Reviewing vision

After having reviewed the vision system in detail, some aspects seem more clear. The forming of a visual concept involves the integration of smaller, low-level parts of the visual system. The smallest components, the photoreceptors, compose the ON- and OFF-center receptive fields of bipolar and ganglion cells. The ganglion cells then send action potentials onward through the LGN to the striate cortex, where first steps of integration happen in layers outside of layer IVC. Binocularity, meaning responsiveness to stimuli coming from either eye, happens in layers superficial to layer IVC. Another form of integration, happening outside layer IVC, is the integration of smaller receptive fields into bar-shaped fields. These fields can be selective of different features, e.g. orientation or direction of movement.

Progressing on to other cortical areas, they further integrate the information from lower structures, with different areas taking care of different operations. Area V5, receiving input from areas V2, V3 and direct axons from layer IVB of V1, is associated with motion selectivity. Areas running in the ventral stream, e.g. area 4, area IT and the fusiform face area are associated with color, shape and even face detection. Their real functioning is much more complex, as most areas receive signals from cells associated with most of these functions.

The idea behind concept forming is the gradually increasing integration of all of these parts of the system. In pattern recognition, many areas activate simultaneously, so there is no single area at the top of the hierarchy, responsible for coming up with the final image. With this said, my current view of concept forming resembles more the gradient-like manner in which colors are perceived: rather than a single set of neurons at a specific area firing on the recognition of a given pattern, maybe the image is formed more like a synchronized approximation involving a variety of areas.

week 9

Excursions to Aalto Neuroimaging Infrastructure & Institute of Occupational Health

This week was an excursion week going to Aalto Neuroimaging Infrastructure on Monday and Institute of Occupational Health on Tuesday. The experiences were quite impressive so I wasn’t able to take any images that I now wish I had.

Aalto Neuroimaging Infrastructure showed us all the different facilities they had for doing research and projects. The coolest was the fMRI machine because of the large scale of it and the feel it gave. Also, interestingly some metals are actually permitted near the MRI machine (basic chemistry here) but came as a shock when the facility master wore chains of silver. I was a bit late to see the EMG and EEG, but what I did see was TMS (Transcranial Magnetic Stimulation) and it seemed cool to stimulate an area of the cortex to view the effects.

Institute of Occupational Health showed us different commercial tools they use to do research on work effects on health. They had stress, sleep and physical activity in focus. The sleeping lab was an interesting place where test subjects could sleep a night and their EEG is measured and recorded. They have master thesis and PhD projects for the summer and possible to use this equipment for those. Otherwise, there is no collaboration between Aalto and the Institute of Occupational Health.

Some concluding thoughts

The course is coming to an end and it is time to draw some concluding lines about the functions of the nervous system. All in all it is an immensely complex system, with probably still much more to be learned than is currently known. The enhanced brain scanning technology gets ever more accurate, with not having to settle for gross level images, but rather the firing of individual neurons at constantly reducing time delays. The overall progress of neuroscience seems, to me, to follow a more general shift in science, where whole systems, rather than just a few main variables are increasingly getting the credit they deserve. The woods are being distinguished from the trees. We see this in environmental studies where the fragility of whole ecosystems, and the importance of even the smaller parts participating in it, are being noticed. The same line of thinking applies to brain models, where certain areas are no longer thought to be individually in charge of certain functions. Rather than one area taking care of e.g. constructing the visual image, it is born from a co-operation of so many different areas. Not withstanding the brains incredible and mysterious tendency for substituting lost functional areas with other ones.

On learning about the brain, the toughest part for me has been to memorize the names, structures and functions of the myriad of different areas, as well as the knowledge of how each part communicates with one another. The complexity seems, at times, startling and one wonders how can this system be ever fully understood. It also begs the question of how far in general is the collective human mental capacity capable of managing the whole picture.

