L4

Question 1

Diencephalon

Answer 1

Pineal gland- only site of melatonin synthesis; Habenula- regulates DAergic (VTA, SN), NAdergic (LC) and 5-HTergic (Raphe) nuclei; Thalamus- main relay for everything going into the cortex (posterolateral- parvo, anteromedial- magno); Subthalamic nucleus- part of nigrostriatal pathway (indirect) to thalamus and motor cortex; Hypothalamus- homeostasis (front most nuclei from POA); Pituitary gland- HPA

Question 2

Telencephalon

Answer 2

Pallium- laminar homogenous ish structure (I-VI), gyri and sulci form w expansion; Sub-pallium- forms nuclear structure, highly heterogenous, clusters form basal nuclei (LGE, MGE, POA)

Question 3

What are the divisions of the telencephalon based on?

Answer 3

Main neuronal cell type
Pallium: excitatory Glu-ergic pyramidal Ns
Sub-pallium: inhibitory GABAergic INs
POA- AChergic Ns

Question 4

Pallium- isocortex

Answer 4

Exterior; 6 layers; frontal, parietal, occipital, temporal lobes

Question 5

Pallium- proisocortex

Answer 5

Interior; modified layers; cingulate cortex (no IV, limbic), insular cortex (multi layer III, gustatory, emotion, homeostasis), parahippocampus (~3-5 layered, perirhinal and enterhinal cortices)

Question 6

Pallium- allocortex

Answer 6

Internal; primitive, 3 layered; hippocampus (limbic, memory, spatial), piriform olfactory cortex and olfactory bulb (actually external)

Question 7

Pallium expansion step 1

Answer 7

(Cortex expansion) Dorsolateral expansion causes outward expansion of isocortex; dorsal midline internalised by expansion, lateral edges tucked underneath; pallium now has distinct subdomain which generate different brain regions; dorsal pallium (iso) folds in on itself to form gyri and sulci; medial and lateral pallium (proiso) folds to a lesser extent; ventral pallium form allo (front and back) w pallial nuclei (middle); cortical hem also forms allo (HC)

Question 8

Pallium expansion step 2

Answer 8

Expansion along r-c axis causes pallium to bulge caudally over diencephalon and mesencephalon; occurs throughout r-c axis; all regions increasingly curved w/r to others; combinatoin of caudal bulding and rotation causes temporal lobes to end up inverted on bottom sides; temporal lobes have split at midline to pass brainstem

Question 9

Pallium expansion step 3

Answer 9

Flexures also straighten to ensure telencephalon flips back ~90 degrees so eyes point forwards not down; midline cells that buckled inside form chloroid plexus-> these expand laterally (ventrally to cingulate), chloroid plexus cells now line ventricle (split into 2 lateral ventricles at midline)

Question 10

Sub-pallium

Answer 10

Mostly forms corpus striatum (caudate nucleus + putamen (tadpole)); caudate follows lateral ventricular curve, runs above amygdala in temporal lobe; Amygdala is complex and multinculear (caudal pallial, LGE, POA); septum-
, olfactory tubercle, NAc (ventral), caudate dorsal) and putamen (dorsal + lentiform), globus pallidus (lentiform)