EEG

In this week we had two EEG studies in Aalto Behavioral Laboratory (ABL) at Otaniemi. Both studies were carried out with same test protocol. The test protocol included different variations of reaction times (sound and visual inputs). The test subject was sitting in a room which was sealed from outside noise and electrical currents. The test lasted about twelve minutes and included different sets of inputs for testing reaction times. It was actually really interesting to take part of preparing the EEG electrodes and see from the screen how different movements caused the EEG to change. For instance, how closing eyes or use of the face muscles caused changes.

Posted by Tomas Villikka

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Excursions to ANI and FIOH

This week there were excursions to ANI (Aalto Neuroimaging Infrastructure) and to FIOH (Finnish Institute of Occupational Health). All the machines shown in the ANI were somewhat familiar for me and especially the TMS, but I did not have a clear image on what the FIOH does.

I had not seen beforehand most of the machines shown in the ANI. Especially the MRI and TMS seemed to link clearly to this course, because one can be used to image the brain and other to stimulate it. I know that the MRI-images are sometimes used to create a plan for the navigated TMS in the patient use. How about in research? Are the ANI-infrastructures machines used commonly together?

It was interesting to learn how the FIOH studies the sleep using the electrooculography. I have never prior thought that the sleep quality and phases could be monitored like that. I have only heard of sleep monitoring using EEG and heart rate. What else other than sleep could be monitored with EOG?

In was discussed in the FIOH that it is not known how the shift work affects the quality of sleep.  Why the subject is not studied more? How could this be studied the best?

Posted by Niina Kanerva

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Neurons that wire together, fire together

This week’s topic was the genesis of neurons and brain connectivity. I had always thought that there is no neurogeneration happening on adults, but that is actually not the case. This week we learned that in hippocampus happens neuroregeneration also on adults. Though, that is the only area.

We also had an excursion to Sooma Medical, which was really intresting. They produce new treatments with tDCS. They have treatments for depression and pain. Treatments are executed with a minor electrical neurostimulation with 30 minutes a time. The stimulation is repeated for few weeks to get the maximum benefit from it. Depending on the placement of electrodes, they can treat different things (pain, anxiety…). This firm was a brilliant example of how much our knowledge from the function of brain can help people.

Posted by Maija Vahteristo

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Sensory and motor systems

Sensory and motor systems were quite familiar to me beforehand. However, for example how the dorsal and ventral horns appear to be a bit swollen, is result from a larger need of spinal interneurons and motor neurons at cervical and lumbar enlargements was new thing for me. At this point it’s appropriate to point out that I’ve felt the book has given really good platform to learn more efficiently. Furthermore, at page 470 the figure 13.18 gave me nice insight how neurons, their responses, muscles and really world (weights) work together. From previous lecture, if I understood correctly the question about the flexor reflex, that could this be something to learn? It’s is so powerful reflex that it could be useful when learning something new, i.e. in combat sports

I consider the motor loop to be the key take-a-way from chapter 14. It’s a good illustration how the information flows through different brain areas during planning and executing a curtain movement. Furthermore, I found it intriguing that actually the movement which one is performing now, has decided few seconds before. Consequently, one could argue that our movements have always delay, which might seem odd idea since we like to think that grapping the phone from table is instantaneous movement without delay. Indeed, the planning of the movement has conducted early on, but it’s done more “behind the curtains”, and therefore we don’t consider it to be part of our movement process.

Posted by Tomas Villikka

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Auditory System

I have had some physiology courses prior, but I had never thought of just how good human hearing is. The dynamic range is huge. The ears have small but complex mechanical systems.

One thing I thought was especially interesting was the role of the outer hair cells. I was surprised that there could be system which would function in a such a manner. The fact that they can act as amplificator by changing their length according to the vibrations of sound was interesting. How they can they adapt to changes in the frequencies? It would be intriguing to learn how such a mechanism has developed.

I had always thought that the sound locating is only based of sound intensity differences between ears. It is fascinating that the ears can notice very small interaural delays and the brain can process them correctly. Also, the phase locking as a concept and its function in the sound location, was entirely new information to me.

The videos shown in lectures showed the relationships between sound and vision. It was interesting how the visuals can effect on how the noise is interpreted by the brain.

Posted by Niina Kanerva

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Vision

The subject of this week was vision. We learned a bit about the anatomy of the eye, which was already familiar to me. It is important to understand all the physiological and anatomical details of the eye, so you can understand the exact mechanism of visual perception, which was the key point of the week.

Visual perception is actually more complicated than one would think. In addition to the anatomical features of the eye, also our nervous system plays an important role in it. There are two types of photoreceptor cells in our eyes, rods and cones. Rods are sensible to low light, but cones enable our colour vision. There are 3 types of cones, each sensitive to different wavelengths of light (red, blue and green). Our brain handles the visual information, which is produced by the photoreceptor cells.

