Neural Function

what’s an example of altered cerebral perfusion

STROKE

• reduced blood flow to brain tissue

what’s an example of abnormal electrical activity

SEIZURES

• disorganized neuronal firing in the brain

what’s an example of developmental brain injury

CEREBRAL PALSY

• early damage to spinal cord pathways

what’s an example of interruption of neural pathways

SPINAL CORD TRANSECTION

• damage to spinal cord pathways

what’s an example of neurodegeneration

PARKISON’s, ALS

• damage to spinal cord pathways

what’s an example of demyelination

MS

• damage to myelin affecting nerve conduction

what does cerebral injury often produce?

symptoms on the opposite side of the body

somatic nervous system

control voluntary movements and reflex arcs

autonomic nervous system

controls involuntary regulation

what is the cerebrum responsible for?

thinking, sensation, voluntary movement, and language

• left hemisphere dominates language

what is the cerebellum responsible for?

• balance and smooth movement

• posture and coordination

if there’s damage to the cerebellum what occurs?

ataxia, uncoordinated movement

what is the brainstem responsible for?

• controls vital autonomic functions

• heart rate

• breathing

• blood pressure

• contains pathways connecting the brain and spinal cord

what is the frontal lobe responsible for?

• reasoning

• behavior

• thinking initiation

• movement

• speaking

• memory

what is the parietal lobe responsible for?

• understanding spatial relationships

• knowing right from left

• sensation

• reading

what is the temporal lobe responsible for?

• understanding language

• behavior

• memory

• hearing

what is the occipital lobe responsible for?

• vision

• color

• blindness

what regions are involved in the posterior cerebral circulation (vertebrobasilar system)?

• posterior cerebral

• basilar artery

• vertebral artery

vertebrobasilar insufficiency (VBI)

decreased blood flow to the brainstem, cerebellum, and posterior brain

what is the middle cerebral artery (MCA) responsible for?

motor, speech, face/arm weakness

anterior circulation of cerebral circulation

internal carotid → MCA

• supplies large portion of the cerebrum

• EX: most ischemic strokes involve the MCA

posterior circulation of cerebral circulation

vertebral-basilar system

• supplies brainstem, cerebellum, and posterior brain

brain metabolism

uses 20% of body’s O2 supply

• neurons rely on aerobic metabolism

ischemic stroke

85%

• obstruction of cerebral blood flow by a thrombus or embolus

• leads to cerebral infarction

hemorrhagic stroke

15%

• caused by rupture of a cerebral artery

• leads to bleeding, intracranial pressure

transient ischemic attack (TIA)

temporary interruption of cerebral blood flow without permanent tissue injury

• symptoms usually last minutes to hours

where do strokes occur?

most commonly in the MCA

• results form internal carotid artery disease

why do strokes occur?

• atherosclerosis → plaque narrows cerebral arteries

• carotid artery stenosis → reduced cerebral blood flow

• aFib → blood stasis → embolic clot to brain

what happens to brain tissue during stroke?

• penumbra = ischemic brain tissue that is injured but still salvageable

• core infarct → neurons die within minutes if perfusion is not restored

what are complications of a stroke?

cerebral edema → increases ICP

• Cushing’s Triad (sign of increased ICP):

  • bradycardia, irregular respirations, hypertension

cardioembolic stroke (Atrial Fibrillation)

clots forms in heart → embolus travels to brain

large artery atherosclerotic stroke (Carotid Stenosis)

plaque narrows carotid artery → reduced cerebral blood flow or clot formation

effects of an arterial rupture (hemorrhagic stroke)

• blood enters brain tissue → compresses & displaces neurons

• bleeding triggers vasospasm in nearby vessels → ischemia

what are the causes of a hemorrhagic stroke?

HYPERTENSION

• ruptured aneurysm: often in the Circle of Willis

what is a severe headache usually an indicator of?

hemorrhagic stroke

what is the diagnosis of a stroke?

non-contrast CT scan to differentiate ischemic vs. hemorrhagic stroke

treatment of an ischemic stroke

tPA if within 3-4.5 hours

• aspirin

treatment of a hemorrhagic stroke

• control ICP

• reverse anticoagulants if present

• clipping/coiling

neurons

specialized cells that generate and transmit electrical signals

acetylcholine (ACh)

muscle movement, memory, & learning

serotonin

mood and sleep

GABA

primary inhibitory (slowing) neurotransmitter in the CNS

Glutamate

primary excitatory (stimulating) neurotransmitter

disease pattern of a seizure

sudden onset, usually brief episodes

• often followed by a postictal phase of confusion or fatigue

what is cerebral palsy?

non-progressive brain injury occurring during fetal development, birth, or early infancy

• damage affects areas responsible for motor control and muscle tone

clinical manifestations of cerebral palsy

• abnormal muscle tone

• poor coordination & balance

• delayed motor milestones

• possible speech, swallowing, or cognitive difficulties

what is spinal cord transection?

interruption of spinal cord pathways due to traumatic injury

• loss of communication between brain and body below the level of injury

• affects motor, sensory, & autonomic function

clinical manifestations of spinal transection

• paralysis below level of injury

• loss of sensation below injury

• bowel & bladder dysfunction

what is Parkinson’s Disease?

progressive loss of dopamine-producing neurons in the substantial nigra (midbrain)

• dopamine loss → relative excess of ACH activity

• leads to tremor, rigidity & slowed movement

TRAP for Parkinson’s

• T: Tremor: at rest

• R: Rigidity: cogwheel resistance

• A: Akinesia/Bradykinesia: slowed voluntary movement

• P: Postural Instability: impaired balance & shuffling gait

is there a treatment for Parkinson’s

NO

what is Amyotrophic Lateral Sclerosis (ALS)?

progressive degeneration of upper & lower motor neurons

• muscle weakness, atrophy, & loss of voluntary movement

• advanced disease can lead to respiratory failure (diaphragm weakness)

is there a cure of ALS?

NO

what is Multiple Sclerosis (MS)?

autoimmune demyelination of the CNS

• T-cell mediated attack damages myelin sheath

  • results in plaque

clinical manifestations of MS

motor

• weakness, balance problems, gait disturbance

sensory/visual

• numbness & tingling, blurred vision or optic neuritis

Other

• fatigue, cognitive changes

risk factors of MS

• females

• Northern Europeans

• living in cooler climates

• genetics

• possible viral triggers