Neuroanatomy Flashcards
Role of an association
Links cortical regions within a cerebral hemisphere
Role of a commissure
Links corresponding cortical regions between 2 hemispheres
Role of projections
Links cortical and subcortical regions
Four association fibers
Superior longitudinal fasciculus
Inferior longitudinal fasciculus
Uncinate fasciculus
Cingulum
Pathway of the superior longitudinal fasciculus
Connects frontal and occipital lobes (plays major roles in language, attention, memory, and emotions)
Pathway of the arcuate fasciculus
Links gyri in frontal and temporal lobes (important for language function)
Pathway of inferior longitudinal fasciculus
Connects occipital and temporal poles (visual recognition)
Pathway of the uncinate fasciculus
Connects anterior and inferior parts of frontal lobe with temporal gyri (behavior regulation)
Pathway of the cingulum
Connects frontal and parietal lobes with parahippocampal and adjacent temporal gyri
Cingulum is involved in:
Emotions, motivation, executive function (including attention), pain, and memory (including spatial processing)
Commissural fibers (4 of them)
Corpus callosum
Anterior commissure
Posterior commissure
Hippocampal commissure
Principal projection fibers
Corona radiata
Internal capsule
Components of the allocortex
Archicortex
Paleocortex
Structures of the archiocortex
Hippocampus, uncut of parahippocampus, dentate gyrus
Structures of the paleocortex
Olfactory (piriform) cortex
Structures of the mesocortex
Cingulate gyrus and remainder of parahippocampal gyrus, orbitofrontal cortex, temporal pole, anterior insula
Structures of the neocortex
Remaining 90% of cerebral cortex
Limbic structures (definitive ones)
Parahippocampal gyrus Cingulate gyrus Hippocampal formation Amygdala Septal area (nuclei)
Brodmann areas of the prefrontal cortex
BA 9, 10, 11, 12
Location of BA 4
Precentral gyrus, anterior paracentral lobule
Other names for the precentral gyrus and anterior paracentral lobule
Primary motor area; M1
Location of BA 6
Superior and middle frontal gyri, precentral gyrus
Other names for the superior and middle frontal gyri and precentral gyrus
Premotor area, supplementary motor area
Location of BA 44, 45
Inferior frontal gyrus (opercular and triangular parts)
Other names for the inferior frontal gyrus
Broca’s area (usually on left)
Location of BA 6, 8
Premotor cortex on the lateral convexity and extends anteriorly
Other name for the premotor cortex on the lateral convexity
Frontal eye field
Location of BA 11, 12
Gyrus rectus and orbital gyri
Other name for the gyrus rectus
Prefrontal association cortex
Other names for the orbital gyri
Orbitofrontal olfactory area; prefrontal association cortex
Divisions of the prefrontal cortex
Dorsolateral
Orbitoventromedial
Role of the dorsolateral region of the prefrontal cortex
Overall management of cognitive processes such as planning, cognitive flexibility, and working memory
Role of the orbitoventromedial region of the prefrontal cortex
Decision making
Location of BA 1, 2, 3
Post central gyrus, posterior paracentral lobule
Other names for the post central gyrus and posterior paracentral lobule
Primary somatosensory area; S1
Location of BA 5, 7
Superior parietal lobule
Other name for the superior parietal lobule
Somatosensory association area
Location of BA 39
Inferior parietal lobule
Other names of the inferior parietal lobule
Angular gyrus; parietal-temporal-occipital association cortex
Location of BA 40
Inferior parietal lobule
Supramarginal gyrus; parietal-temporal-occipital association complex
Other names for the inferior parietal lobule
Location of BA 17
Banks of calcarine sulcus
Other names for the banks of the calcarine sulcus
Primary visual area; V1
Location of BA 18, 19
Surrounding 17
Other names for the area surrounding BA 17
Visual association areas; V2, V3, V4, V5
Location of BA 41, 42
Superior temporal gyrus (transverse gyri of Heschl)
Other names for the superior temporal gyrus at BA 41
Primary auditory area; A1
Other names for the superior temporal gyrus at BA 42
Auditory association area; A2
Location of BA 22
Superior temporal gyrus
Other names for the superior temporal gyrus at BA 22
Auditory association area; posterior portion (on left) is Wernicke’s area
Location of BA 21
