BIOL 320 Lecture Notes - Lecture 10: Lateral Globus Pallidus, Basal Ganglia, Striatum
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Example of convergent evolution
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there doesn't seem to be many options to create this kind of region
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PFC takes in a bunch of inputs and sends it out to a bunch of areas, e.g. basal ganglia!
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REMINDER: tomorrow's conference will be review for Monday's midterm
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(cont.)
Highly conserved across species
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We'll be focusing mostly on dorsal striatum & pallidum
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BASAL GANGLIA
All tetrapods have these divisions
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What about more distant species? e.g. where lampreys split off
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So lampreys were prior to emergence of bony skeleton—we share a very old ancestor with them
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In mammals; there's a pallidal portion (Pall), there's also an external globus pallidus (GPe) and lots of connections between Str + Pall
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do we see the same sort of structures in lampreys? Yes!
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There are some hints of GPe and STN in the middle species, but still not sure
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Not much data on in
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between species
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Similar cell-types with similar chemoarchitecture. Similar morphologies and markers, e.g. medium spiny neurons, cholinergic
neurons, GABAergic interneurons
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Why do we think they're the same?
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10. Basal Ganglia
February 7, 2018 11:37
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So looking at morphology of these different neurons as well as their activity
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very similar across species!
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So, we have this similarity in morphology and also connectivity, and in fact a lot of similarity in function for basal gangli
a!
Similarity at all levels of analysis we can think of
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General framework: cortical-basal ganglia-thalamic loop
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Connectivity
Also receive strong dopaminergic input
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These connections/loops are present across species. What changes is the weight, i.e. how much input is given, changes
across species
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Amphibians/lampreys: s
ome
input from DP, some from amygdala, neither are very strong, but very strong input from thalamus!
Weight is highest from thalamus-Basal ganglia and back. This makes sense!
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Birds/reptiles: more input from cortex. Not as strong an input from thalamus (relative to amphibians).
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Mammals: almost no output to pretectum//tectum. Really strong output to thalamus and strongest input from cortex. Loop
structure!
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Cortex coming in in blu, thalamus in green, basal ganglia in red
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So overall… the boxes are the same. And there's so additional boxes
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but we have 3 main boxes present throughout. And we're
changing the thickness of the lines (either going in or out).
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Document Summary
Example of convergent evolution there doesn"t seem to be many options to create this kind of region. Pfc takes in a bunch of inputs and sends it out to a bunch of areas, e. g. basal ganglia! Reminder: tomorrow"s conference will be review for monday"s midterm (cont. ) We"ll be focusing mostly on dorsal striatum & pallidum. What about more distant species? e. g. where lampreys split off. So lampreys were prior to emergence of bony skeleton we share a very old ancestor with them. There are some hints of gpe and stn in the middle species, but still not sure. Similar morphologies and markers, e. g. medium spiny neurons, cholinergic neurons, gabaergic interneurons. So looking at morphology of these different neurons as well as their activity (cid:1372) very similar across species! So, we have this similarity in morphology and also connectivity, and in fact a lot of similarity in function for basal ganglia! Similarity at all levels of analysis we can think of.
