Neuroanatomy Review Flashcards
How is the primary motor cortex organized ?
Somatotopically organized
Where is the primary somatosensory cortex located?
How is it organized?
The postcentral gyrus (parietal lobe)
It is also somatotopically organized
Name the four subcortical structures
Diencephalon (thalamus, hypothalamus, epithalamus, sub thalamus)
Basal ganglia
Substantia nigra
Sub thalamic nucleus
Where is the cerebellum located? What is it involved with?
In the rear part of the brain BELOW the cerebrum
It is involved in coordination
Where is the brain stem? What originates from the brain stem?
Between the subcortical structures and spinal cord
Where the cranial nerves originate
Where do upper motor neurons originate? Where do they terminate
UPPER motor neurons originate in the cortex, they terminate on lower motor neurons in the spinal cord OR the brain stem
What is the name of the tract that hold the lower motor neurons in the spinal cord?
Corticospinal
What is the name of the tract that holds the lower motor neurons in the brainstem ?
Corticobulbar tract
TRUE/FALSE: LMNs ONLY originate in the spinal cord
FALSE!
LMNs can originate in the spinal cord OR the brainstem
Where do
LMNs terminate?
They terminate on the muscles they innervate
What type of the neuron innervation do the muscles of the limbs receive?
Unilateral contralateral innervation
TRUE/FALSE: muscles of the head and neck mostly receive bilateral motor innervation
TRUE!
They receive innervation from both hemispheres! I.e. Contralateral (opposite side) AND ipsilateral (same side) innervation
What is the pyramidal system responsible for? Which tracts are in the pyramidal system?
Responsible for VOLUNTARY movements in speech and limbs
Consists of:
Corticobulbar tracts
Corticospinal tracts
Where does the corticospinal tract cross? Which muscles does it innervate?
Crosses at the level of the medulla
Innervates the muscles of the limbs
Where does the corticobulbar pathway cross? What muscles are innervated?
crosses at the level of the cranial nerves nuclei they innervate
Innervates ALL MUSCLES involved in speech and swallowing!!
Where is the primary motor cortex located?
The precentral gyrus (frontal lobe)
What is the extra pyramidal system? Damage to this system causes ?
It is an Indirect activation pathway and control circuits
IT INDIRECTLY influences muscles NO DIRECT CONNECTION
TRUE/FALSE: the basal ganglia and the cerebellum are the control circuits of the extrapyramidal system
True! Damage to the control circuits can cause speech disorders
Name the two damage effects of the indirect activation pathway (I.e extrapyramidal system)
Hyperreflexia
Spasticity
Where do the pathways of the extrapyramidal system originate/terminate?
These pathways originate in the cortex, synapse in the brainstem then travel to the cranial nuclei
TRUE/FALSE: the control circuits project to the LMNs
FALSE! They send their output in the cerebral cortex
Name two effects of spasticity on speech
Causes slowness and hyper ADDuction of the vocal folds (hypernasality)
What are some results of spasticity?
Spastic dysarthria
Unilateral upper motor neuron dysarthria
What are parts of basal ganglia
Caudate nucleus
Putamen
Globus pallidus
Brainstem structures included: Subthalamic nucleus Substantia nigra (dopamine produced here)
What is the function of the basal ganglia?
Initiates movement and it’s an inhibitory to cortical discharges
What do we typically see when the basal ganglia is damaged?
Reduced movement or
Excess involuntary movement (excessive movement-jerks)
What is the difference between paralysis and paresis?
Paralysis- absence of movement (gross limitation of movement)
Paresis- weakness of movement (incomplete paralysis)
TRUE/FALSE: UMNs AND LMNs damage can result in paralysis OR paresis
TRUE
What are the three common signs associated with UMN damage?
Hypertonia/Spasticity(excessive tone, resistance to passive stretch)
Hyperreflexia(exaggerated muscle stretch reflex)
Weakness (due to bilateral innervation)
What are the two major signs associated the LMN damage?
Hypotonia(reduced muscle tone): can cause paralysis or paresis
Atrophy (loss of muscle bulk): fasciculation- involuntary muscle controls (visible to the eye) or fibrillations- involuntary contraction of individual muscle fibers (not visible)
What is dyskinesia?
Refers to extrapyramidal damaged BUT can be used for other movement disorders
Classified by fast, slow, rhythmic or nonrhythmic movement
Name the six types of dyskinesias
Tremor Chorea Tartive Athethosis Dystonia Myoclonus
TRUE/FALSE: the cerebellum does not have lobes
FALSE! It has three lobes
Anterior, posterior, flocculonodular
What is the function of the cerebellum?
Coordination of different muscle groups and helps with balance
Plays a role in: motor Programming (not muscle specific) , Maintenance of muscle tone and motor learning
TRUE/FALSE: the cerebellum has MORE efferent pathways than after want pathways
FALSE! It has MORE afferent pathways
What is motor planning?
Formulates a strategy of action by specifying motor goals
This is NOT muscle specific
What is apraxia?
Impairment of motor planning
Inability to execute skilled, learning motor acts DESPITE normal function of motor, sensory systems, comprehension, cooperation and coordination
Which lobe is primarily responsible for motor planning?
The frontal lobe
Where: premotor cortex
How does the cerebellum help in the coordination of movements?
Takes in all the sensory information, uses a feed forward, and sensory feedback mechanism
What is the feedforward, sensory feedback mechanism? Where is it located?
It’s in the cerebellum
Feedforward- provides information about the movements of the muscles, tendons and joints
This information is compared to the sensory feedback from the cerebral cortex.
Then corrections are made if necessary
What is ataxia
Lac of coordination of voluntary motor acts
The rate, range, timing, direction and force of movement may be affected
What is the difference better motor planning and motor programming?
Motor planning is NOT muscle specific; it sets sequential motor goals that are articulator specific
Motor programming IS muscle specific; motor programs are sets of motor specific commands
