Eleventh Week

Dear all,
This week we didn’t have a lecture. During the exercise session we visited the Aalto Behavioral Laboratory and made some electroencephalography (EEG) measurements. EEG measures the electrical activity of the brain using noninvasive electrodes that are placed along the scalp. Surprisingly the most time consuming part of the measurement was the placement of the electrodes. Electrodes were embedded in a cap that was placed on test subject’s head. Blunt needles were stuck through wholes next to the electrodes in the cap and were used to move the hair and to inject conducting gel between the electrode and the scalp.
 
We measured the response to similar test performed during the exercise session of the fourth week. However, this time we measured the EEG when the test subject performed the test. The test subject reacted to visual and auditory stimuli and the reaction time as well as the brain activity were measured. The EEG data was visualized so that we were able to locate the activated areas. We observed that in response to the visual stimuli the visual cortex was activated and in response to auditory stimuli the auditory cortex was activated. The test subject reacted to the stimuli by pressing a button in the keyboard and therefore there was also some activation in the motor cortex.

 

Posted by Satu

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Tenth week

Dear all,
This week’s lecture we got to hear about the topic ”Wiring the Brain”. The brain consists of lots of neural connections in the brain, and this comprehensive map is called connectome. The neural development starts with cell proliferation, thereafter comes cell migrations and finally cell differentiation. An interesting thing that we learned is that the cortex develops “inside-out”, which means that layer VI differentiates before layer V that differentiates before layer VI and so on. The pathways are then formed in three phases: Firstly, the axon must choose the correct path. Secondly, the axon must choose the correct structure to innervate, and lastly, the axon must choose the correct cell to synapse with.

On the exercise session we went on an excursion to BABA (Baby brain activity) Center, which is a clinical research center. At this research center they focus on to understand how the brain functions emerge in babies and infants. Their mission is to understand the development of brain functions, how illness and other adversities affect infant brain development, recognize atypical brain development at infancy, develop new generation methods, and to serve as a hub of knowledge.  On our visit we got to hear about their projects, see some measurement devices and also hear about what a hospital physicist work with.

 

Posted by Cecilia Björkman

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Ninth Week

This week we had no lecture. In stead, during normal lecture time, we visited the Aalto Behavioral Laboratory (ABL), Advanced Magnetic Imaging Centre (AMI Centre), and Aalto TMS. ABL laboratory contains a electrically shielded room and different measurement equipment such as EEG (electroencephalography), eye tracking devices and thermal camera. The AMI Centre houses a 3T magnetic resonance imaging (MRI) device and various other stimulation and measurement systems used together with MRI system. Aalto TMS laboratory, where the TMS stands for Transcranial Magnetic Stimulation, is a measurement laboratory where the you stimulate the brain through the scull with a rapidly changing magnetic field. All these laboratories function under the Aalto University School of Science and it is very cool that the university houses so many research infrastructures that give the researchers a great set of tools to study the human brain.

On Tuesday, we visited Sooma, which is a Finnish company specialized in producing tDCS-stimulators (transcranial Direct Current Stimulation). tDCS is a modality where place two electrodes, a cathode and and anode, on the patients head, and apply a small ~2-4 mA current through the electrodes. The current then causes a small change in the membrain potentials close to the electrodes which makes the neurons more likely or less likely to fire action potentials. This can be used to balance hypo- and/or hyperactivity of stimulated areas. The idea is very similar to TMS where you apply low or high frequency TMS to change the hypo- or hyperactivity of the targeted area. The biggest application of tDCS is currently is treatment of depression, which the TMS can also be used, and the results are very similar to TMS. The biggest advantage of tDCS compared to TMS is, that the devices are much much cheaper and doesn’t require facilities and a lot of staff to be able to apply it to patients. The lecture covered the modality very thoroughly and was very interesting as we where not so familiar beforehand about the tDCS – modality.

Posted by MN

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Eighth week

During this week’s lecture we learned about the motor system and its connection to the brain. The general function and construction of the muscle wasn’t new information, but it was a good repetition, and a couple of new terms were learned such as: motor neuron pool, t tubule, and golgi tendon organ.

The different pathways for in which the brain communicate with the motor neurons of the spinal cord were also new knowledge. The two major groups of pathways are lateral pathways and ventromedial pathways. Axons in the lateral pathway are involved in the control of voluntary movements of distal muscles, and axons in the ventromedial pathway control postural muscles. The axons in the lateral column are under direct cortical control, whereas the axons in the ventromedial pathway are under brain stem control.

One disorder that was mentioned on the lecture and effects the motor system, is Parkinson’s disease. Parkinson’s is a disorder of the central nervous system, which has symptoms in the motor system such as: shaking, slowness of movements, and rigidity. The motor symptoms are a result of cell death in substantia nigra, which is a cell group in the midbrain that uses the neurotransmitter dopamine to transfer the inputs to striatum. One therapy for Parkinson’s disease is to use the compound dopa, which can increase the levels of dopamine.

 

Posted by Cecilia Björkman

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Seventh Week

Dear all,
During this week’s lecture we discussed about human auditory system. We learned how the sounds are first transformed into movement of the structures in the ear and how these movements are transformed into electrical signals. We also learned how the information is processed in the brain. We watched an interesting video about the audiovisual integration. In the video person’s face is shown as he repeats sound BAA and after that sound FAA. When watching the video it seemed that these two sounds are clearly different. It was interesting to learn afterwards that BAA and FAA sounds are actually identical and that apparent difference between the sounds is result of audiovisual integration.
 

