Midterm 2 - Units 4-5 Flashcards
What is the pathway for first order neurons?
They enter the spinal cord, and will split, one branch will ascend in the dorsal column to the brainstem ipsilaterally.
What is the pathway for second order neurons?
From the brainstem this branch will synapse with second order neurons. They cross the midline and ascend up to the thalamus.
What is the Anterolateral Pathway from the Periphery?
Periphery → Spinal Cord → The primary sensory neuron → Dorsal Horn → Second order neuron → Cross the spinal cord → Thalamus → Third order → Somatosensory Cortex.
DCML heavily influences what?
Vibration, Proprioception and Light Touch.
Anterolateral pathways influence what?
Pain, Temperature and Crude Touch/Tickle/Itch.
What is the Somatosensory Cortex?
Most complex processing of somatosensory information. (process from the contralateral side)
What factors are involved in coordinated movements?
Proprioception, Motor Planning, Nervous System Intergration.
What is the primary somatosensory system function and pathway?
Relays informations to the secondary somatosensory cortex then will be relayed to the parietal cortex.
What is the Parietal Cortex known as?
The “Multimodal Association Cortex”
What is the Parietal Cortex Function?
Involved in Spatial Analysis, Integration, Vision, Somatosensory and Vestibular System.
What is the pathway of the Vestibular System from the Periphery?
Periphery → Vestibular Nuclei via Vestibulo-Cochlear Cranial Nerve → Ipsilateral Side.
Where does information from the Vestibular System go?
The Brainstem → Cortex → Thalamus
What is the Vestibular System involved in?
Integration with Visual, Somatosensory information in the Parietal Cortex and Cerebellum
When does information get processed?
Not until 200ms that visual information is used to correct any error
The Nervous System uses Sensory input to…
Control motor commands, trigger commands and correct error.
Dorsal Column-Medial Lemniscus System Pathway
- First Order Neurons from the periphery to ipsilateral brainstem (medulla).
- Second Order Neurons From Medulla to the Contralateral Thalamus.
- Third Order Neurons from the Thalamus to the ipsilateral somatosensory cortex.
What are the three Anterolateral Pathways?
Spinothalamic, Spinorectular and Spinosencephalic Pathways.
What happens to second order neurons (Antrolateral)?
They cross the midline and ascend in the anterolateral white matter to the thalamus.
What is the Somatotopic Map?
They are neighboring neurons that represent neighboring body parts.
What are the Vestibular Nuclei Outputs?
Cortex and Cerebellum.
What is the difference between Somatosensory and Vestibular?
Somatosensory: Input triggers postural response (timing)
Vestibular: Input scales the response (amplitude)
What is Selective Attention?
The process of directing our awareness to relevant stimuli while ignoring irrelevant stimuli in the environment.
What factors do we have to shift our attention between?
Events in the environment, Correcting our actions, and Planning future events.
What is Endogenous Attention?
Consciously direct attention to a particular aspect in the environment. (Voluntary choice based on current goals)
What is Exogenous Attention?
Unexpected stimulus causing a shift of attention/focus from what’s being attended to.
What is Visual Selective Attention?
Measured by recording eye movements.
What is Foveation?
Only a small area in the retina that has clarity with perception.
What is Fixation?
Eyes are fixed on an object, determine whats important.
What is Saccade?
The shift from one fixation to another (Rapid/Involuntary).
What is Smooth Pursuit?
Eye movement where we are taking in information (Slow/Tracking).
What is Auditory Selective Attention?
Paying attention to one ear while ignoring the other, limited capacity to process multiple inputs.
Signal Detention Theory?
The ability to differentiate between “information-bearing patterns” stimulus and “random patterns” that are distractors.
What is perceptual sensitivity (d’) ?
The ability to make correct decisions by distinguishing signals from noise.
What is Criterion (B) ?
A cut off point; moving it changes the outcome.
What are the effects of shifting the criterion?
Top: Criterion is low leading to an increase of hits and high false alarms.
Bottom: Criterion is high leading to a decrease of hits and low false alarms.
What happens when there are beta changes?
The position of the criterion effects the number of correct hits/errors.
What is Discrimination Reaction Time?
More than one signal, but only one correct response.
What impacts DRT?
