Many of the most fundamental scientific questions and some of the most pressing problems of humanity, part 2.
In the first part of this article we mention the first 3 unsolved mysteries in chemistry: How life began? How are molecules (Molecule) created? and: How does the environment affect our genes? In this part will we continue to explore the big mysteries of chemistry.
4. How the brain thinks and creates memories?
The brain is a chemical computer. Mutual reactions between nerve cells that build its circuits mediated by molecules called neurotransmitters (neuro – transmitters). These messengers cross the synapse, the contact point where the nerve cells coupling together. The most impressive parade of the chemistry of thinking is perhaps the operation of memory, a process in which abstract ideas and principles, such as a phone number or emotional associations, embedded in certain situations of neural network using continuous chemical signals. How chemistry creates a continuous and dynamic memory and also allows to recall, to change and to forget it?
We know part of the answer. Cascade of biochemical processes, is leading a change in the amount of neurotransmitter molecules at the synapse that in turn triggers learning of reflexes of the leg. However, even this simple aspect of learning has both short-term steps and long term. In contrast, more complex memory processes called declarative memory (like the memory of people, places, etc.) occurs via a different mechanism elsewhere in the brain. These processes involve the operation of a protein called the NMDA receptor found on certain neurons. Blocking this receptor using drugs prevents the saving of many types of declarative memories.
The declarative day-to-day memories are often encoded through a process called long-term empowerment, involving NMDA receptors and is accompanied by expansion of the neurons synapse region. The synapse grows, it “strengthens” the relationship with neighboring cells, i.e. the voltage soak up nerve signals from the synaptic junction. Biochemistry of this process became apparent in recent years. The process involves the formation of fibers within the nerve cell built from the Actin protein, material participant in building the basic skeleton of the cell and determines the size and shape. But if the biochemical factors prevent the stabilization of new fibers, the process stops and the fibers break down.
Once a long-term memory passes an encoding process, through simple or complex learning processes, it is actively maintained by activation of genes that cause certain proteins to react. Right now it seems that this process may involve a molecule called Prion. Prions are proteins that can oscillate between two different spatial forms. One water-soluble forms and the other is not soluble. Non-soluble form acts as a catalyst causing similar molecules to become an also-solvent and coagulate. Prions were discovered for their role in neurodegenerative diseases such as mad cow disease, but it is now clear that the action of prions also have a beneficial role: accumulation of Prions marks a synapse to use in order to keep a memory.
In the story of memory operations there are still large gaps, many of whom are waiting to be closed by clarifying the chemical details. For example, how a memory is being removed after learned? “This is a profound problem that we are just beginning to analyze” says neurobiologist and Nobel winner Eric Kandel of Columbia University.
Understanding the chemistry of memory offers us the controversial temptation of memory improvement with medication. We already know several memory stimulating substances, such as sex hormones and synthetic chemicals, acting on nicotine receptors, glutamine, serotonin and other neurotransmitters. In fact, the complex sequence of steps leading to learning and long-term memory has many possible targets for memory improvement drugs of this kind, says neurobiologist Gary Lynch of the University of California at Irvine.