Are sulforaphane supplements better than microwaved broccoli sprouts?

Armando asked a good question in Upgrade your brain’s switchboard with broccoli sprouts:

“Is there any way to consume sulphorafane in a supplement form? Rather than have to jump so many hops to consume it from broccoli.”

That blog post referenced a 2017 study, whose sulforaphane amount was:

“100 µmol [17.3 mg] sulforaphane as standardized broccoli sprout extract in the form of 2 gel capsules.”

One answer in A pair of broccoli sprout studies was No:

  • “Plasma and urinary levels of total SFN [sulforaphane] metabolites were ~3–5 times higher in sprout consumers compared to BSE [broccoli sprout extract] consumers.
  • In sprout consumers, plasma concentrations were 2.4-fold higher after consuming the second dose than after the first dose.
  • Calculated SFN bioavailability from broccoli sprouts exceeded 100%.”

That study was from 2015, though. Are better products than broccoli sprout extracts available now?


Image from the US Library of Congress

During Week 5 of Changing an inflammatory phenotype with broccoli sprouts, back in May when I still believed impossible things like we would:

I contacted a distributor of a dried broccoli sprout powder for evidence of their claim:

“Independent assays confirm that EnduraCELL yields more Sulforaphane per gram and per dose than any other broccoli sprout ingredient available! These assays showed that EnduraCell yields around 3.5 times more SULFORAPHANE than the next highest broccoli sprout product.”

I’ve asked three times for the lab assays. They declined each time to provide the data.

The company founder has written several reviews, one of which is entitled Sulforaphane and Other Nutrigenomic Nrf2 Activators: Can the Clinician’s Expectation Be Matched by the Reality? In Section 6.5 Sulforaphane it stated:

“By calculation, MYR [myrosinase]-active whole broccoli sprout supplement yielding 1% SFN could deliver 10 mg SFN per gram of powder, corresponding to ~12 grams of fresh broccoli sprouts (dried powder retains ~8% moisture).

The 2017 study’s dosage of “100 µmol [17.3 mg] sulforaphane as standardized broccoli sprout extract” weighed a gram or less, for a 1.73% sulforaphane yield. A broccoli sprout powder that could deliver “3.5 times” may have a 3.5 x 1.73% = 6.1% sulforaphane yield.

Using worst-case calculations from Estimating daily consumption of broccoli sprout compounds and Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts, I eat at least 76 grams of 3-day-old broccoli sprouts daily. That would be 76 g / 12 = 6.3 grams of a “whole broccoli sprout supplement yielding 1% SFN” or ≈ 1 gram of a powder yielding 6.1% sulforaphane.

I immerse 3-day-old broccoli sprouts in 100 ml distilled water, then microwave them on 1000W full power for 35 seconds to achieve up to but not exceeding 60°C (140°F) per Microwave broccoli to increase sulforaphane levels. Worst-case estimates are 21 mg sulforaphane without microwaving and 30 mg sulforaphane with microwaving. The equivalent weight of a broccoli sprout powder yielding 6.1% sulforaphane for the worst case of microwaved broccoli sprouts is (30 mg / 21 mg) x 1 g powder = 1.4 grams of powder.

This 30 mg / 21 mg worst-case ratio could also be used to calculate a best case. If it’s true that:

  1. “Whole broccoli sprout supplement yielding 1% SFN could deliver 10 mg SFN per gram of powder” and
  2. The equivalent weight of microwaved broccoli sprouts is at least (30 mg / 21 mg) x 1 g powder = 1.4 grams of a broccoli sprout powder yielding 6.1% sulforaphane,

then my daily sulforaphane dosage is at least 10 mg x 6.1 x 1.4 = 85 mg.


My answer to Armando’s question would be No for sulforaphane supplements. I’d consider a whole broccoli sprout powder after lab assays were personally verified.

Day 70 results from Changing to a youthful phenotype with broccoli sprouts

Here are my Day 70 measurements* to follow up Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts, which had these findings:


Keep in mind that I’m not in the population represented by the clinical trial sample:

  1. My chronological age is above their inclusion range;
  2. My BMI is below their inclusion range; and
  3. I take supplements and meet other exclusion criteria.

I also didn’t take Day 0 measurements.

