a collection of 5 anatomical and functionally related grey matter st.
- caudate
- putamen
- globus palidus
- subthalmic nucleus (STN)
- Substantia nigra
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basal ganglia functions
1. Goal directed behaviour loop (non-motor)
2. Social behaviour loop (non-motor)
3. Emotion loop (non-motor)
4. Motor loop (motor)
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basal ganglia function in movement control
- Regulates desired and inhibits undesired movements
- Sends information back to the motor cortex via the thalamus
- Regulates muscle tone (force) and many other things
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two pathways in Basal ganglia allow:
- Accelerator: Direct pathways allow movements (white boxes)
- Brake: Indirect pathway prevents undesired movements (black box)
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dysfunction in basal ganglia
Hypokinetic movement disorder
eg. Parkinson's disease
Hyperkinetic movement disorder
eg. Huntington's disease
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cerebellum - pass information via three cerebellar peduncles
Superior cerebellar peduncle = Midbrain. Primarily cerebellar efferent fibres - via thalamic nuclei to cortex
Middle cerebellar peduncle = Pons. Entirely afferent fibres - information to cerebellum from cerebrum
Inferior cerebellar peduncle = Medulla. Afferent and efferent fibres - afferent from spinal cord, vestibular apparatus, efferent to vestibular nuclei and reticular formation
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blood supply - basilar artery gives rise to:
Anterior inferior cerebellar artery (AICA)
Superior cerebellar artery (SCA)
Posterior inferior cerebellar artery (AICA)
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cerebellum functions
coordinates human movement (includes direction, timing/ speed and force)
Maintaining posture and balance
Coordination of voluntary movement: coordinates the timing and force and synchronisation of different muscle groups to produce fluid movement
Motor learning: adapts and fine tunes motor programs eg. darts
Cognitive -x well understood
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Spinocerebellum
because of extensive connections with spinal cord
Role in making anticipatory, corrective and responsive adjustments or otherwise movement would be uncoordinated
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Vestibulocerebellum
- located in the flocculonodular lobe
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Cerebrocerebellum
- extensive connections with cerebral cortx
role in timing movements, planning movements and coordination of voluntary movement
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dysfunction signs in vestibulocerebellum
unsteadiness
truncal ataxia
nystagmus
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dysfunction signs in spinocerebellum
intention tremor
ataxic gait
dysarthria
dysmetria
...etc.
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dysfunction signs in cerebrocerebellum
finger ataxia
dysathria
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Huntington disease
an inherited neurodegenerative disorder which initially affects the basal ganglia nuclei (caudate & putamen).
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neural changes in HD
death of the neurons of the caudate and putamen (striatum)
also affects neurons in the cerebellum, thalamus
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HD impairments
movement disorder eg. dyarthria
cognitive disorders eg. attentional
emotional and behavioural eg. anxiety
communication disorders eg. decreased complexity
sleep disorder
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BRIEF summary - dysarthria and dysrpaxia
Dysarthria
- umbrella term referring to speech movement disorders
Dyspraxia/ Apraxia of speech
- refers to impairment with the capacity to plan or program speech
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dyspraxia
- inconsistent speech sound errors in repeated productions of syllables and words. > variability
- disrupted and/or lengthened co-articulatory transitions bw sounds and syllables
- impaired prosody
- groping movements
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dysarthria
results in abnormality in different aspects of movement including strength, range, tone, accuracy of movement
can impact any of the muscles utilised in speech production
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corticobulbar tract
arises from primary motor cortex
for voluntary control of muscles for speech
UMN synapses to lower motor neurones in CN nucleus in brainstem >> LMN then innervates muscles for speech, face, tongue and pharynx and larynx
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outcome of lesions on CBT
UMN - direct activation pathway
- lesion in the primary motor cortex or internal capsule eg. stroke
LMN/ final common pathway
- lesion/ pathology from brainstem (eg. stroke) to muscle function
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Location and function of cortical motor areas for speech production
Pre-motor cortex
- role in PLANNING movement
Broca's area
- role specifically in planning speech movement
Supplementary motor area
- programming movement sequences
Primary motor cortex
- responsible for execution of the movement
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neural basis - cortical sensory area for a swallow
Primary somatosensory cortex
