First Anatomy Quiz - Cognitive Neuro

Directional Terms: General

• Superior - inferior: top-bottom/above-below

• Anterior - posterior: front-behind

• Medial (middle) - lateral (away from middle) 

Directional terms: brain-oriented

• Rostral - caudal: towards the front (nose, beak) - caudal (towards the back, tail) 

• Dorsal - ventral: top of brain - bottom of brain

Directional Terms: Body-oriented

• Rostral - caudal: towards head - tail

• Ventral - dorsal: stomach - spinal cord axis (back)

Planes of section & directional terms

• Horizontal/axial/transverse plane: divides brain into upper & lower planes

• Sagittal (sagittus: parallel) plane: left and right halves

• Coronal plane: front and back halves

Major lobes

• Frontal lobe

• Parietal lobe

• Occipital lobe

• Temporal lobe

Major Fissures:

• Longitudinal fissures: separates left & right hemispheres

• Central fissure: separates frontal and parietal lobes

  • Run from longitudinal fissure down to lateral fissures

• Lateral fissure/sylvian: separates frontal & parietal lobe from the temporal lobe.

Cerebral Commissures

Tracts that span the longitudinal fissure:

• Corpus callosum: largest cerebral commissure

• Anterior commissure: inferior to anterior tip of corpus callosum —> left and right temporal lobe communication

• Massa intermedia: located in the middle of the third ventricle ==> communication between left & right diencephalon

Major Gyri of Cerebral Hemisphere

Tend to be adjacent to fissures —> bumps

• Frontal lobe gyri:

  • Precentral gyrus: anterior to central fissure = primary MOTOR cortex

  • Superior frontal gyrus: Runs horizontally along the lobe

  • Middle frontal gyrus: located between superior & inferior frontal gyri

  • Inferior frontal gyri

• Temporal gyri:

  • Superior (inferior to lateral fissure), middle, inferior

• Parietal lobe:

  • Post-central gyrus: posterior to central fissure = primary somatosensory cortex

  • Angular gyrus: located on borther with parietal lobe, temporal and occipital

Cereral cortex

• Neocortex: layers 1-6

• Allocortex: hippocampus & adjacent cortex

Divisions of Frontal Lobe

• Prefrontal cortex:

  • Orbitofrontal cortex

  • Dorsolateral prefrontal

  • Ventrolateral prefrontal (closer to the sylvian fissure)

  • Motor cortex (pre-central gyrus)

  • Somatosensory cortex (post-central gyrus.

• Sagittal view:

  • Medial prefrontal cortex: located on the inner surface of the brain

    • Anterior cingulate cortex (ACC) is located posterior to mPFC

  • Supplementary motor area: inner surface

Five Divisions of Mature Brain

1. Telencephalon: Largest and highest region of the human brain that contains: 

   1. Cerebral cortex

   2. Basal ganglia

   3. Limbic structures

   4. White matter tracts: fiber bundles (e.g. corpus callosum) that connect different brain areas. 

2. Diencephalon: contains the thalamus and hypothalamus.

3. Mesencephalon: midbrain → most superior part of brainstem. ⇒ tectum (dorsal) and tegmentum (ventral) 

   1. Where a lot of neurotransmitters are produced: superior colliculus, periaqueductal gray, red nucleus, substantia nigra.

4. Metencephalon: pons (brainstem) and cerebellum (which is NOT part of the brainstem) 

5. Myelencephalon: contains medulla oblongata (brainstem) 

Major structures of Myelencephalon

Inferior part of brainstem containing the medulla oblongata

• Olives (olivary nucleus): on lateral sides of medulla —> connect to cerebellum

• Pyramids (protrusions): ventral side of medulla —> voluntary motor signals from brain travel down these tracts to spinal cord; decussation site.

• Reticular formation (posterior) to other structures. —> core of brainstem

Metencephalon

Contains:

• Pons (part of brainstem)

  • Bulbous section in the middle of the brainstem

• Cerebellum (NOT part of brainstem)

  • Dorsal to pons

  • Contains the superior, middle, and inferior cerebellar peduncles.

    • Inferior cerebellar penduncles connect cerebellum to brainstem at olives of medulla.

Mesencephalon

Superior part of brainstem (midbrain)

Superior portion of midbrain:

• Tectum: dorsal (top)

  • Superior colliculi (& inferior)

• Tegmentum: Ventral

  • Periaqueductal gray: pain modulation

  • Red nucleus

  • Substantia nigra

Diencephalon: Thalamus

Has two lobes (bilateral) connected by massa intermedia.

• Medial geniculate nucleus (MGN): auditory information => furthest from midbrain connection (towards end of thalamus)

• Lateral geniculate nucleus (LGN): visual information

• Ventral posterior nucleus (VPN): tactile information => closest to midbrain connection

Also has internal lamina: Y-shaped tracts of white matter.

Diencephalon: Hypothalamus

Inferior to thalamus on its anterior side.

• Preoptic nucleus: sexual behavior

• Suprachiasmatic nucleus: circadian rhythm

• Mammillary body: emotion (bulge in the back)

• Ventromedial nucleus: blood glucose —> fat