June 2019 BMI: 24.8

June 2020 BMI: 22.4

2020 IL-6: 1.0 pg / ml. See Part 2 of Rejuvenation therapy and sulforaphane for comparisons.

2020 C-reactive protein: < 1 mg / l.

2019 and 2020 No biological age measurements. Why aren’t epigenetic clocks standard and affordable?


I’ve made four lifestyle “interventions” since last summer:

  1. In July 2019 I started to reduce my consumption of advanced glycation end products after reading Dr. Vlassara’s AGE-Less Diet: How a Chemical in the Foods We Eat Promotes Disease, Obesity, and Aging and the Steps We Can Take to Stop It.
  2. In September I started non-prescription daily treatments of Vitamin D, zinc, and DHEA per clinical trial Reversal of aging and immunosenescent trends.
  3. Also in September, I started non-prescription intermittent quercetin treatments of Preliminary findings from a senolytics clinical trial.
  4. I started eating broccoli sprouts every day eleven weeks ago.

1. Broccoli sprouts oppose effects of advanced glycation end products (AGEs) provided examples of Items 1 and 4 interactions.

2. Two examples of Item 2 treatment interactions with Item 4 are in Reversal of aging and immunosenescent trends with sulforaphane:

  • “The effects of the combined treatment with BSE [broccoli sprout extract] and zinc were always greater than those of single treatments.”
  • “Vitamin D administration decreased tumor incidence and size, and the co-administration with SFN [sulforaphane] magnified the effects. The addition of SFN decreased the activity of histone deacetylase and increased autophagy.”

3. How broccoli sprout compounds may complement three supplements I take was in a 2020 review Central and Peripheral Metabolic Defects Contribute to the Pathogenesis of Alzheimer’s Disease: Targeting Mitochondria for Diagnosis and Prevention:

“The nutrients benefit mitochondria in four ways, by:

  • Ameliorating oxidative stress, for example, lipoic acid;
  • Activating phase II enzymes that improve antioxidant defenses, for example, sulforaphane;
  • Enhancing mitochondrial remodeling, for example, acetyl-l-carnitine; and
  • Protecting mitochondrial enzymes and/or stimulating mitochondrial enzyme activities, for example, enzyme cofactors, such as B vitamins and coenzyme Q10 .

In addition to using mitochondrial nutrients individually, the combined use of mitochondrial nutrients may provide a better strategy for mitochondrial protection.”

The review provided a boatload of mitochondrial multifactorial analyses for Alzheimer’s. But these analyses didn’t include effective mitochondrial treatments of ultimate aging causes. I didn’t see evidence of why, after fifteen years of treating mitochondrial effects with supplements, treating one more effect could account for my Week 9 vastly different experiences.


I nod to An environmental signaling paradigm of aging explanations. Its Section 10 reviewed IL-6, C-reactive protein, senescence, and NF-κB in terms of feedback loops, beginning with:

“It is clear that the increasing number of senescent cells depends on the post-adult developmental stage rather than chronological age. The coincidence that these processes result in particular forms of impairment in old age does not seem to be random as it is present in all mammals, and may be causative of many aspects of aging.”

A derived hypothesis: After sufficient strength and duration, broccoli sprout compounds changed my signaling environment, with appreciable effects beginning in Week 9.

I offered weak supporting evidence in Upgrade your brain’s switchboard with broccoli sprouts where a study’s insufficient one week duration of an insufficient daily 17.3 mg sulforaphane dosage still managed to change a blood antioxidant that may have changed four thalamus-brain-area metabolites. For duration and weight comparisons, I doubled my daily amount of broccoli seeds from one to two tablespoons just before Week 6 (Day 35), and from that point onward consumed a worst-case estimated 30 mg sulforaphane with microwaving 3-day-old broccoli sprouts every day.

Maybe a promised “In a submitted study, we will report that peripheral GSH levels may be correlated with cognitive functions” will provide stronger evidence? I’m not holding my breath for relevant studies because:

  • There wouldn’t be potential payoffs for companies to study any broccoli sprout compound connections with research areas such as aging, migraines, etc. Daily clinically-relevant broccoli sprout dosages can be grown for < $500 a year.
  • Sponsors would have to change paradigms, a very-low-probability event. They’d have to explain why enormous resources dedicated to current frameworks haven’t produced effective long-term treatments.

