Evolutionary Perspectives on Pain, Learned Helplessness, and Depressive Phenotypes

Comprehensive practice flashcards exploring the evolutionary functions of pain, stress-induced analgesia, learned helplessness, and depressive phenotypes across sickness, starvation, and cognitive analysis.

In the experiment by Millsopp and Laming (2008), how did goldfish respond when entering their feeding area ($S2$) resulted in electric shocks of varying voltages ($1\,\text{V}$, $5\,\text{V}$, $10\,\text{V}$, $15\,\text{V}$, or $20\,\text{V}$)?

As the voltage increased, the fish spent less time in the feeding section of the tank and entered it fewer times, demonstrating that pain causes feeding to get lower priority.

How did food deprivation affect the willingness of goldfish to enter a feeding area where they received a $20\,\text{V}$ shock (Millsopp & Laming, 2008)?

The more days the fish were deprived of food ($0$, $1$, $2$, or $3\,\text{days}$), the more time they spent feeding and tolerating the $20\,\text{V}$ shocks, illustrating that pain coordinates tradeoffs between competing goals.

In the study by Willer et al. (1981), what reflexive response was measured in humans, and how did naloxone affect desensitization to repeated foot shocks?

Researchers measured the reflexive contraction of the biceps femoris muscle; over repeated testing, subjects desensitized to shocks, but naloxone (an opioid antagonist) blocked this desensitization, demonstrating the involvement of endogenous opioids in stress-induced analgesia (SIA).

How did prior physical restraint alter the behavioral response of fish (Leporinus macrocephalus) to formaldehyde injection in Wolkers et al. (2013)?

Restraint for $3$ to $5\,\text{minutes}$ buffered the increased swimming speed and distance traveled normally induced by formaldehyde; naloxone prevented this desensitization, confirming it was mediated by endogenous opioids.

What is the evolutionary explanation for why squid are insensitive to warm water ($>30^\circ\text{C}$), trout are insensitive to cold water ($<4^\circ\text{C}$), and humans lack pain receptors in the brain?

Pain mechanisms only evolved to protect against harmful events that occurred in an organism's evolutionary past and about which something could actively be done to avoid or escape harm.

Why do humans possess an innate olfactory warning for hydrogen cyanide ($\text{HCN}$) and hydrogen sulfide ($\text{H}_2\text{S}$), but have no innate sensory detection for carbon monoxide ($\text{CO}$)?

$\text{HCN}$ (almond smell) was encountered ancestrally as plant/predator defense and $\text{H}_2\text{S}$ (rotten smell) in decaying organic matter, whereas toxic levels of $\text{CO}$ ($>35\,\text{ppm}$) were not a recurrent selective pressure in evolutionary history.

What occurred when Richard Solomon attempted to train dogs to jump over a hurdle to escape electric shocks after they had received $64$ inescapable shocks in a harness?

The dogs failed to learn how to jump over the hurdle in response to a sound to avoid the electric shocks.

How is the intuitive notion of "learned helplessness" defined and formally expressed mathematically by Maier and Seligman?

It entails the belief that nothing one does matters, formalized as $p(O|R) = p(O|\sim R)$, meaning the probability of an outcome $O$ is identical whether response $R$ occurs or does not occur.

In the standard triadic shuttle-box design, what percentage of rats in the escapable shock (ESC) and control (CON) conditions learned to escape compared to rats in the inescapable shock (INESC/Yoked) condition?

$90\%$ of rats in the ESC and CON conditions successfully learned to escape, whereas two-thirds ($\approx 67\%$) of the INESC/Yoked rats failed to learn how to escape.

What are the two core original assumptions of the "learned helplessness" hypothesis regarding an organism's default state and response to inescapable shock?

A sense of control is the organism's default state, and inescapable shock produces a learned sense of helplessness characterized by a motivational deficit and a learning deficit.

How long does the passivity produced by inescapable shock typically last in rats, and what is the estimated human equivalence?

Many effects of INESC last approximately $48\,\text{hours}$ in rats, which corresponds to roughly $50$ to $75\,\text{days}$ in a human.

How do escapable shock (ESC) and inescapable shock (INESC) differ in their neurobiological effects on serotonin ($5\text{-HT}$) in the dorsal raphe nucleus (DRN)?

Both ESC and INESC trigger DRN activity and increase $5\text{-HT}$, but with ESC the increase is temporary, whereas INESC produces a persistent increase.

What is the neural circuit that mediates the detection of behavioral control to dampen the stress response?

The ventromedial prefrontal cortex (vmPFC) detects control and sends an inhibitory projection to the dorsal raphe nucleus (DRN) to dampen stress.

What did Rosellini (1978) find regarding appetitive lever-press learning in food-deprived rats previously exposed to inescapable shock?

INESC rats took longer to learn the lever-pressing task initially (longer interresponse times), but completely learned it by the 6th response, indicating that INESC deprioritizes eating rather than abolishing learning capacity.

According to Grau et al. (1981), how does the nature of stress-induced analgesia change as the number of inescapable shocks increases from $20$ to $60\text{--}80$?

