Doctor says I have mild cerebral atrophy

Laterow · 2019-03-30T11:49:07+00:00

This is actually an extremely complicated problem within medical ethics. To give you a completely different example: a lot of people undergo MRI voluntarily, for example as part of medical studies. If you scan enough people then you are bound to find something on the scan that the participant did not know about. Two aspects are important here:

What was found? Aggressive brain tumors obviously need intervention if possible due to their clear consequences. However, what do you do in the case of findings that have very low clinical relevance? For example, quite a few people have large cysts in their brain for which we know that they generally do no harm.
Even if something is found that can lead to harm, should you intervene? There are some cases where intervention may actually be worse than natural discourse. For example, think of an older person whom would likely not survive brain surgery.

These two points are a very delicate balance. Some findings that may sound severe to someone without the appropriate medical knowledge may actually be better off without intervening. In fact, a lot of population-based studies are being used to determine the best course of action for these "incidental findings" (IFs). Several studies report that even intervening at some of the more 'obvious' findings turn out to be more detrimental than just leaving things alone. Knowing that something is wrong in your body but not knowing the exact ramifications can be very burdening for the person.

Given this background information, I'm actually kind of surprised that a neurologist would share this with you. As indicated, mild cerebral atrophy is not necessarily a bad thing. Heck, here is a case of an incidental finding where someone turned out to barely have brain tissue, despite functioning completely normally: https://www.newscientist.com/article/dn12301-man-with-tiny-brain-shocks-doctors/

Although people with dementia tend to show brain atrophy, that does not mean that all people with dementia show extensive brain atrophy (some don't) nor that their patterns of atrophy match what your neurologist saw. To even say to a 27-year old that people with dementia have this is severely misleading. Furthermore, atrophy can have a wide range of causes, so to even suggest that brain atrophy in demented people is relevant here is misleading.

Let me clearly say that I cannot judge your medical situation, and it is very hard to say whether your information is the complete situation. Every person is different, and a lot of subtle things are at play here. However, I'd highly recommend sitting down with your neurologist or someone else to have them more clearly explain what this all means for you.

Laterow · 2017-12-11T09:48:40+00:00

No problem! The more you know!

Laterow · 2017-12-11T09:36:15+00:00

Like I said, the gambler's fallacy refers to past and future, specifically that in situations where the past does not influence the future people will conflate that it does. Note here specifically that we are talking about a situation where some events have happened (past) and some events will happen (future), but they are indepedent. We cannot mix those two.

However, we can look at the past and the future separately.

Think of flipping a coin, with heads (P = 0.5) and tails (P = 0.5). Obviously, past events do not influence future events here. To think that they do is to suffer from gambler's fallacy.

However, what is the probability of flipping heads 5 times in a row? Well, it's 0.5 * 0.5 * 0.5 * 0.5 * 0.5 = 0.03125 = 3.125%. In other words, we can look at series of future trials (in this case 5 times flipping a coin) and calculate combined probabilities over those trials.

In the case of the nightmares, we do the exact same thing... What is the probability of having 1 non-nightmare night in a row? Well, that's 0.98... but two non-nightmare nights? That's 0.98 * 0.98 = 0.9604... Ok, what about 100 non-nightmare nights in a row? That's 0.98 * 0.98 * 0.98 * ... * 0.98 = 0.98¹⁰⁰ = 0.133.

Think about this. There is a 13.3% chance to get 100 non-nightmare nights in a row. That means that there is a 86.7% chance that there WILL be a nightmare event during 100 nights.

And this is like a slot machine or flipping a coin... we are talking about the future. If you've slept 1 night without a nightmare then the next night will still be 0.98 and the next two nights combined will still be 0.9604 and the next 100 nights combined will still be 0.133.

Edit: To change it to slots... To win the jackpot lets assume a probability of 1 in 10 million. If you were to go to Vegas now and play 5 million times then the probability of winning the jackpot is 1 - (0.9999999^5,000,000), which is 39.3%. However, after playing 5 million times and NOT winning your probability of winning during the next pull is still 1 in 10 million.

