EX3 Neuro - Reticular Formation and Cerebellum Flashcards
Where are the raphe nuclei located
midbrain
pons
medulla
- medial nuclei of reticular formation
Where do midbrain raphe nuclei project
cerebral cortex
Where do pontine and medullar raphe nuclei project
spinal cord
Where does the nucleus rape magnus project
spinal cord
What neurotransmitter is associated with the raphe nuclei
serotonin; to supress pain
Where is the raphe spinal tract located
begins at dorsal raphe nucleus, decussates at midbrain
Where does the raphe spinal tract project
synapses on interneurons in lamina I, II, V of spinal cord
What is the relationship between the periaqueductal gray and pain control
it receives and inhibits pain signals
What is the relationship between the PAG and motor behavior
regulates heart/respiration rates
initiates defensive and reproductive behaviors
What is the major source of input to the PAG
ascending sensory system
descending signals from limbic system
Where is the locus ceruleus
located between base cerebellar attachment point and rostral pons “brain watchtower”
What is the input to the locus ceruleus
afferents from hypothalamus (also cingulate gyrus, amygdala)
What are the targets of the neurons that make up the locus ceruleus
excitatory effect on most of the brain
What is the neurotransmitter associated with locus ceruleus and its effect
norepinephrine; pain inhibition
Where is the ventral tegmental area locate
floor of midbrain tegmentum
What are the two major tracts that arise from the ventral tegmental area
mesocortico fibers; to frontal cortex
mesolimbic fibers; to nuclus accumbens and striatum
What is the neurotransmitter associated with the ventral tegmental area and its effect
dopamine; DO things
reward, pleasure, euphoria
The ascending reticular activating system controls what
sleep and wakefulness
How does the dorsolateral pontine tegmentum control sleep and wakefulness
via sending acetylcholine to hypothalamus which promotes wakefulness and to the cortex to maintain wakefulness
How does the hypothalamus control sleep and wakefulness
when the anterior hypothalamus is active = sleep
inactive = awake
What is the switch from asleep to awake
lateral hypothalamus; it maintains being awake
What three things are connected via the sleep - wake cycle
locus ceruleus
raphe nuclei
pontine tegmenum
What cavity of the skull is the cerebellum found
posterior cranial fossa
What is the primary function of the cerebellum
motor coordination; output of motor cortex and motor nuclei
These are the cells that contain the only axon that leaves the cortex aiming for the cerebellar nucleus
Purkinje cells
These fibers arise from spinal cord and brainstem sensory pathway relaying signals from proprioceptive receptors
mossy fibers
These are excitatory cells that give rise to parallel fibers
granular cells
These cells lie in one layer, perpendicular to the parallel fibers
Purkinje cells
Activation of granular cells (via mossy fibers) produce what
simple spikes from Purkinje cells of which are inhibitory (GABA)
What causes Purkinje cells to produce complex spikes
climbing fibers from the inferior olive
What are the three peduncles that connect the cerebellum with the brainstem
superior cerebellar
middle cerebellar
inferior cerebellar
The superior peduncle carries fibers which direction in regards to the cerebellum
out (and in)
The middle peduncle carries fibers in which direction in regards to the cerebellum
in
The inferior cerebellar peduncle carries fibers in which direction in regards to the cerebellum
in (and out)
What sensation is carried in the spinocerebellar tract
joint and limb location
What are the three physiological subdivisions of the cerebellum
vestibulocerebellum
spinocerebellum
pontocerebellum
What does the vestibulocerebellum correlate to regarding anatomical subdivisions
flocculonodular lobe
fastgial nucleus
What does the spinocerebellum correlate to regarding anatomical subdivisions
paranormal area
interposed nucleus
What does the pontocerebellum correlate to regarding anatomical subdivisions
lateral hemisphere
dentate nucleus
The motor cortex does what in the CTCC loop
send out two signals to do a certain action (raise big toe 1 cm)
The first signal from the motor cortex in the CTCC loop goes where
to the spinal cord and spinal musculaure to move the intended target
The second signal from the motor cortex in the CTCC loop goes where
to the pons, then cerebellum; essentially waiting for the propioception response
Once the cerebellum (CTCC) receives the propioception response, what happens
modifications are made if need be; sending signals to the thalamus then to motor cortex again and out once more
The olivo-cerebellar loop is responsible for what
control the timing over short-term
activation of the climbing fibers from inferior olive
“error or teaching” signal
A flocculonodular lobe lesion affects which cerebellar region
vestibulocerebellar tract
What is the result of a flocculonodular lobe lesion
nystagmus; back and forth eye movements (slowly in one direction, fast in the other)
truncal ataxia; disturbances in balance while seated
“inabilty to follow finger”
A paravermal/vermal lesion will affect which cerebellar region
spinocerebellar tract
What is the result of a paraverma/vermal lesion
stance and gait ataxia
“inability to walk white line”
A lesion of the lateral hemisphere affects which cerebellar region
pontoerebellar tract
What is the result of a lesion of the lateral hemisphere
involvement of arm and speech
intention tremors
dysmetria “finger-to-nose” failure (too far or too short)
dysarthria;explosive or slurred speech
What does the martini do to the olive?
Increased activity in inferior olive with tremors
Dysfunction of electrical synapses in inferior olive