Middle temporal gyrus
Other names for the middle temporal gyrus
Visual infernotemporal area
Location of BA 20
Inferior temporal gyrus
Other names for inferior temporal gyrus
Visual inferotemporal area
Location of BA 43
Insular cortex, frontoparietal operculum
Other name for the insular cortex
Gustatory cortex
Components of the basal nuclei
Caudate nucleus Putamen Globus pallidus Subthalamic nucleus Substantia nigra
Branches of the anterior communicating artery (ACA)
Orbital Frontopolar Callosomarginal Pericallosal Internal parietal
Anatomical segments of the middle cerebral artery
M1 segment
M2 segment
M3 segment
M4 segment
Clinical relevance of the M1 segment of the middle cerebral artery
Aneurysms on MCA frequently arise at bifurcation
Clinical relevance of the M2 segment of the middle cerebral artery
Occlusion may result in issues with gustation and viscerosensory cognitive processing
Clinical relevance of the M4 segment of the middle cerebral artery
Serve trunk, upper extremity, and face areas of somatomotor and somatosensory cortex; occlusion may produce deficits affecting these body regions
Branches of the middle cerebral artery
Lenticulostriate branches Orbitofrontal Precentral Central Anterior and posterior parietal Angular Anterior, middle, and posterior temporal
Clinical relevance of the anterior, middle, and posterior temporal branches of the middle cerebral artery
Occlusion of temporal vessels may result in deficits in auditory and associative functions
Clinical relevance of the calcarine artery
Occlusion would result in deficits of primary visual function and visual association
Ventral anterior nuclei proposed function
Relays basal nuclei and cerebellar input to cortex
Ventral lateral nuclei proposed function
Relays basal nuclei and cerebellar inputs to cortex
Ventral posterolateral nuclei proposed function
Relays somatosensory spinal inputs to cortex
Ventral posteromedial nuclei proposed function
Relays somatosensory cranial nerve inputs and taste to cortex
Lateral dorsal nuclei proposed function
Unclear function; limbic system?
Mediodorsal nuclei proposed function
Limbic pathways, major relay to frontal cortex
Pulvinar nuclei proposed function
Behavioral orientation toward relevant visual and other stimuli
Lateral geniculate nuclei proposed function
Relays visual inputs to cortex
Medial geniculate nuclei proposed function
Relays auditory inputs to cortex
Anterior nuclei function in the ____ pathways
Limbic
Properties of the intralaminar thalamic nuclei
Lie within internal medullary lamina
Receive inputs from numerous pathways including basal nuclei
Have reciprocal connections with the cortex
Outputs to basal nuclei
Properties of the reticular thalamic nuclei
Do not project to cerebral cortex
Receives input from cortex and other thalamic nuclei
Makes synaptic connections with other thalamic nuclei
Consists almost entirely of inhibitory GABAergic neurons
Regulates thalamic activity
Structures of the epithalamus
Habenula
Pineal gland
Functions of the habenula
Appears to serve as a possible relay by which limbic system and hypothalamus can influence activity of the midbrain
Structures of the subthalamus
Subthalamic nucleus
Zona incerta
Functions of the subthalamic nucleus
Maintains reciprocal connections with the globus pallidus
Plays important role in regulation of motor functions by basal nuclei
Function of the zona incerta
Uncertain
Hypothalamic nuclei can be divided into 3 areas:
Periventricular nuclei
Medial hypothalamic area
Lateral hypothalamic area
The lateral hypothalamic area is broken down into:
Lateral peroptic nuclei
Lateral hypothalamic nuclei
Medial forebrain bundle
The medial hypothalamic area can be broken down into:
Preoptic area
Anterior (supraoptic) region
Middle (tuberal) region
Posterior (mammillary) region
The preoptic area contains the ______
Medial preoptic nuclei
The anterior (supraoptic) region contains:
Anterior hypothalamic nuclei
Supraoptic nuclei
Paraventricular nuclei
Suprachiasmatic nuclei
The middle (tuberal) region contains:
Arcuate nuclei
Ventromedial nuclei
Dorsomedial nuclei
The posterior (mammillary) region contains:
Medial mammillary nuclei
Intermediate mammillary nuclei
Lateral mammillary nuclei
Posterior hypothalamic nuclei