What long-term benefits could be expected if I continue eating broccoli sprouts every day?

The longest relevant clinical trial I’ve seen – referenced in Part 2 of Reversal of aging and immunosenescent trends with sulforaphane – was twelve weeks. Part 2 also provided epigenetic clock examples of changes measured after 9 months, which accelerated from there to the 12-month end-of-trial point.

Reviewing clinical trials of broccoli sprouts and their compounds pointed out:

“Biomarkers of effect need more time than biomarkers of exposure to be influenced by dietary treatment.”


A contrary argument: Perhaps people don’t require long durations to effectively change their signaling environments?

I apparently didn’t start eating an effective-for-me daily broccoli sprouts dosage until Day 35, when I changed from one to two tablespoons of broccoli seeds a day. If so, Weeks 6 through 8 may account for my substantial responses during Week 9.

Could eating broccoli sprouts every day for four weeks dramatically change a person’s signaling environment?

Do you have four weeks and $38 to find out? Two tablespoons of broccoli seeds = 38 g x 30 days = 1.14 kg or 2.5 lbs.

This is what twice-a-day one-tablespoon starting amounts of broccoli seeds look like through three days:


Maintaining the sprouting process hasn’t been a big effort compared with the benefits.

In the absence of determinative evidence, I’ll continue eating broccoli sprouts every day. Several areas of my annual physical have room for improvements. Extending my four lifestyle “interventions” a few more months may also provide hints toward inadequately researched connections.

* Results may not be extrapolatable to other people, to any specific condition, etc.

Week 10 of Changing to a youthful phenotype with broccoli sprouts

To follow up Week 9 of Changing to a youthful phenotype with broccoli sprouts:

1. I increased three of eight upper body exercises by 50% through adding another set. I did it because I didn’t feel muscle exhaustion after two sets like I’d previously felt. 🙂

Cognitively, see A claim of improved cognitive function and its follow on Upgrade your brain’s switchboard with broccoli sprouts.

2. It’s been inspirational at times, and at other times, dull, duller, dullest, to do what’s necessary and keep on track. But the efforts paid off when Week 9 was unlike any previous week!

I expressed appreciation in Our model clinical trial for Changing to a youthful phenotype with broccoli sprouts because scientific evidence provides great bases for intentional behavior. It’s still up to me to voluntarily carry out my part. And why wouldn’t I act when my healthspan and lifespan are the consequences? Except…

What if I’d been:

  • Tired of the hassle, or bored with self-imposed discipline, or lazy, and quit?
  • Projecting personal problems onto others, such that improving my present and future became less important than act-outs?
  • Distracted by, or believed propaganda, or participated in Madness of Crowds behavioral contagion, and missed day after day of required actions?

I may not have ever experienced Week 9’s intermediate-term benefits!

If I keep going past ten weeks, what long-term benefits could be expected?

Our model clinical trial didn’t say how researchers decided on a ten-week period for subjects to consume broccoli sprouts every day. I asked a study coauthor about trial duration, but no answer yet.

A few of the same coauthors answered generally in Reviewing clinical trials of broccoli sprouts and their compounds:

Biomarkers of effect are early stage end-points, for instance the modulation of phase 2 enzymes by glucosinolates. They need more time than biomarkers of exposure to be influenced by the dietary treatment.

Hence, length or duration of the study must be defined according to the biomarker measured to be modified, that is, to define perfectly the time of exposure to observe changes in relevant parameters. Gene expression is one important target for glucosinolates, and it requires a sufficient period of exposure to (de)activate signaling pathways involved.

It is crucial to find appropriate biomarkers of effect that are linked to later disease outcomes, and more investigation is needed in this sense. Post-study follow-up can be of great value in assessing the persistence of certain effects, or in discovering those that appear more long-term.

3. I’ll go into a clinic on Sunday for Day 70 truth tests. Here they are: Day 70 results from Changing to a youthful phenotype with broccoli sprouts!

Upgrade your brain’s switchboard with broccoli sprouts

Further investigating A claim of improved cognitive function, Part 3 of Rejuvenation therapy and sulforaphane offered:

“Improving brain function does not depend on neurogenesis as much as it does on synapse formation and factors such as NMDA receptors which decline in density with age.”

