Neuroscientifically Challenged - "Know Your Brain" Series

The blog Neuroscientifically Challenged has an on-going series called "Know Your Brain." So far, there have been entries on the cerebellum, amygdala, nucleus accumbens, the HPA axis, hippocampus, prefrontal cortex, and hypothalamus.

There's nothing fancy, just a basic introduction to major areas of the brain.

Here is the entry on the hypothalamus to give you a taste of how these posts are written.

Know your brain: Hypothalamus

May 11, 2014

Where is it?


The hypothalamus is the small red dot in these images.
The hypothalamus is a small (about the size of an almond) region located directly above the brainstem. It is buried deep within the brain and not visible without dissecting the brain.

What is it and what does it do?

The hypothalamus is a collection of nuclei with a variety of functions. Many of the important roles of the hypothalamus involve what are known as the two H's: Homeostasis and Hormones.

Homeostasis is the maintenance of equilibrium in a system like the human body. Optimal biological function is facilitated by keeping things like body temperature, blood pressure, and caloric intake/expenditure at a fairly constant level. The hypothalamus receives a steady stream of information about these types of factors. When it recognizes an unanticipated imbalance, it enacts a mechanism to rectify that disparity.

The hypothalamus generally restores homeostasis through two mechanisms. First, it has connections to the autonomic nervous system, through which it can send signals to influence things like heart rate, digestion, and perspiration. For example, if the hypothalamus senses that body temperature is too high, it may send a message to sweat glands to cause perspiration, which acts to cool the body down.

The second way the hypothalamus can restore homeostasis, and another way the hypothalamus can influence behavior in general, is through the control of hormone release from the pituitary gland. The pituitary gland is a hormone-secreting gland that sits just below the hypothalamus. It consists of two lobes called the anterior and the posterior pituitary. The hypothalamus secretes substances into the bloodstream that are known as releasing hormones. They are so named because they travel to the anterior pituitary and cause it to release hormones that have been synthesized in the pituitary gland. Hormones released by the anterior pituitary due to signals from the hypothalamus (and their general role in parentheses) include growth hormone (growth), follicle-stimulating hormone (sexual development and reproduction), luteinizing hormone (testosterone production and reproduction), adrenocorticotropic hormone (stress/fear response), thyroid simulating hormone (metabolism), and prolactin (milk production).

The hypothalamus also synthesizes a couple hormones of its own: oxytocin and vasopressin. These are then sent to the posterior pituitary for release into the bloodstream. Oxytocin can act as a hormone and a neurotransmitter. It has important roles in facilitating childbirth (hence the use of Pitocin to induce labor) and lactation, but also has been the subject of a lot of recent research due to its hypothesized role in compassion and social bonding. Vasopressin's main functions are to control urine output and regulate blood pressure (although it also seems to play a part in social and sexual behavior).

The hypothalamus thus has widespread effects on the body and behavior, which stem from its role in maintaining homeostasis and its stimulation of hormone release. It is often said that the hypothalamus is responsible for the four Fs: fighting, fleeing, feeding, and fornication. Clearly, due to the frequency and significance of these behaviors, the hypothalamus is extremely important in everyday life.

Kahneman's System 1 & System 2 Thinking - A Primer

From Big Think, this is a brief primer on Daniel Kahneman's System 1 and System 2 thinking, as outlined in his excellent book, Thinking, Fast and Slow.

The author of this piece feels it necessary to claim a couple of limitations to the system 1 and system 2 model, namely that it's "light on evolution." However, this is a misdirection.

I'm sure Kahneman would be first to proclaim that system 1 developed far earlier in our evolution than did system 2. Even today much of our daily survival is taken care of by the system 1 brain, while the system 2 brain is engaged probably around 10% of the time (at best) for most people.

Kahneman's Mind-Clarifying Strangers: System 1 & System 2

by Jag Bhalla
March 7, 2014

Feeling is a form of thinking. Both are ways we process information, but feeling is faster. That’s the crux of Daniel Kahneman’s mind-clarifying work. It won a psychologist an economics Nobel. And strange labels helped.

In Thinking, Fast and Slow, Kahneman wrestles with flawed ideas about decision making. “Social scientists in the 1970s broadly accepted two ideas about human nature. First, people are generally rational…Second, emotions…explain most of the occasions on which people depart from rationality.” But research has “traced [systematic] errors to the… machinery of cognition…rather than corruption…by emotion.”

Kahneman sidesteps centuries of confusion (and Freudian fictions) by using new—hence undisputed—terms: the brilliantly bland “System 1” and “System 2.” These strangers help by forcing you to ask about their attributes. System 1 “is the brain’s fast, automatic, intuitive approach, System 2 “the mind’s slower, analytical mode, where reason dominates.” Kahneman says “System 1 is...more influential…guiding…[and]...steering System 2 to a very large extent.”

The measurable features of System 1 and System 2 cut across prior categories. Intuitive information-processing has typically been considered irrational, but System 1’s fast thinking is often logical and useful (“intuition is nothing more and nothing less than recognition”). Conversely, despite being conscious and deliberate System 2 can produce poor (sometimes irrational) results.

Kahneman launched behavioral economics by studying these systematic “cognitive biases.” He was astonished that economists modeled people as “rational, selfish, with tastes that don’t change,” when to psychologists “it is self-evident that people are neither fully rational nor completely selfish, and that their tastes are anything but stable.”

Kahneman’s potentially paradigm-tipping work has limitations. It is light on evolution, e.g focusing on numerically framed decisions discounts that we didn't evolve to think numerically. Math is a second nature skill, requiring much System 2 training (before becoming a System 1 skill). Also, we evolved to often act without System 2 consciously deciding (habits are triggered by System 1). Indeed cognitive biases might be bad System 1 habits rather than built in brain bugs. And cognitive biases have two sources of error, the observed behavior and what economists suppose is “rational.”

Those limitations aside, whenever pondering cognition, bear in mind the distinct traits of System 1 and System 2. Mapping mental skills (and the mini-skills they consist of) onto those labels can clarify your thinking about thinking.

~ Illustration by Julia Suits, The New Yorker Cartoonist & author of The Extraordinary Catalog of Peculiar Inventions.