Crossman’s Confusion Function
What is Static Visual Acuity?
The ability to distinguish details of static objects when both object and subject are static.
What is Dynamic Visual Acuity?
It identifies details of visual targets when there are movements between the object and subject.
What is Optical Flow Field?
The movement or contraction of all stimuli within a field of view.
What is Time To Contact?
Uses environment information in the initiation of movement.
What is the function of The Primary Motor Cortex (M1)?
The initiation and execution of movement, both direct and indirect connections with alpha motor neurons.
What are the major inputs for M1?
PMS, SMA, primary somatosensory, parietal (area 5), the basal ganglia and the cerebellum.
What are the Outputs for M1?
Motor Nuclei ; Basal Ganglia and Spinal Cord.
What is the Premotor Area (PMA)?
Multi-sensory inputs caused by muscle contraction at multiple joints.
What are the Supplementary Motor Areas (SMA)?
Involves in self-initiated tasks/goal directed, also associated with bimanual control and influenced by the basal ganglia.
What is the Motor Association Neurons function?
The planning of movements, neurons will fire before the movement occurs and continues during the movement.
What are the Lower Motor Neurons?
cortical/brainstem activation (LMN).
What is the pathways for the Upper Motor Neurons?
Originate in the cortex and brainstem, terminates in the spinal cord.
What are the Lateral (Dorsal) Motor Systems?
Lateral (direct) corticospinal and (indirect) rubrospinal tract; goal directed limb movements associated with distal muscles.
What are the Medial (Ventral) Systems?
Anterior (direct) corticospinal, (indirect) vestibulospinal, recticulospinal and tectospinal tract.
What is the Lateral Corticospinal Tract?
- Controls distal muscles
- Originates in the cortex
- Involved with M1, PMA/SMA and Somatosensory Cortex.
What is the Anterior Corticospinal Tract?
- Originate in the primary/premotor.
- Remains uncrossed until spinal cord
- Controls bilateral muscles.
What is the Lateral Vestibulospinal Tract?
Lateral vestibular nuclei and can travel ipsilaterally to the spinal cord, involved in the balance and extensor muscle tone.
What is the Medial Vestibulospinal Tract?
Medial vestibular nuclei, travels bilaterally to the cervical/thoracic spinal cord, involved in the positioning of the head/neck.
What is the Recticulospinal Tract?
Originates from Reticular formation and travels to the spinal cord ipsilaterally.
What is the Tectospinal Tract?
Originates from the superior colliculus and is involved in the eye movement and head control.
What is the Rubrospinal Tract?
Originates from the red nucleus, crosses the midline at the midbrain, involved in goal directed movements and distal muscles.
What is the function of the Basal Ganglia?
Planning of complex movements.
What is the Caudate?
“C” shaped structure (head, body and tail) an input nuclei for the basal ganglia.
What is the Putamen?
Round lateral structure, input nuclei for the basal ganglia, and has cellular bridges to the caudate nucleus.
What is the Globus Pallidus?
Internal medial component (GPi) and External lateral component (GPe). Located on the medial side of the putamen.
The GPi is a major output for nuclei of the basal ganglia.
What is the Subthalamic Nucleus?
Inferior to the thalamus, and has a spindle shape, and has communications with the globus pallidus.
What is the Substantia Nigra?
- Pars Compacta: Dorsal and has dark pigmentend dopaminergic neurons.
- Pars Rectiulata: Vental and is an output nuclei for the basal ganglia.
What is the Basal Ganglia Direct Pathway Structure?
- Striatum receives input from the cortical areas. The cortex is exciting the striatum (more active).
- It has inhibitory projections to the globus pallidus internal (GPi) which inhibits the thalamus.
- Disinhibits the thalamus (removing inhibition)
- Excite the cortex.
What is the Basal Ganglia Indirect Pathway Structure?
1.Cortex exciting the striatum, then neurons will travel to the globus pallidus external (GPe)
2. This inhibits the GPe and excited the striatum.
3. GPe has connections to the subthalamic nucleus which disinhibits.
4. Then travels to the GPi to be activated, GPi has inhibitory effects on the thalamus.
5. Back to the cortex.
What is Parkinson’s Disease?
Caused by neuron death in the Substantia Nigra leading to the loss of dopamine.
What is the function of the Cerebellum?