A PubMed “sulforaphane NMDA receptors” search turned up a 2019 cell study The glutathione cycle shapes synaptic glutamate activity:

Sulforaphane is a potent inducer of the Nrf2 transcription factor, has blood–brain barrier penetration, and might expand the size of the glutathione reservoir by our observation that it increases expression of GCL [glutamate cysteine ligase], the rate-limiting step in glutathione biogenesis. Our recent study in human subjects revealed that sulforaphane elevates peripheral glutathione levels and those of other brain metabolites.”

The referenced study was a 2017 Sulforaphane Augments Glutathione and Influences Brain Metabolites in Human Subjects: A Clinical Pilot Study:

“We found that the naturally occurring isothiocyanate sulforaphane increased blood GSH [reduced glutathione] levels in healthy human subjects following 7 days of daily oral administration. In parallel, we explored the potential influence of sulforaphane on brain GSH levels in the anterior cingulate cortex, hippocampus, and thalamus via 7-T magnetic resonance spectroscopy.

A significant positive correlation between blood and thalamic GSH post- and pre-sulforaphane treatment ratios was observed, in addition to a consistent increase in brain GSH levels in response to treatment. The sulforaphane response in brain GSH levels is not influenced by age, sex, or race.

The participants were given 100 µmol sulforaphane as standardized broccoli sprout extract in the form of 2 gel capsules, and instructed to ingest the extract each morning for 1 week.

Following sulforaphane administration, the increase in blood GSH was positively correlated with GABA, Gln [glutamine], Glu [glutamate], and GSH in the THAL [thalamus]. Although these correlations were not significant following multiple comparison, they remain suggestive. Power analysis calculations suggest that a sample size of n = 50 would yield a significant result, and this will be the focus of a future study.

As has been reported for cardiovascular and cerebrovascular diseases, longer treatment duration and/or higher dosages may be warranted. In a submitted study, we will report that peripheral GSH levels may be correlated with cognitive functions.”


One week of consuming sulforaphane wasn’t long enough to achieve much. Not enough subjects and “higher dosages may be warranted” were also thrown in to explain the lack of significant results.

Sulforaphane: Its “Coming of Age” as a Clinically Relevant Nutraceutical in the Prevention and Treatment of Chronic Disease estimated the “100 µmol sulforaphane” dosage to be 17.3 mg. Worst-case estimates made in Estimating daily consumption of broccoli sprout compounds are that since doubling the starting amount of broccoli seeds from one to two tablespoons in Week 6, I’ve consumed 30 mg sulforaphane with microwaving 3-day-old broccoli sprouts every day.

Something happened where the promised “In a submitted study, we will report that peripheral GSH levels may be correlated with cognitive functions” either wasn’t performed or wasn’t published. The follow-on 2019 study became a cell study instead of a 50+ person study.


The study’s thalamus findings provided plausible explanations for why eating a clinically relevant amount of broccoli sprouts every day since at least Week 6, Week 9 was so much different from the others. Sulforaphane changed a blood antioxidant which may have changed four thalamus metabolites.

The thalamus part of our brain is analogous to a switchboard. Signals pass through it to and from other brain areas.

Signals can be routed better when we clean up and upgrade wiring, and lower circuit resistance.

Reevaluate findings in another paradigm

It’s challenging for people to change their framework when their paychecks or mental state or reputations depend on it not changing.

I’ll use The hypothalamus and aging as an example. The review was alright for partial fact-finding up through 2018. The review’s facts were limited, however, to what fit into the reviewers’ paradigm.

The 2015 An environmental signaling paradigm of aging provided examples of findings that weren’t considered in the review. It also presented a framework that better incorporated what was known at the time.


Here’s how they viewed the same 2013 study, Hypothalamic programming of systemic ageing involving IKK-β, NF-κB and GnRH (not freely available).

Paradigm: “The hypothalamus is hypothesized to be a primary regulator of the process of aging of the entire body.”

