Term
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Definition
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Term
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Definition
| sensory info travels up it to the brain |
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Term
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Definition
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Term
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Definition
| (sometimes called anterolateral column)- carry pain info up and motor info down. |
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Term
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Definition
| also called the corticospinal tracts. Take info from brain and send it to the muscles |
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Term
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Definition
-Has two hemispheres.
-Receives sensory info from spinal cord
-Receives motor info from cerebral corex
-Receives balance info from inner ear
1) deals with motor control, especially postural adjustment and fine tuning movements
2) essential for coordination and planning of movements, learning motor tasks and storing this information.
3) Also used in functions like language |
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Term
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Definition
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Term
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Definition
Part of brainstem
Medulla regulates BP and respiration |
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Term
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Definition
Part of brainstem.
Pons relays from cortex to cerebellum, respiration, taste and sleep |
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Term
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Definition
Part of brainstem
auditory and visual system, dopanergic neurons |
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Term
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Definition
| Contains thalamus and hypothalamus |
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Term
| Organization of cerebral cortex |
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Definition
1. Layer IV: primary input layer
2. II (ipsilateral) and III (contralateral) are cortico-cortical output
3. V (basal ganglia/thalamus/brainstem/spinal cord) and VI (thalamus/claustrum) are descending output |
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Term
| What inactivates sodium channels? |
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Definition
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Term
| What inactivates potassium channels? |
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Definition
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Term
| Why do APs exhibit all or nothing behavior? |
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Definition
| At potentials below threshold not enough Na+ channels open to raise potential high enough to open more channels-at potentials above threshold action potential cycle is activated. |
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Term
| What is the undershoot caused by? |
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Definition
| at some point K+ channels are open and Na+ channels closed, this causes more K+ to flow out than at rest, hyperpolarizes the cell and then inactivates voltage sensitive K+ channels. K+ leak channels and ion transporters bring back cell to resting potential |
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Term
| What causes AP propagation? |
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Definition
Charge rushing in from Na+ chanels can diffuse
inside the axon. Cannot diffuse very far because
of current leakage. Potentials below threshold
taper out fast.
• Potentials above threshold cause increased
depolarization (due to more Na+ channels open).
Now there is enough potential to diffuse laterally
and be above threshold for a new set of Na+
channels. |
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Term
| What causes refractory period? Why don't AP fall back on themselves? |
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Definition
This makes it harder to initiate a new action either from a
new stimulus or from a cut-back of the AP.
• Na+ channels also delay in re-opening after closing. |
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Term
| List the ten stages of synaptic transmission |
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Definition
1.
1. Neurotransmitter is synthesized and packaged into vesicles.
2. An action potential arrives at the presynaptic terminal.
3. Depolarization causes opening of voltage gated Ca++ channels.
4. There is an influx of Ca++ 10-4 outside 10-7 inside. Rushes in fast.
5. Ca++ causes vesicles to fuse with membrane.
6. Neurotransmitter is released into cleft.
7. Transmitter binds to receptors on postsynaptic cell.
8. This opens or closes postsynaptic channels.
9. Postsynaptic current flows inside post-synaptic cell.
10. Retrieval of membrane via endocytosis. |
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Term
| What defines a neurotransmitter? |
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Definition
1.
1. Must be present in the presynaptic neuron.
2. Must be released in response to a depolarization and be Ca2+ dependent.
3. Must have specific receptors localized on the post-synaptic cell.
4. Note: It does not have to be uniquely a neurotransmitter, may have other functions. For example glutamate, glycine, ATP. |
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Term
| What are catecholamines derived from? |
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Definition
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Term
| What is serotonin derived from? |
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Definition
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Term
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Definition
| The major brain area containing dopamine is the corpus striatum which coordinates body movements. Also believed to be involved in motivation, reward and reinforcement. |
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Term
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Definition
| G-coupled. Activates or inactivates adenylyl cyclase |
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Term
| Removal of dopamine from synapse |
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Definition
| Reuptake of dopamine by neurons or glial cells by a sodium-dependent dopamine transporter (DAT) |
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Term
| Glutamate receptors (ionic) |
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Definition
All three are ionotropic, nonselective cation channels
Always produce excitatory responses
1. NMDA (allows entry of calcium as well; opening requires coagonist, glycine)
2. AMPA
3. kainate |
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Term
| Name the two most common inhibitory neurotransmitters |
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Definition
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Term
| Ionotropic GABA receptors |
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Definition
A. usually inhibitory because they are permeable to Cl
B. Form is of petamers.
C. Has binding sites for GABA, barbituates, steroids, all on within the pore domain. Outside the pore is a binding site for benzodiazepines. |
