Quiz 5 Flashcards
Which neurotransmitter is important for muscle contractions?
Acetycholine
What is apraxia?
Inability to perform voluntary movements
What part of the brain is critical for procedural memory?
Basal Ganglia
Major structures involve in motor movement.
Primary motor cortex - this structure is responsible for motor movement execution
Parietal cortex- becomes active before making the movement, meaning it plans the movement before it is executed. ( damaged to this region results in apraxia and contralateral neglect)
Dorsolateral prefrontal cortex- it is involve in strategy making (similar to parietal cortex function)
Secondary motor cortex- this structure helps initiate motor movements ( initiation of motor movements)
Premotor cortex- externally generates motor movements (catching a ball when is thrown at you)
Supplementary motor area- works as a sequencer and planner (voluntary movements)
Basic organization of primary motor cortex and somatosensory motor cortex.
Somatotopic organization- things attached close to each other on body are similarly mapped out on brain
Disproportionate Representation: more premotor cortex area dedicated to areas of body used the most (hands, face muscles)
Plasticity: with the constant use of a body part, brain representation of that body part expands
Lateralization: left primary motor cortex controls motor function in right side of body (vice versa)
Precentral Gyrus
Somatosensory Cortex: somatotopic organized in terms of layout Postcentral Gyrus Disproportionate Representation Plasticity Lateralization
What is the knee-jerk-reflex? ( state other possible terms to refer to this reflex)
Tap on the knee–> sensory nerve responds to muscle stretch–> sends signal to spinal cord–> connects to motor neuron from single synapse–> motor neuron stimulates quadriceps to contract and reduce stretch.
This reflex is also known as the monosynaptic stretch reflex
Which are the positive symptoms of PD?
Tremor at rest ( usually appear as disease progresses not when onset takes place)
Muscular rigidity
Involuntary motor movements
Oculogyric crisis- eyes tend to shift involuntary to one side and freeze for a few seconds
Dyskenisia- decrease in voluntary movements and increase of involuntary movements, similar to tics or chorea.
Which are the negative symptoms of PD?
Disorders of posture(fixation)- odd positions
Disorders of locomotion
Disorder of speech
Akinesia (moderate to later)is the inability to initiate movement, due to problems with selecting and activating motor programs in the brain. It is a common consequence of Parkinson’s disease caused by dopamine loss in the direct pathway of movement.
Masked facial expression- emotionless expresion
Festination- involuntary tendency to take short steps while walking, accelerating steps while walking
Bradykinesia - abnormal slowness in movement.
Hypokinesia - abnormally diminished motor function or activity.
What is festination?
Hard time engaging walking, but once it starts it is hard to slow down.
What is the cogwheel rigidity?
Occurs when there is also a tremor and is characterized as “stop and go” effect during range of motion maneuver . (Sort of stop motion effect)
In PD, how do tremors change as disease progresses? Do tremors stop during some behaviors?
Tremors start in one limb and are mild, however! As PD progresses tremors will worsen. The tremors may transfer to the other side of the body and is not unilateral anymore.
Tremor usually stop as patients try to reach for something or try to execute volitional movement, meaning that once an action is executed (e.g., reaching for an object), the tremors may cease temporarily.
What neurotransmitter is depleted in patients with PD? How can you get a measure of dopamine levels in a living PD patient?
Dopamine (DA)
In patients with PD, DA levels are left at 10% ( due to cells dying in the substantia nigra)
Measuring levels of homovanillic acid in urine (urine test). HMA is a DA metabolite. Higher volumes of it mean higher volumes of DA being metabolized.
What is the primary drug use to treat patients with PD? Why is this drug use rather than dopamine?
L-Dopa is used to treat patients with PD because it can cross the blood barrier. The problem with dopamine is that it get metabolized before it crosses the blood barrier. L-Dopa is often paired with Cardidopa, which prevents L-Dopa from being metabolized. In addition, some negative effects of this drug is that patients develop some psychotic symptoms similar to those of schizophrenia and that it helps patients just for a while, but then the drug has no effect on treating PD and patient tend to get worse. Its targets are rigidity and bradykinesia, it has no effect on posture or balance.
Review PD with dementia. When do the symptoms of dementia begin in patients with PD with dementia?
30% of patients get this (develop this condition)
70 years+ develop this disease, usually after 10-15 years of first onset at age 60 patients are diagnosed with PD
Psychotic symptoms : hallucinations
PD: mild cognitive impairment
Do PD patients who do not show dementia still show some level of cognitive impairment?
Show attention and cognitive problems, executive functioning problems
Memory problems: there is a major decrease in procedural memory
Visuospatial line orientation test
Patients show prospective, episodic, short term memory, procedural, source and retrieval memory dysfunction as well.
