What does a brain machine interface measure to decode movements?
The activity of neurons in the motor cortex while a person imagines a movement.
What was the main result of the Hochberg study regarding decoding accuracy?
It was possible to decode the imagined reach direction with an accuracy of about 80 percent.
What device was implanted in the participant MN during the Hochberg study?
A Utah array consisting of 100 microelectrodes.
What was the task that participant T5 was asked to perform in the Willett et al. study?
focuses on BMIs for communication
To imagine doing handwriting.
2 utah arrays in M1 hand area
what injury did T5 have ?
C4 spinal injury
- paralysed from neck down
What is the specific type of decoding algorithm used in the Willett et al. study?
Recurrent neural network.
trained to decode characters
What was the error rate achieved by T5 when imagining handwriting without predictive text?
Around 5 percent.
How many characters per minute was T5 able to produce by the end of the study?
90 characters per minute.
similar to smart-phone typing speed !
strengths of willet et al.
- addresses degrees of freeedom limitation
- achieves peer typing speed
limitations of willet et al
- one participants
- needs a dedicted lab
not easily accessible
What are the two parallel systems of motor control involved in speech?
One through the cortex and one through the brain stem.
What muscles are primarily involved in speech production?
Lips, tongue, jaw, and larynx.
major peripheral nerves for control of speed and where they are located
brain stem
- facial nerve
- hypoglossal
- trigeminal motor
- laryngeal
cell bodies of these nerves in the brain stem (LMNs and premotor)
What happens if there is a lesion in the M1 face area?
cortical control
Complete loss of voluntary control over speech-related muscles.
Who first reported a specific functional deficit from damage to a part of the cerebral cortex?
Broca.
Fill in the blank: Broca’s area is located in regions _______ of the primary motor cortex.
44 to 45
What does damage to Broca’s area affect?
The ability to produce language, while comprehension remains intact.
despite still having ability to move mouth musles
What significant finding did Penfield discover regarding speech control?
A wide area of the cortex is involved in speech control beyond just Broca’s area.
What kind of injury did participant Bravo-1 experience?
Moses et al. 2021
A stroke in the pons
eye movements ok
True or False: The decoding process in the Willett et al. study was less advanced than in previous studies.
False.
What does an MRI scan from Bravo1 reveal in the pons?
A missing triangle indicating tissue destruction due to a stroke.
The intact tissue appears light gray while the damaged area is dark gray.
What major symptoms did Bravo1 experience due to the stroke?
- Anarthria (inability to talk)
- Quadriparesis (paralysis of all four limbs)
What communication method did Bravo1 initially use before the brain-machine interface?
Computer-assisted typing methods.
What device was implanted in Bravo1 to record neural activity?
Electrocorticography (ECOG).
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Introduction to Motor Systems42
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Muscle contraction mechanisms77
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Motor Units60
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Spinal interneurons and spinal reflexes65
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Motor neuron disease 126
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Motor neuron disease 274
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Proprioception and motor control51
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Rhythmic movement 137
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Rhythmic motor movements 255
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Voluntary control and descending pathways61
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Motor Cortex71
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Neural coding and brain machine interfaces60
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Neural coding and brain machine interfaces 241
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Oculomotor movements75
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superior colliculus68
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Vestibular Systems83
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Vestibular influences on oculomotor control and posture102
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Cerebellum and disease127
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basal ganglia + diseases135