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Term
| GABA receptors (metabotropic) |
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Definition
A. Widely distributed throughout the brain.
B. Also inhibitory due to activation of potassium channels.
C. Sometimes blocks calcium channels (tends to hyperpolarize cells). |
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Term
| Innervation of muscle spindle |
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Definition
| By group 1A (detect changes in length) and II (detect sustained tension) afferents. |
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Term
| What kind of muscles have few spindles? What have many? |
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Definition
| Large muscles; hands and neck |
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Term
| What kind of fibers innervate Golgi tendons? |
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Definition
| Type IB afferents. Detect changes in force/tension. |
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Term
| What is the name of the system that takes tactile information from the body up to the brain? |
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Definition
| Dorsal Column-Medial Lemniscal System |
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Term
| What is the name of the system that takes tactile information from the face to the brain? |
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Definition
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Term
| What goes to the ventral posterior complex of the thalamus? |
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Definition
| ascending somatic sensory pathways coming up from brainstem and spinal cord |
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Term
| What are general properties of nociceptors? |
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Definition
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Term
| Name the two faster pathways that respond to dangerously intense mechanical and/or thermal stimuli |
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Definition
| Aδ mechanosensitive and mechanothermal nociceptors |
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Term
| What respond to thermal, mechanical and chemical stimuli? |
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Definition
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Term
| What are the two types of pain? |
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Definition
| First (sharp, mediated by Aδ) and second (slow and aching, C fibers) |
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Term
| Where do the axons of nociceptor nerves enter the spinal cord? |
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Definition
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Term
Where do the the axons of cutaneous mechanosensory afferents enter the spinal cord?
What side do the majority of the mechanosensory axons go up? |
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Definition
Dorsal roots
Ipsilaterally through dorsal columns |
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Term
| Where do the axons for proprioceptic afferents enter the spinal cord? |
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Definition
| Same as cutaneous sensation, through the dorsal roots |
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Term
| What is the difference between cutaneous sensory and pain nerves? |
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Definition
Proprioceptic bifurcate into ascending and descending branches.
They are on opposite sides below the medulla |
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Term
| General qualities of sensory receptors: What is the QUALITY of a stimulus determined by? |
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Definition
| The quality of stimulus (what it represents and where it is) is determined by the relevant receptor, and neuron’s targets in the brain. |
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Term
| General qualities of sensory receptors: What is the QUANTITY or strength determined by? |
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Definition
Quantity or strength of stimulus is
determined by the rate of action potential
discharge. |
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Term
| All sensory axons map where? |
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Definition
| All map to primary somatic sensory cortex, located in the central sulcus. |
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Term
| What pathway do mechanoreceptors and proprioceptors use? |
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Definition
Mechanoreceptors and proprioception receptors use the
Dorsal-column-medial lemniscus pathway |
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Term
| What pathway do pain and temperature afferents take? |
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Definition
| • Pain and temperature use spinothalamic (anterolateral pathway) |
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Term
| Where do sensory axons from the dorsal root ganglia end up in the brain? |
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Definition
They terminate in the gracile and cuneate nuclei (dorsal column nuclei) in the caudal (posterior) medulla.
Axons are organized such that lower limbs are mapped medially (gracile tract) and the upper limbs, trunk, and neck in the Cuneate tract. |
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Term
| Name the two somoatosensory parts of the thalamus |
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Definition
ventral posterior complex:
-VPL receives projections from the medial lemniscus carrying all somatic sensory information
from the body and posterior head.
-VPM receives axons from the trigeminal info from the face.
-VPC contains a complete representation of the body. |
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Term
| Explain the distinctions between the pain and mechanosensory pathways |
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Definition
1. for mechanosensors, axons enter the spinal cord, turn and ASCEND in the ipsilateral dorsal columns all the way to the medulla, where they synapse on neurons in the dorsal column nuclei, THEN cross the midline and ascend to the contraleral thalamus
2. for pain, first order neurons terminate in the dorsal horn, and second order neurons send their axons across the midline and ascend on the contralateral side of the cord to their targets in the thalamus and braqinstem. |
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Term
| What would a unilateral spinal cord lesion result in? |
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Definition
| a unilateral spinal cord lesion results in dorsal column symptoms on the side of the body ipsilateral to the lesion, and anterolateral symptoms (pain and temperature defects) occur on the contraleral side of the body |
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Term
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Definition
| Axons from neurons with low-threshold mechanoreceptors synapse onto inhibitory neurons in spine. The activation of inhibitory interneurons dampens pain signal |
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Term
| Name the three chemosensory systems in the face |
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Definition
| Olfactory, gustatory, trigeminal |
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Term
| Describe the pathway of olfaction |
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Definition
Olfactory receptors synapse onto olfactory bulb via olfactory nerve.