Function of the periventricular nuclei
Produces somatostatin
Function of the medial preoptic nuclei (preoptic area)
REgulation of endocrine function and temperature (heat loss [cooling])
Function of the anterior hypothalamic nuclei
Regulates temperature (heat loss [cooling])
Function of the supraoptic nuclei
Produces ADH and oxytocin
Function of the paraventricular nuclei
Produces aDH, oxytocin, and gonadotropin-releasing hormone
Function of the suprachiasmatic nuclei
“Master clock” for circadian rhythms; receives direct input from retina
Function of the arcuate nuclei
Controls anterior pituitary
Function of the ventromedial nuclei
Induces satiety
Function of the dorsomedial nuclei
Involved in behavior control
Function of the mammillary nuclei
Input from hippocampal formation via for IX, projects to anterior thalamic nucleus
Function of the posterior nuclei
Involved in thermoregulation (heat conservation [warming])
Function of the lateral preoptic nuclei
GABA and galanine projections that promote sleep onset
Function of the lateral hypothalamic nuclei
Induces eating when stimulated
The anterior pituitary gland ____ hormones, while the posterior pituitary gland ____ hormones
Produces; releases
Hypothalamic nuclei that have been implicated in central control of CV function
Paraventricular nucleus
Lateral hypothalamic area
Dorsomedial nucleus
Arcuate nucleus
Functions of the limbic system
Homeostasis
Olfaction
Memory
Emotion
Hippocampal formation function
Memory (immediate, short-term, long-term, retrograde, anterograde)
Wernicke encephalopathy often results from a ______
Thiamine (B1) deficiency
Symptoms of Wernicke encephalopathy
Opthalmoparesis/nystagmus
Ataxia
Acute altered mental status
Wernicke encephalopathy is/is not reversible
Is
Korsakoff syndrome results from
Thiamine (B1) deficiency, is secondary to a history of Wernicke encephalopathy
Symptoms of Korsakoff syndrome
Short-term memory deficits
Long-term memory deficits
Confabulation
Korsakoff syndrome is/is not reversible
Is not
Predominant function of the amygdala
Aversion center
A lesion to the amygdala would lead to _____
Placidity
Hyperorality
Hyperphagia
Hypersexuality
Fear is the stimulation for the ______
Amygdala
Predominant function of the nucleus accumbens
Gratification center
Joy/pleasure is the stimulation for the ______
Nucleus accumbens
A lesion to the nucleus accumbens would lead to ______
Addiction
Impulsive behavior
Kluver-Bucy Syndrome presents with _____
Hyperorality Hypermetamorphosis Placidity Hyperphasia Hypersexuality
Function of the septal area
Serves as a relay between hippocampal formation and hypothalamus
Damage to the suprachiasmatic nucleus would lead to ______
Sleeping disorder
Damage to the lateral nucleus would lead to ______
Decreased eating
Damage to the ventromedial nucleus would lead to _____
Excessive eating
Damage to the dorsomedial nucleus would lead to _____
Stimulation: Rage
Destruction: decreased aggression
Separates the two hemispheres of the brain
Medial longitudinal fissure
Sulcus that creates the posterior border of the frontal lobe
Central sulcus
Sulcus that creates the lateral border of the frontal lobe, between the temporal and parietal lobes
Sylvian fissure
Sulcus that creates the posterior border of the parietal lobe, in between the parietal and occipital lobes
Parietal-occipital sulcus
Sulcus found in between the superior front gyrus and the middle frontal gyrus
Superior frontal sulcus
Sulcus found between the middle frontal gyrus and the inferior frontal gyrus
Inferior frontal sulcus
Sulcus found between the precentral gyrus and the middle frontal gyrus
Precentral sulcus
Also known as the Sylvian sulcus
Lateral sulcus
Two rami found within the inferior frontal gyrus
Anterior ramus (found more lateral) Ascending ramus (found more medial)
The precentral gyrus corresponds with BA __
4
The inferior frontal gyrus is divided into three portions: _______, _______, and ____
Pars orbitalis (most anterior) Pars triangularis (in between the other two portions) Pars opercularis (most posterior)
Separates the pars orbitalis from the pars triangularis
Anterior ramus
Separates the pars triangularis from the pars opercularis
Ascending ramus
Broca’s area corresponds to BA ___ and ___
