David J. Linden

“On average, dopamine receptor density is reduced in the VTA target regions of obese subjects as compared with those lean subjects (a characteristic that can be measured in a brain scanner). But the key question remains: Do obese individuals show reduced dopaminergic activation of VTA target areas in response to food? Is a blunted pleasure response to food involved in obesity?”

“How does stress influence the midbrain pleasure circuit (or the feeding control circuits)? The short answer is that we don't really know. However, there are some tantalizing initial clues. Recall that twenty-four hours after a single exposure to cocaine, the excitatory glutamate-using synapses recived by VTA dopamine neurons express LTP. This change, which will result in greater dopamine release in VTA target areas, could also be produced by nicotine, mophine, amphetamines, or alcohol. Amazingly, even breif exposure to stress (a rat's five-minute-long forced swim in cold water) also produced LTP of the VTA synapses that was indistinguishable from that evoked by drugs. What's more, the stress-induced LTP could be prevented by pretreatment with a corticosterone receptor blocker. This suggests that drugs and stress rewire the pleasure circuit in overlapping ways and that the stress response to trigger LTP in the VTA requires a stress hormone signaling loop from the brain to the body and back.”

“The head/heart duality is a well-known cultural phenomenon. In everyday speech we use "heart" as a shorthand to refer to our emotional state or our faith and "head" to refer to cognition or reason. Should I follow my head or my heart? Both "head" and "heart," while they are literally the names of body parts, are commonly used to stand for nonbodily phenonmena, for mental processes. But what body part do we use when we want to refer explicitly to our coporeal self? Whe, the humble "ass," of course! Consider the seminal gangsta rappers Niggaz with Attitude, who in thier classic track "Straight Outta Compton" rhyme: "Niggaz start to mumble / They wanna rumble / Mix 'em and cook 'em in a pot like gumbo / Goin' off on a motherfucker like that / With a gat that's pointed at yo ass." Do the guys in NWA mean to say that a gun is literally pointed downward, at your tuchas? Of course not. We understand that in this context "ass" means "corporeal self.”

“Experiements that have been devised to inflict even mild social pain (like exclusion form a group task or betrayal by a partner in a gambling game) have demonstrated significant activation of the sinula and the anterior cingulate cortex. Emotional pain isn't just a metaphor: In terms of brain activation, it partially overlaps with physical pain.”

“Human sexual and social behavior shares some similaries with that of rodents, but has some important differences as well. It shows much greater variability and individuality, for example, and is less closely tied to the olfactory system. At present, it is tempting to speculate that those of us with cheatin' hearts might have differences in brain dopamine, vasopressin, or oxytocin signaling when compared to our more faithful friends who have adopted the prairie vole lifestyle.”

“Male Amazon river dolphins will even insert thier penises in each other's blowholes in the only known example of nasal sex.**I refuse to make the obligatory "blowjob" joke here. Science writing is very serious business.”

“Clearly, Siberian reindeer are not fighting over drugged urine for its nutrative value.”