Three to four years later, however, the researchers found an increase in gray matter in the posterior hippocampi, or the back part of the hippocampus, among the 39 trainees who ultimately qualified as taxi drivers. This change was not observed in the non-taxi drivers or trainees who had failed the exams. [...]
Qualified taxi drivers showed better memory performance for London-based information during the follow-up testing than controls or those who failed the test; however, they displayed “surprisingly poorer learning and memory for certain types of new visual information,” compared with controls, the researchers write online today in the journal Current Biology, “suggesting there might be a price to pay for the acquisition of their spatial knowledge.” (via.)
Cannabinoid receptors involved in placebo analgesia.
Placebo analgesia is mediated by both opioid and nonopioid mechanisms, but so far nothing is known about the nonopioid component. Here we show that the specific CB1 cannabinoid receptor antagonist 5-(4-chlorophenyl)-1-(2,4-dichloro-phenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide (rimonabant or SR141716) blocks nonopioid placebo analgesic responses but has no effect on opioid placebo responses. These findings suggest that the endocannabinoid system has a pivotal role in placebo analgesia in some circumstances when the opioid system is not involved. (via
When Transcranial Electromagnetic Stimulation (TMS) was used to inhibit the activity of the neurons in the posterior medial frontal cortex, the participants did not change their ratings of the photographs so they were more in line with the rest of the group.
Dr Klucharev believes this part of the brain is responsible for generating an “error” signal when individuals deviate from the group opinion, triggering a cascade that leads them to conform with the group view.
He said: “What if that mechanism could be suspended for a time? The group who were exposed to the TMS changed their views to a much lesser extent – they were immune to ‘group pressure’.
“Individuals differ in the strength of the error signal – which is why some people are more conformist than others. It also tells us that conformity is a rather automatic process that is based on an old evolutionary mechanism.”
Read the rest of the article at: The Telegraph
Study finds that CB1 receptor knockout mice have increased brain inflammation, which leads to earlier cognitive decline.
Brain aging is associated with cognitive decline that is accompanied by progressive neuroinflammatory changes. The endocannabinoid system (ECS) is involved in the regulation of glial activity and influences the progression of age-related learning and memory deficits. Mice lacking the Cnr1 gene (Cnr1?/?), which encodes the cannabinoid receptor 1 (CB1), showed an accelerated age-dependent deficit in spatial learning accompanied by a loss of principal neurons in the hippocampus. The age-dependent decrease in neuronal numbers in Cnr1?/? mice was not related to decreased neurogenesis or to epileptic seizures. However, enhanced neuroinflammation characterized by an increased density of astrocytes and activated microglia as well as an enhanced expression of the inflammatory cytokine IL-6 during aging was present in the hippocampus of Cnr1?/? mice. The ongoing process of pyramidal cell degeneration and neuroinflammation can exacerbate each other and both contribute to the cognitive deficits. Deletion of CB1 receptors from the forebrain GABAergic, but not from the glutamatergic neurons, led to a similar neuronal loss and increased neuroinflammation in the hippocampus as observed in animals lacking CB1 receptors in all cells. Our results suggest that CB1 receptor activity on hippocampal GABAergic neurons protects against age-dependent cognitive decline by reducing pyramidal cell degeneration and neuroinflammation. (via.)
Rhythms in the brain that are associated with learning become stronger as the body moves faster, UCLA neurophysicists report in a new study. The research team, led by professor Mayank Mehta, used specialized microelectrodes to monitor an electrical signal known as the gamma rhythm in the brains of mice. This signal is typically produced in a brain region called the hippocampus, which is critical for learning and memory, during periods of concentration and learning.
The researchers found that the strength of the gamma rhythm grew substantially as running speed increased, bringing scientists a step closer to understanding the brain functions essential for learning and navigation. (via.)
Excellent quote from a really good article by David Eagleman:
Instead of debating culpability, we should focus on what to do, moving forward, with an accused lawbreaker. I suggest that the legal system has to become forward-looking, primarily because it can no longer hope to do otherwise. As science complicates the question of culpability, our legal and social policy will need to shift toward a different set of questions: How is a person likely to behave in the future? Are criminal actions likely to be repeated? Can this person be helped toward pro-social behavior? How can incentives be realistically structured to deter crime?
The important change will be in the way we respond to the vast range of criminal acts. Biological explanation will not exculpate criminals; we will still remove from the streets lawbreakers who prove overaggressive, underempathetic, and poor at controlling their impulses. Consider, for example, that the majority of known serial killers were abused as children. Does this make them less blameworthy? Who cares? It’s the wrong question. The knowledge that they were abused encourages us to support social programs to prevent child abuse, but it does nothing to change the way we deal with the particular serial murderer standing in front of the bench. We still need to keep him off the streets, irrespective of his past misfortunes. The child abuse cannot serve as an excuse to let him go; the judge must keep society safe.
Or put more simply: how can our justice system be slightly less stupid and broken.
The U.S. Department of Health and Human Services released information today about research on melatonin supplements. The research was conducted at the University of Alberta for the U.S. National Center for Complementary and Alternative medicine. U of A researchers did a comprehensive review of all studies on the use of melatonin supplements to treat sleep disorders.
Click here to read the synopsis of what they found. Not looking so good for melatonin, me thinks!
Strenuous exercise increases plasma melatonin, cortisol, and ?-endorphin concentrations. Furthermore, a relationship between endogenous opioids and melatonin has been proposed. We measured plasma melatonin, cortisol, and ?-endorphin in 46 subjects before and after a 28.5-mile high altitude race. Thirteen of the subjects received the orally active opioid antagonist naltrexone immediately before the race. The mean plasma melatonin, cortisol, and ?-endorphin levels were higher after the race than before it; the melatonin results were confirmed by gas chromatography-mass spectrometry assay of 12 subjects. Naltrexone had no effect on the increase in any of the three hormones. (via.)
This study was briefly mentioned in “DMT: The Spirit Molecule.” I happened to run across it and thought I’d tuck it away on the blog in case it ever comes up again for some reason.
The bacteria responsible for stomach ulcers have been linked to Parkinson’s disease, according to researchers in the US.
Mice infected with Helicobacter pylori went onto develop Parkinson’s like symptoms.
The study, presented at a meeting of the American Society for Microbiology, argues that infection could play “a significant role”.
I’ve been skipping breakfast a lot lately, and that hasn’t been my habit in years past. It occurred to me after reading 4 Hour Work Week by Timothy Ferris (who advocates a high protein meal in the morning) that I may be doing some legitimate harm to myself.
This study isn’t exactly my age group, but I think it might still be applicable… I’ll consider myself a student of life until I’m dead. Maybe I should consider making an effort to grab breakfast in the morning? See below:
Conducted in public schools in Philadelphia and Baltimore, the study found that increased school breakfast participation correlated with less tardiness and absence, higher math grades, and reductions in problems like depression, anxiety and hyperactivity. The researchers also found that students were more like to participate in school breakfast programs when the meals were offered free to all students, compared with programs that provided free meals to low-income youngsters while others paid for their breakfasts. [...]
They also showed greater improvement in student-reported levels of depression and anxiety and, for the Baltimore students, reduced levels of hyperactivity, as reported by teachers. (via.)