Has "induced savantism" been further explored beyond Snyder 2009?

Question

The Mechanism/Neurological subsection of the Wikipedia article Savant Syndrome says:

Savant syndrome results from damage to the left anterior temporal lobe, an area of the brain key in processing sensory input, recognizing objects and forming visual memories.[citation needed] Savant syndrome has been artificially replicated using transcranial magnetic stimulation to temporarily disable this area of the brain.(16)

and reference (16) links to:

• Snyder, A. (2009). Explaining and inducing savant skills: privileged access to lower level, less-processed information. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1522), 1399-1405. doi: 10.1098/rstb.2008.0290

The article describes experimental work earlier than 2009 in which savant-like skills were "artificially induced by low-frequency repetitive transcranial magnetic stimulation."

My guess is that almost ten years on induced savantism would have been explored further experimentally and either 1) refuted, or 2) more thoroughly proven and potential explanations tested with more complex experiments.

Has either happened?

See also this substantial answer from 2012.

Answer 1

There are no other studies I can find where TMS (Transcranial Magnetic Stimulation) was used in the same way, but there is a paper mentioning Snyder (2009) whilst discussing safety and other ethical considerations required regarding neural enhancement using noninvasive brain stimulation.

Hamilton, et al. (2011) said the following about Snyder (2009)
^{(References re-numbered for formatting purposes and converted to APA style)}

Finally, one set of cognitive skills in which the role of TMS and tDCS has been especially controversial is the unmasking of so-called savant-like abilities. Snyder² argued that inhibition of the left anterior temporal lobe (LATL) with brain stimulation interferes with semantic networks that normally impose top-down constraints on human perception—in short, making conception play a diminished role in perception. These investigators suggest that suppressing the LATL increases access to less-processed information, improving performance in perceptual abilities on tasks such as drawing, proof-reading, numerosity judgment,¹ and other cognitive processes in which conceptual knowledge biases performance.^3,4

1. Snyder, A. W., Mulcahy, E., Taylor, J. L., Mitchell, D. J., Sachdev, P., & Gandevia, S. C. (2003). Savant-like skills exposed in normal people by suppressing the left fronto-temporal lobe. Journal of integrative neuroscience, 2(2), 149-158.
   DOI: 10.1142/S0219635203000287
   PDF: http://howieswebs.ipage.com/pdf/savantskills.pdf

2. Snyder, A. (2009). Explaining and inducing savant skills: privileged access to lower level, less-processed information. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1522), 1399-1405.
   DOI: 10.1098/rstb.2008.0290
   PDF: http://rstb.royalsocietypublishing.org/content/364/1522/1399.full.pdf

3. Gallate, J., Chi, R., Ellwood, S., & Snyder, A. (2009). Reducing false memories by magnetic pulse stimulation. Neuroscience letters, 449(3), 151-154.
   DOI: 10.1016/j.neulet.2008.11.021
   PDF: http://www.centreforthemind.com/publications/FalseMemories160109.pdf

4. Oliveri, M., Romero, L., & Papagno, C. (2004). Left but not right temporal involvement in opaque idiom comprehension: A repetitive transcranial magnetic stimulation study. Journal of cognitive Neuroscience, 16(5), 848-855.
   DOI: 10.1162/089892904970717
   PDF: https://www.researchgate.net/profile/Costanza_Papagno/publication/8506415_Left_But_Not_Right_Temporal_Involvement_in_Opaque_Idiom_Comprehension_A_Repetitive_Transcranial_Magnetic_Stimulation_Study/links/09e4150b4c7a9f03be000000.pdf

Regarding the safety of TMS, Hamilton, et al. (2011) said the following:

There are known and possibly unknown safety concerns associated with noninvasive brain stimulation. The most important safety risk associated with TMS is the risk of inducing seizures. Since the introduction of published safety parameters for the use of rTMS, the incidence of induced seizure is exceptionally rare. All current evidence indicates that tDCS is extremely safe; its main safety risks are mild headache and a mild burning or itching sensation under the electrodes. Given the newness of these methodologies, one caveat is that not much is known about the chronic effects of either magnetic or electrical brain stimulation. Future studies may reveal unsuspected side effects and risks that are more serious than those associated with some conventional methods of behavioral cognitive manipulation (e.g., psychotherapy)....

There is quite a bit more on the safety and other ethical considerations, which I will leave you to read.

References

Hamilton, R., Messing, S., & Chatterjee, A. (2011). Rethinking the thinking cap: Ethics of neural enhancement using noninvasive brain stimulation. Neurology, 76(2), 187-193.
DOI: 10.1212/WNL.0b013e318205d50d

Answer 2

Sort of. Snyder togher with Chi have published a paper in 2012 in which they claim to have obtained a fairly similar result using tDCS to vastly improve the odds of solving the nine-dot problem, which certainly strengthens their case (although not as much as if this were replicated by others). The abstract of the latter paper doesn't quite let on how related their two studies are, but in the discussion the authrors emphasize that:

Importantly, our paradigm for brain stimulation is unlike other attempts for enhancing cognition [...] in that we did not aim to enhance an existing ability by exciting a specific brain region associated with that ability. Instead, our stimulation protocol aims to mirror left hemisphere inhibition together with right hemisphere facilitation, a condition that characterizes some individuals with extraordinary savant like skills [...].

They further their point that unusual brain functioning might indeed be the mechanism facilitating the solution to the nine-dot problem with a case report in which the sole participant who did solve the problem sans tDCS aid turned out to have had a brain injury.

I also found a 2012 piece in Wired (covering mainly the latter paper) which is a bit ambivalent whether Snyder's results (in general) could be replicated:

It sounds like a Michael Crichton plot, but Snyder, of the University of Sydney, Australia, says he wouldn’t be surprised to see a prototype of the creativity cap within a couple of years. His research suggests that brain stimulation improves people’s ability to solve difficult problems. But Snyder's interpretation of his findings remains controversial, and the science of using brain stimulation to boost thinking is still in its early stages.

"I think it’s a bit of a minefield," said psychologist Robyn Young of Flinders University in Australia, who has tried to replicate Snyder’s early experiments. "I’m not really sure whether the technology is developed that can turn it into a more accurate science."

[...]

Snyder’s earlier studies used magnetic, rather than electrical, stimulation to try to elicit savant abilities. One study showed a change in artistic ability, while another found improved numerosity, the ability to precisely estimate a large number of objects without counting them.

But as of yet, not many of Snyder’s studies have been replicated. Australian psychologist Robyn Young did a study in 2004 that examined the effect of magnetic stimulation on savant-type skills such as drawing, memory, mathematics and calendar calculating. In five out of 17 subjects, some improvement was observed, but most of the findings weren't statistically significant. A follow-up study failed to show any effect of the stimulation.

Young thinks the idea of improving cognition with brain stimulation is plausible, but "there were so many variables involved," she said, such as where to stimulate and how long the effect lasts, that she dropped the work to pursue other research.

So apparently the Snyder studies are difficult to replicate, methodologically... and there doesn't seem to be much interest. Bummer.