Forebrain & Lobes
The embryonic prosencephalon gives rise to these two regions, which together make up the forebrain.
Cerebrum + diencephalon
This structure, found in the lateral, third, and fourth ventricles, produces most CSF.
Choroid plexus
Where is gray matter found in the cerebrum vs. in the spinal cord?
Cerebrum: outer cortex (plus deep nuclei). Spinal cord: central H-shape.
These two nuclei make up the dorsal striatum.
Caudate nucleus + putamen
List the three parts of the brainstem from superior to inferior.
Midbrain > pons > medulla
This lobe handles voluntary motor control, executive function, and speech production via Broca's area.
Frontal lobe
In the blood-brain barrier, these junctions between capillary endothelial cells form the main barrier.
Tight junctions
The corpus callosum is the largest example of this tract type.
Commissural tracts (connect the two hemispheres)
Catching a ball vs. deciding to stand up: which motor planning area handles each?
Catching a ball = premotor cortex (external cues). Standing up = SMA (internally generated).
Superior colliculi vs. inferior colliculi: which handles which reflexes?
Superior = visual reflexes (orient eyes/head). Inferior = auditory processing and reflexes.
This lobe contains the primary auditory cortex and Wernicke's area, and helps with memory and olfactory processing.
Temporal lobe
Name one circumventricular organ AND explain why the brain needs CVOs at all.
Any of: subfornical organ, OVLT, median eminence, pineal gland, area postrema. The brain needs to directly monitor blood (hormones, osmolarity, nutrients, toxins).
U-fibers and the cingulum are both this tract type. Which one is short and which is long?
Association tracts (within one hemisphere). U-fibers = short (adjacent gyri); cingulum = long.
Name the three layers of the cerebellar cortex from outer to inner.
Molecular → Purkinje cell layer → granular cell layer
The pons houses nuclei for which cranial nerves, and which nuclei relay cortex → cerebellum?
CN V–VIII; pontine nuclei
Hidden deep in the lateral sulcus, this 'fifth lobe' processes taste, visceral sensation, and interoception.
Insula
The choroid plexus capillaries are fenestrated and leaky. So where exactly is the blood-CSF barrier?
Tight junctions between the choroid plexus EPITHELIAL cells
The thalamus relays most sensory information to the cortex. Which sense is the exception?
Olfaction (smell)
Dopamine from the substantia nigra pars compacta: what does it do to the direct pathway, the indirect pathway, and overall movement?
INCREASES direct pathway, DECREASES indirect pathway, overall INCREASES movement
About what % of corticospinal fibers cross at the pyramidal decussation, what tract do they form, and what does the UNcrossed tract mainly control?
~85–90% → lateral corticospinal tract (precise limb, hand, and finger movement). Uncrossed anterior CST (~10–15%) → axial/proximal muscles; many fibers cross at the spinal level.
Put these in order from least to most integrated: association areas, primary areas, secondary areas. Then give one example of a primary area.
Primary → secondary → association.
Ex. primary visual, primary somatosensory, or primary motor cortex.
Trace CSF reabsorption: through what structures, into what, and finally draining into which veins?
Arachnoid granulations → dural venous sinuses (mainly the superior sagittal sinus) → internal jugular veins
The thalamus forms the lateral walls of the third ventricle. What does the hypothalamus form, and name two things it regulates?
Floor of the third ventricle. Any two: body temperature, hunger, thirst, circadian rhythm, autonomic activity, endocrine function via the pituitary.
Walk through the indirect pathway from striatum to thalamus with +/− signs. What's the result?
Striatum (-) GPe → STN disinhibited → STN (+) GPi → GPi (-) thalamus more → ↓ movement
Where in the spinal cord do corticospinal fibers synapse, and what neurotransmitter do lower motor neurons release at the neuromuscular junction?
Ventral horn gray matter (mostly via interneurons, some directly onto alpha motor neurons); acetylcholine (ACh)