44 and 45
Sulcus that separates the superior temporal gyrus from the middle temporal gyrus
Superior temporal sulcus
Sulcus that separates the middle temporal gyrus from the inferior temporal gyrus
Inferior temporal sulcus
Sulcus that separates the inferior temporal gyrus from the fusiform gyrus
Occipital-temporal sulcus
Sulcus that separates the fusiform gyrus from the parahippocampal gyrus
Collateral sulcus
The parietal lobe is broken up into the ____, _____, and _____
Postcentral gyrus, inferior parietal lobe, and superior parietal lobe
Sulcus that separates the postcentral gyrus from the inferior parietal lobe
Postcentral sulcus
Sulcus that separates the postcentral gyrus from the superior parietal lobe
Marginal sulcus
Sulcus that separates the inferior and superior parietal lobes
Interparietal sulcus
Also known as the primary somatosensory cortex
The postcentral gyrus
The postcentral gyrus corresponds to BA __, ___, and __
3, 1, and 2
Located at the posterior end of the lateral fissure
Supramarginal gyrus
Located posteriorly to the supramarginal gyrus
Angular gyrus
Wernicke’s area corresponds to BA __, __, and __
40, 39, and 22
Occipital lobe corresponds to BA __, __, and __
17, 18, and 19
Also known as the “5th lobe”
Insular lobe
Sulcus that separates the frontal lobe from the insular lobe
Anterior peri-insular sulcus
Sulcus that separates the parietal lobe from the insular lobe
Superior peri-insular sulcus
Posterior peri-insular sulcus
Sulcus that separates the temporal lobe from the insular lobe
Inferior peri-insular sulcus
Sulcus that separates the anterior lobule of the insula from the posterior lobule of the insula
Central sulcus of the insula
Also known as the anterior lobule of the insula
Short gyri of the insula
Also known as the posterior lobule of the insula
Long gyri of the insula
Linen insula is the location where the ____ penetrates the insula and is a common site of infarcts
Middle cerebral artery (MCA)
The development of the corpus callosum begins with the ___ and then continues posteriorly along the body to the ____
Genu; splenium
Sulcus that separates the frontal lobe from the cingulate gyrus
Cingulate sulcus
Sulcus that separates the cingulate gyrus from the corpus callosum
Callosal sulcus
Sulcus that separates the gyrus rectus from the rostral gyrus
Rostral sulcus
The precuneus is found in the _____ lobe
Parietal
Sulcus that separates the cuneus from the lingual gyrus
Calcarine sulcus
Also known as the “6th lobe”
Limbic lobe (not a true lobe)
Located on the basal (bottom portion) side of the brain (11 components - both gyri and sulci)
Lingual gyrus Parahippocampal gyrus Uncus Collateral sulcus Fusiform gyrus Occipitotemporal sulcus Inferior temporal gyrus Lateral sulcus Gyrus rectus Olfactory sulcus Orbital sulci
Gyri of the occipital lobe
Superior occipital gyrus
Lateral occipital gyrus
Inferior occipital gyrus
Location of the orbital gyrus
Located closest to the eye socket
The inferior parietal lobe is separated into the _____ and the _______
Angular gyrus and the supramarginal gyrus
Located on the medial aspect of the brain (11 - both gyri and lobules)
Superior frontal gyrus Cingulate gyrus Gyrus rectus Paracentral lobule Precuneus Cuneus Lingual gyrus Parahippocampal gyrus Fusiform gyrus Uncus Inferior and middle temporal gyri
Broca’s area is responsible for
Motor expression of speech
Role of the primary motor cortex
To generate neural impulses that control the execution of movement
Function of the supplemental motor area
Contributes to the control of movement
Functions of the premotor cortex
Diverse and not fully understood
Functions of the prefrontal cortex
Implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior
How would a patient present if the had a lesion to the primary motor cortex?
The person will typically present with poor coordination of movements and poor dexterity
How would a patient present with a lesion to the supplemental or premotor cortex?
They would exhibit apraxia, oral apraxia, and alien hand syndrome.
How would a patient present with a lesion to Broca’s area?
Inability to create speech. Able to comprehend speech, but difficult to physically produce the words
How would a patient present with a lesion to the prefrontal cortex?
