Ascending and Descending Pathways
The ascending pathway carries pain and temperature sensation, with its second-order neurons decussating in the anterior white commissure of the spinal cord
What is the spinothalamic tract (anterolateral system)?
The gyrus situated immediately anterior to the central sulcus, contains the primary motor cortex.
What is the precentral gyrus?
A type of motor neuron lesion which results in increased muscle tone, hyperreflexia, and a positive Babinski sign.
What is an upper motor neuron lesion?
The two paired arteries that respectively provide, the anterior and posterior blood supply to the brain.
What are the internal carotid arteries (anterior circulation) and the vertebral arteries (posterior circulation)?
The dorsal column–medial lemniscal pathway which has first-order neurons carrying fine touch and proprioception from the lower limb ascend in this fasciculus, running medial to fibres from the upper limb.
What is the fasciculus gracilis?
The diencephalic structure that relays essentially all sensory information, with one major exception, to the cerebral cortex.
What is the thalamus (and the exception is olfaction)?
Following an acute stroke affecting the upper motor neurons of the corticobulbar pathway to cranial nerve VII, this part of the face is characteristically spared due to bilateral cortical innervation.
What are the upper facial muscles?
The terminal branch of the internal carotid artery travels laterally through the lateral sulcus and supplies the lateral frontal, parietal and temporal lobes — including cortex controlling arm/face motor and sensory function, speech and personality.
What is the middle cerebral artery (MCA)?
The extrapyramidal tract which originates in the red nucleus, decussates almost immediately in the ventral tegmentum, and mainly excites flexor tone in the distal upper limb.
What is the rubrospinal tract?
The posterior part of the superior temporal gyrus, which produces fluent but semantically empty speech with impaired comprehension.
What is Wernicke's area (producing Wernicke's aphasia)?
Weakness/sensory loss is typically worse in the arm than leg in this cerebral artery stroke.
What is a middle cerebral artery stroke?
The anastomotic arterial ring at the base of the brain that links the anterior and posterior circulations, and the two communicating arteries that complete it.
What is the Circle of Willis; the anterior communicating artery (joins the two ACAs) and the posterior communicating artery?
A lesion confined to this spinal cord region abolishes conscious proprioception, vibration sense and discriminative touch ipsilaterally below the lesion, while sparing pain and temperature on that same side.
What is the dorsal column (posterior funiculus)?
The white matter bundle that connects Broca's area and Wernicke's area; its disruption produces a fluent aphasia with intact comprehension but markedly impaired repetition.
What is the arcuate fasciculus (conduction aphasia)?
Involuntary muscle twitches, muscle atrophy, and hyporeflexia without muscle stiffening point to a lesion at this level of the motor pathway.
What is a lower motor neuron lesion?
The small, thin-walled perforating branches of the MCA supply the basal ganglia and internal capsule, and are frequently the site of stroke.
What are the lenticulostriate arteries?