Motor Cortex Flashcards
What area makes up M1?
4
What is the difference between M1-4p, and M1-4a?
M1-4a relies on sensory feedback
Which M1 area is responsible for initiation of movements/
M1-4p
What M1 area can be activated by imagining movements or listening to speech?
M1-4a
What results from lesions to M1?
Contralateral UMNL
- Weakness
What is the organization of M1?
- Arranged in columns related to movement and muscles acting on single joints
What 2 factors are determined by M1?
Force (frequency of firing)
Duration
How is direction determined by M1?
Algebriac summation of all possible trajectories being generated by the cortex
How are the sensory and motor humunculi different?
Motor has smaller lips
What tract predominantly originates from M1?
Corticospinal
What gyrus is M1 found on?
Precentral
From what lobe does the pre-motor area receive most of its afferents?
The parietal lobe
What triggers movements in the pre-motor area?
External sensory information
What does the PMA project to?
- Motor cortex
- Brainstem via ventral medial system
What are the 2 portions of the PMA?
Lateral dorsal
Lateral ventral
Is the lateral dorsal PMA related to reaching or grasping? The lateral ventral?
Lateral dorsal: Reaching
Lateral ventral: Grasping
What is meant by the associative learning that occurs in the lateral dorsal PMA?
- Associate sensory events with a motor output
What occurs with a lesion to the lateral dorsal PMA?
Difficulty with associative learning
What area of M1 is the lateral ventral PMA connected with?
The hand area
What are mirror neurons? Where are they found?
- Found in lateral ventral area of PMA
- Activate during observation of action
What type of learning occurs in the lateral ventral PMA?
- Higher order, abstract representations of goal oriented actions/ motor learning
What will occur with a lesion to the lateral ventral PMA?
- Can’t grasp as well
What is the function of the supplementary motor area (M2)?
- Plans complex movements
- Coordinates movements between both hands
- Integrates learned sequences from memory
Are motor commands initiated autonomously or by sensory input in M2?
Autonomously
What effects will a lesion to M2 have?
- Can’t orient digits and hands when reaching
- Can’t use hands together
- Can’t make postural adjustments during movement
What is the function of the pre-supplementary motor area?
- Semantic processing
What structures does the pre-supplementary motor area connect to?
- Caudate
- Frontal cortex
How do the basal ganglia, cerebellum, cerebrum, and spinal cord connect in the motor circuit?
- Basal ganglia provides reward system
- Cerebellum removes errors
- Cerebrum initiates movements
- Cerebellum gets a copy
- Command goes to spinal cord
What are the 6 executive functions of the prefrontal cortex?
- Planning ahead
- Monitoring
- Sustained attention
- Goal directed behavior
- Working memory
- Problem solving
What areas form the “What” pathway of the prefrontal cortex?
44, 45, 47, 12
What areas for the “Where/ How” pathway of the prefrontal cortex?
8, 9, 4, 6
Is the “What” pathway of the prefrontal cortex ventral or dosal? The “where” pathway?
What: Dorsal
Where: Ventral
What 3 functions are performed by the prefrontal lateral dorsal complex?
- Spatial relationships between stimuli
- Working memory
- Planning ahead
What are the functions of the prefrontal lateral ventral cortex?
- Characterizes stimuli in envrionment
- Selects/ retrieves semantic/ linguistic knowledge
- Inhibits rumination over problems to help with attention
What does the left side of the prefrontal lateral ventral complex do?
Control attention through distractions
What does the right side of the prefrontal lateral ventral complex do?
Vigilance
What chemical activates the prefrontal lateral ventral cortex?
Dopamine
What lobe does the prefrontal lateral ventral cortex work with?
Temporal
What is the function of the oribitofrontal cortex?
Regulates emotions
What are inputs to the OFC? What system generates these inputs?
- Fear
- Hunger
- Thrist
- Love
- Envy
- Generated by limbic system
What are outputs of the OFC?
- Behavior
- Physiological response
What are symptoms associated with lesions to the OFC?
- Inappropriate behavior/ emotions
- Impulsive
- Unprovoked emotions
- Lack of initiative
- Unable to plan or correct behaviors
- Inability to read emotions or non-verbals
What 2 senses related to the reward system stimulate the OFC?
- Smell
- Taste
What structures send signals to the OFC?
- Sensory systems
- Postcentral gyrus
- Limbic system
What effect to pain and pleasure have on the OFC?
Activation
What is the function of the cingulate gyrus?
- Emotion formation and processing
- Learning
- Memory
- Links response to pain
- Regulates aggression