Either they would have a loss of emotions or they would have overexpression of emotions
How would a patient present if they had a lesion to the primary somatosensory cortex?
Loss of sensation to the LE on the contralateral side
How would a patient present if they were to have a lesion to Wernicke’s area?
Unable to comprehend speech. Able to physically produce speech, but unable to comprehend what they hear or even what they say
How would a patient present if they had a lesion to the posterior parietal cortex?
Apraxia, agnosia, Gertzmann syndrome
What is the function of the dorsal stream?
Connects and analyzes motion (determines “where”)
What is the function of the ventral stream?
Analyzes forms, colors, and numbers (determines the “what”)
How would a patient present if they had a lesion to the primary visual cortex?
Contralateral loss of vision in the same field of vision
How would a patient present with a lesion to the secondary and tertiary visual cortex?
Visual agnosia and color agnosia
Function of the superior temporal gyri
Interprets noises and sounds, identifies what we are hearing
Function of the middle temporal gyri
Perception of moving objects
Function of the inferior temporal gyri
Recognition of faces and shapes
How would a patient present if they had a lesion to the superior temporal gyri?
Unable to interpret the sounds they are hearing (acoustic agnosia)
How would a patient present if they had a lesion to the middle temporal gyri?
Unable to distinguish between an object that is moving and an object that is stationary (movement agnosia)
How would a patient present if they were to have a lesion to the inferior temporal gyri?
They would be unable to recognize familiar faces
Function of lower motor neurons
Efferent neurons of the PNS that connect the CNS with the muscle to be innervated
Function of upper motor neurons
Control lower motor neurons
Location of lower motor neurons
Ventral horn of the spinal cord or the cranial nerve nuclei in the brainstem
Location of upper motor neurons
Cerebral cortex or the brainstem
Function of the basal ganglia
Modulate activity of neurons of motor regions of cerebral cortex
Function of the cerebellum
Principal integrator of motor function
Descending tracts
Lateral corticospinal Anterior coticospinal Reticulospinal Vestibulospinal Tectospinal Rubrospinal
Descending tracts that originate in the cerebral cortex
Lateral corticospinal
Anterior corticospinal
Site of origin of the lateral corticospinal tract
Primary motor cortex and other frontal and parietal areas
Site of decussation of the lateral corticospinal tract
Pyramidal decussation
Levels of termination of the lateral corticospinal tract
Entire cord
Function of the lateral corticospinal tract
Movement of contralateral limbs
Site of origin of the anterior corticospinal tract
Primary and supplemental motor cortices
Site of decussation of the anterior corticospinal tract
Does not decussate
Levels of termination of the anterior corticospinal tract
Cervical and upper thoracic cord
Function of the anterior corticospinal tract
Control of bilateral axial and girdle muscles
Neurons located more posterior innervate ______
Flexors
Neurons located more anterior innervate ____
Extensors
Neurons located medially innervate ______ and ______ musculature
Axial and limb girdle
Neurons located laterally innervate _____ parts of extremities
Distal
Where does the corticospinal tract arise?