The lecture was good, and I liked that the video in the summed up all the things we learned in the lecture. The exercises also look good, because in them we will have to apply our knowledge different ways and really think what we have been learning.

Posted by Maija Vahteristo

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Chemical control of the Brain and Behaviour

To begin with, I think it’s fascinating how does the different pathways spread widely into the brain. As we have learned so far during the course, there are many areas in neuroscience where there are caps in knowledge. Especially different types of neurons, patterns among other things. How does these pathways actually work and what is our understanding about their functions? Personally, I’m really interested about the complexity of the brain. One good example of these caps in our knowledge and complexity of the brain are ascending pathways from locus coeruleus. It has 12 thousand neurons, and each has approximately 250 thousand synapses across cortex and cerebellum. As we know, this part of the brain and pathways are connected to for e.g. mood and depression. We all know that neuroscience today can’t give completely perfect answers for each question. To really understand this kind of system might not be in near future.

Hypothalamo-pituitary portal circulation functioning is rather interesting. The fact that axons from hypothalamus does not extend into the anterior lobe, but instead use of hormones and blood veins, tells me even more about brain’s complexity.

The excursion to Elekta was truly interesting. During the two hours presentation I learned a lot about the magnetoencephalography (MEG) technology. The similarities and key differences between EEG and MEG were interesting as well.

Posted by Tomas Villikka

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Neurotransmitter chemistry, responses and response times

In my prior studies, the neurotransmitter chemistry and responses were only briefly introduced. I had no idea how complex the small molecular sized system could be. There is a lot of different receptor subtypes, agonists, antagonists and complex responses, and the whole system works in a combination of divergent and convergent elements.

It made me wonder, how much there is still to be found in the neurotransmitter chemistry area. I know that today there are a lot of incurable neuro-related diseases. Is it possible to one day cure them all? How the complex neurological network can be modelled? What is the role of kainate receptors? Could the glia cells have an unknown role in transmission process?

It was interesting to learns that the Alzheimer’s diseases mechanisms are somewhat knowns, and the memory loss can be decreased with the inhibition of ACh breaking enzymes. In the future, is it possible to prevent the cause of Alzheimer’s disease, which is loss of cholinergic neurons?

In the exercise it was interesting to learn more about altering the CNS, and about the reaction times. The reaction time test was fun to do and it was interesting to notice how much the results varied.

Posted by Niina Kanerva

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Learning about neuronal transmission and anatomy of the brain

I have a strong background in molecular biology, so most of the things on this week were already familiar to me. Though, it was interesting to learn these things from the perspective of brain. I also learned a lot of new nomenclature and classifications.

The book is well-written and easy to understand so I learned a lot by reading the chapters 4 and 5 before Mondays lecture. The classification to Gray’s type I and type II neurons was new for me as well as the principles of synaptic integration. It really was eye-opening to learn the difference of spatial and temporal summation. The shunting inhibition is also a new important thing, that I had to understand, in order to fully know how neuronal transmission works.

At the lecture I really started to wonder the effects of glial cells. As we spoke there, the exact function of glial cells is not yet known, but there are suspicions that they may have a bigger role. I started to wonder how much these non-neuronal cells can affect to the formation and progress of action potentials and to the synaptic transmission. In the future we will need much more research that concentrates on glial (and other non-neuronal) cells.

It was nice to learn about new methods. I have heard of patch clamp before but never fully understood how it is used. Optogenetics also intrigued me and I think that it will be an important method in future brain research.

Exercises were also useful, because I had never learned the different brain areas and their nomenclature. It was fun to use Play-Doh as a learning tool.

Posted by Maija Vahteristo

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Intelligence, firing frequency and selectivity of ion channels

First of all, it has been really interesting to learn about human brain in past few weeks. I have always been interested in intelligence. We talked briefly in class that people could be willing to enhance their IQ. The questions which raised from that discussion was that what intelligence really is? What we know already is that larger head (meaning larger cerebral cortex surface usually) correlates with IQ. However, in order to design any kind of drugs or machines we should first know deeply where the intelligence comes from. Somehow related to intelligence, I found it very fascinating to think that there are around 1015 synapses in our brain and different firing frequencies which tells us a great deal about the complexity of our brains. No wonder that it’s commonly said that human brain is the most complex system in the universe.

The other question which came from reading the book is about action potential. The maximum firing frequency is 1000 Hz and absolute refectory period is stated to be about 1ms. For my future reading I should find out how it can be so that the next action potential can be started without undershoot. One interesting thing which I founded when reading the book, “…a pore in the membrane that is highly selective to Na+ …” The question for myself is that are these channels permeable also for other ions which shouldn’t pass the channel. Furthermore, what kind of problems there might be regarding this topic. I’ll probably get an answer for this question in following chapters.

When wondering these questions, it has come clearer for me that what is the level of analysis that I’m most interested. For now, I think it might be system level.

Posted by Tomas Villikka

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