The paper, Gamma frequency entrainment attenuates amyloid load and modifies microglia makes clear that the light-flickering affected the visual cortex, which makes sense, as the light reaches the brain through the eyes. But wait, thinks I, what about tACS (transcranial Alternating Current Stimulation)… haven’t I seen numerous papers implying the ability to ‘entrain’ brain waves with tACS? What if you could increase 40hz Gamma in other parts of the brain? (Google Scholar Search: transcranial alternating, entrain, gamma)
But then I discovered that Radiolab just covered this exact story and it’s totally amazing! Really a must listen. So fun to hear the researcher’s amazement at this accidental (sort of) discovery!
So what’s with the photo of the Foc.us v2 device set up for a 40hz tACS session? Just that…
More about The Picower Institute for Learning and Memory at MIT
Featuring Swansea University researcher Claire J. Hanley @clairejhanley. Lucy Owen explores a new way of improving her memory. Will she score better at a memory test once her brain has been stimulated by electromagnetic impulses?
@DIYtDCS the montage used was position T7 (anode)/T8(cathode) from the 10-10 system
For the first time, UNC School of Medicine scientists report using transcranial alternating current stimulation, or tACS, to target a specific kind of brain activity during sleep and strengthen memory in healthy people.
Memory has always fascinated me and it’s thrilling to be alive at a time when breakthroughs in our understanding of memory are happening so frequently. I had never heard of Highly Superior Autobiographical Memory before catching a recent (this will slip behind a paywall in a week or so) This American Life episode that features Jill Price discussing how having the extremely rare condition, HSAM for short, has left her ruminating over her husbands passing for years. (More about Jill Price from 60 Minutes Australia here).
As someone who has journaled for most of my adult life the idea of being able to recall every single day in vivid detail seemed thrilling and I wondered if Jill Price’s experience was the norm among people with HSAM. That led to these 60 Minute pieces. The first two are from 2010.
After the show aired, hundreds of people contacted Dr. James McGaugh including the family of 10 year old Jake Hausler who also has HSAM. Scientists at Washington University are working with Jake to try to understand how it’s done.
And finally, ‘Memory Hackers’ from NOVA, has an update on the Jake Hausler research, and also delves into a wide variety of cutting edge memory research.
[Note (updated 8/9/15): Alex is using a research version of the mindGear device. The device as available to the general public does not include a tDCS program.]
The folks at the Neural Engineering Group (associated with Marom Bikson’s NY City College Neural Engineering Lab) are producing a series on tDCS. Here is their first episode!
My Notes: Could you force an action potential with tDCS? (TMS does) Visual memory improved by non-invasive brain stimulation (paywall)
Richard P. Chi, Felipe Fregni, Allan W. Snyder
Dosage: mA x time, i.e. 30 mA minutes could be 1.5mA for 20 minutes.
Memory improvement montage: Anode between T8 & FT8, Cathode between T7 & FT7
I’m exposing my bias here, which is the hope that tDCS will be found to facilitate memory retrieval. This study, in mice, retrieved dormant memories using light (optogenetics) to activate cells used in memory formation. Recent studies suggest that memories are formed within a synaptic network, parts of which extend to areas of the brain more frequently targeted by tDCS. Probably closest to the research I’d like to see done (that I’m aware of) was reported in 2009, “Where Are Old Memories Stored in the Brain?“. I imagine a study where early memory, triggered by photos and recollections, are imaged using fMRI and that later, those same areas are targeted using tDCS. In the study reported on above, Medial Temporal Lobe Activity during Retrieval of Semantic Memory Is Related to the Age of the Memory, researchers concluded that older memories associated with regions in the frontal lobe, temporal lobe, and parietal lobe. (Though seems inconclusive as to whether memories are ‘stored’ there… “An additional way to understand the increasing involvement of some cortical areas, especially frontal cortex, as time passes is that older memories require more strategic, effortful search.”) Now, back to the post title article…
The researchers then attempted to discover what happens to memories without this consolidation process. By administering a compound called anisomycin, which blocks protein synthesis within neurons, immediately after mice had formed a new memory, the researchers were able to prevent the synapses from strengthening.
When they returned one day later and attempted to reactivate the memory using an emotional trigger, they could find no trace of it. “So even though the engram cells are there, without protein synthesis those cell synapses are not strengthened, and the memory is lost,” Tonegawa says.
But startlingly, when the researchers then reactivated the protein synthesis-blocked engram cells using optogenetic tools, they found that the mice exhibited all the signs of recalling the memory in full.
“If you test memory recall with natural recall triggers in an anisomycin-treated animal, it will be amnesiac, you cannot induce memory recall,” Tonegawa says. “But if you go directly to the putative engram-bearing cells and activate them with light, you can restore the memory, despite the fact that there has been no LTP.”
Sham or anodal tDCS (1 mA) was applied for 20 min during motor practice and retention was tested 30 min, 24 hours and one week later. All subjects improved performance during each of the two sessions and learning gains were similar. Our main result is that long term retention performance (i.e. 1 week after practice) was significantly better when practice was performed with anodal tDCS than with sham tDCS. This effect was large and all but one subject followed the group trend. Our data strongly suggest that anodal tDCS facilitates long-term memory formation reflecting use-dependent plasticity. Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like (long-term potentiation) mechanism, which is in accordance with previous research.
Medtronic [a medical device manufacturer] will be developing a 256-channel brain stimulator, not only to stimulate but to record and analyze brain activity and [to] try to modify and synthesize it within the brain.
The ultimate goal is to send patients with memory disorders home with a device implanted into their brain to improve their memory.
How will the study work?
The 256-channel device will be far more than a brain stimulator. It will be an intelligent device that continuously monitors brain function for signals that indicate how well our memory system is operating. As it tracks these signals, in real time, it will use mathematical models of brain function to determine whether and how to stimulate at each of these locations. By cycling very rapidly between recording, analyzing and stimulating, it will try to continuously maintain good memory function in patients with neurological injury or disease.
Though TMS not tDCS, it would be interesting to see the original paper (paywall). My understanding is that the hippocampus is a difficult target for tDCS. But perhaps insights from this study could lead to ideas for a ‘memory enhancing’ tDCS montage.
To test this, Voss and his team of researchers had 16 healthy adults between the ages of 21 and 40 undergo MRIs so the researchers could learn the participants’ brain structures. Then, the participants took a memory test which consisted of random associations between words and images that they were asked to remember. Then, the participants underwent brain stimulation with TMS for 20 minutes a day for five days in a row. TMS uses magnetic pulses to stimulate areas of the brain. It doesn’t typically hurt, and has been described by some as a light knocking sensation. The researchers stimulated the regions of the brain involved in the memory network.
Throughout the five days, the participants were tested on recall after the stimulation and underwent more MRIs. The participants also underwent a faked placebo procedure. The results showed that after about three days, the stimulation resulted in improved memory, and they got about 30% more associations right with stimulation than without. Not only that, but the MRIs showed that the brain regions became more synchronized by the TMS.
Another significant player popped up today. Juri Kropotov (bio) Institute of the Human Brain of the Russian Academy of Sciences. You can download his 2006 Powerpoint presentation, “Transcranial Direct Current Stimulation (tDCS): a new old tool in neurotherapy” Here. You can see the Google Quick View version (and print it) here. Of special interest may be Kropotov’s use of tDCS in treating ADHD.