"Introduction to Psychology" Notes (1) —— Brain

I start my exploration on psychology field from online Yale open course "Introduction to Psychology". It was teached by Professor Paul Bloom and tried to provide a comprehensive overview of the scientific study of thought and behavior. As the first step of a long journey, it is lucky for me to have such chance, guiding me through this discipline systematically, bringing me back to the university virtually, allowing me to experience the teaching style of the famous scholars in western world. The only pity is lacking of interaction with them.

Since I found this golden mine in internet I keep thinking of the word "Zeitgeist" which I learned from you at the first time. If I could choose, I would name the zeitgeist of the new internet age as "open, share and collaboration". Yes, we are blessed to live in such an internet age, the ways to learn, share and communicate are fast changing, the cutting-edge technologies change our life dramatically. What makes me the most depressed is that I can't share the benefit of it together with you.

I know I digress again. Let me come back to what I learned from this course. As usually, I scribbled down the notes during the course. This course explores a very wide range of topics including the brain, children, language, perception, morality,sex, memory, madness, love, emotion, dreams, personality, individual differences, mental illness and happiness. In the end, it escalates my interest in human's mind and strengthens my feeling there is so much more remain to be understood. So, let me retrospect the start of this journey -- "unlocking the mysteries of human mind". Meanwhile, I try to collect those related theories and findings which I encountered and were scattered around here and there in internet. For trace.
...

Lecture 2 - Foundations: This Is Your Brain


Dualism theory is claiming the duality of people: material bodies + immaterial souls.
Arguments from Rene Descartes:

1. We are not mere machines: Humans are capable of coordinated, creative, spontaneous things; Human can choose while machine can not.
2. The body and the mind are seperated: He used the method of doubt to duduce the argument "there's something really different about having a body that's always uncertain from having a mind" and to support this idea.

Dualism is emmeshed in our language, common sense and culture.

Nowadays, the scientific consensus is that dualism is wrong, that all of mental life including consciousness and emotions and choice and morality are the products of brain activities. Several reasons to support this conclusion:

1. Dualists fail to explain a lot of things like how a physical body connects to an immaterial soul.
2. Physical things can do a lot and this opens up the possibility that humans are physical things, in particular, that humans are brains.
3. There is strong evidence that the brain seems to correspond in intricate and elaborate ways to our mental life.

The basic structure of brain:

Neuron -- The basic unit of brain:

• 3 major parts of Neuron:

1. dendrites: get signals from other neurons (excitatory or inhibitory)
2. axon: transmit electrical signals from a nerve cell to other nerve cells or to muscles
3. myelin sheath: serve as an insulator to protect nerves, help the transmission work quicker

• 3 kinds of neurons:
1. Sensory neurons: take information from the world
2. motor neurons: telling the muscles what to do
3. interneurons: connect the two and do the thinking
• Neuron working mechanism is all-or-nothing: fire or not fire.
• 2 ways to encode intensity:
1. expressed the number of neurons firing
2. expressed the frequency of firing.

Synapses - The infinitesimal gap between the axon of one neuron and the dendrite of another.

Neurotransmitters - The chemicals sends by an axon through the gap and affect the dendrites so that neurons communicate to one another chemically.

2 sorts of drugs：

1. agonists: to increases the effect of neurotransmitters,either by making more neurotransmitters or stopping the cleanup of neurotransmitters
2. antagonists:to slow down the amount of neurotransmitters,either by destroying neurotransmitters or making it hard to create more

Brain is not wired up like a personal computer because:

• it highly resistant to damage
• it works extremely fast
• itworks through massively parallel processing

Subcortical structures: very low-level internal structures, underneath the cortex.

• Medulla: responsible for heart rate and respiration.
• Cerebellum: responsible for body balance and muscular coordination.
• Hypothalamus: responsible for feeding, hunger, thirst, and to some extent sleep.

Cortex is the outer layer:where all the neat stuff takes place. It is divided into different lobes:

• Frontal lobe （额叶）: involved in motor function, language, memory, impulse control, and many other functions.
• Parietal lobe（顶叶）: receives and processes sensations, perception, and integrating sensory input.
  
• Occipital lobe （枕叶）:responsible for visual interpretations and for combining visual images with recognition.
  
• Temporal lobe （颞叶）:associated with audition, speech, and memories
  

Less than 1/4 of the human cortex is devoted to projection areas, the rest is involved with language, reasoning, moral thought, etc.

Brain can be divided into:

• Right hemishphere: controls the left side of the body, parallel processor;
• Left hemisphere:controls the right side of the body, sequential processor
• Corpus callosum: major pathway between 2 hemispheres, connect them.

Some functions are ‘lateralized’： language on left, math,music on right.

TBD...

P.S. All credits go to Yale University and Professor Paul Broom.