Everyone dreams – even people who believe that they “never dream” and can’t remember any of their dreams. That’s according to a group of French researchers writing in the Journal of Sleep Research: Evidence that non-dreamers do dream.
Are there areas of the cerebral cortex purely devoted to vision? Or can the “visual” cortex, under some conditions, respond to sounds? Two papers published recently address this question.
Am I a hypocrite about peer review?
I was thinking about this today. Here’s why I might be one.
On the one hand, I regularly criticize peer-reviewed research papers for being unsound. I’ve also expressed doubts about the reliability of the peer review process itself. And I do all this on my blog, which is not peer reviewed. So it seems that I don’t respect peer review as a guarantee of scientific truth.
However, I also criticize things for not being peer reviewed. For instance, I roll my eyes at journalists who dare to write about research before it’s been published in a peer reviewed journal.
In Part 1 of this post I discussed the first issue of a new scientific journal, the Journal of Reward Deficiency Syndrome (JRDS). JRDS is an unusual publication because one man, Kenneth Blum, was involved in editing, publishing, and writing most of the papers in it. In Part 2 I examined the science of “reward deficiency syndrome” (RDS), Blum’s neurobiological theory of addiction.
In this post, I’ll explore another aspect of the RDS story – the business side.
There are dozens of neurotransmitters in the human brain. How do neuroscientists decide which transmitters are most important? Are there trends and fashions in neuroscience, such that some transmitters rise and fall in popularity?
I searched PubMed for nine different neurotransmitters, and downloaded the ‘Results by Year’ data to track the number of peer-reviewed papers published each year from 1960 to 2014. The results are very interesting:
Here are some of my observations in no particular order:
The stagnation of serotonin (red): after growing steadily from 1960 to 2005, the number of papers about serotonin has flat-lined. This is possibly a reflection of the stagnation of research into selective serotonin re-uptake inhibitor (SSRI) antidepressants which likewise plateaued around 2005 (although it has started to grow again lately, unlike serotonin). This, in turn, may be related to the fact that most of the SSRI drugs went off-patent around this period. However, this can’t explain why GABA (purple) and endocannabinoids (black) stagnated over the same period. Hmm.
Dopamine (blue) is on the march: it’s the only transmitter that’s been steadily growing research since 1960.
The decline of noradrenaline/norepinephine (green): it was once the hottest transmitter, but something happened in the mid 1980s, and noradrenaline’s research output flat-lined, and then began to shrink. What went wrong? Maybe it was related to…
The rise and fall of substance p (orange) and the endorphins (pale blue): these two neuropeptides were discovered to be neurotransmitters in the late 1970s. Research on them grew rapidly but it didn’t last – by the early 1990s, they had each entered a decline from which they’ve never recovered. At one point the endorphins were more popular than GABA, but by 2014, 28 times more papers were published about GABA than about endorphins.
Note: This post is an update of one of my first ever posts, from 2008.
Meta-analyses are systematic syntheses of scientific evidence, most commonly randomized controlled clinical trials. A meta-analysis combines the results of multiple studies and can lead to new insights and more reliable results.
However, according to Italian surgeon Giovanni Tebala writing in Medical Hypotheses, meta-analyses are becoming too popular, and are in danger of taking over the medical literature.
Another day, another alarming brain-related story hits the news: