After providing all the funding for The Brain from Top to Bottom for over 10 years, the CIHR Institute of Neurosciences, Mental Health and Addiction informed us that because of budget cuts, they were going to be forced to stop sponsoring us as of March 31st, 2013.

We have approached a number of organizations, all of which have recognized the value of our work. But we have not managed to find the funding we need. We must therefore ask our readers for donations so that we can continue updating and adding new content to The Brain from Top to Bottom web site and blog.

Please, rest assured that we are doing our utmost to continue our mission of providing the general public with the best possible information about the brain and neuroscience in the original spirit of the Internet: the desire to share information free of charge and with no adverstising.

Whether your support is moral, financial, or both, thank you from the bottom of our hearts!

Bruno Dubuc, Patrick Robert, Denis Paquet, and Al Daigen

Monday, 21 November 2022
Zebrafish brain images may reveal neuronal bases of emotional memory

As is well known, memories with heavy emotional connotations—especially negative ones—are very strong. In extreme cases of post-traumatic stress, such memories can be so recurrent and intrusive that they make life a living hell. In mammals, the brain structure most highly involved in such negative memories is the amygdala. But while much research has been done on the hippocampus, which is the brain structure involved in spatial, lexical and other forms of memory, the amygdala has received much less attention, in part because it is so hard to access. To get around this problem, a research team at the University of Southern California, in Los Angeles, used larval zebrafish and a fluorescence-based imaging method to visualize the changes that occurred in the synapses of the pallium (the fish brain structure equivalent to the amygdala) after aversive conditioning. The surprising results were published in the journal PNAS in January 2022, in an article entitled “Regional synapse gain and loss accompany memory formation in larval zebrafish”.

In the team’s experiments, the larval zebrafish were exposed to light together with heat to which they showed an aversive response, and some of them subsequently learned to respond to the light alone the same way that they had to the combination of light and heat. Before and after images were captured of the synapses in the pallium. Increases in the intensity of the fluorescence detected in these synapses would have indicated strengthening of these synapses, the most common mechanism for making neural circuits more efficient for a certain time (for example, in the hippocampus, for forming memories of new paths or new words). But surprisingly, the zebrafish who learned this conditioned response did not show any such increases in synaptic strength. Instead, they showed increases in the number of synapses in one part of the pallium and decreases in another—a far more radical mechanism than a mere increase in synaptic efficiency. The authors suggest that the explanation for this finding may lie in the more profound and durable nature of negative emotional conditioning, often associated with trauma.

Since its publication, however, this study has been criticized for having used larval-stage zebrafish rather than adults (this decision was made for practical reasons: unlike adults, larval zebrafish are still transparent, which makes their brain structures easier to access and visualize). In fish, just as in humans and other mammals, a great deal of synaptic pruning occurs naturally in early stages of development, so that only the synapses that get used the most survive. Hence, the critics argue, the pruning observed in this negative-conditioning study may not have been specific to this kind of learning, but simply to the natural process of synaptic pruning in the developing brain. As the saying goes, further research will be needed.

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Monday, 31 October 2022
A set of stunning animations

Today I want to let you know about a set of stunning animations produced by the DNA Learning Center, which was founded by the Cold Spring Harbor Laboratory in 1988 to educate the general public about issues related to genetics. The DNA Learning Center’s Biology Animations web page contains some 50 animations about DNA, RNA, proteins and their complex interactions. Most of these animations are just a few minutes long, and all of them are are so realistic that they take your breath away—a far cry from the 2D and 3D animations that you may have seen where everything is smooth and steady and all the colours are uniform. Instead, in these animations, everything moves and pulsates, as if you were moving through the living molecular jungles inside the tiniest human cells. (more…)

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Monday, 10 October 2022
A free neuroscience textbook

Today I want to tell you about an excellent neuroscience textbook that you can read online absolutely for free! Neuroscience: Canadian 2nd Edition Open Textbook” is a very complete, typical undergraduate-level treatment of its subject, divided into four units: 1. Neuroscience: The Basics; 2. Neurodegeneration; 3. Fundamental Neuroscience Techniques (and when to use them); and 4. Emergent Topics in Neuroscience. Unit 1 covers not only the anatomy and physiology of the entire nervous system, but also those of the system, which is so closely linked to it. Unit 3, on neuroscience techniques, is fairly extensive, explaining highly complex techniques such as optogenetics. Unit 4 delves into subjects that are getting a lot of attention from cognitive scientists today and that you’d never have seen in a neuroscience textbook 10 or 20 years ago, such as the beneficial effects of art, exercise and meditation on the brain. The book also includes quiz questions and links to videos on other websites. (more…)

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Monday, 22 August 2022
Neurons as Works of Art

If you visit the website that I’m going to tell you about today, you’re likely to kill a lot of time there, as I just did. But if visiting a museum to enjoy beautiful art isn’t really killing time, then neither is visiting NeuroArt® —an online gallery of gorgeous images of neurons and the brain, produced with dyes, tracers and a variety of other technical methods. (more…)

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Friday, 15 July 2022
Who Fact-Checks the Fact-Checkers?

That’s not so simple a question as it may seem, because although we are often rightfully warned against people who claim to have “done their research” on some subject or other and to have discovered unbelievable secrets about it, we are also often asked to accept fact checkers as sources of absolute truth, when they’re really not. They’re just ordinary journalists who are being paid to do their jobs as best they know how while dealing with complex, specialized disciplines and concepts with which they are no more familiar than you or I. So in the end, what do fact checkers offer us? Their own subjective accounts of small slices of reality that they think they have understood and that we hope most of them are presenting in a responsible way—in other words, a far cry from what is suggested by the categorical labels of “true” and “false” that all too often litter fact checkers’ articles on complex subjects such as the human brain, or Covid-19. (more…)

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