Neuroprosthese and Brain-Machine Interfaces

Question 1

Neuroprostheses designed to? Uses…? It’s an interface for…? (2) What do they do?

Answer 1

• Designed to interface directly with the CNS or PNS via …
• Selective electrical stimulation of sensory or motor pathways
• Interface with peripheral sensory or motor nerve
• Interface with particular network within a specified region of the cortex
• Record and interpret activity within the nervous system for use in guiding robotics, prosthetics, assistive devices

Question 2

Neuroprostheses can use?

Answer 2

arrays of microelectrodes that can penetrate into neural tissue and stimulate or record from them

Question 3

Microelectrode arrays can be used to detect? (3)

Answer 3

• Detect sounds to allow functional hearing via a cochlear implant for some people with profound deafness
• Detect points of light allowing implants into the occipital cortex to provide some vision after cortical blindness
• Detect brain wave patterns in the primary motor and other areas and use those to control a cursor on a computer screen (and ultimately wheelchairs, etc.)

Question 4

Neuroprosthesis: Paraplegic stance - difficulty is to? Another difficulty? Need to? The challenge is to?

Answer 4

• Difficulty is to activate the motor neuron pools in a manner that’s similar to actual physiological process
• Larger, less selective electrodes activate too many MN’s at once. Causes the entire MN pool to be activated maximally, often creating tremors, and fatiguing very quickly.
• Need to selectively activate muscle fibers at submaximal levels, and vary which fibers are activated from one moment to the next.
• The challenge is to create graded muscle contractions that can be maintained for long periods to support standing posture

Question 5

Neuroprostheses for controlling prosthetic limbs - red and blue circles represent? Actuators are designed to?

Answer 5

• Red represents motor, blue sensory (check this!)
• Actuators at the joint are designed to
move the prosthesis …
in response to signals derived from sensors in the prosthetic hand and projected back to the CNS

Question 6

Targeted Muscle Re-innervation: DARPA Arm - sx done to? Target mm are?

Answer 6

• Surgery done to transfer intact residual nerves to muscles in the residual limb or chest
• Target muscles are “reinnervated” so the individual can use those muscles to control the prosthesis

Question 7

What is a fully integrated prothesis? How does it work? It provides?

Answer 7

– Proto-1©
• Targeted muscle re-innervation allows muscle signals to control 8 degrees of freedom controlled by muscle signals
• Prosthesis provides sensory feedback to allow for more fine-tuning of the movement

Question 8

DARPA Arm - Proto-2 has? Allows for? Benefit? More than? May include?

Answer 8

• More than 25 degrees of freedom
• Allows for individual finger movements
• Strength and speed of movement approaching typical human limb
• More than 80 individual sensory elements for feedback of touch, temperature, and limb position.

Question 9

What is near infrared spectoscopy (NIRS)?

Answer 9

uses near infrared light between 650 and 950 nm to non-invasively probe the concentration and oxygenation of hemoglobin in the brain, muscle and other tissues and is used e.g. to detect changes induced by brain activity, injury, or disease.

Question 10

Transcranial Magnetic Stimulation (TMS or rTMS) can?

Answer 10

Can stimulate or inhibit brain areas by manipulating a magnetic current outside the cortical area of interest

Question 11

Transcranial Direct Current Stimulation (TCDS or TDS) can? Pro?

Answer 11

• Can stimulate or inhibit brain areas by presenting an electrical current outside the cortical area of interest
• Low cost and simple technology

Question 12

Brain-controlled interfaces capture? Those signals can be used to? What are the Various devices available to record brain activity via? (3)

Answer 12

• capture brain transmissions
• Those signals can be used to control prosthetic device
• Record form scalp
• On the surface of the brain
• Within the cerebral cortex

Question 13

Brain Controlled Prostheses - Lots of development to? (3) Provide?

Answer 13

• engineer the tissue-electrode interface
• generate new electrode designs
• extraction algorithms to transform the recorded signal to movement
• Provide immediate somatosensory feedback
from the prosthesis to the brain in response
to the movement

Question 14

Brain Controlled Prostheses still in? Initial work with? Findings? (2) Demonstration projects in humans showing?

Answer 14

• Still in development stages
• Initial work with monkeys
• They can learn to control prosthetic arm to receive food rewards.
• Can develop stable cortical map of prosthetic arm
• Demonstration projects in humans showing control of computer cursor, wheelchair motion

Question 15

How do you measure neuronal activity? (4)

Answer 15

• Single-Unit Recording (S-U)
• Electroencephalography (EEG)
• Electrocorticography (ECoG)
• Local Field Potentials (LFPs)

Question 16

Patient Selection = Successful Outcomes - questions to ask? (4)

Answer 16

• What is the patient/user’s acceptance of their amputation? Counseling or therapy to aid amputees in their adjustment may be helpful
• What is their level of expectation? Patient/user should be informed of both the capabilities and the limitations of the prosthesis
• What is the patient’s priority?
  » Help develop technology
  » Achieve new function
  » Cosmesis
• What is their previous experience with prostheses?
  » Are they due a refit and are they an educated buyer?

Question 17

Wrap-up = Goal is to make? Additional goal is?

Answer 17

• Goal is to make the range of available movement skills as broad as possible and as similar to typical human movement as possible
• Additional goal is allow for ‘natural’ process of re-learning, similar to typical motor learning processes

Question 18

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Answer 18

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