Question | Answer |
Pyramidal neurons | NT=Glutamate; apical dendrite points to cortex surface; axon points down. III, V, VI |
Spindle neurons | NT= glutamate; in deep cortical layers; axon points down, leaves cortex; dendrites go to superficial surf. of cortex; VI |
Granular interneurons | NT=GABA; multiple short neurites; II, IV |
Cells of Marinotti | NT=glutamate; deepest layer of cortex; AXON POINT UP to superficial cortical layers; VI |
I | Molecular layer: synaptic layer; extra- intra-cortical axons and dendrites |
II | External granular layer: granule cells |
III | External pyramidal layer: pyramidal cells increasing in size as you go deeper |
IV | Internal granular layer: dense granular cells |
V | Internal pyramidal layer: large and medium pyramidal cells |
VI | Multiform layer: variety, pyramidal, spindle, Marinotti cells |
Homotypical cortex | Has all six layers, including defined internal granular layer (IV) |
Heterotypical cortex | AGRANULAR CORTEX, almost no int.gran.layer (IV). KONIOCORTEX: granular cortex reduced int. pyramidal (V)layer, but enlarged internal gran. layer (IV) |
Homotypical cortex example | prefrontal association cortex, stuff anterior to Brodmann 6. |
Heterotypical cortex example | AGRANULAR: primary motor cortex = Brodmann's area 4. KONIOCORTEX: primary visual cortex, Brodmann 17. |
Hippocampus | only 3 cortical layers; I, V, and VI |
Primary sensory areas | Visual, auditory, somatosensory. |
Sensory association areas | Visual association; auditory association, somatosensory association |
High order association areas | Parieto-temporal; prefrontal; limbic. |
Motor association areas | Areas 6 & 8 |
Primary motor regions | Area 4 |
Cortex Inputs | From modality-specific thalamic nuclei; from association thalamic nuclei; from non-specific thalamic nuclei; from brainstem (modulatory monoaminergic & cholinergic); from same hemisphere cortex (association); from other hemisphere cortex (commissural). |
Modality specific thalamic nuclei | VPL, VPM geniculate nuclei to primary sensory areas; VA and VL nuclei to motor cortex; anterior and lateral dorsal limbic thalamic nuclei to cortical limbic areas. |
Association thalamic nuclei | Dorsomedial, pulvinar, and posterior nuclei to association cortex (multimodal sensory info) |
Nonspecific thalamic nuclei | Reticular, intralaminar, midline to most cortical areas (involved in sleep/wakefullness) |
Brainstem | Modulatory monoaminergic and cholinergic inputs to multiple areas of cortex |
Association | from same hemi |
Commissural | from the other hemi |
Cortex gives rise to: | association/commissural fibers; corticospinal/corticobulbar tracts; corticothalamic fibers; corticostriatal fibers (to basal ganglia); corticohypothalamic fibers. |
Bulbar | Brainstem |
Corticostriatal fibers | Cortex -> basal ganglia; sensorymotor, associative, limbic activity. |
Corticothalamic fibers | Cortex <->thalamic nuclei |
Corticohypothalamic fibers | Limbic cortex -> hypothalamus |
(IN) Modality specific and association thalamic nuclei project to | Layer IV (internal granular) |
(IN) Nonspecific thalamic nuclei project to | diffusely all layers |
(IN) Modulatory fibers synapse in | different layers depending on origin and area of cortex where they synapse |
(IN) Association and commisural fibers synapse mostly on | layers I, II, and III. |
(OUT) Layer V (internal pyramidal) goes to | all subcortical regions EXCEPT thalamus |
(OUT) Layer VI pyramidal and spindle cells (also has other cells) goes to | thalamus |
(OUT) Layer II & III (pyramidal cells, even though II is mostly granule cells) goes to | ipsilateral & contralateral cortex |