lecture 5 - neuroanatomy 4 Flashcards
What are the 3 gyri of the anterior frontal lobe, and what divides them?
Superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, divided by the superior frontal sulcus and inferior frontal sulcus
Which gyrus contains the primary motor cortex?
The precentral gyrus
What are the 3 divisions of the inferior frontal gyrus?
superior to inferior: opercular, triangular, orbital
What divisions of the inferior frontal gyrus make up Broca’s Area?
Opercular and triangular (superior 2 divisions of the gyrus)
What is the location of Broca’s Area?
At the inferior end of the precentral gyrus in the inferior frontal gyrus
What are the overall functions of the prefrontal cortex?
Intellect, complex learning/cognition, recall, personality
What gyrus contains the primary somatosensory cortex?
Postcentral gyrus
What are the 2 regions of the parietal lobe that are separated by the intraparietal sulcus?
The superior and inferior parietal lobules
Which gyrus surrounds the end of the lateral fissure in the parietal lobe?
Supramarginal gyrus
What is the function of the supramarginal gyrus?
tactile sensory data interpretation, proprioception
What gyrus sits posterior to the supramarginal gyrus in the parietal lobe?
angular gyrus
What is the function of the angular gyrus?
language, number processing, spatial cognition, etc.
What type of movement is initiated by the corticospinal tracts?
Fast, skillled movement
What is the origin of the corticospinal tracts?
primary motor/premotor/sensory cortices
What is the brain pathway of the corticospinal tracts?
cortex, internal capsule, midbrain, pons, medulla
Where is the decussation of 90% of fibres from the corticospinal tracts?
Medulla
Where are the cell bodies of lower motor neurons from the corticospinal tracts?
Ventral horn of spinal cord
What sensations are part of the discriminative pathway?
Fine touch, vibration, conscious proprioception
What sensations are part of the non-discriminative pathway?
Pain, pressure, temperature
What is the other name for the discriminative pathway?
Dorsal column-Medial leminscus pathway
What is the name for the non-discriminative pathway?
Spinothalamic pathway
Where are the cell bodies for first order neurons in the discriminative pathway?
Spinal dorsal root ganglia
Where are the cell bodies for second order neurons in the discriminative pathway?
In the gracile or cuneate nuclei (collectively called the dorsal column nuclei) in the medulla
Where does the gracile nucleus receive the majority of its somatosensory input?
The lower limb
Where does the cuneate nucleus receive the majority of its somatosensory input?
The upper limb
Where are the cell bodies of the third-order neurons of the discriminative pathway located?
The thalamus
Where is the decussation of the discriminative pathway?
medulla
Where is the cell body of the first order neurons of the non-discriminative/spinothalamic pathway?
spinal dorsal root ganglia
Where is the cell body of the second order neurons of the non-discriminative/spinothalamic pathway?
The dorsal horn of the spinal cord (at level where nerve entered cord)
Where is the cell body of the third order neurons of the non-discriminative/spinothalamic pathway?
The thalamus (axons project to the post-central gyrus)
Where is the decussation of the non-discriminative/spinothalamic pathway?
the spinal cord, at the level where neurons enter the cord
What is the biggest difference between the arrangements of the discriminative and non-discriminative sensory pathways?
Discriminative has decussation at the medulla, while non-discriminative has decussation immediately when it enters the spinal cord
What type of information is conveyed by the spinocerebellar tract?
Sensory information from muscles or tendons about stretch - but NOT conscious sensation
What are the features of the spinocerebellar tract?
No third order neuron, no decussation
What is the name for the key horizontal/transverse sulcus in the occipital lobe?
Calcarine sulcus
What is the location of the primary visual cortex?
Gyrus forming the walls of the calcarine sulcus, deep within the occipital lobe
What is the name given to the occipital lobe, except for the primary visual cortex?
The Visual association area
Where in the brain is the area responsible for facial recognition?
The temporal lobe
What are the 3 lateral gyri of the temporal lobe, and what divides them?
Superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, divided by the superior and inferior temporal sulci
What gyrus contains the hippocampus?
Parahippocampal gyrus
What 2 structures lie medial to the rhinal sulcus?
The uncus and amygdala
What is the function of the uncus?
Olfaction
What is the function of the amygdala
process and memory of emotions
Which ventricle does the hippocampus sit medial to?
The inferior horn of the lateral ventricle
What is the name for the bundle of fibres that leave the olfactory bulb?
Olfactory tract
What lobe of the brain is associated with olfaction?
Temporal lobe
What part of the temporal lobe contains the olfactory cortex?
The uncus
What is the function of the olfactory cortex?
Conscious perception of smell
What is the role of the hippocampus in olfactory projection pathways?
Olfactory memory
What is the role of the amygdala in olfactory projection pathways?
Emotional responses to smell
What is the role of the reticular formation in olfactory projection pathways?
visceral responses to smell
What are the 5 key centres in the brain where olfactory information is sent?
Olfactory cortex (uncus), hippocampus, amygdala, hypothalamus, reticular formation
What gyrus contains the primary auditory cortex?
The transverse temporal gyrus
What is the location of Wernicke’s Area?
The superior temporal gyrus in the dominant hemisphere
Which cranial nerve carries auditory information to the brain?
The vestibulocochlear nerve
What are the parts of the auditory pathway, from the ears to the primary auditory cortex?
vestibulocochlear nerve, cochlear nucleus, superior olivary nucleus, inferior colliculus, thalamus, primary auditory cortex
How is the dominant hemisphere of the brain defined?
The hemisphere where language resides - i.e. Broca’s and Wernicke’s Area
Which hemisphere is dominant in 90% of people?
Left
What is the name for the fibres that connect Broca’s and Wernicke’s Areas?
Arcutate Fasciculus
What condition arises from damage to Broca’s Area?
Non-fluent aphasia (difficulty forming speech)
What condition arises from damage to Wernicke’s Area?
Fluent aphasia, fine to produce speech but it does not make sense
What condition arises from damage to the arcutate fasciculus?
Conduction aphasia, where expression and comprehension are intact, but there is isolated difficulty with speech repitition
What does the pineal gland produce?
Melatonin - the sleep inducing signal
Why is the pineal gland radiopaque in adults?
It contains calcium salts (pineal sand)
What are the functions of the hypothalamus?
body temperature, food intake, water balance/thirst, sleep-wake cycles, endocrine function, emotional response, autonomic control centre
What structures in the eye produce local currents in response to light?
Rods & cones
What are the 2 parts of the retina that see 2 visual fields?
The nasal retina (medial) and temporal retina (lateral)
Which parts of the retina of each eye see the right half of the world?
Right nasal retina, left temporal retina
Which parts of the retina of each eye see the left half of the world?
Left nasal retina and right temporal retina
Which nucleus of the thalamus does visual information pass through?
Lateral geniculate nucleus
What visual field defect causes loss of vision in one eye?
Mononuclear blindness
What visual field defect causes loss of vision in the temporal (lateral) sides of each eye?
Bitemporal hemianopsia
What visual field defect causes loss of vision in the same side on each eye (one temporal and one nasal)?
Homonymous hemianopsia
What type of visual field defect occurs when there is a lesion at the optic nerve of one eye?
Mononuclear blindness (one eye is totally blind)
What type of visual field defect occurs when there is a lesion where fibres cross at the optic chiasma?
Bitemporal hemianopsia (lateral vision in both eyes is gone)
What type of visual field defect occurs when there is a lesion in the optic tract on one side?
Homonoymous hemianopsia (blindness on the same half L/R of each eye)
Which fibres coming from which part of the retina will not cross over at the optic chiasma?
Fibres from the temporal retina