Surely, different inner fields of neuroscience focus on very narrow aspects and single individuals don’t even try to comprehend the whole picture. That said, it will be interesting to see in the future, are we capable of coping with the full mass of information. In the field of physics, a “collapse” or compression of information holding equations to simplified forms can be seen every now and then. I wonder if the same thing is possible with “descriptive” information? Or will the task of information holding and thus the formation of any meaningful new theories be outsourced to some future AI? Also, today’s brain models seem to be far from complete. The more accurate image we want to create requires taking into account more and more details, eventually going to the level of the whole body. It will be interesting to see is it possible to construct a feasible “mind-brain-structure”, without all the feedback loops of other bodily systems.

week 8

Motor System and Movement Control

I’ve always been fascinated with Stephen Hawking. Not because everyone else was (especially in the nerdy school lunch talks), but because I had a personal connection. My dad had always encouraged me on my fascination for the stars and the movement of planets. I had read the books ‘A Brief History of Time’ and ‘The Universe in a Nutshell’ in my early teens and spun my childhood imagination to the galaxies and science-fiction. But most importantly I had a godfather, Jorma Louko, who studied under Stephen Hawking at the University of Cambridge and went on to the University of Nottingham to do research in the interplay of gravity and the quantum. Even with these great role models I somehow never managed myself into pure mathematics. Just didn’t have the aptitude for it, instead choosing to roam around in the warm fuzzy arts and engineering field.

Now you might be asking what has this got to do with week 8 and the human motor system, and movement control. Well yes, the first paragraph almost nothing, except with Stephen Hawking everything… he had a rare early-onset slow-progressing form of motor neurone disease (also known as amyotrophic lateral sclerosis, “ALS“, or Lou Gehrig’s disease), that gradually paralysed him over the decades. This disease was also referenced in our chapter readings Box 13.1 “ALS: Glutamate, Genes, and Gehrig” depicting it as a “particularly cruel disease that was first described in 1869 by the French neurologist Jean-Martin Charcot” that show as muscle weakness and atrophy and progresses to movement loose and eventually to death by failure of the respiratory muscles. The disease has no effect on sensations, intellect, or cognitive function making the victim watch their own bodies deteriorate with no way of affecting it. ALS degeneration affects large alpha motor neurons leaving other neurons in the CNS intact. The causes of the disease are unknown, but it is believed to have something to do with excitotoxicity (“overstimulation by the excitatory neurotransmitter glutamate and closely related amino acids can cause the death of otherwise normal neurons” – Chapter 6). Interestingly only 10% of ALS cases are inherited the rest seem to be caused by environmental causes, such as, cycad nuts, which contain an excitotoxic amino acid. Looking at inherited ALS recent research has identified mutations of about 16 genes. And there is still so much to be understood and treatments are still in the distant future, with “neuronal stem cells to replace lost neurons and glia, and genetics-based strategies to suppress the effects of mutations”.

A science-fiction leap forward would be if technology could replace our bodies as in the cult movies chappie, Robocop, ghost in the shell, etc. This would allow for ALS patients to move from their broken bodies into completely new ones. A far in the future possibility, but interesting to speculate since we already have working concepts coming out in cybernetics. An example is MIT designer Hugh Herr who builds “prosthetic knees, legs and ankles that fuse biomechanics with microprocessors to restore (and perhaps enhance) normal gait, balance and speed”. He’s captivating ted talk can be viewed here.

From thought to action

Muscle movement is a necessity to express behavior initiated in the cortex of the brain. The overall picture of descending pathways seems nowadays pretty clear. The central motor system is arranged as a hierarchy of control: the neocortex takes care of the planning together with the basal ganglia of the forebrain. After a quick meeting, they come up with a strategy. The strategy is sent onward to the tactics department (motor cortex and cerebellum), which flip through the files of previous success and decide the best set of actions to execute. They in turn send their plans to the level of execution (which is just one step above the proletarian level aka “the muscle”). The two executives, the brain stem and spinal cord, activate the motor neuron and interneuron pools, altering motivational speeches and threats of co-operation negotiations. In all, the whole show is run like the R&D department of Nokia, except with a better success rate and an inclination for improvement.