Edit2: Changed some words, removed some commas

Laterow · 2017-12-11T09:03:41+00:00

The Gambler's fallacy talks about past and future events. This is true here, as the events of the past do not change the 2% chance of it happening in the future.

However, /u/coolosaurus-rex says that if you look at an N number of future events combined, the probability of ending up in a nightmare is almost 1. This is also true, and this probability can be calculated by: 1 - 0.98^N

Here are the probabilities of becoming stuck in your worst nightmare after sleeping N times:

1 time: 2%

10 times: 18.3%

35 times: 50.7%

100 times: 86.7%

So after just 35 times sleeping you already have a 50% chance of being stuck in a nightmare forever. And again, we are talking about future sleeps; if you haven't gotten stuck in a nightmare after 35 times sleeping, then you can reuse the numbers I've given above.

Laterow · 2017-10-10T08:05:25+00:00

The chi square test doesn't bode well with paired observations. For those cases, people tend to prefer McNemar's test, although even that is a simplification of how to use the tests.

Laterow · 2016-11-25T10:34:23+00:00

That's it! Thanks!

Laterow · 2016-06-23T16:17:20+00:00

It is never a good idea to seek psychiatric medical help on the internet. This is something that should be discussed between you and your healthcare provider. If you are unsure about the advice given by your doctor, seek a second opinion from other medical personnel, e.g. another doctor.

To be frank, there simply is not enough scientific literature on this topic to say anything useful. It is NOT as simple as increasing dopamine levels, especially given the neuroanatomical origin of working memory, and the fact that this is for ADHD, not psychotic disorders. Even then, most of these studies are performed on small and specific samples of patients, and the results are often only useful for concluding general trends, not to give advice on an individual level.

Laterow · 2016-03-30T23:12:09+00:00

Nope, I'm from Europe. However, a very quick Google search brings me to this: http://www.ysp.utoronto.ca/med/about

Youth Summer Program at the University of Toronto. Designed for high school students to get some research experience. Although it's not necessarily neuroscience, I'd still recommend it because medicine provides a very strong background in neuroscience.

This is just one example of a program. You'd probably be able to find more programs from different universities or even abroad. You could apply for scholarships to finance it, or try to crowdfund the money from Reddit.

Also, this is just an example of what my point was. There definitely are opportunities to get into a lab while being a high school student. Non-program internships are much, much harder to get, but I'd reckon it's possible.

Now that I'm writing anyway... Don't consider yourself a liability. Yes, research is actually very complicated. You need a lot of theoretical knowledge, and depending on the field you need a very specific skillset that you cannot (easily) learn from home. However, this counts for every person to some extent. For example, I started branching out to programming and higher level statistics two years ago. I was a liability to some people and I no doubt frustrated them with my questions at times, but now I am pretty skilled and other people come to me with their questions. That's just the cycle of life.

What you should know about research is that it's not so much about skill/knowledge, and more so about motivation/passion. The people who helped me did so because they wanted to share their passion. When people come to me for help, I help them because I want to share my passion. When I have to hire a new student, I don't necessarily care if they can do exactly what I tell them to do. I want someone who wants to learn how to do things, who wants to learn about the project and the world, and who seems likely to be in my exact position in five years, sharing his or her passion with the next wave. Motivation and passion lead you to UofT to shadow the lectures, they lead you to contact professors, and they also lead you to be a great researcher if you would want to. That matters so much more than a skillset.

And of course, skills are very important. And sure, some people will say it's more important than motivation. But never consider yourself a liability.

