Topic 8.2 - Visual and Motor Dysfunction Flashcards
Damage to the left hemisphere often results in loss of what abilities?
Loss of logical thinking ability, analytical skills, intellectual abilities, and communication skills.
What area of the brain is important for speech production?
Broca’s
What area of the brain is imporant for language comprehension?
Wernicke’s
Damage to the right side of the brain often results in what kind of impairments?
–> Impairs appreciation of music and art
–> Behavioural problems
–> Spatial orientation and recognition of relationships might be deficient
–> Self-care deficits are common
What is an early sign of acute brain disordors?
Changes in LoC
What is a vegetative state?
A loss of awareness and mental capabilities where the brainstem functions to maintain vitals and life.
Not responsive to external stimuli.
Do those in a vegetative state sleep?
Yes, they have a normal sleep/wake cycle
What is locked in syndrome?
Individual is aware and capable of thinking but is paralyzed and cannot communicate.
What cortexes are included in the frontal lobe?
The premotor cortex, motor cortex, and Broca’s area.
Which area of the brain can directly control movement via its projections to the spinal cord?
The primary motor cortex (M1)
–> This direct control is best developed in primates.
The motor homunculus matches what structure?
The topographic organization of the primary somatosensory cortex (S1).
Where does the corticospinal (pyramidal) tract run from?
Runs from M1 to the contralateral spinal cord and terminates directly on motor neurons and interneurons.
Which spinal cord tract can initiate movements and modulate spinal reflexes?
The pyramidal or corticospinal tract.
What is the role of the vestibulospinal pathway?
When the body tilts it activates vestibular afferents to the vestibular nuclei. In turn, these neurons activate the extensors of the opposite leg to prevent us from falling down.
What is the role of the tectospinal pathway?
To evoke the head turning reflex for strong unexpected visual stimuli. Initiated by neurons in the superior colliculus.
What is the role of the pontine reticular formation and its associated reticulospinal tracts?
To maintain standing posture while acting on the extensors of the lower limb.
What is the role of the medulla in reflexes and balance?
Antagonist to pontine standing reflex - liberates these muscles from reflex control.
What side of the body will be affected by upper motor neuron damage?
Side of body contralateral to the damage
What side of the body will be affected by lower motor neuron damage?
The side ipsilateral to the damage
What is decorticate posturing? what causes it?
Abnormal flexion of upper limbs with internal rotation of feet.
–> Usually occurs in person with severe damage to hemisphere.
What is decerebrate posturing? What causes it?
Abnormal extension of limbs and neck.
–> Occurs in individual with brain stem lesion.
What cortex is located in the parietal lobe?
Somatosensory cortex
What cortex is located in the occipital lobe?
Visual cortex
What cortexes are located in the temporal lobe?
–> Auditory cortex
–> Olfactory cortex
–> Wernicke’s area
Which regions of the body are more dense in somatosensory nerve endings?
Fingers & hands, lips & tongue
Optic fibers from which area of the right eye cross to the left side through the optic chiasm?
The nasal retina
Optic fibers from which area of the eye do not cross in the optic chiasm?
The temporal retina fibers stay on their associated side.
The input from the left and right eyes are kept separate in the…
Lateral Geniculate Nucleus
How many layers does the lateral geniculate nucleus have? Which layers receive input from which eye?
The LGN has 6 layers and receives input from the contralateral visual field.
—> 1, 4, 6 receive input from contralateral nasal retina
—> 2, 3, 5 receive input from ipsilateral nasal temporal retina
What is hemianopia?
Loss of vertical vision field.
Damage to the optic chasm would result in…
complete blindness (unless damage was partial)
Damage to one optic tract or half of the occipital lobe would result in…
Loss of visual field on side opposite to that of the damage
What is receptive or sensory aphasia? What causes it?
Inability to read or understand spoken language
–> Caused by damage to Wernicke’s area
What is expressive or motor aphasia? What causes it?
Impaired ability to speak or write fluently or appropriately
–> Caused by damage to Broca’s area
What is dysarthria?
Motor dysfunction that affects muscles used to articulate speech.
What is global aphasia?
Combination of expressive and receptive language
–> Major damage to all language centers and their communicating fibers
What is fluent aphasia?Which area of the brain is it associated with?
Speech of normal pace but using made-up words.
–> Wernicke’s area
What is non-fluent aphasia? What part of the brain is it associated with?
Patients have slow, labored short phrases
–> Broca’s area
What is agraphia?
Impaired writing ability
What is Alexia?
Impaired reading ability
What is agnosia?
Loss of recognition or association
Reduced arousal can be produces by brainstem lesion in the…
Reticular Activating System
What is the role of the cerebellum?
To integrate motor intention and command with sensor input.
Spinal segments are associated with corresponding body segments. What neurons are housed in the cervical enlargement?
Motoneurons necessary for control of arm and hand muscles
Spinal segments are associated with corresponding body segments. What neurons are housed in the thoracic enlargement?
Control of torso muscles - ventral horns are smaller in size
Spinal segments are associated with corresponding body segments. What neurons are housed in the lumbar enlargement?
Contains many motoneurons necessary for controlling leg and feet muscles.
Which spinal enlargement has the least motor neurons?
Thoracic segment
Muscles are controlled by motoneurons located in which horn on the spinal cord?
Ventral
What is the name of the interneuron that moderates spinal reflexes?
DI3
What might cause cervical spine injuries?
hyperextension or hyperflexion of the neck
Dislocation of the vertebrae may do what to the spinal cord?
Crush or compress it
Great force being applies to the top of the skull of feet can result in what kind of spinal cord injury?
Compression
What are the four classifications of spinal cord injuries?
Simple, compression, wedge, dislocation
What is a simple spinal cord injury?
A single line break
What is a compression spinal cord injury?
Crushed or shattered bone in multiple fragments
What is a wedge spinal cord injury?
A displaced angular section of bone
What is a dislocation spinal cord injury?
When a vertebrae is forced out of its normal position
How are vertebral fractures assessed?
Using dermatome map, which can assess movement and sensory responses to determine the degree of damage or recovery
Damage to nerves can be temporary or permanent, depending if axonal regrowth may occur. What situations would lead to permanent damage?
Complete transection (laceration of nerve tissue by bone fragments) or crushing of cord.
What are the two stages of a spinal cord injury?
Spinal Shock and Recovery
What occurs in the spinal shock phase of a spinal cord injury?
In the beginning of injury, all neurological activity is shut down and no reflexes are present
–> May persist for days or weeks
What occurs during the recovery phase of a spinal cord injury?
Gradual return of reflex activity.
At this point, the extent of the damage will slowly reveal.
Voluntary motor and sensory activity will present at level below the damage.
