Lectures 9 & 10 (cortex, deep nuclei + diencephalon, brainstem, cerebellum)) Flashcards
grey matter vs white matter in different sections of CNS
Cerebral cortex:
- grey on outside (somas/cell bodies)
- white on inside (axons)
- deep grey matter (thalamus + basal nuclei)
Spinal cord
- white on outside
- grey on inside
names for grooves vs bumps on brain (names, notable ones)
fissures (deep grooves)
- longitudinal fissure (separate L&R)
- lateral/sylvian fissure (separate upper & temporal)
sulci (shallow grooves)
- central sulcus (separate frontal & parietal)
gyri (bumps)
lobes of the brain
- frontal
- parietal
- occipital
- temporal
- insula/insular lobe
primary cortex’s
- primary motor (posterior frontal lobe)
- primary sensory (anterior parietal lobe)
Arterial blood supply to brain
anterior cerebral artery: superior middle of brain
middle cerebral artery: lateral portions of brain
posterior cerebral artery: inferior portion of brain
frontal lobe cortex + areas
- prefrontal
- premotor
- primary motor
- frontal eye field
- Broca’s area (physical aspects of speech) *only on left
- *olfactory cortex (also temporal)
parietal lobe cortex + areas
- primary sensory
- somatosensory (voluntary)
- *Wernike’s area (also temporal, non-physical aspects of speech) *only left
temporal lobe cortex + areas
- primary auditory cortex
- *Wernike’s area (also parietal, non-physical aspects of speech) *only left side
- *olfactory cortex (also frontal)
occipital lobe cortex + areas
- visual cortex
- primary visual cortex
deep cerebrum structures + cortex’s
- insular cortex (balance, emotional context to sensation)
- primary gustatory cortex
- cingulate gyrus (emotional + behavioural processing)
- corpus callosum (connects R&L lobes)
- internal capsule
purposes of left vs right brain
L - Logical
- movements + sensation on right
- spoken and written language
damage can lead to aphasia (loss of language)
R - Creative
- movements + sensation on left
- spacial orientation + object recognition
damage can lead to loss of emotional component of speech
types of white matter fibres
- commissural fibres (between hemispheres)
- association fibres (between lobes)
- projection fibres (to different part of CNS) eg: brain to spinal cord
Basal nuclei (location, purpose, anatomical structures)
- lateral to ventricles
- initiate, coordinate + stop motor movement
- skill/muscle memory (eg: walking)
- dopamine is the main neurotransmitter
- caudate nucleus (head + tail)
- striatum (between caudate and putamen)
- lentiform nucleus (putamen + globus pallidus)
- substantia nigra
Basal nuclei neural pathway
cortex –> basal nuclei –> thalamus –> cortex
Basal nuclei pathology
- Huntington’s chorea: neurodegeneration of striatum, cannot inhibit motion, increased movements
- Parkinson’s: diminished substantia nigra neurons, hard to start/stop movements
Limbic system (anatomical structures + pathway)
- amygdala
- hippocampus
- fornix
- mammilary bodies
After:
anterior thalamic nuclei —> entorhinal cortex —> thalamus –> prefrontal cortex + cingulate gyrus –> amygdala (memories)
role of hippocampus
consolidate and encode memories (short term)
role of amygdala + pathologies
- threat detection/assessment, can evoke fight or flight response via ANS + Endocrine
Damage: inability to recognize fearful situations, loss of emotional memories + inhibition
Abnormal activation: PTSD, panic disorder, GAD
types of amnesia
- anterograde: can’t form new memories (long term still in-tact, muscle memories can still be formed)
- retrograde: loss of long term memories
Diencephalon (structures + functions)
- posterior pituitary gland (*anterior not connected by neurons)
- hypothalamus (ANS regulation)
- thalamus (gateway nucleus, selective attention)
- pineal gland (sleep + circadian rhythms)
Specific purposes of thalamus
- memory: links mammillary bodies to cingulate cortex
- motor: balance between basal nuclei and cerebellar output
- sensations: all except smell
thalamic syndrome
stroke affecting thalamus (eg: posterior artery blockage), contralateral loss of sensation (ALL, except smell)
regions of the brainstem
- midbrain
- pons
- medulla
Anterior brainstem anatomy
- cerebral peduncles
- middle cerebellar peduncle
- olive
- pyramidal tracts
- pyramidal decussation
Posterior brainstem anatomy
- superior colliculi (vision reflex relay)
- inferior colliculi (auditory reflex relay)
- cerebellar peduncles
- somatosensory tracts
cranial nerves (above pons)
1 - olfactory I
2 - optic II
3 - oculomotor III
4 - trochlear IV
cranial nerves (‘on’ pons)
5 - trigeminal V
6 - abducens VI
7 - facial VII
8 - vestibulocochlear VIII
cranial nerves (below pons)
9 - glossopharyngeal IX
10 - vagus X
11 - spinal accessory XI
12 - hypoglosseal XII
Reticular activating system (purpose + tract)
sensory stimuli to help regulate conciousness, alertness and sleep via reticular formations in brain stem
Cerebellum (structures)
lateral sections for lateral control
- anterior lobe
- posterior lobe*
- flocculonodular lobe (eye movements)
- vermis (axial control)
cerebellar peduncles (purpose)
superior: cerebellum to brainstem
middle: cortex to cerebellum
inferior: spinal cord to cerebellum (eg: proprioception)
Appendicular pathway (cerebellar)
Loop:
Cortex - contralateral to desired motion
*Midbrain - cerebral peduncle (cross to ipsalateral)
Pons - pontine nuclei
Cerebellum - from middle cerebellar peduncle, out superior CP
Midbrain - red nucleus
*Thalamus - cross to contralateral
Cortex - contralateral –> corticospinal tract
Axial pathway (cerebellar)
Up to cortex:
Spinal cord - spinocerebellar tract
Cerebellum - from inferior cerebellar peduncle, out superior CP
Midbrain - cerebral peduncle
*Thalamus - cross to contralateral
Cortex –> vestibularspinal tract (same as cortico but skips thalamus)
Cerebellum pathologies
Ataxia - medial cerebellum (difficulties stabilizing trunk)
Intention tremor - lateral cerebellum (difficulty executing motions)