During the exercise session we visited Elekta. Elekta provides equipment and software related to treatment of brain disorders and cancer. The excursion started with presentation about Elekta as a company but the main focus of the visit seemed to be magnetoencephalography (MEG) imaging technique. MEG measures magnetic signals produced by electrical currents in the brain. It is used to map neuronal activity. MEG is used in localization of the source of epileptiform brain activity in patients with epilepsy as well as in research of the brain function

Posted by Satu

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Sixth Week

Dear all,
This weeks topic of the lecture was the human visual system. The lecture started once again with a quiz and the topics of the quiz was also about the human visual system.
The lecture started with the anatomy of the human eye and the organization of retina. There on we moved on how the visible light hyperpolarizes photoreceptors. Then we learned how about the different types of photoreceptors and the perception of colors. There we moved to ganglion cell receptive fields and learned how ganglion responses is produced by the differences of the center and surrounding receptive fields. On the lecture there was some nice examples of optical illusions demonstrating the “relativity” of the human colour perception.
The next parts of the lecture was about the central visual system and started with the visual pathways and continued to lateral geculate nucleus (LGN) and visual cortex. We learned how the output of retina is moved through visual pathway and how different deficits in optic nerves impairs parts of vision. We also learned how the retinal output is projected to different layers of the LGN depending on the ganglion cell types and retinal areas.
The exercises of this week where also mainly about the human visual system with the exeption of one question being about the localization of sound.

 

Posted by MN

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Fifth week

Dear all,
On this week’s lecture we continued the subject “Neurotransmitter systems” and learned about the different pathways for acetylcholine, norepinephrine, dopamine and serotonin. We also got to hear about the basics of Alzheimer’s and Parkinson’s diseases.

Alzheimer’s is a common disease and it was interesting to hear what actually causes it. Today there are only treatments that slow down the process, but no cure exists on the market. The Alzheimer’s association (www.alz.org) writes that the majority of people with Alzheimer’s are 65 and older, but the disease can also have an earlier onset. The first symptom of Alzheimer’s is that the person has problems remembering newly learned things and on the lecture we also learned that acetylcholine (ACh) cell death is linked as an early sign of Alzheimer’s disease.

Parkinson’s disease is a movement disorder, which still also exists without a cure. Parkinson’s disease occurs as neurons producing dopamine die, which results in that the brain having problem controlling movements and coordination.

As an exercise we got to write about some drug or disease that alters the function of the central nervous system. It will be interesting to start writing and learn more about some specific drug or disease.

 

Posted by Cecilia Björkman

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Fourth week

Dear all,
During this week’s lecture of the course ”Structure and operation of the brain” we discussed about neurotransmitters. We started the lecture by watching couple of related animations. The animations were really informative even though they were quite short. It was easier to understand the processes by watching the animations than to just hear or read the description of the events.  After the animations we continued to the most common neurotransmitters of the brain. We discussed about different neurotransmitters, their receptor subtypes, agonists and antagonists. We learned many new terms but it was nice that we also discussed about more familiar substances such as ethanol, nicotine and benzodiazepine. It was surprising to hear that most common inhibitory neurotransmitter GABA is actually excitatory in infants. It would be interesting to learn how and at what age the transfer from excitatory to inhibitory occurs.
 
In the exercise session we did a small experiment related to reaction times. We tested reaction times to both visual and aural stimuli and compared them. We also tested how repeating the test affects the reaction times. For our test subject the reaction times to visual stimuli were shorter than the reaction times to aural stimuli and for visual stimuli the reaction times became shorter when the test was repeated. However, reaction times to aural stimuli did not change with repetition. I hope that we will at some point hear what kind of results the other groups got.

 

Posted by Satu

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Third Week

Dear all,
On the third week’s lecture we first continued the examination of action potentials. Then we continued how the action potential moves through the axon with the case of myalinated and un-myalinated axon. It was really interesting to learn about the different phases of action potential and how the phases make the current move forward and making it impossible to move in the other opposite direction. Then we continued to the axon terminal and learned how the the signal is transferred to another cell. We learned that there are two types of synapses: electrical synapses which transfer the ionic current directly through gap junctions to another cell, and chemical synapses where the axon terminal and post synaptict dendrite has cleft and the current is transferred by neurotransmitters to another cell. The lecture gave us a nice view of the movement of current in the central nervous system (CNS). We also learned about different arrangements, and different shapes and sizes of the synapses in the CNS.

In the exercise session we first glipsed through the correct answers of the mondays quizz. In the quizz there was multiple choice question about Alzheimer’s disease and all the answer options were actuall diseases, which where intresting to learn. After we went through the quizz we continued with exercises which pretty much revolved on topics of this weeks lecture.

 

Posted by MN

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Second week

Dear all,

Now we have had our second week with the course ”Structure and operation of the human brain” and this week we also had our first exercise lesson. At the normal lesson we got to hear about what a neuron consists of, an introduction to synapses and also about what mechanisms that works for keeping the concentration difference over the membrane.

As we came to the exercise lesson we got the task to build our own brain model with play dough. With different color of play dough we made the brain step by step. We started with the different parts of the brain stem, continuing with the cerebellum and last but not least cerebrum with its four different lobes. As we were building the brain we also got to hear about the functions of these different parts of the brain. This was a good way to learn about the brain anatomy and at the same time get an introduction in which part of the brain that works in which situation.

It will be interesting to get deeper into the brains function, for example how we are able to make memories or from where our personality and behavior origins. The brain is really an extraordinary tool for us.

Posted by Cecilia Björkman

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