Average brain has 100 billion neurons. Synapses are the microscoping gaps allowing the neurons to transmit electrical/chemical signals. The chemicals transmitting signals through the synapses are the neurotransmitters.
The tissue of the brain is made up of grey matter and white matter.
Grey matter is to contain the neural cell bodies (also nerve synapses), while white matter are bundles of axons to transmit the signals int he brain and the spinal cord.
An important concept of the brain is neuroplasticity: that is the capacity of the brain to change and be adaptable. For instance if a certain part of the brain is damaged, then new neural connections will be formed so that other parts of the brain can take over the functions of the damaged parts. To activate new connections, however, the neurons need to be stimulated. Plasticity decreases with age (this is why learning a new language later in life is harder).
Neuroplasticity allows us to master a skill in case we repeat a certain activity over and over again (thereby potentially increasing the grey matter density in a certain area). However once we a mastered a skill, brain activity is weaker than at the beginning of learning because less concentration is needed (this was shown when doing brain imaging on patients playing Tetris)
When experiments are made, scientists use the electro-encephalogram (EEG) to measure with electrodes which parts of the brain are more activated during such experiment.
Another technique is to measure the blood flows in the brain, because more neural activity in one part of the brain means an increase in blood flow to that part.
“Neural processes are thought to occur on a 0.1 millimeter scale in 100 milliseconds (msec)” 
All of these techniques are known as ‘brain imaging’, though critics of ‘brain imaging’ claim that it is hard to interpret brain images and that their only reliable purpose is to provide a geography of the brain rather than certain cause-effect explanations.
Brain activity occurs in circuits of neurons ‘firing’ among each other.
The proportionally big cortex in human’s brains is what allows humans to have higher skills than other animals like language and consciousness.
Most of what our brain does is ‘automatic’ and we are not aware of it.
Our behaviour is deeply affected by emotions.
Phenomena in the brain are either controlled or automatic (certain reactions like perceiving someone as aesthetically attractive or not may be automatic).
Many automatic phenomena are believed to occur at the back of the brain (occipital), at the top (parietal) and at the side (temporal). The Amygdala (being deep down the cortex) is believed to be responsible for emotional automatic responses like fear. The amygdala and the insula are responsible for bodily sensations.
However the pre-frontal cortex is also known as the ‘executive’ part of the brain because it takes inputs from all other parts of the brain and allows the human being to plan in the long-term by taking into account these inputs (apparently this is what animals are not able to do).
The medial pre-frontal cortex is responsible for introspective thinking (the brain processes information).
The medial-pre frontal cortex has two parts: the Ventromedial part processes information that the person finds similar to oneself (apparently too much activity in this area can cause anxiety and depression because the person may be overly-ruminating on a personal circumstance that he found worrying), the Dorsomedial part processes information related to things the person finds dissimilar (such as thinking about other people’s feelings, which may cause empathy).
One benefit of meditation, according to researcher Rebecca Gladding, is to increase activity of the pre-frontal cortex (the more cognitive, rational part that allows us to plan), while reducing the connection between the medial-pre frontal cortex and the amygdala and insula which may cause stress after too much thinking.
The amygdala is downplayed by the ventromedial Ventromedial part and by the hippocampus (less density of grey matter in the amygdala, while enhancing the density in the hippocampus).
Always according to the same researcher, meditation enhances the person’s ability to respond rationally to potentially anxious situations by maximising the planning part of the brain. This is known as ’emotional regulation’.
Meditation may also enhance empathy by activating the dorosmedial prefrontal cortex.
Mindfulness meditation may enhance the Striatum and the Anterior cingulate cortex (involved with attention control). The Anterior cingulate cortex also helps in conflict monitoring when the brain processes information (it detects the presence of contradictions).
In general meditation activates a network of brain regions that is favourable for fear extinction.
The brain learns through approximations: in order to make sense of the multitude of perceptions, it tries to find patterns to render the understanding of the surrounding environment much easier.
-Experiments show that when rats are rewarded with pleasurable ‘electrical brain simulation’ for a certain behaviour, then they will try to replicate that behaviour .
-The insula cortex of the temporal lobe is active when people are disappointed for what they consider as a low pay off in a bargaining game. The insula is also responsible for bodily sensations of pain/joy and the feeling of a bad odor.
-Taxi drivers have higher density of grey matter in their hippocampus, allowing them to enhance their spatial knowledge
In 1871 Jevons expressed his idea that economists should be able to quantify human feelings.
-BINDING PROBLEM: this problem is divided in two parts. Firstly, the segregation problem: we do not know yet how our brains can separate sensory inputs so that we can focus on discrete elements- for instance if we see a red circle inside a blue square, somehow our brains can separate the two shapes into discrete elements. Secondly, the combination problem: we also do not know how our brains integrates different experiences into a coherent whole- for instance when a red car is driving down the road, our brain is somehow capable of making sense of that event by combining different perceptions (shape, colour, sound and motion) into a single coherent experience.
-HARD CONSCIOUSNESS: why are we conscious? Roger Penrose suggested that a theory of everything in physics must also include an explanation of how consciousness arises in a living being.
 Neuroeconomics: How Neuroscience Can Inform Economics by COLIN CAMERER, GEORGE LOEWENSTEIN, and DRAZEN PRELEC∗