Limbic System

Evolution Behavior

3 building blocks:

1. individual selection: goal is to maximize copies of one’s own genes in next production
2. kin selection: help kins for reproduction because they share gens
3. reciprocal altruism
   • game theory. cooperation and cheating
   • tit for tat -> forgiving tit for tat -> trust-based tit for tat

Intercourse competition lying in genes

• imprinted genges: only in tournament-based specicies. male part of gene and female part of gene may do opposite respective purpose for competition
• founder effect
• human is in between tournament-base/polygamy and monogamy

Limbic System

all limbic system does is to send signal to hypothalamus (下丘脑) to control its behavior

• **amygdala

  杏仁核**

  • emotional learning: fear, anxiety, aggression, sexual; declarative & episodic memory

• **hippocampus

  海马体**

  • consolidation from short-term memory to long-term meory, stress response, spatial memory

• **hypothalamus

  下丘脑**

  • link the nervous system to the endocrine system: body temperature, hunger, parenting, thirst, fatigue, sleep, circadian rhythms, sexual and aggressive behaviors

• **septum verum

  隔膜**

  • medium between cortex and subcortical limibic neuclei (inhibit aggression from amygdala)

• **mammillary body

  乳头体**

  • a relay for impulses coming from the amygdalae and hippocampi, via the mamillo-thalamic tract to the thalamus

• **thalamus

  丘脑**

  • relaying of sensory signals, including motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness

• **ventral tegmental area

  VTA

  腹侧被盖区**

  • reward cognition (motivational salience, associative learning, and positively-valenced emotions) and orgasm, several psychiatric disorders

• **nucleus accumbens

  伏核**

  • cognitive processing of motivation, aversion, reward (i.e., incentive salience, pleasure, and positive reinforcement), and reinforcement learning. hence, it has a significant role in addiction

• **prefrontal cortex

  PFC

  前额皮层**

  • executive functions, such as planning, decision making, working memory, personality expression, moderating social behavior and controlling certain aspects of speech and language. Executive function relates to abilities to differentiate among conflicting thoughts, determine good and bad, better and best, same and different, future consequences of current activities, working toward a defined goal, prediction of outcomes, expectation based on actions, and social “control” (the ability to suppress urges that, if not suppressed, could lead to socially unacceptable outcomes).

• **anterior cingulate cortex

  ACC

  前扣带回**

  • attention allocation, reward anticipation, decision-making, impulse control (e.g. performance monitoring and error detection), and emotion, empathy, metaphorical linking
    • mirror neuron (on-going study for bio cause of empathy)

• ![limbicsystem.png

  300](/assets/images/limbic-system.png)

Human sexual behavior

• 50% rule
  • introdcing a maybe of 50% will maximize dopamine level to push toward a goal
• oxytocin (催产素) actively generated in intercourse indicates monogamy relationship is a continuning product of mother-offspring relationship

Aggression

• frontal cortex modulates animal behavior in human
• 25% of men on death row is associated with frontal cortex damage
• McNaughton Rule in law: decide if an individual is organically impaired enough to not be able to tell right and wrong
• moral reasoning comes after moral decision is made with affect
• PFC is usually against amygdala, but there are situations when riskier path is the reasonable one
• serotonin (血清素). facilitate frontal cortex metabolism. lowers levels of waste products of serotonin are associated with higher levels of aggression and anti-social behaviors
• alcohol amplifies preexisting social pattern: aggression or inhibition. Same with pain, frustration, stress, crowding.
• opposite of love is not hate, it is indifference. same for hate
• there’s no love without hate. there’s no aggression without fear.
• aggression is contagious. it can originate from frustration, anxiety or stress
• the poorer a person is economically, the higher chance it is getting more aggressive
• post-conventional Kohlberg stage: do the right thing that sometimes needs to break current law
• peer socialization plays a key role
• cheating is a strategy. Cognitive control increases honesty in cheaters but cheating in those who are honest
• tragedy of the commons. with infinite shared resources but limited repeated interactions, cooperation is not favored. selfishness is.
• a decrease in homicide within a group is a prerequisite for genocide between groups
• madman theory: advantage of perceived madness in coercive bargaining

Language

• resides in left hemisphere of brain
• deeply connected to limbic system. (one can feel better by talking to someone)
• language shapes thinking

Individuality

• you have the capacity to sin
• even it’s complicated, you gotta do something

depression

• depression is aggression turned inward