- Timing: Correct order/timing of individual muscle activation.
- Coordination: Assemble components of complex multi-joint/limb movement.
- Comparator: Compensates for errors in movement by comparing sensory feedback with motor intention.
- Motor Learning: Continually correcting for errors to then develop new motor skills.
What is the structure of the Cerebellum?
Dorsal to the pons, it has outer grey matter (cortex) and inner white matter.
What is the Cerebrocerebellum?
- Originates from the Cerebral Cortex.
- Input from Efference copy.
- Inputs to the Lateral Hemisphere
- Has deep Cerebellar Nuclei from the Denate.
- Output to the Cortex via Thalamus.
- Function: Planning and executing movements.
What is the Spinocerebellum?
- Originates from the Peripheral Somatosensory Receptors.
- Inputs from Multi-Sensory.
- Inputs to the Intermediate Hemisphere and Vermis
- Has deep Cerebellar Nuclei from Interposed (Emboliform and Globose) and Fastigial.
- Output to the Cortex via Thalamus/Red Nucleus and Brainstem.
- Function: Regulates limb/body movements; balance and tone.
What is the Vestibulocerebellum?
- Originates from the Semicircular Canals and Otoliths Organs.
- Inputs from Vestibular and Visual Systems.
- Inputs to the Flocculondular lobe.
- Output to the Vestibular Nuclei.
- Function: balance and eye movements.
What is Dysmetria?
Abnormal Amplitude: Over/undershoot of movement.
What is Dysrhythmia?
Abnormal rhythm and timing of movements.
What is Dysdiadochokinesia?
Abnormality to perform alternating movements.
What is Hypotonia?
Abnormally low muscle tone.
What is Cerebellar Ataxia?
Abnormal execution of multi-jointed voluntary movements, lack of coordination.
What is Appendicular Ataxia?
Ataxic Movements of the extremities (tremor).
What happens when there are lesions of the Flocculondular Lobe?
Unstable stance, gait impairments and visuomotor difficulties.
What is Non-Associative Learning?
Change in communication between neurons which can increase/decrease it’s ability to respond.
What is Associative Learning?
Associating one stimulus with another; conditioned a response.
What is Procedural Learning?
Learning to perform tasks at a more automated/less conscious thought.
What are the Neural Structures of Motor Learning?
In the initial phase, the M1, V1, SMA, PMA BG, and Cerebellum are active.
What happens when learning turns into long term memory?
- A ↓ in activity in the Cerebellum, Posterior Parietal and Prefrontal Cortex.
- SMA activity and Striatum.
What happens when we reduce the activation of the premotor areas?
There’s an ↑ of errors when learning a new task.
What happens when there is damage to the Cerebellum?
Difficulty with adapting motor behaviour, can’t update motor plans/reduce errors.
What is Trial and Error Learning?
Performing a task after an error, taking the error into account and adjusting/adapting.
What is Plasticity?
Structural and Chemical changes in the nervous systems.
What are the Synpatic Modification Short Term Effects?
Strengthens the synapse between two neurons.
What are the Synpatic Modification Long Term Effects?
There are changes in the structure of the Pre/Post Synaptic Neuron.
What is the difference in Early Development Vs Neuroplasticity in an Adult?
Early Development: Structural Changes.
Neuroplasticity in Adults: Synpatic Strengthening/Chemical Related Changes.
What are the 4 factors that influence RT?
- Number of Stimulus-Response Alternatives (CRT and Hick’s Law)
- Stimulus-Response Compatibility.
- Population Stereotypes.
- Practice and Anticipation.
How does the Number of S-R Alternatives influence RT?
↑ of the number of Alternatives/Stimulus/Responses = ↑ amount of time to respond/react to the stimulus.
What is Hick-Hyman Law?
CRT = a + b log2 (N)
How does Stimulus-Response Compatibility influence RT?
If you ↑ the relationship between Stimulus and Response = Reduces the RT required to make a decision.
How does Population Stereotypes influence RT?
We act habitually due to specific cultural/societal learning.
How does Effect of Practice influence RT?
2 Major Effects: Amount of practice and Nature of practice.
What are the three types of Predictions?
Event: What is going to happen.
Spatial: What an event is going to be.
Temporal: When an event will occur.
