The source for your link is the same article being discussed here.

But given how simple their light setup is, they could easily have added a control group.

I think the point of wanting a control is still valid. Science always benefits from having a control

Another:

"Red (660 nm) or near-infrared (810 nm) photobiomodulation stimulates, while blue (415 nm), green (540 nm) light inhibits proliferation in human adipose-derived stem cells" (2017) https://www.nature.com/articles/s41598-017-07525-w

TIL it's called "red light optogenetics" even when the cells aren't modified for opto-activation.

And,

"Green light induces antinociception via visual-somatosensory circuits" (2023) https://www.sciencedirect.com/science/article/pii/S221112472...

"Infrared neural stimulation in human cerebral cortex" (2023) https://www.sciencedirect.com/science/article/pii/S1935861X2... :

> In a comparison of electrical, optogenetic, and infrared neural stimulation, Roe et al. [14] found that all three approaches could in principal achieve such specificity. However, because brain tissue is conductive, it can be challenging to confine neuronal activation by traditional electrical stimulation to a single cortical column. In contrast, optogenetic stimulation can be applied with high spatial specificity (e.g. by delivering light via a 200um fiber optic apposed to the cortex) and with cell-type specificity (e.g. excitatory or inhibitory cells); however, optogenetics requires viral vectors and gene transduction procedures, making it less easy for human applications [15]. Over the last decade, infrared neural stimulation (INS), which is a pulsed heat-mediated approach, has provided an alternative method of neural activation. Because brain tissue is 75% water, infrared light delivered near peak absorption wavelengths (e.g. 1875 nm [16]) permits effective delivery of heat to the brain tissue. In particular, experimental and modelling studies [[17], [18], [19]] have shown that 1875 nm light (brief 0.5sec trains of 0.25msec pulses forming a bolus of heat) effectively achieves focal (submillimeter to millimeter sized) activation of neural tissue

Does NIRS -based (neuro-) imaging induce neuronal growth?

Are there better photonic beam-forming apparatuses than TI DLP projectors with millions of tiny actuated mirrors; isn't that what a TV does?

Cold plasma also affects neuronal regrowth and could or should be used for wound closure. Are they cold plasma-ing Sam (Hedlund) in "Tron: Legacy" (2010) before the disc golf discus thing?

Does cold plasma reduce epithelial scarring?

A certain duration of cold plasma also appears to increase seed germination rate FWIW.

To find these studies, I used a search engine and search terms and then picked studies which seem to confirm our bias.