Monthly Archives: October 2018

Week 15.10 – 21.10

Lecture 15.10

This week we discussed about the Visual System – which are chapter 9 (The Eye) and 10 (The Central Visual System) of the book Neurocience: Exploring the Brain.

This is a topic I particularly find very interesting. The complexity of this sphere, and everything that is behind, really fascinates me. We started by talking a bit about the anatomy of the human eye and how light affects it (the lens, specially). We briefly discussed some malfunctions of the eye, such as myopia or hyperopia.

Light must pass through many cell layers before it reaches photoreceptors at the back of the retina. These photoreceptors can be of two types: rods – that make vision possible in low light – and cones – enable us to see in the daylight. What photoreceptors do is transduce light energy into changes in membrane potential. We can perceive colours due to the contributions of short-, medium- and long-wavelength cones to the retinal signal. A curiosity on this topic: have you ever wondered if we all see colours the same way? The answer is no! Females are known to have more cones than males. That allows them to distinguish between similar colours better than men, who, in general, have more rods. Just as a conclusion to this curiosity, this happens because long time ago, men would go hunt, meaning they needed a better sense for shapes, whereas women would stay still gathering berries, for example, and needed to distinguish the colours to avoid poisonous food. Those who couldn’t do it would die, so the genes for more cones in women and more rods in men were passed onto the next generations.

About the central visual system, in this part of the lecture we explored how the information extracted by the retina is analysed by it. Our visual system provides us with a unified picture of the world around us, yet we have two eyes and therefore two visual images in our head that need to be merged. To see how the brain does that, we examine the stimuli that make different neurons in the visual cortex respond and how these response properties arise.

The left side of the retina is connected to the right side of the brain, as well as the right side of the retina is connected to the left side of the brain. This happens because the optic nerve fibers cross in the optic chiasm.

To finish the lecture we watched a movie about colour understanding and it was very informative.

 

Exercises Class 16.10

On this week’s exercise session, we answered some questions related to the topic. One of them was about optical illusions and how we can trick our eyes into seeing something that is different from the reality.

 

FOR FUN: visit https://eyewire.org/. It’s a 2012 game to map the brain that challenges players to map neurons in 3D. The goal is to identify and classify cell types as well as potentially expand the known broad classes of retinal cells.

Week 08.10-14.10

The class on monday started with a 5 minute quiz about the 15th chapter. Then we learned about the different diffuse modulatory systems : We started with the Acetylcholinergic pathway, and the implications that a malfunction on it mean. We then went over the Catecholaminergic, Norepinephrine and Dopaminergic pathways. Some malfunctions of these pathways were also discussed. How accurately can we really evaluate these malfunctions? How soon could we expect to see some more advanced interventions  in medicine on these pathways?

We then discussed the serotonin pathway and its mediation by the hypothalamus and the pituitary gland.

To get a full image, we went over each of the hormones secreted by the pituitary gland : Oxytocin, related to birth and therefore usually linked with love and compassion; Vasopressin, our thirst regulator; Cortisol, our main stress indicator; etc…

The following matter to be discussed was the Autonomic Nervous System. This was particularly interesting when the contrasts between the sympathetic and parasympathetic systems were drawn. (arousing VS calming).

 

 

 

The idea of how complex and interconnected these pathways actually are are highlighted numerous times. Each pathway influences all other making some imbalances very hard to track down.

 

To make some sort of introduction for the following day we started the subject of how we can see and study the brain through different imaging techniques.

The first one was the PET scan.

Then a super interesting study was mentioned and discussed for a bit. It was about Adult attachment styles in social bonding and how you can evaluate them through the level of attachment avoidance.

On that same day in the afternoon we had an excursion to a company called MEGIN. We arrived and were welcomed into a very nice environment where one of their employees walked us through everything that they do on that company.

MEGIN was originally named Neuromag, it was founded in 1989 and it has been a leader in whole-head magnetoencephalography ever since then. In the office we visited they no longer manufacture their products but instead develop new ones and take care of all the logistics and business for the ones already on the market.

To better make us understand why MEGIN is so innovative and essential to Neuroscience research he gaves a good insight on how the MEG and EEG work, how they can be filtered, improved, adapted to different kinds of patients, etc…

Then we got to see the MEGIN most break-through products, from the Superconducting SQUID sensors in liquid helium in a helmet-like structure that we got to hold in our own hands, to the  new TRIUX™ neo . We got an extensive scientific explanation for how all of them worked. Some questions were raised by students about adapting the different machines to children or babies but apparently there is no need to do so. This was quite interesting. Some signal processing with specific filters is apparently sufficient.

This was the first week we had an excursion so it was quite exciting. We are very much looking forward for the next ones J

Week 01.10 – 07.10

Lecture 01.10

The focus on this week lecture was the neurotransmitter, the chapter 6 – Neurotransmitter systems – of the book “Neuroscience: Exploring the Brain (2015)”.

The first transmitter studied further was the glutamate. It is the most common excitatory neurotransmitter in the brain and if it doesn’t work properly, it may causes some serious damages that can push to the death of the neuron.

On the other hand, another important neurotransmitter is GABA which is known to be the most common inhibitory neurotransmitter in the brain. Therefore it is mainly found in inhibitory synapse that when activated and located between the excitatory synapse and the soma, will dissipate the current signal and then no change of potential will be recorded in the soma.

The G-proteins were also an important factor looked into in the lecture. It is essential to understand how they work since they are really common proteins, especially in the brain. The G-proteins induce a cascade of called second messenger. It is a significant process since it can influence the signal a lot. The main second messengers cascades advantage is the signal amplification. In consequence, more than one protein can be activated from a single G-protein activation.

I think this week lecture was really interesting as we learned more about the complexity of the neurotransmitters. In addition, I was glad the teacher showed us some little videos about the different mechanism. I personally like it because it gives me a visual approach that helps me a lot to understand and remember the different processes.

 

Exercises Class 02.10

This week exercise session was a bit different from the others. We were in the computer room and actually did a real experiment; we were measuring the aural and visual speed of reaction. Even though the conditions might not have been the optimal for an experiment related on quickness of mind, I still think if was interesting. It gave me an good idea of how some easy tests can already give some good information about how the brain works.