Brain anatomy

Terms & divisions
Meninges membranes surround the brain: dura mater	arachnoid	pia mater
Common terms:  rostral/anterior (front)		dorsal (top)	caudal/posterior (back)		ventral (bottom)

Perspectives: saggital (side view);   coronal  (halo; face on)        horizontal (top view)

Major brain divisions:
Rhombencephalon: hindbrain
Mesencephalon: midbrain     (together hind & midbrain = brainstem)
Diencephalon:  base of the forebrain
Telencephalon: top layer of forebrain

Afferents & efferents
Cranial nerves of psychological importance:
1. Olfactory
2. Optic
(3,4, 6 control eye movements: oculomotor, trochlear, abducens)
5.  Motor mastication jaw, sensory: oral sensation of hot & spicy, touch, pain
7. Motor facial expression,  sensory: taste
8. Auditory-vestibular  (kalat calls this: statoacoustic) 
9, 11, 12:  motor:  speech movements of  throat & tongue
10: vagus:  hunger, thirst, visceral sensory & motor (parasympathetic)
Spinal organization:  dorsal nerves and horns are sensory (narrow horns & ganglion);  ventral horns and nerves are motor  (bell/magendie law).  This imposes a constraint on brain organization too:  motor systems tend to be ventral, whereas sensory systems tend to be dorsal.

3. Internal structures to know

I. Hindbrain:  pons & medulla oblongata.  This division contains:
1. A cranial nucleus for each cranial nerve
2. Additional integrative nuclei  (e.g. Nucleus of solitary tract: integrates taste &  visceral hunger cues)
3.  Massive fiber tracts going up/down  (motor ventral pyramids;   sensory lateral dorsal tracts)
4. Reticular formation
5. Special structures
	a) cerebellum
	b) raphe nucleus  [ name means seam](on either side of aqueduct)
	c) locus coeruleus [blue spot] (medulla: at either corner of 4th ventricle)

Ii. Midbrain
1.  Same 1-4 above (cranial & integrative. Nuclei, tracts, reticular system)
2 or 5. Special structures:
	a) superior colliculus (optic tectum): vision (also touch, motivation)
	b) inferior colliculus (torus semicircularis in nonmammals) hearing
	c) substantia nigra
	d) red nucleus

Iii diencephalon forebrain:
1. Thalamus  (central chamber): sensory,  every modality region
2. Hypothalamus: motivation
3. Pineal (epithalamus): not soul;   homologue to 3rd eye; still photoreceptive in birds;  indirect light-linked circadian rhythms in mammals)

Iv  telencephalon
	1. Hippocampus-fornix-mammilary bodies circuit memory
		on top in most, pushed back, down (seahorse s shape) in us
	2.  Striatum/basal ganglia  (caudate/putamen/globus pallidus): base below cortex: complex motor/thought patterns
	3. Amygdala (almond at end of caudate tail): emotion/motivation
	4. Septum: emotion/motivation
	5.  Cortex (neocortex) -lobes: frontal, parietal, occipital,  temporal

Principles of brain evolution:  what makes us different from reptiles?
Encephalization:  two major aspects
1. Brain size increase: growth of rostral structures:
	addition of subunits (e.g. Cortical columns [kalat])
	elaboration from pre-existing structures (e.g. Pyriform cortex: 3 layers ancient)
2.  Invasion of autonomy:
	our subcortical systems are less competent (on their own) than a rat's;  a reptile is essentially entirely subcortical 			in organization, and entirely autonomous.

Ontogeny of human brain development
-weeks 1-2 of gestation : brain forms as a tube from skin substrate on top of head
-1 month:  basic divisions form:  forebrain (telencephalon/diencephalon), midbrain (mesen-), hindbrain (rhomben-)
	 (superficial principle of 'ontogeny recapitulates phylogeny')
-3 months: forebrain swells, but still smooth
-9 months- similar in appearance to adult but 25% adult size (most subsequent growth happens in first year)