Study assessment:

“The age-associated inflammation increase is mediated by IκB kinase-β (IKK-β) and nuclear factor κB (NF-κB) in the microglia and, subsequently, nearby neurons through the microglia–neuron interaction in the mediobasal hypothalamus. Apparently, blocking the hypothalamic or brain IKK-β or NF-κB activation causes delayed aging phenotype and improved lifespan.

Aging correlates with a decline in the hypothalamic GnRH expression in mice and, mechanistically, activated IKK-β and NF-κB significantly down regulates the GnRH transcription. Notably, GnRH therapy through either hypothalamic third ventricularor subcutaneous injection leads to a significant recovery of neurogenesis in the hypothalamus and hippocampus and a noticeable improvement of age-related phenotype in the skin thickness, bone density, and muscle strength when applied in middle-aged mice.”

Paradigm: Environmental signaling model of aging

Study assessment:

“A link between inflammation and aging is the finding that inflammatory and stress responses activate NF-κB in the hypothalamus and induce a signaling pathway that reduces production of gonadotropin-releasing hormone (GnRH) by neurons. GnRH decline contributes to aging-related changes such as bone fragility, muscle weakness, skin atrophy, and reduced neurogenesis. Consistent with this, GnRH treatment prevents aging-impaired neurogenesis and decelerates aging in mice.

Zhang et al. report that there is an age-associated activation of NF-κB and IKK-β. Loss of sirtuins may contribute both to inflammation and other aspects of aging, but this explanation, also given by Zhang et al. merely moves the question to why there a loss of sirtuins.

The case is particularly interesting when we realize that the aging phenotype can only be maintained by the continuous activation of NF-κB – a product of which is the production of TNF-α. Reciprocally when TNF-α is secreted into the inter-cellular milieu, it causes the activation of NF-κB. In their study, Zhang et al. noted that the activation of NF-κB began in the microglia (the immune system component cells found in the brain), which secreted TNF-α, resulting in a positive feedback loop that eventually encompassed the entire central hypothalamus.

The net result of this is a diminution in the production of gonadotropin-releasing factor which accounted for a shorter lifespan because provision of GnRH eliminated that effect, while either preventing NF-κB activation (or that of the IKK-β upstream activator) or by providing gonadotropin-releasing factor directly into the brain, or peripherally, extended lifespan by about 20%.

In spite of the claim of Zhang et al. that the hypothalamus is the regulator of lifespan in mice, their experiments show that only some aspects of lifespan are controlled by the hypothalamus, as preventing NF-κB activation in this organ did not stop aging and death. Similar increased NF-κB activation with age has been seen in other tissues as well and said to account for dysfunction in aging adrenal glands. It was demonstrated that increased aging occurred as a result of lack of gonadotropin-releasing hormone and that increased lifespan resulted from its provision during aging.

In this manner:

  1. The aging of hypothalamic microglia leads to
  2. The aging of the hypothalamus, which leads to
  3. Aging elsewhere in the body.

So here we have a multi-level interaction:

  1. The activation of NF-κB leads to
  2. Cellular aging, leading to
  3. A diminished production of GnRH, which then
  4. Acts (through the cells with a receptor for it, or indirectly as a result of changes to GnRH-receptor-possessing cells) to decrease lifespan.

So the age state of hypothalamic cells, at least with respect to NF-κB activation, is communicated to other cells via the reduced output of GnRH.”


Not using the same frameworks, are they?

In 2015, the researcher told the world what could be done to dramatically change the entire research area. He and other researchers did so recently as curated in Part 3 of Rejuvenation therapy and sulforaphane which addressed hypothalamus rejuvenation.

Prenatal stress heightened adult chronic pain

This 2019 McGill rodent study found:

Prenatal stress exacerbates pain after injury. Analysis of mRNA expression of genes related to epigenetic regulation and stress responses in the frontal cortex and hippocampus, brain structures implicated in chronic pain, showed distinct sex and region-specific patterns of dysregulation.

In general, mRNA expression was most frequently altered in the male hippocampus and effects of prenatal stress were more prevalent than effects of nerve injury. Recent studies investigating chronic pain-related pathology in the hippocampus in humans and in rodent models demonstrate functional abnormalities in the hippocampus, changes in associated behavior, and decreases in adult hippocampal neurogenesis.