Cerebral cortex
Descent of the corticospinal tract
Internal capsule of telencephalon
Cerebral peduncles
Base of brainstem to medullary pyramids
Majority of fibers cross at junction of ____ and ____ at pyramidal decussation to form lateral corticospinal tract
Medulla and spinal cord
Remaining fibers of the corticospinal tract remain uncrossed and descend as _______
Anterior corticospinal tract
The corticospinal tract originates from 3 cortical regions
Primary motor cortex
Primary somatosensory cortex
Supplementary motor area and premotor area
Axons of the corticospinal tract from the cortex enter ____ ____ and descend toward internal capsule
Corona radiata
Components of the internal capsule
Anterior limb
Genu (location of corticobulbar fibers)
Posterior limb (location of corticospinal fibers)
In the internal capsule, motor fibers from most anterior and medial to progressively posterior and lateral supply the:
Face
Arm
Trunk
Leg
Location of corticospinal fibers throughout the brainstem
Midbrain - middle third of cerebral peduncle
Basilar pons - fibers pass between masses of pontine nuclei
Medulla - fibers aggregate on ventral surface coursing within the pyramids
Crossed fibers form the ____ corticospinal tract
Lateral
Uncrossed fibers form the _____ corticospinal tract
Anterior
Lateral corticospinal fibers innervate ____ aspects of ventral horn and serve to control movements of the _____
Lateral; extremities
Anterior corticospinal tract fibers innervate ____ aspect of ventral horn to regulate _____ mechanisms
Medial; postural
Most of the corticobulbar fibers innervate the ____ bilaterally
Cranial nerve nuclei
Cranial nerve nuclei that are innervated contralaterally by the corticobulbar fibers
VII
XII
Connects the cerebral cortex to the red nucleus
Corticorubral fibers
Connects the cerebral cortex to pontine and medullary reticular formation nuclei
Cortcioreticular fibers
Connects vertebral cortex to pons
Corticopontine fibers
Descending pathways (8 of them)
Medial vestibulospinal tract Tectospinal tract Lateral corticospinal tract Rubrospinal tract Medullary reticulospinal tract Pontine reticulospinal tract Lateral vestibulospinal tract Anterior corticospinal tract
Signs of a lower motor neuron lesion
Flaccid paralysis followed eventually by atrophy
Fibrillations and fasciculations
Hypotonia
Hyporeflexia or areflexia
Signs of an upper motor neuron lesion
Muscles are initially weak and flaccid but eventually become spastic
Hypertonia
Hyperreflexia
Usually affect groups of muscles
Certain pathologic reflexes and signs often appear (e.g. Babinski sign)
Ascending tracts usually represent various types of ___ input
Sensory
Ascending tracts include:
Gracile and cuneate fasciculi = dorsal (posterior) columns
Anterolateral system = spinothalamic
Includes gracile and cuneate tracts which receive afferents carrying fine, discriminative touch (tactile), vibratory sense and proprioception
Posterior column-medial lemniscus pathway
Part of the dorsal column that carries sensory information from the lower body
Gracilis fascicle
Part of the dorsal column that carries sensory information from the upper body
Cuneate fascicle
The 1st order neurons in the dorsal column-medial lemniscus pathway travel ______ through the spinal cord
Ipsilaterally
Where do the 1st order neurons of the dorsal column-medial lemniscus pathway synapse?
The medulla in their respective nuclei (gracilis or cuneate)
Where do the 2nd order neurons in the dorsal column-medial lemniscus pathway decussate?
Medulla
Where do the 2nd order neurons in the dorsal column-lemniscus pathway synapse?
The ventral posterolateral nucleus of the thalamus
Where do the tertiary neurons of the dorsal column-medial lemniscus pathway synapse?
Primary somatosensory cortex
The spinothalamic tract relays information regarding: _____, ____, _____, and ______
Crude touch, pain, pressure, temperature
The dorsal column-medial lemniscus pathway carries information including: _____, _______, __________, and _____
Vibration, proprioception, two-point discrimination, and touch
Where do 1st order neurons of the spinothalamic tract synapse?
In the posterior or dorsal horn
The anterior spinothalamic tract carries what type of information?
Crude touch and pressure
The lateral spinothalamic tract carries what type of information?
Pain and temperature
Where do the 2nd order neurons of the spinothalamic tract decussate?
In the anterior commissure of the spinal cord
Neurons in the spinothalamic tract travel _______ through the spinal cord
Contralaterally
Where do 2nd order neurons of the spinothalamic tract synapse?
The ventral posterolateral nucleus of the thalamus
Where do 3rd order neurons of the spinothalamic tract synapse?
Primary somatosensory cortex
What type of information does the spinocerebellar tract carry?
Helps coordinate muscles in trunk and limbs, unconscious proprioception sensations
Where do 1st order neurons of the spinocerebellar tract synapse?
In the ipsilateral gray matter of the spinal cord
Dorsal spinocerebellar tract fibers do/do not stay on the ipsilateral side of the spinal cord (on the side where the 1st order neurons synapse)
Do
Ventral spinocerebellar tract fibers do/do not stay on the ipsilateral side of the spinal cord (from where the 1st order neurons synapse)
Do not
The ventral spinocerebellar tract will decussate a second time at what location?
Superior cerebellar peduncle
Where do the neurons of the ventral spinocerebellar tract synapse?
Ipsilateral cerebellar cortex
Where do the fibers off the dorsal spinocerebellar tract travel to?
