Neuroscience Flashcards
The function of the brainstem is
- postural control & locomotion
- a large number of facial connections
- Arousal and awareness
The brainstem is composed by
- hindbrain
- midbrain
- medulla
- pons
The cerebellum receives inputs from:
- receives input from spinal cord (feedback about movements)
- receives input from cerebral cortex (planning of movements)
The main purpose of the cerebellum
adjust the motor responses based on comparison of sensory feedback and planned movement
Diencephalon is composed by
- Thalamus
- Hypothalamus
Thalamus role
receives almost all information going to the cortex
Cerebral hemispheres composed by
- cerebral cortex
- basal ganglia
Basal ganglia function
planning of motor strategies
Areas of the basal ganglia
- Caudate nucleus
- Putamen
- Globus Pallidus
- Substantia Nigra
Cerebral cortex function
programming events
What is action potential?
Neurons that are excited have positive nerve impulses, or spikes
3 types of synaptic transmission
- summation (spatial vs temporal
- synaptic facilitation (releasing more transmitter)
- defacilitation (habitutation)
Spatial summation
larger presynaptic neurotransmitters are released until AP
temporal summation
a single presynaptic neuron is activated at a high enough frequency to elicit AP
Pheripheral Receptors
- Muscle spindle
- Golgi tendon organs
- Cutaneous receptors
Muscle spindle is concerned with
length or stretch
Where in the body do we find the highest percentage of spindles?
- eyes
- neck
- hands
What is the spindle made up of?
- Intrafusal fibers (nuclear bag, nuclear chain)
- Afferent neurons (Ia & II)
- Gamma motor neurons (gamma dynamic, gamma static)
Alpha motor neurons excite?
Extrafusal fibers
Gamma motor neurons excite
Intrafusal fibers
Gamma motor neurons are important for?
muscle tone
Dynamic stretch
connects to bag fiber
Static stretch
connects to bag and chain fiber
Ia
connects to bag and chain fiber
II
connects to chain
Ascending pathways
Dorsal column-medial leminiscal (DC-ML)
dorsal column- medial leminiscal is involved with
- fine touch
- vibration
- 2 point discrimination
- propioception
The Dorsal column- medial leminiscal decussation point occurs?
-lower medulla
Pathways for descriminative touch and conscious propioception how many neurons relay?
three-neuron
1st order neuron
from receptors to to the medulla
2nd order neuron
from medulla to thalamus
3rd order neuron
from thalamus to the cerebral cortex
secondary neurons include
- cell bodies located in the nucleus gracilis or cuneatus
- axons that cross the midline as the internal arcuate fibers, then ascend to the thalamus
Spinal nerves
- Dorsal funiculus/ dorsal column
- Lateral funiculus
- Ventral funiculus
Dorsal column divides into?
- fasciculus gracilis
- fasciculus cuneatus
Fasciculus gracilis
transmit information to the cerebrum coming from areas inferior to T6
Fasciculus cuneatus
transmits information to the cerebrum coming from areas superior to T6
first to second order neuron decussation occurs at?
medial leminiscus
Anterolateral system tracts
- spinothalamic tract
- spinoreticular tract
- spinomesencephalic tract
Anterolateral system role
- minor role in crude touch and pressure
- thermal
- nociception
Somatosensory is?
where we start to see cross-modality processing
association cortices is found in?
- parietal
- temporal
- frontal
- occipital lobes
exteroceptive sense
vision allows us to identify objects in space and determine their movements
visual proprioception
where our bodies are in space
vertical cells
rods and cones
horizontal cells connect to the vertical cells laterally, these are
rods and cones –> bipolar cells –> ganglion cells
horizontal cells are critical in?
regulating contrast sensitivity
Superior colliculus has a direct line of communication with?
auditory and somatosensory information
ventral stream
“what” stream (color, texture, shape, size)
dorsal stream
“where” stream (location, movement, spatial transformation)
the membranous labyrinth is filled with?
endolymph
Pyramidal tracts
from the cerebral cortex to the spinal cord and brain
the pyramidal tracts are responsible for?
the voluntary control of the musculature of the body and face
2 pyramidal tracts are
- corticospinal tract
- corticobulbar tract (facial nerves)
extrapyramidal tracts
originate in the brain stem to the spinal cord
the extrapyramidal tracts are responsible for?
the involuntary and automatic control of all musculature (muscle tone, balance, posture, and locomotion)
the 3 extrapyramidal tracts are?
- vestibulospinal tract (balance and posture)
- rubrospinal tract (upper extremity/ hand)
- tectospinal tracts (head/eye coordination)
What is the main function of the primary motor cortex?
to control absolute force and speed of movement
90% of the decussation occurs at?
lateral corticospinal tract (neck, shoulder, and upper extremity muscles)
the 10% of the decussation occurs at?
the anterior corticospinal tract (trunk and lower limbs)
All upper motor neurons terminate at?
the ventral horn of the spinal cord
what are the functions of the supplementary motor and premotor areas?
-areas send projection to primary motor cortex and spinal cord
Supplementary motor areas are activated when?
movements are planned (internal)
Premotor areas are activated when?
the presentation of a stimulus normally elicits a response (external)
the main function of the cerebellum is to?
adjust motor responses based on the comparison of sensory feedback and planned movement
the parts of the cerebellum are?
- Flocculonodular lobe (vestibular system)
- Vermis (execution of movement, muscle tone (gamma MN’s, feedforward command)
- Lateral hemispheres (planning, preparation and evaluation of movement)
Motor responses require cerebellar input from?
cerebral cortex and spinal cord
feeback from the cerebellum to the spinal cord through?
brainstem and cerebral cortex
the cerebellum is attached to the brainstem by?
- inferior cerebellar peduncle (afferents)
- middle cerebellar peduncle (afferents)
- superior cerebellar peduncle (efferent fibers)
the 3 lobes of the cerebellar cortex are?
- anterior
- posterior
- flocculonodular
the status and position of the individual and groups of muscle is sent to the?
cerbellum (anterior lobe)
The posterior spinocerebellar tract
nonconscious proprioception from ispsilateral lower limb and trunk
The anterior spinocerebellar
nonconscious proprioception from ipsilateral lower limb and trunk; conveying information regarding movement of muscle groups.
the cuneocerebellar tract
noncoscious proprioception form ispsilateral upper limb; equivalent of posterior spinocerebellar tract
Afferent tracts from the brainstem
information on coordination of movements and movements that govern equilibrium and maintenance of an erect posture
whta are the 3 afferent tracts from the brainstem
-olivocerebellar tract
-vestibulocerebellar fiber
reticulocerebellar fibers
