I was digging in a very positive Berberine article: Berberine: A Promising Treatment for Neurodegenerative Diseases 2022
When I came across this: "Meanwhile, there are several studies offer some important insights into the neurotoxic effects of berberine. It is reported that in the Parkinson’s disease model rats induced by 6-OHDA, berberine aggravate the degeneration of dopaminergic neuron in the substantia nigra of rats (Shin et al., 2013). In addition, berberine can aggravate the cytotoxicity induced by 6-OHDA in PC12 cells and aggravate of dopaminergic neuron death (Kwon et al., 2010)."
So... these are the referenced articles:
Neurotoxic effects of berberine on long-term L-DOPA administration in 6-hydroxydopamine-lesioned rat model of Parkinson's disease 2013 pubmed.ncbi.nlm.nih.gov/235... "However, both concentrations of berberine in 6-OHDA-lesioned groups treated with L-DOPA aggravated the numbers of TH-immunopositive neurons in the substantia nigra and the levels of dopamine, norepinephrine, DOPAC and HVA in the striatum as compared to rats not treated with berberine. These results suggest that berberine leads to the degeneration of dopaminergic neuronal cells in the substantia nigra in the rat model of PD with chronic L-DOPA administration. Long-term L-DOPA therapy that may involve possibly neurotoxic isoquinoline agents including berberine should involve monitoring for adverse symptoms."
Effects of berberine on 6-hydroxydopamine-induced neurotoxicity in PC12 cells and a rat model of Parkinson's disease 2010 pubmed.ncbi.nlm.nih.gov/208... "In addition, treatment with berberine (5 and 30mg/kg, i.p.) for 21 days in 6-OHDA-lesioned rats markedly depleted tyrosine hydroxylase-immunopositive cells in the substantia nigra as compared to berberine-untreated rats. Further, the levels of dopamine and norepinephrine were also significantly decreased by berberine administration (5 and 30mg/kg) in the striatal regions of 6-OHDA-lesioned rats. These results suggested that berberine aggravated 6-OHDA-induced cytotoxicity in PC12 cells, and led to the degeneration of dopaminergic neuronal cells in the substantia nigra of 6-OHDA-lesioned rats. It is, therefore, suggested that the use of long-term l-DOPA therapy with isoquinoline derivatives including berberine may need to be examined for the presence of adverse symptoms."
I will keep digging.
I can't find the right words 
Mitochondria and NMDA Receptor-Dependent Toxicity of Berberine Sensitizes Neurons to Glutamate and Rotenone Injury 2014 journals.plos.org/plosone/a...
"Our study confirms previous reports on the neurotoxicity of BBR [19], [57] and suggests a mechanistic basis to understand how BBR could enhance neurodegenerative processes. These findings raise concerns over the CNS safety profile of BBR, particularly when used in the long-term in the aging population, in patients at risk of silent strokes or ischemic episodes [71], or in people at risk of chronic systemic pesticide exposure [50], [72]. Importantly, our results also suggest that memantine, a clinically available NMDA receptor antagonist, may be used to protect neurons against BBR toxicity. Widely available nutraceuticals and dietary supplements have gained considerable interest due to their potential health effects and presumed safety. However, more attention should be paid to both regulatory and research needs in this field."
"Mitochondria and NMDA Receptor-Dependent Toxicity of Berberine Sensitizes Neurons to Glutamate and Rotenone Injury [particularly in people at risk of chronic systemic pesticide exposure]." This is not good.
They just acknowledged the method of toxicity in organophosphate pesticides. This is why NMDAR antagonists like Memantine are therapeutic across the spectrum of NDDs and neuropsychiatric disorders like autism, ADD/ADHD/OCD, depression, anxiety...
Could you please explain this to me like the idiot I am?
You're not an idiot! I appreciate your self depreciation [I only have a high school education] but don't sell yourself short. You can't earn a degree for common sense.
I had a different experience than most people on this forum and therefore a reason to look for causation (I'm the Canary in the coal mine). Having this background has given me insight into pathogenesis of some chemicals. Those with advanced degrees lack real world experience. It's theoretical science for them - I am living proof and no one can trump this, they've tried.
So... "They just acknowledged the method of toxicity in organophosphate pesticides." means Berberine is toxic?
But "This is why NMDAR antagonists like Memantine are therapeutic across the spectrum of NDDs and neuropsychiatric disorders like autism, ADD/ADHD/OCD, depression, anxiety..." is saying Berberine is still good for you?
"They just acknowledged the method of toxicity in organophosphate pesticides." means Berberine is toxic?" YES, via this biological process: Mitochondria and NMDA Receptor-Dependent Toxicity of Berberine Sensitizes Neurons to Glutamate and Rotenone Injury [particularly in people at risk of chronic systemic pesticide exposure]."
"This is why NMDAR antagonists like Memantine are therapeutic across the spectrum of NDDs and neuropsychiatric disorders like autism, ADD/ADHD/OCD, depression, anxiety..." is saying Berberine is still good for you? NO. I wouldn't take it given my history of pesticide poisoning. Memantine is being under utilized and has a wide range of uses beyond Alzheimer's dementia.
I'm taking memantine along with rytary and metoprolol.
Thanks for the explanation. Berberine is still off my list.