Archive for January, 2012
Human pheromones: the chemistry of love
This article from the New York Times is a timely prequel to a more technical representation of cause and effect that is “in press” for the open access journal Socioaffective Neuroscience & Psychology.
“We may respond to the same honeyed aromas that make fruit flies amorous, so chemists include them in perfumes.”
read more January 15, 2012 • 10:17 AM
Genes, neuroanatomy, thoughts, and behavior
It all starts with gene activation by sensory stimuli from the environment, a biological fact that is downplayed in this otherwise fantastic representation of what’s known about epigenetic influences and their effects on the brain, which leads to their affects on behavior. The 3-minute video is entertaining and informative; the article even more so. Watch, read, learn!
New techniques, including advances in brain scans, are helping to reveal the hidden anatomy of brain wiring and giving scientists a new understanding of how thoughts, memories and emotions are formed. WSJ’s Robert Lee Hotz reports.
New Research Seeks to Map Billions of Neural Links That Make the Mind Work
“It may be the first new perspective on neuroanatomy in 100 years,” “That is a million times more connections than the genome has letters of DNA,” said computational neuroscientist
read more January 26, 2012 • 7:13 PM
Misrepresentations of biologically based cause and effect:
“Negative” impacts on understanding the development of intelligence and human behavior.
Molecules of deoxyribonucleic acid (DNA) contain genes. The genomes of organisms appear to self-engineer genetic changes that depend on environmental factors, which include ecological factors. The effect of the environmental factors is driven by electrical signals. For example, at the molecular level, the absorption of a single quantum of photic energy by only one of the approximately one hundred million molecules of rhodopsin contained in a single rod is sufficient to generate and transmit an electrical signal. (more…)read more January 29, 2012 • 5:03 PM
Human pheromones, pharmacogenomics, psychologists, and litigation (558 words)
On January 1, 2012, in discussion on the psychiatry research yahoo group, I wrote: “… there is nothing inherently rewarding about dopamine, so why are behaviorists praying to a dopaminergic god of operant conditioning?”
The same can be asked about serotonin, oxytocin, and other hormones / neurotransmitters that are commonly proposed as causes of human behaviors. The link between oxytocin and “bonding” associated with love is perhaps the most commonly proposed cause and effect relationship. But love is profoundly social. How could a hormone, like oxytocin, that has no inherent social value cause anyone to think, believe, or feel like they are in love? It can’t!
I will now try again to clarify my point about the FDA Critical Path Initiative and the gene, cell, tissue, organ, organ system pathway, which I have detailed. The issue is how pharmacogenomics establishes the relative salience of sensory stimuli associated with behavior.
It is important for psychologists to understand how salience is established because treatment outcomes may sometimes depend on that understanding. (more…)read more January 15, 2012 • 3:11 PM
Scientists recreate evolution of complexity using ‘molecular time travel’
“Much of what living cells do is carried out by “molecular machines” – physical complexes of specialized proteins working together to carry out some biological function. How the minute steps of evolution produced these constructions has long puzzled scientists, and provided a favorite target for creationists.”
Groups of molecules that happen to stick are credited with tinkering, degradation, and good luck during evolution. Does that mean each of our ancestors as far back as single-celled organisms was preserved because they helped our other ancestors to survive? If so, I have a problem with what appears to be a one-way model. For example, how does the accumulation of simple, degenerative changes over long periods of times cause speciation, which incorporates many of the complex molecular machines present in organisms today? I think the accumulation of simple, degenerative changes in different organisms must stop for one species to establish its ecological niche but I don’t see any explanation for stop-and-start degenerative changes. That’s why one-way models of evolved complexity don’t work for me, but especially when the “one way” is via degradation. For contrast, Lynch et al find no evidence for stepwise evolution.
“There is a broad consensus that many of the genetic changes underlying the evolution of morphology occur by the stepwise modification of individual pre-existing cis-regulatory element modules5,6,29. However, it is questionable whether the origin of complex novelties—such as the origin of new cell types, which involves the recruitment of hundreds of genes—can be achieved by these small-scale changes7,29.”
The importance of the evolved mammalian placenta to human behavior cannot be overstated. The chemical communication that occurs in utero between mother and child probably are responsible for the genetically predisposed mother-infant bond, which sets the post-natal stage for the development of differences in adult behavior. I will have more to say about this in a follow-up post.read more January 08, 2012 • 9:09 PM
Mapping the human genome in 3-D
My comment: Food odors and social odors have direct effects on gene activation. Is it likely that food odors up-regulate and social odors down-regulate gene expression responsible for speciation and species-specific behaviors? If so, the direct effect of food odors and social odors on signalling pathways would make chemical cues as important to the understanding of human behavior as they are to the understanding of behavior in every other species on the planet. Wouldn’t it?read more January 04, 2012 • 11:06 AM