Good science on the blogs these days!

Broca’s Area, 1865:

This doesn’t sound too out there to us now, but at the time it caused a lot of controversy. The problems wasn’t the localization to the inferior frontal lobe, it was Broca’s claim that it was the LEFT inferior frontal lobe. This didn’t sit well with a lot of scientists at the time. It was pretty accepted that, when you had two sides or halves of an organ, the both acted in the same way. Both kidneys do the same thing, both sides of your lungs, and both of your ovaries or testes. Your legs and arms will do essentially the same thing, though due to handedness (or footedness), you may have more strength or dexterity on one side. Therefore, if the left part of your brain was involved in language, the right must be also.

Operant and classical learning can be differentiated at the genetic level:

Learning about relationships between stimuli (i.e., classical conditioning) and learning about consequences of one’s own behavior (i.e., operant conditioning) constitute the major part of our predictive understanding of the world. Since these forms of learning were recognized as two separate types 80 years ago, a recurrent concern has been the issue of whether one biological process can account for both of them. Today, we know the anatomical structures required for successful learning in several different paradigms, e.g., operant and classical processes can be localized to different brain regions in rodents and an identified neuron in Aplysia shows opposite biophysical changes after operant and classical training, respectively. We also know to some detail the molecular mechanisms underlying some forms of learning and memory consolidation. However, it is not known whether operant and classical learning can be distinguished at the molecular level. Therefore, we investigated whether genetic manipulations could differentiate between operant and classical learning in Drosophila. We found a double dissociation of protein kinase C and adenylyl cyclase on operant and classical learning. Moreover, the two learning systems interacted hierarchically such that classical predictors were learned preferentially over operant predictors.

This food doesn’t taste right … or is it me?:

Flavor is a result of what happens with taste-receptors in the mouth (including but not exclusively those on the tongue) and with olfactory receptors. The 40 or so kinds of taste-receptors interact with the chemicals in what you’re tasting (yes, all your food is made of chemicals!) and create a nerve impulse that sends a signal to the brain. Meanwhile, the 300 or so olfactory receptors send their own smell-signal based on the volatile components of your food. The taste-signal and the smell-signal are correlated in the brain to make the flavor you’re experiencing.

Evolving snake fangs:

I keep saying this to everyone: if you want to understand the origin of novel morphological features in multicellular organisms, you have to look at their development. “Everything is the way it is because of how it got that way,” as D’Arcy Thompson said, so comprehending the ontogeny of form is absolutely critical to understanding what processes were sculpted by evolution. Now here’s a lovely piece of work that uses snake embryology to come to some interesting conclusions about how venomous fangs evolved.

The Evolution of Cats: Sabertooth vs. Regular:

There are two kinds of “true cats”. Cat experts call one type feline or “modern” partly because they are the ones that did not go extinct. If you have a pet cat, it’s a modern/feline cat. This also includes the lions, tigers, leopards, etc. The other kind are called “sabercats” because this group includes the saber tooth. It is generally believed but not at all certain that these two groups of cats are different phylogenetic lineages (but that is an oversimplification).

Male fish deceive watching rivals about their top choice of females:

They say that all’s fair in love and war, and that certainly seems to be the case of Atlantic mollies (Poecilia mexicana). These freshwater fish are small and unassuming, but in their quest to find the best mates, they rely on a Machiavellian misdirection.

CLOACA, the Defecation Device:

This made me wonder – what exactly IS poop? Other than having a vague idea of nutrients, bacteria, and fiber, I had never deeply contemplated it before.

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