Cortex - Lecture 2 Flashcards
What is the role of the Subthalamic Nucleus (STN) in Parkinson’s disease?
The STN is targeted for Deep Brain Stimulation (DBS) to relieve motor symptoms of Parkinson’s disease. DBS modulates STN activity to improve motor control.
What are the three primary functional subdivisions of the STN?
The motor, associative, and limbic subdivisions.
How does the STN impact motor function?
The motor subdivision of the STN influences motor inhibition and movement control, and lesions here can cause involuntary movements like hemiballismus.
What type of neurotransmitter is primarily used by the STN, and what effect does it have?
Glutamate; it provides excitatory signals within the basal ganglia, particularly impacting motor control regions.
Describe the role of dopamine in STN function.
Dopamine influences the STN by modulating activity related to reward and motivation. Dysregulation in dopamine affects STN function and is related to symptoms in Parkinson’s disease.
What imaging techniques are used to study the STN, and what is their primary limitation?
Structural and functional MRI, as well as in vivo imaging, are used. A primary limitation is the low anatomical detail, which complicates precise analysis.
How does DBS impact other functions outside of motor control in Parkinson’s patients?
DBS can have effects on mood, motivation, and behavior, sometimes causing neuropsychiatric side effects, such as apathy, hypomania, or changes in emotional regulation.
What are calcium-binding proteins, and why are they significant in STN studies?
Calcium-binding proteins, like parvalbumin and calretinin, are markers used to differentiate neuronal populations within the STN, supporting theories of functional zonation.
Describe the role of tracing studies in understanding STN connectivity.
Tracing studies help map anatomical connections within the STN, providing insight into the convergence and overlap of motor, associative, and limbic circuits within this nucleus.
What neuroanatomical changes are noted in Parkinson’s disease within the STN?
The STN does not degenerate in Parkinson’s, but its dysregulated activity due to loss of dopaminergic input from the substantia nigra contributes to motor symptoms.
Explain the significance of the indirect pathway involving the STN.
The indirect pathway, with the STN as a relay, helps regulate motor control by modulating inhibitory output through connections with the globus pallidus and substantia nigra.
What are the two main methods used in STN studies for anatomical and functional analysis?
Histological (post-mortem studies) and imaging (MRI, in vivo) methods are commonly used, each with strengths and limitations regarding anatomical detail and connectivity insights.
What are GABAergic inputs, and what is their role in the STN?
GABAergic inputs inhibit STN neurons, balancing excitatory signals and contributing to the regulation of motor output within the basal ganglia.
What challenges do researchers face in studying subdivisions within the STN?
Challenges include variability in findings across species, limited observations, and technical limitations in identifying precise subdivisions within the STN.
How does STN activity differ between obsessive-compulsive disorder (OCD) and Parkinson’s disease?
STN firing rates are lower in OCD compared to Parkinson’s, indicating functional differences within the STN subdivisions for different conditions.
Why is the tripartite subdivision hypothesis of the STN debated?
Some researchers argue that the motor, associative, and limbic subdivisions overlap, challenging the notion of clear, anatomically separated zones within the STN.
What is the relationship between beta-band activity and the STN in Parkinson’s disease?
Increased beta-band activity in the STN is associated with motor dysfunction in Parkinson’s, particularly in the dorsal STN region.
Describe how event-related potentials (ERPs) are used in STN studies.
ERPs help assess STN responses to emotional stimuli, with dopamine medication impacting ERP magnitude, especially in the ventral STN.
What is the role of high-resolution MRI in STN-targeted DBS?
High-resolution MRI aids in precise DBS electrode placement within the STN, enhancing the specificity of treatment and reducing side effects.
What future research directions are suggested to better understand STN functions?
Future studies are encouraged to explore anatomical overlap within subdivisions, improved imaging techniques, and computational modeling to clarify parallel versus convergent pathways.
What are the two main types of cortex in the human brain?
Neocortex and allocortex.
What are the subdivisions of the allocortex?
Archicortex and paleocortex.
What is the field called that studies the differences between cortical regions based on cell type distribution?
Cytoarchitectonics.
Who developed the concept of Brodmann areas and in what year?
Korbinian Brodmann in 1909.
