Week 6 – Auditory and vestibular systems

This week’s topic was again very interesting, and I again came up with a few questions. In the stimulus intensity part, it was mentioned that when a stimulus gets more intense, more hair cells are activated, and that the increase in the number of activated hair cells causes a broadening of the frequency range to which the fiber responds. Does this mean, that it is more difficult to realize the frequency of noise when it’s louder?

Also it was mentioned that the hearing frequency range (20-20,000 Hz) decreases with age, especially at the high-frequency end. But it was never explained why this happens. Do the hair cells or the stereoclia get damaged with age, or do they wear out?

Finally a third question, how linear is the tonotopic map on the basilar membrane, and is there much variability between people? For example, some people have better “sävelkorva” than others, could this have something to do with the properties of of the basilar membrane? Could it be possible that because of small irregularities in the basilar membrane, some frequency ranges are heard better than others? Or that some people are just unable to recognize some frequencies properly, because hair cells with that characteristic frequency just doesn’t exist?

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Week 4

Much of this week’s topic -neurotransmitter systems-  were again pretty much just learning a by heart a lot of new names and definitions for different neurotransmitters and related topics. Nice new pieces of information were that for example ATP (adenosine triphosphate) and NO (nitric oxide) are thought to be synaptic transmitters. It also helped to broaden the subject a bit; if the molecule is capable of depolarizing the next neuron, it can basically serve as a neurotransmitter. And if these molecules do the job, why not use them. After all, the word neurotransmitter is just another fancy word to describe a molecule with certain function, it doesn’t mean that the molecule itself is fancy at all.

Other nice to know facts: antidepressants work by inhibition of serotonin reuptake, which is the process where a neurotransmitter is removed from the synaptic cleft. It’s pretty crazy that something like depression can be treated by pumping the patient’s body full of reuptake inhibitors. This also brought up another question: what happens in a drug resistant depression, and why is some patient’s body able to resist the drug? Is the reuptake process somewhat different, are for example the molecules involved a somehow mutated etc.

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Week 3

Hey there!

I’m the other author of this blog (posted by Oligodendroglia for technical reasons), a starting complex systems student and on the course out of pure curiosity towards the human brain. The brain is the sole reason our society got to where it is now and studying something brain related would be very interesting! However, on this course I very early stumbled upon the fact that since I wasn’t able to attend early contact teaching on the course and doing the exercises remotely would give me less points than doing them on spot, I have no motivation to even try to do any subtasks for the course and am somewhat forced to do the course by examination. It is not very pleasent to me, since studying such a large topic just for one examination is a) suboptimal for my learning and b) very likely not to give as good a metric of my knowledge as a continuous evaluation would.

For this reason I find it very disturbing that course personnel think my competence in a quiz is less valuable if I’m not doing the quiz on the spot and only doing it online and the quizzes account for such a vast percentage of overall score. The course would give me so much more should it allow me to prove my skills remotely and there were good online learning tools plus I wasn’t forced to come and sit in the lecture room where professors, although academically very prestigious, give somewhat poor pedagogic teaching in the traditional Finnish rally English. It’s just not for me, maybe it is valuable for another student on this course, who knows. Anyways, I’ll see you guys in the examination in December.

Cheers!

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Week 2

The second week of the course concentrated mainly on the astonishing world of action potentials and synapses. Chapter 4 – The action potential – was mostly familiar to me, except for the concepts of saltatory conduction and conduction velocity in general. I hadn’t even thought there are factors affecting the speed of action potential, so everything related to it was interesting.

In chapter 5 the principles of synaptic integration were also especially intriguing. So far the information about synapses and action potential has basically been about how the information is transmitted from cell to cell; now we got the first glimpse/molecular basis on how the inhibition of signals happens, and what are the mechanisms to control which signals are passed forward and which are not. Now it’s a bit easier to think the brain as an sophisticated algorithm; if some effect is inhibited, maybe this happens because the action potential has passed through a pathway (or an algorithm block) that has an inhibitory effect.

It was also interesting to learn the fact that dendrites don’t have ion channels. This I could nicely relate to the earlier learned fact that dendrites are short; if they were longer, they couldn’t conduct the depolarization. This also lead me to think, how much does the dendrite length affect on whether some information gets passed; are some dendrites longer because they are meant to pass the action potential only if the depolarization is strong enough?

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Week 1

Greetings to the numerous people reading our learning blog!

Most of the ideas I had this first week relate more to the consept of how to learn the structure and operation of the brain, than the subject itself. For an engineering student, a course that requires pure memorizing of stuff instead of programming or calculating is a true rarity. Thus, the old learning approaches last used in high school need to be rememorized, and the gluteal muscles must be reminded of their purpose.

The most valuable player of the course is definitely Vesa Vahermaa whos insanely good Brainscape flashcards I will definitely use a lot. It’s pretty annoying though to start the course by learning again how the action potential and the neurons work (for example Aalto’s bioinformation technology students have already studied this subject twice in their bachelor program, in the Physiology and the Biophysics courses). Although I do understand that if I want to understand the brain, it’s essential to understand it’s building blocks. I’m hoping that by the end of the course, I’m better able to understand (or to have a less vague idea) the connections between the molecular level, individual neurons and the function of the brain.

Another problem that I will have to face on the course is how to learn to memorize and perfectly write all the wonderful words such as oligodendroglia and boutons en passant. The fact that my biology studies have been mostly in finnish in the past make this even more difficult; it’s pretty difficult to try and tell your brain that the membrane inside cell that is coated with ribosomes is rough endoplasmic reticulum and not karkea solulimakalvosto (aargh).

Quote of the week: The brain obeys the laws of physics.

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