30 - Cortex Flashcards
Neurulation Defects
- Anencephaly: failure of anterior neuropore to close
- Rachischisis: failure of posterior neuropore to close
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Spina Bifida: incomplete formation of vertebrae and meninges
- Occulta: vertebrae defect
- Meningocele: meninges live under skin
- Meningomyelocele: meninges and SC live under skin
Heterotopia
- Gray matter malformation of cortical development
- During migration (stage 5)
- Clusters of neurons have stalled along their migration route (haven’t migrated from the ventricle to the cortex, hence why they appear in the ventricle ->)
- Depending on how extensive they are, neurologic and developmental effects may be severe or isolated (e.g., focal seizures with normal psychomotor development)
Fetal Alcohol Syndrome
- Many developmental defects including microencephalopathy (abnormally small brain) due to alcohol-induced interference with neuronal proliferation or alcohol-induced death of vulnerable neurons in the early stages of differentiation
- Children often have impaired learning, hyperactivity, and seizure disorders
Cocaine Abuse during Pregnancy
- Drug can cross the placenta and interact with receptors on fetal neurons
- Cocaine impairs synaptic re-uptake of monoamine NTs epinephrine, norepinephrine, and DA
- Because monoamines influence the development of neuronal circuits, exposure to cocaine during fetal life can permanently alter the physiological and structure of developing neurons
- Individuals exposed to cocaine in utero often have neurological, cognitive, and behavioral dysfunction throughout their lives
- Cocaine can also induce vasospasm, leading to ischemic stroke
Multiple Sclerosis
- Autoimmune disease in which CNS lesions result from perivascular immune cell infiltration associated with damage to myelin, oligodendrocytes, and neurons.
- May arise from interaction between genetic and environmental factors
- Signs/symptoms vary widely depending on the functional neuroanatomy of the regions affected
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Three main characteristics:
- Formation of lesions (plaques) in CNS
- Inflammation
- Destruction of myelin sheaths of neurons
- Why may there be cognitive impairments and mood disorders?
- Neuromodulators need myelination to reach further neurons
- Ex: disruption of cholinergic axonal projections originating from the NBM may affect attention systems, behavior, etc.
- Neuromodulators need myelination to reach further neurons
Pyramidal Cell Layers, Components, and Connections
- Predominant in levels III and V
- Components
- Large apical dendrite that arises from apex of cell body and extends towards the molecular layer
- Basal dendrites run in horizontal direction
- Abundant dendritic spines receive majority of contacts
- Single axon originates from the base of soma, leaves the cortex and passes deeply into white matter
- Connections
- Cortico-cortical
- Cortico-fugal

Granule Cell Layers
Layer II and IV
Staining Techniques
- Golgi stain: lights up entire cell, paradoxically about 1 in every 100 cells
- Nissl stain (RNA)
- Weigert stain: elastin glycoprotein stain
Bands of Baillarger
- Horizontal myelinated fibers in layers IV and V, readily visible on Weigert stains

Stria of Gennari
- Enlarged outer band of layer IV in the primary visual cortex

Agranular vs Granular
- Agranular: thick pyramidal layers (limbic, motor cortex)
- Granular: thin pyramidal layers (sensory)
Short Association Fibers
Originate in layer II
Long Association FIbers
Originate in layer III
Callosal/Commissure Fibers
- Originate in layer III
- Have Von Economo spindle neurons
- Originate in layer
- Comprise the claustrum
- Important for consciouness, duration of coma
Superior longitudinal fasciculus
connects frontal to occipital lobe, as well as points between (parietal)

Arcuate fasciculus
connects Wernicke’s and Broca’s (language)

Inferior longitudinal fasciculus
temporal pole to occipital pole

Cingulum
interconnecting neurons within cingulate gyrus

Inferior fronto-occipital fasciculus
frontal lobe to occipital lobe inferiorly

Uncinate fasciculus
prefrontal cortex to temporal pole (hook shape)

Lateralization of FUnction
- LEFT
- Language
- Emotions from verbal stim
- Spatial functioning of OBJECTS
- RIGHT
- Non-verbal language
- EMotions from nonverbal
- Spatial functioning HOLISTIC