- located on the post-central gyrus
- receives sensory information from multiple sources
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Classes of movement
1. voluntary
- complex actions
- purposeful and goal orientated
2. rhythmic motor patterns
- combines voluntary and reflexive acts - chew, walking and running
- initiation and termination is voluntary
- once initiated, are repetitive and reflexive
3. reflexes
- involuntary, rapid, stereotyped movements: gag reflex
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ORAL PREP
ORAL PREPRATORY
- food is kept in front part of mouth > moistened with saliva
- voluntary
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ORAL OESAPHAGEAL
- cricopharyngeal muscles closes up to prevent regurgitation
- oesophageal muscles use peristalsis- coordinated muscle contraction and relaxation to move bolus down to stomach
involuntary
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ORAL TRANSIT
- tongue raises up against hard palate while back on tongue drops to allow bolus to move to the back of the mouth
- soft palate raises up while closing off passageway to nose, preventing regurgitation
- voluntary
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ORAL PHARYNGEAL
- rapid sequential activity where bolus is propelled into oesophagus
- larynx elevates while epiglottis flips down to protect airway
- pharyngeal muscles contract to squeeze bolus downward
- involuntary
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corticospinal tract - UMN
UMN cell bodies are found either in the Primary motor cortex (see motor homunculus) or the brainstem
pathways originating from the cortex include: CORTICOspinal tract and CORTICObrainstem (a.k.a corticobulbar) tract
pathways originating from the brainstem: vestibulospinal, reticulospinal, rubrospinal and tectospinal
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corticospinal tract
Origin:
Primary motor cortex (as well as supplementary, premotor area and somatosensory cortex)
Terminate:
on lower motor neurons (alpha motor neurons) in anterior (aka ventral) horn of the spinal cord
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function of corticospinal tract
voluntary control of precise movement involving distal muscles of limbs (lateral CST)
control of less precise movements of proximal muscles of limbs and trunk (medial CST)
small percentage of CST projects to doral horn to modify sensory information
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corticobrainstem
Terminate:
Cranial nerve motor nuclei in brainstem which includes:
Origin:
lateral aspect of primary motor cortex
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function of corticobrainstem
serves as UMNs to all motor cranial nerves
facilitates voluntary control of all the aforementioned cranial nerves (LMNs)
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motor unit
- one alpha LMN and all the muscle fibres it innervates
-when one neuron fires ALL of the muscle cells which are stimulated by that neuron will also contract
- the strength of a muscle contraction is determined by the size and number of motor units being stimulated
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what is the relationship bw motor units and motor homunculus
Inverse relationship with the motor homunculus
LARGER cortical tissue (ie. more UMN cell bodies) = SMALL motor unit
SMALLER cortical tissue (ie. less UMN cell bodies) = LARGE motor unit
90
UMN dysfunction
paralysis of paresis of affected muscles
hypertonia: increase in muscle tone
spasticity
hyperreflexia
muscle atrophy: wastage (with disuse)
impaired postural control
involuntary muscle contractions
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LMN dysfunction
- loss of fractionation of movement - with CST involvement
- paralysis or paresis of affected muscles
- hypotonia (decrease in muscle tone)
- flaccidity
- hyporeflexia
- muscle atrophy - wastage (with disuse)
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reflexes
reflex is an involuntary motor response to an external stimulus
can be protective (eg. avoiding hazardous situations)
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secondary motor areas
Pre-motor cortex
- receives input from sensory areas
- role in planning movement ("P" stands for)
- related to sensory input/ sensory guidance of movement
- spatial guidance of movement
- lateral in our frontal lobe
Supplementary Motor Cortex
- sequencing movement
- feeds correct motor instructions in correct sequence to
the primary motor cortex
active during mental rehearsal of coordinated movements
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Primary motor cortex
Structure - Aka Area 4, M1
- located in the pre central gyrus (frontal lobe)
- houses upper motor neurons
- executes commands to motor neurons
- stimulation elicits simple movements of single joints
organised
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Principles of experience-dependant neuroplasticity
- Use it or lose it
- Use it and improve it
- Specificity
- Repetition matter
- Intensity matters
- Time matters
- Salience matters
- Age matter
- Transference
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Neural recovery after injury
- neurons in PNS can regenerate if injury is just to the axon
- cannot regenerate in CNS > damaged neurons results in cell death
Why can nerves regenerate in the PNS not the CNS?
- debris from damaged axons is cleared much quicker and more efficiently in the PNS compared to CNS