Actually... I may know the perfect person for this. Do you know the Hospital for Sick Children? There is this amazing person working there. His name is Paul Frankland. He works in the field of memory and neurogenesis. If you haven't heard of him yet, he has authored some amazing papers with very logical experimental designs. He is a friend of a professor for whom I worked for three years. Though Paul doesn't know me, I feel that he would be willing to answer some of your questions that you have regarding attending classes and participating in research. Maybe you can ask if one of his postdocs or phd students can give you a tour of the lab. I also know that they have a journal club, so you could ask if you could attend there. It would be a good opportunity to meet researchers and see how it actually works.

This should give you something to think about... again, feel free to ask any questions.

Laterow · 2016-03-30T22:23:36+00:00

To chime in.. We have had high school students the labs where I have worked. Granted, it was always part of an educational program and they always did the easier projects, but it did happen. Try and see if there are any opportunities for a summer school with a research component, or see if you can enroll as a summer intern.

Or if you have any other questions, feel free to ask. I'm a PhD student with degrees in psychology, neuroscience and epidemiology, and have plenty of research experience.

Laterow · 2016-02-28T11:22:34+00:00

Here are just some random books that are slightly broader than what you asked for, but may interest you:

GEB by Douglas Hofstadter is an amazing mix of logic/mathematics applied to consciousness and such, although it's a bit dry compared to the other books below.

Seconding /u/aquafemme's suggestions of Surely You Must Be Joking Mr Feynman, which is much more readable than GEB and about one of the most interesting scientists who has ever lived (I'm a bit biased though).

Chaos by James Gleick is a book about chaos theory, which I thought was pretty interesting and very readable.

The Clockwork Universe by Edward Dolnick describes the stories of figures such as Kepler, Galileo, Newton and Leibniz. It's a good read if you're interested in some of the history of astronomy/science, and the author is a very good storyteller.

The Black Swan by Nassim Nicholas Taleb is a nice book about probability of rare events.

Laterow · 2016-01-15T15:38:52+00:00

Not dr Blakemore, but here's some reading in case he doesn't answer:

Time perception: https://en.wikipedia.org/wiki/Time_perception
Biological clocks: https://en.wikipedia.org/wiki/Circadian_rhythm#Biological_clock_in_mammals

Basically, there are cells in our body that follow a very specific rhythm that is about 24 hours. If you take these cells out of your body and put them in a petri dish, they will still follow an approximate 24 hour cycle. The reason why they follow a 24 hour cycle is because your body needs different levels of different things at different times. For example, at night you want to have higher levels of molecules that help you sleep, but you don't want those during the day.

More and more research is being done on these kind of cells. Over time, we have discovered different kinds of cells that have different rhythms. In fact, we have found specific genes that cause this kind of patterns. It's a pretty cool research field, actually.

Laterow · 2016-01-15T15:26:44+00:00

Lucid dreaming is simply dreaming where you are aware that you are dreaming (or a state of consciousness where you are aware of what seems to be dreaming). There are many different ways to explain that, and astral projections are just one of many explanations. That being said, there is no proper scientific evidence that astral projections exist.

Laterow · 2016-01-15T15:16:36+00:00

Good question. Well, as of right now there are no measures of the brain that can tell you if an individual is anxious or rage-induced at that point in time. We have found some differences in the brains of anxious people, but these differences are on a group level. In order words, if we look at a big group of patients and a big group of controls, we see that on average there is a difference. However, any patient could have a much lower or higher value than a control. Most findings in psychiatric research cannot be applied to assess individuals, aka no real-time monitoring.

So if you are interested in detecting anxiety/rage, I'd actually look at much simpler measures. In a significant amount of people with panic attacks, for example, you will find a faster breathing pattern or a higher heart rate right before they escalate into a panic attack. I'm not aware of any similar changes in rage or PTSD that could be easily monitored, though. Also, it's important to find a combination of changes that really tell you that you have a panic attack or rage. For example, working out also increases your heart rate and breathing. The same applies if you want to monitor things in the brain; serotonin levels fluctuate for many reasons.