The change in expression of epigenetic- and stress-related genes is not a consequence of nerve injury but rather precedes nerve injury, consistent with the hypothesis that it might play a causal role in modulating the phenotypic response to nerve injury. These findings demonstrate the impact of prenatal stress on behavioral sensitivity to a painful injury.

Decreased frontal mRNA expression of BDNF and BDNF IV in male offspring following neuropathic pain or prenatal stress respectively. Relative mRNA expression of other stress-related genes (GR17, FKBP5) and epigenetic-related genes (DNMTs, TETs, HDACs, MBDs, MeCP2) in male offspring.

A drastic decrease in expression of HDAC1 was observed in all groups compared to sham-control animals. CCI: chronic constriction injury.”


The study’s design was similar to the PRS (prenatal restraint stress) model, except that the PRS procedure covered gestational days 11 to 21 (birth):

“Prenatal stress was induced on Embryonic days 13 to 17 by restraining the pregnant dams in transparent cylinder with 5 mm water, under bright light exposure, 3 times per day for 45 min.”

None of the French, Italian, and Swiss PRS studies were cited.

The limitation section included:

  1. “Although our study shows significant changes in expression of epigenetic enzymes, it didn’t examine the impact of these changes on genes that are epigenetically regulated by this machinery or their involvement in intensifying pain responses.
  2. The current study is limited by the focus on changes in gene expression which do not necessarily correlate with changes in protein expression.
  3. Another limitation of this study is the inability to distinguish the direct effects of stress in utero vs. changes in the dam’s maternal behavior due to stress during pregnancy; cross-fostering studies are needed to address this issue.
  4. Functional experiments that involve up and down regulation of epigenetic enzymes in specific brain regions are required to establish a causal role for these processes in chronic pain.”

What do you think about possible human applicability of this study’s “effects of prenatal stress were more prevalent than effects of nerve injury” finding?

Are there any professional frameworks that instruct trainees to recognize that if a person’s mother was stressed while pregnant, their prenatal experiences could cause more prevalent biological and behavioral effects than a recent injury?

https://www.sciencedirect.com/science/article/pii/S0166432819315219 “Prenatal maternal stress is associated with increased sensitivity to neuropathic pain and sex-specific changes in supraspinal mRNA expression of epigenetic- and stress-related genes in adulthood” (not freely available)

OCD and neural plasticity

This 2019 New York rodent study investigated multiple avenues to uncover mechanisms of obsessive-compulsive disorder:

“Psychophysical models of OCD propose that anxiety (amygdala) and habits (dorsolateral striatum) may be causally linked. Numerous genetic and environmental factors may reduce striatum sensitivity and lead to maladaptive overcompensation, potentially accounting for a significant proportion of cases of pathological OCD-like behaviors.

Our results indicate that both the development and reversal of OCD-like behaviors involve neuroplasticity resulting in circuitry changes in BLA-DLS and possibly elsewhere.”


The researchers explored two genetic models of OCD, showed why these insufficiently explained observed phenomena, then followed up with epigenetic investigations. They demonstrated how and the degree to which histone modifications and DNA methylation regulated both the development and reversal of OCD symptoms.

However, the researchers also carelessly cited thirteen papers outside the specific areas of the study to support one statement in the lead paragraph:

“Novel studies propose that modulations in gene expression influenced by environmental factors, are connected to mental health disorders.”

Only one of the thirteen citations was more recent than 2011, and none of them were high-quality studies.

https://www.nature.com/articles/s41598-019-45325-6.pdf “Amelioration of obsessive-compulsive disorder in three mouse models treated with one epigenetic drug: unraveling the underlying mechanism”

How do memories transfer?

This 2018 Chinese study electronically modeled the brain’s circuits to evaluate memory transfer mechanisms:

“During non-rapid-eye-movement (NREM) sleep, thalamo-cortical spindles and hippocampal sharp wave-ripples have been implicated in declarative memory consolidation. Evidence suggests that long-term memory consolidation is coordinated by the generation of:

  • Hierarchically nested hippocampal ripples (100-250 Hz),
  • Thalamo-cortical spindles (7-15 Hz), and
  • Cortical slow oscillations (<1 Hz)

enabling memory transfer from the hippocampus to the cortex.

