Good evening all,
I read a lot of science each week. More accurately, I scan a lot of science journal Tables of Contents, and science news headlines, and I select articles to read from them. Throughout the term, I will occasionally send you links to articles, along with a short 'blog' about why I think the article is worth sharing.
The article whose link I am forwarding below describes a recent study, whose primary finding may seem, at face value, insignificant. In this study, scientists monitored multiple (several thousand) neurons in the brains of fish, which they had trained to left, or right, in response to a sensory cue. Then, analyzing the neural recordings they had obtained, they could predict (from the neural data they collected) which direction the fish would turn, up to 10 seconds before the turn.
Wow, right? They can predict whether a fish turns one way, or the other. It doesn't sound like much. But, it is a useful result, for a number of reasons.
Experiments like this are designed to assess decision-making, something that our brains have to do an incomprehensible number of times each day. Sure, we make many 'big' decisions, conscious ones, including many with life-altering consequences (like staying in our lane on the freeway). But, we make untold more smaller decisions, many unconsciously, steadily throughout the day. Think of something like typing, or writing - each letter requires a series of motor actions, in order, that have to planned and executed, against a background of many alternative movements that are possible. That's a lot of decision-making, even just to write or type a single word. How do our brains accomplish it? What can go wrong to impair decision-making? What can we do when that happens? Each of these 'big questions' must be addressed in tiny pieces, like in the study described here.
In the neuroscience research community, there are lots of different experimental models for decision-making. Larval zebrafish do not seem like an obvious choice, but they offer several specific advantages. They are small, easy to breed and house. They are relatively low on the 'scale' of vertebrate animals, such that their use raises relatively little ethical concern. Importantly here, they (1) readily learn this simply task, (2) reliably report their decision, and, (here's the big one) have brains that are small and nearly transparent. This allows researchers to monitor essentially every neuron at once, which is quite remarkable. (Remember - these are free-swimming animals, less than a cm in length, with *tiny* brains.)
Most studies of decision-making in mammals focus on the frontal cortex. Neurons there are engaged in decisional tasks, and damage to this cortex impairs decision-making (causing slower, and often faulty, performance). This new study suggests that decision-making activates neurons across the entire brain, including in areas thought to be primary reflexive, or involved in motor coordination (like the cerebellum). It's an interesting result, and one that will cause those who focus narrowly on one region or another to take a step back, and evaluate their scope of investigation.
The second primary advantage of a model system such as this is that a system of only 5,000 neurons is one that can be computer-modeled in its entirety. We may not have all of the information about how these neurons are connected, or their individual biophysical characteristics, but we definitely have the computing power to incorporate all of them into a single model. They are multiple, ambitious projects to map and model the human brain, but they remain limited both by data as well as by computing power. The more we learn about the brain, the more we realize that neurons across the brain seem to be involved in collective networks. That's a much harder nut to crack than a group of neurons in one location being solely responsible for some singular function.
So, the next time you see even the simplest of organisms behave, such as a fly taking-off or landing, recognize that its nervous system is performing functions very analogous to our own!
I will occasionally pass along articles of this type during the semester. My purpose in doing so is to help you to become more aware of current neuroscience topics, and also to help you assess how you obtain your science and health news.
Those of us working in science obtain our scientific news, quite often, directly from the original sources: the people conducting the studies and reporting the results. They publish their findings in science journals, or present them at conferences.
Most people do not obtain their science news directly, but hear news via secondary sources, such as news releases from scientific organizations, or as science news stories from the major news outlets. These secondary reports often are then carried by tertiary outlets (smaller/other reporting sources). I'd encourage you to think a little about the translation of news from source to consumer, and the reputability of the news outlets that you use.
Along the way from source to audience, science news is normally distilled (a lot) - much of the detail is excluded or simplified, and the reports often are boiled-down to singular take-home messages, which may, or may not, be good representations of the original work. When you browse the links that I will forward, or when you access science and health news on your own, I'd encourage you to delve a little bit deeper into them, to read more than just the summaries, and to follow links back to original sources when possible (like this one: https://www.cell.com/cell/fulltext/S0092-8674(19)31380-7). Some of these ultimate sources will be behind paywalls, but others will be accessible, especially if accessed via an IUP campus computer. If you ever really want to chase down one of the source articles and cannot, let me know and I can help you get to it.
Some of the science and news sources whose links I will forward allow only a handful of free articles each month; I will try to use them sparingly. I also will generally send reports only from sources (professional societies and reputable science and news outlets) that I trust.
The material that I send you as science news will not specifically be represented on our course exams, but I do hope that the material in them makes its way into our conversations.
Have a great rest of the weekend -