Cognitive control signals for neural prosthetics
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Cognitive Control Signals for Neural Prosthetics . Sam Musallam The Andersen Lab [email protected] What is a cognitive signal? . Signals that lie along the sensory to motor pathway but away from sensory and away from motor Not visual Not motor Encode higher order variables Intention

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What is a cognitive signal
What is a cognitive signal?

  • Signals that lie along the sensory to motor pathway but away from sensory and away from motor

    • Not visual

    • Not motor

  • Encode higher order variables

    • Intention

    • Motivation

    • Value of a reward


Cognitive based rather than motor based
Cognitive-based rather thanmotor-based

  • May require fewer cells, less invasive

  • Cognitive variables-expected value

  • Hierarchical control using smart machines

PMC



Arrays are implanted in medial intraparietal sulcus

Electrodes Dorsal Premotor Cortex

C

Arrays are Implanted in Medial Intraparietal Sulcus


We are currently implanting 160 electrodes in prr and in dpmc
We are currently implanting 160 electrodes in PRR and in DPMC

  • - 32 electrode arrays

  • - Made from platinum and iridium

  • - 80 microns at the shaft

  • 2-3 micron tip


Decoding Goals DPMC

E

Reach Trials

Brain control trials


Database built on memory period activity
Database Built on Memory Period Activity DPMC

Monkeys are in the dark and are not allowed to move

their:

  • Hands

  • Eyes

    This memory period activity is cognitive


Example of feedback performance 6 parietal neurons

75% DPMC

chance

chance

Example of feedback performance:6 Parietal neurons

Fixation maintained throughout trial.

Decoding 900 ms of memory period


More neurons also improve the decode dpmc
More neurons also improve the decode DPMC(dPMC)

8 targets decoded with 16 neurons



2 types of databases used
2 types of databases used (25%)

  • Adaptive

    • Database updated after every successful feedback trial

  • Frozen

    • Database ‘frozen’ after the end of the reach trials


Frozen or adaptive database doesn t seem to matter
Frozen or adaptive database? (25%)Doesn’t seem to matter


Type of reward changes the tuning of neurons in prr
Type of reward changes the tuning of neurons in PRR (25%)

Black=orange juice

Red = water



Our decoding ability improves with preferred reward condition
Our decoding ability improves with preferred reward condition

Decode on 5

single units




Decoding direction and reward from a monkey with no single units
Decoding Direction conditionand Reward from a monkey with no single units

Without the reward schedule

barely above chance.

Reward schedule improves

decode


Advantages of a cognitive prosthetics
Advantages of a Cognitive Prosthetics condition

  • Cognitive signals will allow us to directly determine the mood of patients

    • This can be done without requiring patients to indicate this preference using overt behavior.

  • Optimize control of prosthetic devices

    • counter neuronal sample biases.(surgical placement of electrodes, etc.)

    • allow multiple tool use.(update or variable functionality of prosthesis)


Conclusion
Conclusion condition

  • Cognitive neural activity not directly related to visual input or motor output can be used for as prosthetic control signals.

  • Cognitive signals can also give us information about the patient’s preference or mood.


Acknowledgment

Kelsie Pejsa condition

Lea Martel

Viktor Shcherbatyuk

Tessa Yao

Richard Andersen

Brian Corneil

Bradley Greger

Hans Scherberger

Grant Mulliken

Rajan Bhattacharyya

Igor Fineman

Bijan Pesaran

Daniella Meeker

Acknowledgment


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