Consolidation has also been demonstrated in other brain tasks, such as:

  • In the acquisition of motor skills, where there is a shift from activity in prefrontal cortex to premotor, posterior parietal, and cerebellar structures; and
  • In the transfer of conscious to unconscious tasks, where activity in initial unskilled tasks and activity in skilled performance are located in different regions, the so-called ‘scaffolding-storage’ framework.

By separating a neural circuit into a feedforward chain of gating populations and a second chain coupled to the gating chain (graded chain), graded information (i.e. information encoded in firing rate amplitudes) may be faithfully propagated and processed as it flows through the circuit. The neural populations in the gating chain generate pulses, which push populations in the graded chain above threshold, thus allowing information to flow in the graded chain.

In this paper, we will describe how a set of previously learned synapses may in turn be copied to another module with a pulse-gated transmission paradigm that operates internally to the circuit and is independent of the learning process.”


The study had neither been peer-reviewed, nor were the mechanisms tested in living beings.

https://www.biorxiv.org/content/early/2018/07/27/351114 “A Mechanism for Synaptic Copy between Neural Circuits”

The hypothalamus and aging

This 2018 Korean review discussed aspects of the hypothalamus and aging:

“A majority of physiological functions that decline with aging are broadly governed by the hypothalamus, a brain region controlling development, metabolism, reproduction, circadian rhythm, and homeostasis. In addition, the hypothalamus is poised to connect the brain and the body so that the environmental information affecting aging can be transmitted through the hypothalamus to affect the systematic aging of the peripheral organs.

The hypothalamus is hypothesized to be a primary regulator of the process of aging of the entire body. This review aims to assess the contribution of hypothalamic aging to the age-related decline in body functions, particularly from the perspective of:

  • energy homeostasis,
  • hormonal balance,
  • circadian rhythm, and
  • reproduction,

and to highlight its underlying cellular mechanisms with a focus on:

  • nutrient sensing
  • inflammation,
  • loss of stem cell,
  • loss of proteostasis, and
  • epigenetic alterations.”


The reviewers didn’t consider aging to be an “unintended consequence” of development. This perspective was found in a reference to A study of DNA methylation and age:

“Aging is not and cannot be programmed. Instead, aging is a continuation of developmental growth, driven by genetic pathways.

Genetic programs determine developmental growth and the onset of reproduction. When these programs are completed, they are not switched off.

Aging has no purpose (neither for individuals nor for group), no intention. Nature does not select for quasi-programs. It selects for robust developmental growth.”

The epigenetic clock theory of aging cited the same author, and modified his point to say:

“The proposed epigenetic clock theory of ageing views biological ageing as an unintended consequence of both developmental programmes and maintenance programmes.”

The current review’s opposite paradigm was:

“The hypothalamus is hypothesized to be a primary regulator of the process of aging.”

Almost all of the details discussed were from rodent studies.


As detailed in How to cure the ultimate causes of migraines? and its references, the hypothalamus is a brain structure that lacks feedback mechanisms for several of its activities. This structure develops shortly after conception and has an active prenatal role.

The hypothalamus plays its part in getting us developed and ready to reproduce, with certain feedback loops being evolutionarily unnecessary. The hypothalamus perfectly illustrates the point of:

“When these programs are completed, they are not switched off.”

Evolutionarily unnecessary feedback for aspects of hypothalamic activity may result in it not winding down when its developmental role is over. This activity shouldn’t be interpreted to construe a role that has some other meaning or purpose.

https://www.sciencedirect.com/science/article/pii/S0047637418300502 “Role of hypothalamus in aging and its underlying cellular mechanisms” (not freely available)

Ideaesthesia!

This 2018 UK review subject was colored-hearing experiences from music:

“Music-colour synaesthesia has a broad scope encompassing not only tone-colour synaesthesia elicited on hearing individual tones, but a complex and idiosyncratic mixture of phenomenological experiences often mediated by timbre, tempo, emotion and differing musical style.

The possession of synaesthesia or absolute pitch was shown to have very little effect on the actual colours chosen for each of the musical excerpts, but it might be reasonable to expect that music that elicits a strong emotional response may be more likely to induce synaesthesia than music that does not.