Inferior cerebellar peduncle
Where do the neurons in the dorsal spinocerebellar tract synapse?
Ipsilateral cerebellar cortex
Descending tracts (motor pathways) only have how many neurons within a tract?
Two (upper motor neurons and lower motor neurons)
Where are the upper motor neurons located?
Cerebral cortex
Deep nuclei of brainstem
Where are lower motor neurons located?
Anterior or ventral horns of spinal cord
Direct motor pathways are also known as _____
Pyramidal tracts
What information do the pyramidal tracts carry?
Fine, conscious muscle movements
What are the upper motor neurons of the pyramidal tracts?
Pyramidal cells
Where are pyramidal cells located?
Primary motor cortex
What is the role of the anterior corticospinal tract?
Controls muscle of trunk
What portions of the brain does the anterior corticospinal tract travel through?
Internal capsule
Cerebral peduncle
Where do the neurons in the anterior corticospinal tract decussate?
In the anterior commissure at the desired spinal level
Where do upper motor neurons of the anterior corticospinal tract synapse with lower motor neurons?
In the ventral horn of the spinal cord
What structures in the brain do the fibers of the lateral corticospinal tract travel through?
Internal capsule
Cerebral peduncle
Where do the neurons of the lateral corticospinal tract decussate
At the decussation of pyramids in the medulla
Where do upper motor neurons of the lateral corticospinal tract synapse with lower motor neurons?
At the ventral horn of the spinal cord, contralateral side
The upper motor neurons of the corticobulbar pathway synapse, in the brainstem, with contralateral lower motor neurons for: __, __, __, and __
CN V, CN VII, CN XI, and CN XII
What information do the extra pyramidal tracts carry?
Innervate larger muscles
Balance, body posture, coarse movements
Upper neurons of the extrapyramidal tracts originate from the _____
Deep nuclei of the brainstem
What information do the fibers of the lateral vestibulospinal tract carry?
Help provide inputs to promote balance of the extensor muscles of trunk and extremities
Within the medulla, there are four vestibular nuclei: ____, ____, ____, and ____
Superior, medial, lateral, and inferior
The lateral vestibular nucleus contains upper motor neurons that make up the _________ tract
Vestibulospinal tract
What is the role of the four vestibular nuclei in the medulla?
They gather information about balance
What information do the fibers of the reticulospinal tract carry?
Transmit motor input for extensor muscles, to help maintain balance
The reticular formation is in charge of: ____, _____, ______, and _____
Sleep, alter ness, cardiovascular control, and motor control
The fibers of the pontine (medial) reticulospinal tract descend to _____ spinal cord
Ipsilateral
The neurons of the pontine (medial) reticulospinal tract directly.indirectly activate lower motor neurons
Indirectly
The fibers of the medullary (lateral) reticulospinal tract directly or indirectly ____ lower motor neurons
Inhibit
Role fo the tectospinal tract
Transmits motor impulses for neck muscles
Role of the rubrospinal tract
Transmits motor impulses for flexor muscles of extremities
The ___ _____ houses the upper motor neurons of the rubrospinal tract
Red nucleus
Motor areas of the brain
Primary motor cortex
Premotor cortex
Frontal eye field
Broca’s area
Functions of the prefrontal cortex
Working memory for spatial tasks
Executive area for task management
Working memory for object-recall tasks
Solving complex multi-task problems
Somatic sensation areas
Primary somatosensory cortex
Somatosensory association cortex
Functions is related to taste
Gustatory cortex
The corpus callosum is the ____ commissure
Largest
Function of the corpus callosum
Connects the right and left hemispheres of the brain
Ascending tracts
Dorsal columns
Spinothalamic
What are the fasciculus gracilis and cuneatus a part of?
Dorsal column-medial lemniscus pathway
Where do the secondary neurons of the posterior column-medial lemniscus pathway synapse?
Ventral posterolateral nucleus of the thalamus
The fasciculus gracilis conveys info from _____
Lower limbs
The fasciculus cuneatus conveys info from ____
Upper limbs
This pathway shifts its position as it ascends through the brainstem but maintains somatotopic organization
Medial lemniscus
Neurons, in the posterior dorsal-medial lemniscal pathway, from the primary somatosensory cortex then send info to _____________ and __________
Secondary somatosensory association cortex
Superior parietal lobule
What nuclei provide sensory systems for the face and head?