Olfactory bulb synapses onto various targets such as:
Pyriform cortex
Olfactory tubercle
Amygdala
Entorhinal cortex
From there, they synapse on
Thalamus
hypothalamus
hippocampus
Orbitofrontal cortex |
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Term
| What is the only sensory system not gated by the thalamus? |
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Definition
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Term
| Can olfaction influence behavior? |
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Definition
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Term
| What does the vomeronasal organ do? |
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Definition
Pheromone detection
Projects directly to amygdala |
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Term
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Definition
|
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Term
| Describe olfactory epithelium structure |
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Definition
| Oflactory cilia project from the olfactory knob. The axons project through the cribiform plate to the olfactory bulb |
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Term
| What kind of receptors are olfactory receptors? |
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Definition
| G protein coupled receptors |
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Term
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Definition
| are broadly tuned but can detect subtle differences (R form from S form) |
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Term
| Name the three kinds of papillae |
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Definition
Fungiform
Circumvallate
Foliate |
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Term
| What are the three types of movements |
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Definition
Reflex
Rhythmic motor
Voluntary |
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Term
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Definition
| Sum total of extrafusal muscle fibers innervated by a single alpha motor neuron |
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Term
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Definition
| More stimulation leads to more contraction. Provides a range of forces to perform different motor tasks |
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Term
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Definition
| All motor neurons innervating a single muscle |
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Term
| Stretch reflex is modulated by... |
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Definition
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Term
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Definition
Helps prevent fatigue
helps maintain constant force |
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Term
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Definition
| Golgi tendons fire when muscle contracts; spindle does not (spindle feels stretch) |
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Term
| What does muscle spindle primarily sense and control? |
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Definition
| Sense stretch and controls length. |
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Term
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Definition
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Term
| What are brainstem areas especially important for? |
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Definition
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Term
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Definition
Receive info from inner ear
project to medial (middle) regions of spinal gray matter
control axial and proximal limbs
called vestibulospinal tract |
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Term
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Definition
Projects to medial cell groups in cervical cord
influences neck muscles |
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Term
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Definition
Recieves input from higher motor cortex
Important for posture
Called reticulospinal tract |
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Term
| What tract is important for muscle anticipation of movement? |
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Definition
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Term
| What is the direct pathway between the motor cortex and spinal cord |
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Definition
| Lateral corticospinal tract |
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Term
| What does the lateral corticospinal tract control? |
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Definition
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Term
| Do axons of the lateral corticospinal tract cross the midline? |
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Definition
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Term
| If the corticospinal tract is cut, what will it affect and not affect? |
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Definition
Will affect distal find movements
Will not affect walking, running |
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Term
| What is the indirect pathway between the motor cortex and the spinal cord? |
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Definition
| Corticoreticulospinal tract |
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Term
| What is the name of the primary motor pathway to facial muscles called? |
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Definition
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Term
| Where is the motor cortex located? |
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Definition
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Term
| Where is the primary motor cortex located? |
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Definition
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Term
| What does the motor cortex get input from? |
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Definition
| Basal ganglion and cerebellum |
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Term
| What is the output layer of the motor cortex? |
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Definition
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Term
| What side does the primary motor cortex control? |
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Definition
| Contralateral side of the body |
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Term
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Definition
| Important in conditional motor tasks that pair a movement with a visual cue |
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Term
| What is used for intention to move? |
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Definition
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Term
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Definition
Mediates selection of movements
Important for selecting movements based on memory |
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Term
| What are the three main nuclei of the basal ganglia? |
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Definition
Caudate
Putamen
Globus pallidus |
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Term
| Aside from its three nuclei, what else interacts with the basal ganglia to make a full loop in the cortex with upper motor neurons? |
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Definition
| Substantia nigra and the subthalamic nucleus |
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Term
| What are the basal ganglia neurons needed for? |
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Definition
|
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Term
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Definition
| Contains the caudate and putamen |
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Term
| What is the input zone for the basal ganglia? |
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Definition
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Term
| What two areas do NOT project to the corpus striatum? |
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Definition
| Primary auditory and visual cortices. |
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Term
| What is the primary input(s) to the caudate? |
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Definition