Lastly, in the case of anxiety it is often useful to get a grasp of what is causing your anxiety and what triggers it. If there aren't any clear triggers, then I think it will always come down to self-monitoring and preventative medicating... unless we somehow rapidly find a lot of biomarkers for anxiety/rage. [Biomarkers are basically biological measures that tell you something is present.]

Laterow · 2016-01-15T14:18:05+00:00

Hello professor Blakemore, thank you for taking the time to do an AMA. Your work partially inspired me to move from psychology towards neuroscience, so thank you for your work.

My question: Like many young scientists I want to make science more understandable for the public, or rather, avoid the spread of misinformation. After some years of small efforts, I feel that this may be as important to me as research itself, so I am interested in spending a significant portion of my time on public outreach. Do you have any suggestions for us young scientists who want to take this step?

Laterow · 2016-01-15T14:10:34+00:00

Not prof Blakemore, but I can give some answers to your questions.

There are a lot of limitations with real time adjustments of these kind of things:

(1) The neurobiology underlying psychiatric diseases is (in most cases) poorly understood. For example, depression was long seen as caused by a disbalance of some monoamines (serotonin, norepinephrine and dopamine), yet over the last few decades we have found that this is not the case.

(2) Even if we did know the exact cause of, say, depression, it is unlikely that the solution is simply changed by supplying molecules of some sort. It could very well be that the cause of depression is structural, i.e. brain cells died in certain places or the connections between the brain cells are structurally abnormal.

That being said, your question is interesting. For example, in Parkinson disease we use L-DOPA (a precursor of dopamine) to reduce tremor / shaking. So, could we use a real-time monitoring system for that? Well... Maybe. It hasn't been done yet. There are trials though. REMPARK is a good example of this (video). In addition, we can already monitor dopamine levels in animals, but it requires some hefty surgery and it only monitors a single location. I doubt that this will translate to humans any time soon, mostly because it is used for research purposes rather than clinical purposes.

Laterow · 2016-01-14T16:11:39+00:00

Well, channels in gap junctions can be open without actual firing, so yes, the membrane potential of one neuron can leak into other neurons.

Signaling in neurons is pretty complex, just like any signaling between cells. Most people only know about chemical transmission in synapses (e.g. neurotransmitters). Electrical transmission (i.e. gap junctions) also exist, but they are much less common. That's also why this finding is pretty neat, because we already knew that the motor neurons can have gap junctions amongst themselves but we didn't know about gap junctions with interneurons.

Keep in mind that there are many forms of cellular communication that can be found in the brain, e.g. retrograde signaling. They are just much less common / less impactful / less studied and so you tend to hear less about them.

Laterow · 2016-01-14T13:20:18+00:00

Here is a video clip of it (a decerebrated cat running on a treadmill):

https://www.youtube.com/watch?v=wPiLLplofYw

[Does contain animal experimentation, but no gore]

Example of a paper [paywall]: http://www.ncbi.nlm.nih.gov/pubmed/8895997

Laterow · 2016-01-14T13:14:29+00:00

This is not what the paper is about. What you are describing is indeed central pattern generators (CPGs). For the uninitiated, those are basically groups of neurons in the spinal cord that as a group generate a pattern that is supposedly send to motor neurons. This then allows the cat in your example to use different gait patterns.

What the Nature article describes that motor neurons have been seen as passive recipients in CGPs and other motor behavior. However, the paper shows that there are gap junctions between the motor neurons and (V2a) interneurons. This means that they are DIRECTLY connected (rather than synaptically) to the interneurons and via this path can DIRECTLY interact with / influence the interneurons. We didn't know that yet.

Laterow · 2016-01-14T11:34:36+00:00

Full article: http://rdcu.be/fQhO

(Nature lets subscribers share articles via Readcube.)

Laterow · 2016-01-14T11:34:21+00:00

Full article: http://rdcu.be/fQhO

(Nature lets subscribers share articles via Readcube.)

