Memory improvement via stimulation of temporal cortex

Stimulation of temporal cortex with electrodes at memory encoding time boosted recall by 15%, in humans.

In the first phase, researchers listened to brain activity while subjects were memorizing nouns. They trained a model to try to predict, based on the brain activity at encoding time, if that word would be remembered or not. In the second phase, researchers ran the model while subjects were memorizing words, and if the model predicted that the word was more than 50% likely to be forgotten, they zapped the brain for 0.5 seconds (through a single pair of adjacent electrodes in the lateral temporal cortex, at amplitudes ranging from 0.5 mA to 1.5 mA (for electrodes deep in the cortex) or 3.5 mA (for the cortical surface) (amplitude was the maximum within this range such that stimulation didn’t appear to cause afterdischarges). Stimulation in this fashion improved recall by 15%. After stimulation, the classifier was more likely to say that the subject would remember the word, which might suggest that the stimulation improved recall by sometimes nudging the brain into a state that the classifier recognized as good for memory encoding.

As an aside, imo one should keep in mind that this doesn’t necessarily mean that this would be a good thing to do every time you are learning something. The way i like to think about this experiment is to imagine that you have some big machine that you don’t know how it works. The machine sometimes makes humming noises and other times it makes sputtering noises. You notice that when it makes the sputtering noise, this correlates somewhat with it not doing its job so well. So, whenever you hear a sputtering noise, you kick it really hard. Sometimes when you kick it, it makes it hum again. You record data and find out that if you kick it when it sputters, that improves output by 15%. That’s very interesting, but does it mean that it’s a good idea to kick the machine whenever it sputters? No — maybe kicking the machine damages it a little (or has some small probability of damaging it sometimes), or maybe the sputtering was something (such as a self-cleaning cycle) that the machine needs to do for its long-term health even at the cost of short-term performance. In other words, there is a clear gain to kicking the machine when it sputters, but it is unknown if there is also a subtle cost.

 

Youssef Ezzyat, Paul A. Wanda, Deborah F. Levy, Allison Kadel, Ada Aka, Isaac Pedisich, Michael R. Sperling, Ashwini D. Sharan, Bradley C. Lega, Alexis Burks, Robert E. Gross, Cory S. Inman, Barbara C. Jobst, Mark A. Gorenstein, Kathryn A. Davis, Gregory A. Worrell, Michal T. Kucewicz, Joel M. Stein, Richard Gorniak, Sandhitsu R. Das, Daniel S. Rizzuto & Michael J. Kahana. Closed-loop stimulation of temporal cortex rescues functional networks and improves memory.

 

https://www.wired.com/story/ml-brain-boost

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Neural Engineering System Design programme (DARPA funding award announced)

https://www.darpa.mil/news-events/2017-07-10

 

“The NESD program looks ahead to a future in which advanced neural devices offer improved fidelity, resolution, and precision sensory interface for therapeutic applications,” said Phillip Alvelda, the founding NESD Program Manager. “By increasing the capacity of advanced neural interfaces to engage more than one million neurons in parallel…”

 

  • A Brown University team led by Dr. Arto Nurmikko will seek to decode neural processing of speech, focusing on the tone and vocalization aspects of auditory perception. The team’s proposed interface would be composed of networks of up to 100,000 untethered, submillimeter-sized “neurograin” sensors implanted onto or into the cerebral cortex. A separate RF unit worn or implanted as a flexible electronic patch would passively power the neurograins and serve as the hub for relaying data to and from an external command center that transcodes and processes neural and digital signals.
  • A Columbia University team led by Dr. Ken Shepard will study vision and aims to develop a non-penetrating bioelectric interface to the visual cortex. The team envisions layering over the cortex a single, flexible complementary metal-oxide semiconductor (CMOS) integrated circuit containing an integrated electrode array. A relay station transceiver worn on the head would wirelessly power and communicate with the implanted device.
  • A Fondation Voir et Entendre team led by Drs. Jose-Alain Sahel and Serge Picaud will study vision. The team aims to apply techniques from the field of optogenetics to enable communication between neurons in the visual cortex and a camera-based, high-definition artificial retina worn over the eyes, facilitated by a system of implanted electronics and micro-LED optical technology.
  • A John B. Pierce Laboratory team led by Dr. Vincent Pieribone will study vision. The team will pursue an interface system in which modified neurons capable of bioluminescence and responsive to optogenetic stimulation communicate with an all-optical prosthesis for the visual cortex.
  • A Paradromics, Inc., team led by Dr. Matthew Angle aims to create a high-data-rate cortical interface using large arrays of penetrating microwire electrodes for high-resolution recording and stimulation of neurons. As part of the NESD program, the team will seek to build an implantable device to support speech restoration. Paradromics’ microwire array technology exploits the reliability of traditional wire electrodes, but by bonding these wires to specialized CMOS electronics the team seeks to overcome the scalability and bandwidth limitations of previous approaches using wire electrodes.
  • A University of California, Berkeley, team led by Dr. Ehud Isacoff aims to develop a novel “light field” holographic microscope that can detect and modulate the activity of up to a million neurons in the cerebral cortex. The team will attempt to create quantitative encoding models to predict the responses of neurons to external visual and tactile stimuli, and then apply those predictions to structure photo-stimulation patterns that elicit sensory percepts in the visual or somatosensory cortices, where the device could replace lost vision or serve as a brain-machine interface for control of an artificial limb.