| association corticies and motor areas that control eye movements |
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Term
| What is the primary input(s) to the putamen? |
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Definition
| Primary and secondary sensory cortex and visual cortex, premotor and motor cortex, auditory association areas |
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Term
| What kinds of inputs does the basal ganglia receive? |
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Definition
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Term
| What other inputs, aside from the caudate and putamen do the medium spiny neurons (MSNs) get? |
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Definition
| dopaminergic inputs from the substantia nigra pars compacta |
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Term
| Why are MSNs usually silent? |
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Definition
| Because they need lots of stimulation. |
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Term
| What do the putamen neurons tend to fire in anticipation of? |
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Definition
|
|
Term
| What do the caudate neurons tend to fire in anticipation of? |
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Definition
|
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Term
| What kind of projections come from MSNs of putamen and caudate? |
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Definition
| Inhibitory GABAnergic projections. |
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Term
| Where do the putamen and caudate project? (also the main OUTPUT center of the basal ganglia) |
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Definition
| globus pallidus and the pars reticulata |
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Term
| Where does the globus pallidus internal neurons then project? |
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Definition
| Back to the cortex vial the thalamus |
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Term
| What is the output from the basal ganglia normally? |
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Definition
|
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Term
| Where do the pars reticulata neurons project? |
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Definition
| To the superior colliculus that commands eye movements without going through the thalamus. |
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Term
| What are the two direct pathway of outputs from the basal ganglia? |
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Definition
Caudate project to pars reticulata, which projects to the superior colliculus
Putament project to the globus pallidus which projects to the thalamus which projects to the frontal cortex |
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Term
| Is the direct pathway between the putament and the cortex excitatory or inhibitory? |
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Definition
|
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Term
| Describe the indirect pathway of the basal ganglia |
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Definition
| Cortex to putamen to globus pallidus external to subthalamic nuclei to globus pallidus internal to thalamus back to cortex |
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Term
|
Definition
| Violent involuntary movements of limbs |
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Term
| What part of the indirect loop of the basal ganglia fails in people with hemiballismus? |
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Definition
| subthalamic nucleus of the contralateral side of movements |
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Term
| Dopamine is used by the direct pathway to: |
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Definition
|
|
Term
| Dopamine in the indirect path is used to... |
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Definition
|
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Term
| Aside from the cortex, what else projects to the caudate/putamen? |
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Definition
| Substantia pars nigra compacta |
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Term
| What fails in the basal ganglia to cause Parkinsons? |
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Definition
| The degeneration of dopanergic neurons projecting from the substantia nigra pars compacta |
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Term
| What causes huntingtons disease? |
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Definition
| Progressive deterioration of the caudate and putamen |
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Term
| Center surround circuit: describe in detail the ON signal |
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Definition
1) A cone synapses with two bipolar cells, an "on center" and an "off center"
2)"On center" are INHIBITED by glutamate
3) "Off center" are ACTIVATED by glutamate
to signal "on"
Light hits cone, leads to hyperpolarization, decrease in glutamate release
On center gets less glutamate, becomes depolarized, releases more glutamate
On center retinal ganglion cell gets more glutamate and depolarizes |
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Term
| Center surround: describe off circuit |
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Definition
1) A cone synapses with two bipolar cells, an "on center" and an "off center"
2)"On center" are INHIBITED by glutamate
3) "Off center" are ACTIVATED by glutamate
to signal "off"
Light hits cone, hyperpolarization, decrease in glutamate release
off bipolar gets less glutamate, hyperpolarized, decrease in glutamate
off RGC gets less glutamate, not depolarized |
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Term
| Center surround: The surrounding! |
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Definition
When the surround is illuminated, cones hyperpolarize, decrease glutamate release
less glutamate means less hyperpolarized horizontal cell, less GABA released
Less GABA means depolarize photoreceptors including center which INCREASES glutamate
More photoreceptor glutamate release means less on center RGC firing |
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Term
| What are the four main retinal ganglion targets? |
|
Definition
Dorsal lateral geniculate nucleus
Pretectum
Superior colliculus
Suprachiasmatic nucleus |
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Term
| Dorsal lateral geniculate nucleus |
|
Definition
dLGN
located in thalamus
receives visual info from retina, relays to cortex
most important retinal projection for visual perception |
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Term
| What is the most important retinal projection for visual perception? |
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Definition
| Dorsal lateral Geniculate Nucleus |
|
|
Term
| What is responsible for the pupillary light reflex? |
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Definition
|
|
Term
| What does the superior colliculus coordinate? |
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Definition
|
|
Term
| What retinal target is involved with day and night cycles? |
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Definition
|
|
Term
| What is the first site of cortical visual processing? |
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Definition
|
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Term
| Where does the pretectum project to? |
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Definition
| Edinger westphal nuclei--which projects to cilliary ganglion that project to iris constrictor muscles |
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Term
| What is used for reflexive actions, related to vision? |
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Definition
|
|
Term
| The left visual field is processed by neurons on which side of the brain? |
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Definition
|
|
Term
| What does the primary visual cortex receive input from? |
|
Definition
| Dorsal Lateral Geniculate Nuclei |
|
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Term
|
Definition
| 1. Gain: The level of gamma motor neuron activity, also called gamma bias. |
|
|
Term
| How can gain be adjusted? |
|
Definition
| Gain can be adjusted by upper motor neuron pathways as well as by local reflex circuitry. |
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