The examination of eight neuroimaging studies were found to be largely inconclusive in respect of confirming the perceptual nature of music-colour synaesthesia. Neither the hyperconnectivity nor the disinhibited feedback theory currently holds as a single categorical explanation for synaesthesia.

Theories promoting the notion of ‘ideaesthesia’ have highlighted the importance of the role of concept and meaning in the understanding of synaesthesia..and a replacement definition: Synaesthesia is a phenomenon in which a mental activation of a certain concept or idea is associated consistently with a certain perception-like experience.”

Much of the review was philosophizing and casting around for clues. The review cited interesting studies and reviews, including The Merit of Synesthesia for Consciousness Research.


One relevant element missed by the underlying research and the review was critical periods of human development. A cited reference in How brains mature during critical periods was Sensitive periods in human development: Evidence from musical training (not freely available) which illuminated some aspects of the research:

“In contrast to a critical period, where a function cannot be acquired outside the specific developmental window, a sensitive period denotes a time where sensory experience has a relatively greater influence on behavioral and cortical development. Sensitive periods may also be times when exposure to specific stimuli stimulates plasticity, enhancing changes at the neuronal and behavioral levels.

The developmental window for absolute pitch may be more similar to a critical than a sensitive period.

The auditory cortex appears to have an unusually long period of developmental plasticity compared with other sensory systems; changes in its cellular organization and connectivity continue into late childhood.

The effects of musical training have been shown to impact auditory processing in the brainstem as well.”

Let’s say that a researcher wanted – as one cited study did – to examine absolute pitch, a rare trait, present in a subset of synesthetes – music-color, another rare trait. The study as designed would probably be underpowered due to an insufficient number of subjects, and it would subsequently find “very little effect.”

Let’s say another researcher focused on brain areas in the cerebrum, and like the eight cited studies, ignored the nuclei in the pons part of the brainstem which are the first brain recipients of sound and equilibrium information from the inner ear via the eighth cranial nerve. Like those studies, the researcher was also biased against including limbic brain areas that would indicate “a strong emotional response.” A study design that combined leaving out important brain-area participants in the synesthesia process with a few number of synesthetes would be unlikely to find conclusive evidence.

The reviewer viewed the lack of evidence from “eight neuroimaging studies” as indicating something about the “perceptual nature of music-colour synaesthesia.” An alternative view is that the “inconclusive” evidence had more to do with study designs that:

  • Had a small number of subjects;
  • Omitted brain areas relevant to the music-color synesthesia process;
  • Didn’t investigate likely music-color synesthesia development periods; and
  • Didn’t investigate associations of music-color synesthesia with epigenetic states.

Consider the magnitude of omitting the thalamus from synesthesia studies as one “perceptual nature” example. Just the background information of Thalamus gating and control of the limbic system and cerebrum is a form of memory indicated its relevance to synesthesia:

Despite the fundamental differences between visual, auditory and somatosensory signals, the basic layouts of the thalamocortical systems for each modality are quite similar.

For a given stimulus, the output neural response will not be static, but will depend on recent stimulus and response history.

Sensory signals en route to the cortex undergo profound signal transformations in the thalamus. A key thalamic transformation is sensory adaptation in which neural output adjusts to the statistics and dynamics of past stimuli.”

One of this study’s researchers described ways that an individual’s “stimulus and response history” became unconscious memories with the thalamus. Including the thalamus in synesthesia studies may also have findings that involve reliving or re-experiencing a memory, possibly an emotional memory.

In such future research, it could be a design element to ask synesthetes before and after the experiment to identify feelings and memories accompanying synesthesia experiences.

It shouldn’t be a requirement, however, to insist that memories and emotions be consciously identified in order to be included in the findings. Human studies, for example, Unconscious stimuli have a pervasive effect on our brain function and behavior have found:

“Pain responses can be shaped by learning that takes place outside conscious awareness.

Our results support the notion that nonconscious stimuli have a pervasive effect on human brain function and behavior and may affect learning of complex cognitive processes such as psychologically mediated analgesic and hyperalgesic responses.”


Does an orangy twilight of aging sunflowers help you feel?

https://www.sciencedirect.com/science/article/pii/S1053810017305883 “Music-colour synaesthesia: Concept, context and qualia” (not freely available)