Looking at the big picture, we seem to be missing one important part of the hierarchy: the investors. If the neocortex is coming up with the business strategy, who is it trying to please? Which part of the brain constructs the necessity to want something in the first place? Could the lower company levels just cast off the investors and start working solely for the common benefit? Or would it lead to a conflict of interests, causing the organism to dash around aimlessly like a beheaded chicken?

week 6

Chemical Control of the Brain and Behaviour (personal thoughts)

I find the connection between the biological bodily mechanisms and behaviour intriguing. We’ve found out that hormones, neurotransmitters and even the diet play a part in behaviour and the body, but everything from outside influences to inside reactions brings about behaviour. If we didn’t eat foods high in dietary amino acid tryptophan, for example, the body wouldn’t be able to synthesise serotonin, thus leading to depression, lack of sleep and craving for carbohydrates. And if we see a bear right in front of us in the forest don’t we get the “fight and flight” response from the nervous system. So both the outside world, as well as, the inner workings of the brain affect our behaviour, but what came first? Was it learned or was it biological? I think this was talked about in the introduction chapter of the book (nurture or nature), but while the answer eludes us it does make one think.

When it comes to human behaviour and the understanding of it we can only rely on averages of the population. These statistics are used in a variety of fields from marketing to technology. Coming from a design field I recently wrote about the relationship between neuroscience perspective on behaviour and human centered design. It is said that human centered design (HCD) and neuroscience are two disciplines as far from each other as any two subjects and generally not to be discussed in the same breath. But they actually have a lot in common, since both study humans and their behaviours in relation to the world around them. HCD emphasizes producing reliable solutions for services and products focusing on the understanding human actions and behaviour in relation to a design problem. I strongly believe that neuroscience could give new tools that would allow for innovative design solutions. HCD “is a framework of processes in which usability goals, user characteristics, environment, tasks and workflow of a product, service or process are given extensive attention at each stage of the design process.” [1] To this endeavor advancement in discoveries within neuroscience that link behavioral disorders to biology could be used to design better in all stages of the design process in order to make human friendlier designs.

Examples of designing better using neuroscience knowledge, for example, is the serotonin regulation in the body. Low levels are believed to cause depression and even weight gain, but the estimated levels of serotonin are possible to measure from blood samples with a new MIP-based biomimetic sensor [2]. This could one day be used in products or alongside other design tools to give a deeper understand during different prototype testing phases, probing exercises or workshops. New transdermal optical imaging (TOI) technology that assesses basal stress by mapping facial blood flow it is possible to see changes with a common digital video camera, revealing bluffing and other emotions [3]. This reaction is beyond our conscious control and is not visible to the naked eye of the observer. The method reveals high anxiety and can give clues on level of difficulty and understanding. These revelations from sensors might be substantial depending on the design task and questions presented and in relation to the design problem being solved.

The field of human centered design has always taken inspiration from other fields and should now also take from neuroscience. It’s been seen that design research, design practice has taken from social sciences and humanities. Human computer interaction has taken from computer science. Experience driven design uses knowledge from psychology and even Mattelmäki, Vaajakallio and Koskinen agree that “during the past few years, the researchers interest has been in finding methods for envisioning increasingly radical design vistas” and has always had a role in design” [4]. The combination of HCD and neuroscience allows for this radical experimentation and could possibly produce some useful offspring to design practice because design has always been fascinated to understand design choices, solve design problems by analyzing emotions, thoughts and behavior.

