Topic 11 Flashcards
Where does paresis occur due to lesions in the primary motor cortex and premotor cortex?
Primary Motor Cortex (M1) lesions:
Damage- paresis of the effected area is the homunculus
Recovery- Slow, beginning in axial and proximal muscles, gradual improvement toward digits
Maintain- movement of the trunk and arms (premotor cortex); the ability to learn/ remember motor sequences (SMA)
Loss- Manuel dexterity—-independent digit control
Premotor Cortex:
Damage- paresis of axial and proximal muscles
Recovery- preform slow complex motor sequences
Loss- interferes with complex movements depending on afferent—
ex. visually guided movements (PP)
What does over activity in the subthalamic nucleus and Glob us Pallidus internus & Sustantia l Nigra par Retriculata do to the excitatory input to the cortex?
Leads to reduced excitatory input to the cortex. This is because hey are part of the indirect pathway, which ultimately inhibits movement. Excessive inhibition contributes to the movement difficulties in Parkinson’s disease.
How does deep brain stimulation (DBS) alleviate the symptoms of Parkinson’s Disease?
Deep brain stimulation (DBS) involves implanting electrodes in specific brain regions, such as the subthalamic nucleus (STN) or globus pallidus internus (GPi), and delivering high-frequency electrical stimulation. This disrupts the abnormal activity in these areas, effectively reducing the excessive inhibition of movement and improving motor symptoms like tremors, rigidity, and bradykinesia (slowness of movement)
What is the difference between open- and closed Loop DBS with respect to the control of the stimulation?
Open loop: delivers continuous stimulation regardless of the patient’s current brain activity or symptoms. This is the more traditional approach.
Closed Loop: Monitors brain activity and adjusts the stimulation parameters in real time based on the patient’s needs. This allows for more personalized and responsive treatment, potentially improving effectiveness and reducing side effects