The first $20$ shocks induce a non-opioid form of SIA, whereas $60$ to $80$ shocks produce an opioid-dependent SIA that is blocked by naltrexone.

What did Hemingway and Reigle (1987) demonstrate by administering naloxone prior to the initial stress session in rats?

Giving naloxone before initial inescapable stress prevented the subsequent shuttlebox escape deficit $48\,\text{hours}$ later, showing that endogenous opioids released during INESC cause the shuttlebox deficit.

In Will et al. (1998), how did prior exposure to inescapable shock affect rats' conditioned place preference for morphine?

Rats previously exposed to INESC spent significantly more time in the morphine-paired compartment than control or escapable shock rats, demonstrating an increased preference for analgesia.

How does inescapable shock impact classical fear conditioning (pairing a sound with periorbital shock to produce an eyeblink) according to Shors (2004)?

INESC rats acquire the conditioned response significantly faster than unstressed rats, an enhancement Maier and Seligman termed "potentiated fear conditioning."

In Glazer and Weiss (1976), how did INESC rats perform on the FR3 bar press task compared to the nosing task?

INESC rats were slower to learn the FR3 bar press task but quicker to learn the nosing task, proving their performance deficits result from reduced motor activity rather than an inability to learn.

Under what specific condition in Experiment 3 of Minor et al. (1984) did preshocked (INESC) rats perform worse in the Y-maze than restrained control rats?

Under the preshocked delayed human (PDH) condition, where a variable delay between choice and shock termination was combined with the presence of a human observer, demonstrating heightened attention to external cues.

In the water escape task by Lee and Maier (1988), how did INESC rats perform when placard color indicated the escape route (Experiment 3)?

INESC rats were quicker to reach criterion than control or ESC rats because they actively engaged in hypothesis testing regarding the meaning of the color cues.

What are the distinguishing properties of Type 1 versus Type 2 problem-solving styles as outlined by Evans, Stanovich, and Kahneman?

Type 1 is fast, automatic, intuitive, error-prone, and heuristic-driven; Type 2 is slow, analytical ("divide-and-conquer"), energetically expensive, attentionally demanding, and requires working memory.

What key clinical symptoms did Hart (1988) identify as defining "sickness behavior"?

Attenuation of parasympathetic tone, HPA axis activation, reduced appetite, altered thermoregulation, flattening of diurnal rhythms, decreased social/physical activity, increased slow-wave sleep (SWS), reduced REM, impaired learning/memory, pain, and fatigue.

What is the estimated metabolic cost of mounting a fever for every $1^\circ\text{C}$ increase in human core body temperature?

Every $1^\circ\text{C}$ increase in core body temperature requires a $10\%$ to $12\%$ increase in metabolic rate.

How does the body selectively allocate glucose to immune tissues during an infection while depriving non-immune tissues?

It induces insulin resistance (IR) in non-immune tissues (such as skeletal muscle) while preserving insulin sensitivity (IS) in immune tissues.

Why is suppressing sickness behavior with antipyretics, high physical exercise, and forced social activity considered clinically counterproductive?

Sickness behavior is an evolved adaptation that coordinates the reallocation of limited energy to the immune system; suppressing these symptoms compromises host defense and healing.

What happens to the oxygen uptake and core body temperature of humans subjected to prolonged semi-starvation (Keys et al., 1950; Rising et al., 1992)?

Oxygen uptake drops to approximately $60\%$ to $70\%$ of baseline and core body temperature drops, reflecting metabolic downregulation to conserve energy.

How are peripheral tissues and the brain fuel supplies regulated via insulin resistance during starvation?

Peripheral tissues and skeletal muscle develop insulin resistance and switch to fat fuels, while the brain remains insulin-sensitive to consume glucose, and insulin sensitivity in protein catabolism is preserved to supply amino acids for gluconeogenesis.

How does leptin regulate locomotor activity during periods of semi-starvation, according to Exner et al. (2000)?

Leptin circulates proportionally to fat reserves and suppresses hyperactivity; when fat reserves decline during starvation, falling leptin disinhibits locomotor activity to stimulate foraging behavior.

What physiological event causes refeeding syndrome when an individual breaks a prolonged fast with a high-carbohydrate meal?

The carbohydrate meal causes an insulin spike that rapidly drives production of ADP and phosphorylated compounds, causing sudden depletion of circulating blood phosphate and fatal cardiac arrest.

How do the clinical symptoms of anorexia nervosa correspond to the evolved physiological response to starvation?

Both exhibit severe food restriction, increased motor activity, significant weight loss, decreased core body temperature, suppressed sexual behavior, and elevated HPA axis activity.

What is the central premise of the "energy reallocation hypothesis" of depressive phenotypes?

Depressive phenotypes evolved as coordinated physiological and behavioral states designed to reallocate limited energy resources to critical bodily challenges, such as immune defense, starvation foraging, or complex cognitive analysis.

In Keller et al. (2002), how did depressed women perform compared to non-depressed women when using the Gail model to predict personal breast cancer risk?

Depressed women were not more pessimistic and had equivalent factual recall, but they modified their risk estimates more accurately in accordance with the Gail model data, demonstrating enhanced Type 2 analytical processing.