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Transcranial Direct-Current Stimulation Could Speed Learning by 40%

posted by martyb on Tuesday October 24 2017, @01:16AM   
from the no-more-monkeying-around dept.

takyon writes:

HRL Laboratories (a research center owned by General Motors and Boeing) has found that transcranial direct-current stimulation (tDCS) can improve learning:

Done in collaboration with McGill University in Montreal and Soterix Medical in New York, the study was sponsored by the Defense Advanced Research Project Agency (DARPA)'s Restoring Active Memory (RAM) program. Published October 12, 2017, in the journal Current Biology, tDCS in animals showed learning accelerated by about 40% when given 2 mA noninvasively to the prefrontal cortex without increased neuronal firing. This study showed it was modulated connectivity between brain areas, not neuron firing rates, that accounted for the increased learning speed.

The behavioral task in this experiment was associative learning. The macaques had to learn arbitrary associations between a visual stimulus and a location where they would get a reward—a visual foraging task. The initial foraging trials took about 15 seconds, and once the animal learned the location of the reward, it took approximately 2 seconds to recall and find the target. Subjects in the control condition required an average of 22 trials to learn to obtain the reward right way[sic]. With tDCS they required an average of 12 trials.

"In this experiment we targeted the prefrontal cortex with individualized non-invasive stimulation montages," said Dr. Praveen Pilly, HRL's principal investigator on the study. "That is the region that controls many executive functions including decision-making, cognitive control, and contextual memory retrieval. It is connected to almost all the other cortical areas of the brain, and stimulating it has widespread effects. It is also the target of choice in most published behavioral enhancement studies and case studies with transcranial stimulation. We placed the tDCS electrodes on the scalp in both our control and stimulation conditions. The behavioral effect was revealed when they learned to find the reward faster."

Transcranial Direct Current Stimulation Facilitates Associative Learning and Alters Functional Connectivity in the Primate Brain (DOI: 10.1016/j.cub.2017.09.020) (DX)

Previously: Cognitive Enhancement May Not be All It's Cracked Up To Be.
Zapping Your Brain may Reduce Depression, Ease Pain

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Original Submission

• TDCS makes monkeys like juice TDCS makes monkeys like juice (Score: 1, Insightful) by Anonymous Coward on Tuesday October 24 2017, @11:26AM (2 children)

  by Anonymous Coward on Tuesday October 24 2017, @11:26AM (#586802)

  Animals were seated in front of a monitor that subtended 30 360 degrees of visual angle at a viewing distance of 40 cm. Eye position
  and pupil area were monitored at 500 Hz with an infrared eye tracking system (SR Research; Ontario).

  Our experimental paradigm was an adaptation of one previously shown to provide a useful probe of associative learning in humans
  [29]. Each trial began with the appearance of a black fixation spot on a gray screen. Animals were required to fixate within 2 deg. of the
  spot for 750-1000 ms, after which a full-screen image appeared. Images were chosen from a collection of Creative-Commons and
  public domain photographs of natural scenes and patterns (flickr.com). Different images were selected for every day of recording.

  Within each image on each day, a small (2� radius) patch at a random location was designated as the response zone (RZ). The RZ
  was initially not cued, and animals were allowed to freely view the image for 15 (Monkey F) or 20 s (Monkey M). If their gaze remained
  within the RZ for at least 100 ms, they received a large drop of juice and the trial ended. However, when subjects could not find the RZ
  within the allotted time, a high contrast cue appeared within it, and subjects received a much smaller reward for fixating the cue.

  To increase the task difficulty, the RZ’s position was jittered according to a bivariate normal distribution (s = 1� or 4�). Each block
  contained 2-3 image/RZ pairs, presented 75-100 times each. The image order was randomized. We also interleaved control trials, in
  which the animal received a small reward for making a saccade to the same cue, presented against a neutral gray background. These
  trials ensured that the eye tracker remained calibrated and reduced carry-over effects between trials.

  From the methods, I don't see how they can tell the difference between making monkeys learn better vs making them enjoy juice more (and hence more likely to cooperate with the task).

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• Re:TDCS makes monkeys like juice Re:TDCS makes monkeys like juice (Score: 3, Touché) by hemocyanin on Tuesday October 24 2017, @02:45PM (1 child)

  by hemocyanin (186) on Tuesday October 24 2017, @02:45PM (#586877) Journal

  Maybe you don't have to teach monkeys to like flavored sugar. You sure don't have to teach humans to like it.

  Parent

  • Re:TDCS makes monkeys like juice (Score: 0) by Anonymous Coward on Tuesday October 24 2017, @07:59PM

    by Anonymous Coward on Tuesday October 24 2017, @07:59PM (#587067)

    I'm not talking about teaching them to like it. I'm referring to the possibility the stimulation affects the sense of taste:

    (A burning or tingling sensation or a metallic taste in the mouth is a common side effect, though some people don’t feel anything at all.)

    https://www.newyorker.com/magazine/2015/04/06/electrified [newyorker.com]

    The strangest side effect I experienced was a mild metallic taste in my mouth, but it was not too bothersome. (At first I thought I was imagining such a sensation, but I later read some reports from others reporting the same issue.)

    http://adifferentdrum.org/my-brain-on-electricity-a-130-day-tdcs-experiment/ [adifferentdrum.org]

    I personally experience a metallic taste in my mouth but this is common.

    http://www.instructables.com/id/tDCS-Thinking-Cap/ [instructables.com]

    If a monkey has a bad taste in its mouth, perhaps it will be more motivated to consume something with a pleasant flavor. Is this so crazy of an idea?

    Parent