1) Language function is primarily located in the left hemisphere, with Broca's area responsible for speech production and Wernick's area in the superior temporal lobe responsible for speech comprehension. 2) Injuries to the upper motor neurons can cause distal muscles to be weaker than proximal muscles and extensors to be weaker than flexors. 3) The primary motor cortex is located in the pre-central gyrus and projects to the corticospinal tract which decussates at the pyramidal decussation before synapsing with lower motor neurons.

1. Clinical Neuroanatomy
language function
95% in left hemisphere
Broca's area
injury causes inability to speak
Wernick's area (superior temporal lobe)
injury causes inability to comprehend
upper motor neuron
injury
distal muscles are weaker
than the proximal muscles
extensors muscles are weaker
than the flexors muscles
pre-central gyrus
primary motor cortex
corticospinal tract
sends axons through posterior limb of internal capsule
injury here involves
face, arm and leg (just
like a lesion of the
whole precentral gyrus)
goes through the brainstem
cross at pyramidal decussation
(right before spinal cord)
goes through spinal cord
synapses with lower motor neuron
post-central gyrus
primary sensory cortex
2 parallel systems mediation sensation from the body
thalamus injury involves
both systems, just like
a lesion of the whole
postcentral gyrus
posterior or dorsal column pathway vibration and proprioception
1st neuron goes through spinal cord and synapses in the brain stem
2nd neuron crosses and goes to the
thalamus where it synapses again
3rd neuron projects to postcentral gyrus
spinotalhamic pathway temperature and pain
1st neuron immediately synapse at spinal cord
2nd neuron crosses at spinal cord and ascends up
the brain stem to the thalamaus where it synapses
3rd neuron projects to the postcentral cortex
primary visual cortex
right occipital lobe see the
left side of the world and vice-versa
sends optic radiations to the eyeballs
ocular motor neurons
left hemisphere starts drives the
eyes to the right and vice-versa
this is acomplished by frontal
eye fields (distinct areas of brain)
injury causes deviations to
the side of the lesion
vascular supply to the brain
2 carotid arteries
supplies the interior
2/3 of the brain
2 vertebral arteries
supplies the posterior
portion of the brain