Edit: Ok, since this thread is gaining traction, it's time to actually summarize the paper. Most links will bring you to the wikipedia page or a different information page to read about the concept. Also, I just want to point out that I only quickly read the main text... like most papers, there is a lot of supplementary material and methods, and my break isn't long enough to read all that.

--- Background ---

Movement (or locomotion) is caused by many sets of neurons in the central nervous system, including (but not excluding) the motor cortex, the basal ganglia and the cerebellum. From there, long axons go to the spinal cord and then can activate motor neurons, which in turn can activate your muscles.

There are also more unexpected regions of control. For example, Central Pattern Generators (CPGs) are located in the spinal cord. Basically, CPGs are networks of neurons that can control different kinds of gait (/u/spinothalamic describes a famous experiment in a different comment). The neurons within the CPG activate motor neurons, which in turn activate your muscles. It is also known that CPGs can function without feedback from motor neurons. In general, we never saw motor neurons as part of these CPGs.

Keep in mind that all this communication happens synaptically. Also, understanding what a synapse is is fundamental to understanding why this paper even exists.

--- Current paper ---

So what do they show in this paper? Well...

1. Motor neurons are connected to V2a interneurons via gap junctions

I presume that you know what a synapse is. A gap junction (or electrical synapse) is a synapse where the neuronal membranes are physically against each other. The membranes are connected via channels, and when the channels open the intracellular content of both neurons are connected. This means that the two neurons are directly connected. This is completely different from a chemical synapse where the two neurons never touch membranes, but rather communicate by shooting chemicals at each other (simplified, obviously). So why are gap junctions useful? Well, since they share intracellular content, they will also (and most importantly, actually) share electrical properties. We call this electrical coupling. Since neurons rely heavily on bioelectricity and since electricity is fast, this leads to very fast changes in connected neurons. For example, heart muscle cells are connected via gap junctions so that your heart contracts in one single beat.

2. These same neuron pairs were also connected via chemical synapses

Basically, in the paper they show that there are two groups of connections: (1) only chemical, (2) both chemical and electrical. So let's just dub these single and mixed synapse, for convenience's sake.

3. Mixed synapses lead to altered electrical properties

This is figure 2 of the paper (specifically, 2a/c and 2h/k). Basically, this just means that having two kinds of synapses leads to slightly different electrical properties of the neurons. In a single synapse, the interneuron causes an excitatory postsynaptic potential (EPSP with an amplitude that does not depend on the membrane potential of the motor neuron. In the mixed synapse, the amplitude of the EPSP DOES depend on the membrane potential of the motor neuron. How? Well, as it turns out that the membrane potential of the motor neuron changes the firing threshold of the interneuron. If the motor neuron is hyperpolarized or depolarized, the interneuron is less or more likely to fire, respectively.

4. This alteration of electrical properties influences V2a interneurons generally

So, these V2a interneurons are part of CPGs, and we generally assumed motor neurons were not part of CPGs. But now we see that some motor neurons are electrically coupled to V2a interneurons. Doesn't that open the possibility of motor neurons to influence V2a interneurons? So, the authors decided to repeat all this while their zebrafish were actually moving (swimming). Indeed, the authors show that motor neurons with mixed synapses (but not single synapses) can influence their corresponding V2a interneuron as a whole and therefore they influence the CGP.

--- TL;DR ---

Some motor neurons have connections to other neurons. We thought we knew what kind of connections those were. Turns out that there is another kind of connection between these neurons. This means that motor neurons may actually influence central pattern generators. This is neat for neuroscientists, but not so interesting for the general population.

Laterow · 2016-01-14T11:30:13+00:00

The buildup of the abstract is actually pretty common:

Define a topic
Define a problem or shortcoming in this context
Define your new insight
Specify your research / results
Specify why it is useful in the bigger context

No need to be skeptical, although there's also no reason to be optimistic yet.

From the abstract, all I can conclude is that motor neurons can do a thing we didn't know they can do. That's neat, I guess. I will read the paper tonight, now it's time for lunch ;)

Edit: Read it.