1. Wikipedia contributors. (2018, October 24). User-centered design. In Wikipedia, The Free Encyclopedia. Retrieved 09:10, November 2, 2018, from https://en.wikipedia.org/w/index.php?title=User-centered_design&oldid=865523045

2. Peeters, M., Troost, F. J., van Grinsven, B., Horemans, F., Alenus, J., Murib, M. S., … & Wagner, P. (2012). MIP-based biomimetic sensor for the electronic detection of serotonin in human blood plasma. Sensors and Actuators B: Chemical, 171, 602-610.

3. Lee, K. (2016, February). Kang Lee: Can you really tell if a kid is lying? | TED Talk [Video file]. Retrieved from https://www.ted.com/talks/kang_lee_can_you_real ly_tell_if_a_kid_is_lying

4. Mattelmäki, T., Vaajakallio, K., & Koskinen, I. (2014). What happened to empathic design?. Design issues, 30(1), 67-77.

Week 5

As partly distinct from the rest of the brain, the optic system seems to be a relatively clearly perceived entity. Far from simple in functioning, its outlines can be categorized into the eye and its structure, the cells of the retina, the optic nerve pathways and the brain areas which the optic nerves lead to. Many structures can already be explained in remarkable detail, however, the current challenge lies in explaining the way images form from the signals initiated by the retinal cells.

Most of the axons from the optic tract innervate the lateral geniculate nucleus (LGN) of the dorsal thalamus, where the information is passed onward to cortical areas of the occipital, temporal and parietal lobes. Around two dozen cortical areas have been identified to be part of visual information processing, many of which functions are still largely unclear. However, it seems different parts manage different aspects of the processing. E.g. from the two large-scale cortical streams involved, the dorsal stream appears to analyse visual motion and visual control of action, while the ventral stream is thought to be involved in building a perception of the visual world and recognition of objects.

For me, the most devouring question lies in how in the world are the initial electrical signals transformed into a subjective experience of seeing? Where in the brain does the image of the visual field reside?

Apparently, the current hypothesis of perception is that certain groups of neurons, receptive fields, are activated according to different objects of the physical world (e.g. the face of my clamorous nocturnal neighbor which occasionally resembles a punching bag). Yet, this approach opens up more questions than it answers: concepts of objects are also utilized in the act of thinking. How do thoughts utilize the concepts built by the visual system? How do initial concepts form? Which was first: the concept or the visual? Where do thoughts come from and who does the thinking? How did this text come into being, and is it understood by anyone?

week 4

Neurotransmitter Systems and week 4

This post is a little late, but the reason is quite understandable as the weeks topic was one of the hardest to comprehend and digest. Putting it plainly, chemistry has never been my strongest subject so the amount of effort in googling and note taking of chapters 5 (last weeks chapter, but required for this weeks understanding) & 6 took some time. It took three times of reading the chapters through to be exact. No joke!

From neurotransmitter systems to neurotransmitter chemistry the exact mechanisms that allow for pre- & postsynaptic neurons to relay messages fast through transmitted-gated channels and slower through g-protein-coupled receptors opened my eyes to the complexity and thereby the weaknesses of our neural system. I’ve always been fascinated about how our brain can ignite memories, emotions and movement coordination with such precision. To top this, it’s amazing that there are only three types of neurotransmitters that do all of it – amino acids, amine and peptides. What creates differences is where these messages are being sent (PNS or CNS), the type of presynaptic neuron sending the neurotransmitter and the postsynaptic neuron receiving. Even the thought of the multitude of different combinations and arrangements of subunits of receptors gives rise to numerous outcomes of what happens in signaling. As said in the book:

“The immense chemical complexity of synaptic transmission makes it especially susceptible to the medical corollary of Murphy’s law, which states that if a physiological process can go wrong, it will go wrong.” – chapter 6, page 131

But again it was interesting to read on all the things that could go wrong! The most interesting being about cell death and how easily it can happen. And mammalian brain cells don’t regenerate so we are stuck with what we have. Glutamate the most abundant neurotransmitter is also a neuron killer when blood flow ceases. Within a few minutes permanent damage is done. With the production of ATP stopped membranes depolarize, and Ca2+ leaks into cells causing rapid depolarization of neurons. This overexciting of neurons is called excitotoxity and is equivalent to neurons digesting themselves.