See https://www.darpa.mil/attachments/FactsheetNESDKickoffFinal.pdf for more details.

Limited mediated telepathy

A rat was implanted with a 32-unit microelectrode cortical array in either M1 or S1. The rat was then trained to choose between two alternatives based on external stimuli.

Meanwhile, another rat was implanted with 6 stimulating electrodes in the same area as the first rat. It was trained to choose between the same two alternatives based on a stimulation pattern conveyed via the electrodes.

Then the signals recorded from the first rat’s brain were processed ald sent into the second rat’s brain. Both rats were trained together and both were rewarded when both made the right choice. The second rat learned to make the same choice as the first rat 60% of the time.

Miguel Pais-Vieira, Mikhail Lebedev, Carolina Kunicki, Jing Wang, Miguel A. L. Nicolelis. A Brain-to-Brain Interface for Real-Time Sharing of Sensorimotor Information. Scientific Reports 3, Article number: 1319. Received 20 December 2012.


http://www.reuters.com/article/2013/02/28/us-science-brain-mindmeld-idUSBRE91R0U620130228

Mobile phone increases brain glucose metabolism near phone antenna

This study claims that glucose metabolism in the brain goes up near a cellphone antenna. At first blush this may appear to conflict with other studies that claim that cellphones don’t cause cancer, but this can be resolved by supposing that cell phones don’t cause cancer, but affect the brain in other ways. As Volkow notes at the end of the Nytimes article, this may lead to the discovery of a mechanism for brain stimulation. Right now they don’t know what the mechanism is by which the electromagnetic field is causing the glucose metabolism. If neuronal firing is being altered, and if the bandwidth turns out to be sufficiently high (i.e. if the stimulation can be made sufficiently precise), this could eventually lead to a wireless brain-machine interface/neural prosthetic.

PET scans showing effect

Nora D. Volkow, Dardo Tomasi, Gene-Jack Wang, Paul Vaska, Joanna S. Fowler, Frank Telang, Dave Alexoff, Jean Logan, Christopher Wong. Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism. JAMA. 2011;305(8):808-813.

Summary in NYtimes: Cellphone Use Tied to Brain Changes

Transcranial Pulsed Ultrasound Stimulates Intact Brain Circuits

Yusuf Tufail, Alexei Matyushov, Nathan Baldwin, Monica L. Tauchmann, Joseph Georges, Anna Yoshihiro, Stephen I. Helms Tillery, William J. Tyler. Transcranial Pulsed Ultrasound Stimulates Intact Brain Circuits. Neuron, Volume 66, Issue 5, 681-694, 10 June 2010.

In motor cortex, ultrasound-stimulated neuronal activity was sufficient to evoke motor behaviors. Deeper in subcortical circuits, we used targeted transcranial ultrasound to stimulate neuronal activity and synchronous oscillations in the intact hippocampus. We found that ultrasound triggers TTX-sensitive neuronal activity in the absence of a rise in brain temperature (<0.01°C). Here, we also report that transcranial pulsed ultrasound for intact brain circuit stimulation has a lateral spatial resolution of approximately 2 mm and does not require exogenous factors or surgical invasion.

Neural Interfaces workshop, conference, June 20-23 (student status letter due tomorrow)

1. Beyond Brain Machine Interface: From Senses to Cognition
Co-sponsored by IEEE Engineering in Medicine and Biology Society and Army Research Office
June 20, 2010, Long Beach, CA
Travel fellowships, poster abstracts, and registration:
http://tnsre.bme.jhu.edu/

2. 39th Neural Interfaces Conference
Co-sponsored by NIH Deep Brain Stimulation Consortium
June 21-23, 2010, Long Beach, CA
Free registration for students (Faculty Advisor letter due May 21)
Program, registration, and further information:
http://www.neuralinterfaces2010.com/
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