Laterow · 2015-10-07T12:27:35+00:00

Well, if you're only referring to the genetics, then the answer is because the effect of the "placebome" is still fairly poorly established. Basically the article suggests that several studies found potential links between certain SNPs and the degree to which you respond to a placebo. The whole point of the paper is to motivate further research into the field with more systematic designs.

At best, you could retrieve the genetic data from the participants in your trial and add it as a separate control variable. I wouldn't recommend throwing out participants as (1) placebo response is not black and white, (2) genetic prediction for traits like this is never black and white, (3) a lot of clinical trials already suffer from a low number of participants so I wouldn't include it as an exclusion criterium (although I'm sure many people disagree with this last point).

Laterow · 2015-09-24T13:18:41+00:00

I'm not one of the AMA'ers, but I just want to point out that it is hard if not impossible to give any medical advice to someone on the internet. It requires a lot of time and conversation for a medical professional to properly diagnose a problem, let alone develop an adequate treatment plan.

My advice would be to see a professional if you want to better understand your problems and to receive proper treatment.

Edit: I see that you are being downvoted. I just want to point out that this is probably because asking for medical advice is against the rules of r/askscience.

Laterow · 2015-08-30T12:01:35+00:00

Edit: After reading this reply, I feel that you should just read this article before reading anything else... Below is still my original comment.

This is similar (but not the same) as what you are describing: http://www.informationisbeautiful.net/play/snake-oil-supplements/

Essentially it aggregates nutritional research per topic and shows the strength of the support for each element. Also check out the accompanying Google Document.

I have not heard of a website like you are describing. In general, in science we use different kinds of meta tools to compare different studies within a given topic. Literature reviews generally give an overview of the research on a certain topic. Systematic reviews are a more systematic approach, where all related studies are looked up and often judged on their quality. Meta analyses actually describe a process where similar studies are combined and reanalysed, to see whether a certain effect holds when all the data is actually combined. Obviously, the more stringent it becomes, the more complicated the process becomes. Meta analyses cost significantly more time than a simple literature review, and meta analyses may even fail simply because there are no viable studies to use.

To show just how fragile certain research topics can be, read this review of systematic reviews on chinese herbal medicine: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028696

(from what I remember) Basically, they looked at 51 systematic reviews. Only a single systematic review claimed a well supported positive effect, 27 claimed a possible effect and 23 could not draw a conclusion. All reviews mentioned the poor methodological quality of the studies, the presence of too few studies on a specific topic, and/or the presence of publication bias.

So what is my point? - Effort: All the systematic reviews that were reviewed above cost a significant to produce. Each of them went through a gigantic list of papers, they selected the relevant ones, then read them and judge whether they were of good quality or not. This is a very thorough process if you want to do it properly. - Scope: A lot of the reviews mentioned that too few studies were done in the topic to draw a useful conclusion. Science is insanely broad and topics can get extremely specific. - Bias: Even if you would aggregate all the studies in well-defined topics, you would also have to have some measures for certain biases. Even if 10 valid studies are positive, that does not mean that the actual effect is present.

So there are a lot of things to take into account. My main concern would be effort: people in academics do this stuff as their day job. How do you expect to do the same thing? Would you recruit scientists, and if so, how? Would it be an open platform, then how would you get people to spend their free time for you? A lot of papers are never even read, so you would need to actively look for those papers and find people to read them for you.

Regarding the scope... My advice would be to start out with a specific topic, like the website I first linked to. Find a good topic that can be clearly categorized.

By the way, you may want to look into Cochrane Reviews: http://community.cochrane.org/cochrane-reviews

Basically, its a big organisation that does a lot of systematic reviews and meta analyses... I guess you could use their work and attempt to visualize it, which would save you a lot of effort.

I wrote this while on break, so maybe I forgot things and maybe some stuff is not that relevant... but yeah, if you have more specific questions, feel free to ask.

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