What are my thoughts on all of this? Well I came to thinking about migraines. I’ve suffered from them almost my entire life and it would be interesting to find an answer to what causes them. Its said to be a chemical imbalance in the brain involving the nerves and blood vessels, but what exactly causes them is still unknown. Could it be an underlying problem with a neurotransmitter or receptor? Or a neuro transporter issue?

I don’t have any more enlightening thoughts, but hope the following weeks readings won’t be as hard to digest 😀

Week 3

This weeks topics were the structures and mechanisms associated with synaptic transmission, such as neurotransmitters, receptors, synapses, transmitter synthesis and degradation etc. I was actually quite familiar with most of the structures and functions from my previous studies of physiology. For me, the most intriguing part of the chapter was the question of how to relate the observed processes of neurons to existing theories of information processing.

To come up with a theory, the first thing you need is the elementary units (i.e. building blocks) from which to start working upwards. As far as I understood, the most elementary unit considered in neural information processing is the postsynaptic reception of a single vesicle. This process is tied to our existing theories by measuring the voltage (EPSP) caused by the reception. This way, any measured voltage in the neuron can be reduced to multiples of a single EPSP. Still being new to the subject, I assume the single EPSP’s are central in the modelling of neural information processing, the same way 1’s and 0’s are in explaining computer behavior.

This led to several questions:

Can the information processing of the brain be explained or modelled by XOR operations?

What would be a sensible way to compare the processing capacities of a brain vs a computer? What are the main limitations in the underlying structures? E.g. the speed of current running in neurons vs circuits, synaptic delays vs some components of a circuit, or maybe the wiring (e.g. the brain is not wired as an optimal data processor).

Week 2

Neuronal Membrane at Rest (ch. 3), Action Potential (ch. 4)

The first weeks reading requirement was chapters 2-3 and on the Monday lecture 17.09.2018, we went through chapters 3-4.

What struck me as the most interesting aspect of this weeks lecture and reading was the knowledge of the “importance of regulating the extracellular potassium (K+) concentrations within the body”. The increased extracellular potassium depolarizes neurons.
The sudden increase is prevented by the blood-brain barrier, but in the body, muscles are susceptible to this change. The sudden change causes membrane potentials of the neurons to become less negative and disrupting neuronal function. As an example, a ten-fold change in extracellular potassium causes a 48mV depolarization of the membrane and in the body would result in cardiac muscle cells no longer generating impulses that lead to contractions resulting in heart failure.

Now to understand this the relative ion permeability of the membrane, Nernst equation, Goldman equation, ionic equilibrium potential, concentration gradient, electrical potential, and the importance of water as a polar solvent in action with amino acids had to be understood within the context of the neuron. The human body seems to really be a balanced machine where even a minute defect can cause irreparable consequences for the individual. For example, this small change from the norm could be an inherent neurological disorder caused by certain mutations of the specific potassium channels resulting in forms of epilepsy.

Questions that arose this week:

  1. Could neuro stimulants be produced to help in more efficient potassium regulation and preventing neural fatigue and increase learning?
  2. How could we integrate neural chips in the future that could translate “the morse code” produced by neurons and store this information? Could we then hold more accurate information in the chip (just learned) and store it indefinitely? Could this make us smarter? Could this prevent us from having “false memories”?
  3. Not exactly related to current chapters: I’ve understood that some parts of the brain are less active and that the human doesn’t use all of its brain capacity. Why? Can we learn to expand our brains capacities and how?

Note:

Week 1 of the course from 10th of August to 16th of August was an introduction week when the course administrators and tutors explained the structure of the course and the requirements. Below the information on this course if you are interested in knowing more: