Chemical Control of the Brain and Behavior

Text written by Nicholas Colb 

This week we focused on the aspects which allow widespread chemical communication between the brain and the rest of the body. The analogy in the book was descriptive: the point-to-point, rapid synaptic transmission in the sensory and motor systems can be compared to a telephone system making a link between two specific places, while the chemical control of the brain, operating in expanded space and time, can be compared to a television talk show which is broadcasted on a satellite network for millions of people. I find the complexity of the brain extremely fascinating; every week of the course, a completely new and mysterious aspect of the brain is unraveled.

It was stated that the hypothalamus is responsible for homeostasis, and that body heat in the cold is generated by shivering, goose bumps and shunting blood away from the surface of the body. However, it would be interesting to know how fever is generated—presumably by the hypothalamus—to increase body temperature radically. I’d consider it unlikely to be caused only by shivering, goose bumps and reduced blood circulation, while they can, of course, be considered symptoms of having a fever, too.

Furthermore, an interesting topic was the effect of stress on the brain. It seemed surprising to me that evidence has been found of a correlation between chronic stress and brain damage in mammals. Stress is ubiquitous and even encouraged in modern society, and the fact that it is detrimental to the brain sounds extremely alarming.

Posted by susanna

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Neurotransmitter systems

Probably everyone who have studied some physiology have heard of the neurotransmitters, but the systems of those neurotransmitters weren’t familiar to me. With this topic, based on the book it was a bit difficult to form understanding of the whole picture. However, the lecture offered more help with understanding the relationships with the subtopics of the chapter.

The most interesting takeaway of the chapter was the introduction of the methods to study the transmitter receptors. I find it interesting, how these different receptors have been identified with neuropharmacological analysis of synaptic transmission, ligand-binding methods, and molecular analysis of receptor proteins. However, the molecular analysis of the receptor proteins was left a bit unclear to me. What the analysis covers and how they are using the knowledge gained from the analysis.

Overall this chapter was challenging due to the intense content of the transmitter synthesis for different transmitters. I had difficulties in internalizing how the systems work between different transmitters. It was also more difficult to answer to the quiz as it was really difficult to remember all the content from reading the chapter.

Which consequences are related to lack of production of each of the transmitters? For example, lack of dopamine has been proven to relate to Parkinson’s disease.

As the book mentioned that one of the most interesting findings during past few years have been the endocannabinoids, what are the potential findings or functions related to endocannabinoids that researches are hoping to find addition to existing knowledge?

Is there any signal cascades in other receptors than the G-protein-coupled receptors?

-Erika

Posted by Erika Ojanperä

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The Chemical Senses, The Eye, and The Central Visual System

This week’s lecture focused on the basics of the chemical senses, that is, taste and smell, the function and structure of the eye, as well as the central visual system. The lecture was very fact-heavy and thus pretty difficult to digest. However, the professor did a great job at explaining the different concepts so that we could understand them and link them to previously learned material. The main ideas of the lecture were familiar to me, but the details were new and fascinating.

Something I found extremely interesting was that taste buds, or taste receptor cells, have similar structures to neurons. For example, the fact that taste buds transfer information via synapses was completely new to me. In addition, I learned that ATP works as a neurotransmitter in the gustatory process. ATP is released by sweet, bitter and umami taste cells. Sour and salty taste cells release serotonin as a neurotransmitter. The olfactory, or smell, process was much more familiar to me. I have studied the behaviour of the odorant particles and how their binding to the receptor proteins leads to action potentials and eventually to the sensation of smell.

The structure of the eye has been studied multiple times, but especially the microscopic anatomy of the retina was extremely interesting. However, the process of phototransduction was actually a bit confusing and I didn’t really understand the details of dark and light adaptation.

The most difficult topic was the central visual system. It was mostly new information for me, and I most certainly have to study it a bit more. I believe we did not have time to finish all of the material the professor had prepared for us, but luckily the textbook goes into detail about every process!

 

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Action Potentials and Brain Anatomy

Text written by Nicholas Colb 

This week we learned about the action potentials and synaptic transmission, and the chemistry behind these phenomena. I found it extremely interesting that the interaction between neurons can be explained thoroughly by examining particles on a molecular level, and that the relatively uncomplicated concept of the flow of ions is what essentially creates our intricate reality of thoughts, feelings and senses as well as all of our voluntary and involuntary bodily functions.

Furthermore, we learned about the general structure and organization of the mammalian brain. It was fascinating to see how much the brains of animals, such as rats or sheep, resemble the human brain. While at first glance the abundance of complicated terms did seem overwhelming, it was nice to realize that the terms were surprisingly easy to internalize. Compared to, for example, learning a new language and memorizing hundreds of words and grammatical structures, the anatomical terms of the brain seem relatively apprehendable (ironically, to the brain itself).

What sparked my imagination in this week’s readings was the introduction of neural activation maps, especially of the olfactory cortex. If it is so that each distinct odor triggers activity in certain subsets of neurons, and that we can map these neurons with modern imaging techniques, would it be possible to utilize these images in machine learning to predict which neuronal combinations are universally related to each odor? If this would indeed be possible, could these sections of neurons be artificially activated in the human brain to create a sense of odor?

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Structure and function of neurons

The introduction to neurons included both familiar and new information based on the previous studies in Bioinformation Technology. The structure and the basic functions of the neurons were already familiar but the information about the differentiations of neurons and function of glia cells were new. The history behind how all this information has been found is really interesting. I am constantly amazed by how the scientists have been able to develop the research and methods this far.

I had some difficulties understanding the ion channels and pumps, or more like why the cells will always have the resting potential less or more than zero. Why the body wants to use ATP and extra energy to maintain imbalance between different sides of the membrane. I understand how in the book it is stated that the cell needs this in order to survive, but the basic idea behind this is still a bit unclear.

One other thing I was wondering, why it is predicted that the scientists might not be able to find a treatment solution for Alzheimer’s disease? Why it is so difficult to find a solution that would prevent the building up of amyloids? Science has reached so much during the past decades so it surprises me that there might not be an answer to this problem.

I felt that the exercise session was well designed to encourage us to connect the theory and practise. For example the assignment to think what would happen without cilia cells really pushed us to use these new learnings of their functions and what would happen if they did not exist, what would happen without these functions.

-Erika

Posted by Erika Ojanperä

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