Chief (main or principal) trigeminal sensory nucleus
Spinal trigeminal nucleus
Trigeminal lemniscus arises from _____
Chief sensory nucleus
Trigeminothalamic tract arises from _______
Spinal trigeminal tract
Where do the first order neurons of the spinothalamic tract synapse on second order neurons?
In laminae I and V
Where do the neurons of the spinothalamic tract synapse in the thalamus?
Ventral posterolateral nucleus
In the dorsal columns, the more medial you are correlates to what part of the body?
Lower part of the body
In the anterolateral system, the more medial you are in the spinal cord corresponds to what portion of the body?
The upper portion (e.g. neck and then descends as you progress laterally)
What symptoms would you expect to see with an upper motor neuron lesion? (E.g. Brown-Sequard Syndrome)
Weakness, hyperreflexia, and increased tone
What symptoms would you expect to see with a lower motor neuron lesion? (E.g. Brown-Sequard Syndrome)
Weakness, atrophy, fasciculations, hyporeflexia, decreased tone
Motor function of the cerebral cortex
Most important source of upper motor neurons
Motor function of the basal nuclei
Modulate activity of neurons of motor regions of cerebral cortex
Motor function of cerebellum
Principal integrator of motor function
Motor function of brainstem
Upper motor neurons give rise to spinal tracts that exert different influences on spinal motor neurons
Descending tracts
Lateral corticospinal
Anterior corticospinal
Descending tracts that originate in the cerebral cortex
Lateral corticospinal
Anterior corticospinal
Descending tracts that originate in the brainstem
Reticulospinal
Vestibulospinal
Tectospinal
Rubrospinal
Traditional naming for somatic motor nerve modality
General somatic efferent (GSE)
Special somatic efferent (SSE)
Traditional name for visceral motor (PS) nerve modality
General visceral efferent (GVE)
Traditional name for branchial (“somatic”) motor nerve modality
Special visceral efferent (SVE)
Traditional name for somatic sensory nerve modality
General somatic afferent (GSA)
Traditional name for visceral sensory nerve modality
General visceral afferent (GVA)
Traditional name for special (visceral) sensory (taste, smell) nerve modalities
Special visceral afferent (SVA)
Traditional name for special (somatic) sensory (vision, hearing, equilibrium) nerve modalities
Special somatic afferent (SSA)
Cranial nerves that are classified as somatic motor (GSE) nerves
CN III, IV, VI, XII
Cranial nerves that are classified as branchial motor (SVE) nerves
CN V, VII, IX, X, XI
Cranial nerves that are classified as parasympathetic (GVE) nerves
CN III, VII, IX, X
Brainstem nuclei for CN III, IV, VI, XII
Oculomotor, trochlear, abducens, and hypoglossal
Brainstem nuclei for CN V
Motor nucleus of CN V
Brainstem nuclei of CN VII
Facial nucleus
Brainstem nuclei of CN IX, X
Nucleus ambiguus
Brainstem nuclei of CN XI
Accessory spinal nucleus
Brainstem nuclei of CN III
Edinger-Westphal nucleus
Brainstem nuclei of CN VII
Superior salivatory nucleus
Brainstem nuclei of CN IX
Inferior salivatory nucleus
Brainstem nuclei of CN X
Dorsal motor nucleus of CN X
Cranial nerves classified as visceral sensory (SVA) nerves
CN VII, IX, X
Cranial nerves classified as visceral sensory (GVA) nerves
CN IX, X
Brainstem nuclei of CN VII, IX, X
Nucleus solitarius (rostral portion, gustatory nucleus)
Brainstem nuclei of CN IX, X
Nucleus solitarius (caudal portion, cardiorespiratory nucleus)
Cranial nerves classified as general somatic sensory (GSA) nerves
CN V, VII, IX, X
Brainstem nuclei of CN V, VII, IX, X
Trigeminal nuclei
Cranial nerves classified as special somatic sensory (SSA) nerves
CN VIII
Brainstem nuclei of CN VIII
Cochlear nuclei, vestibular nuclei
Motor nuclei are generally located _____, while sensory nuclei are generally located _____
Medially; laterally
