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The next installment of the Nature Network Neuroscience group journal club is now live. The paper is on somatosensory processing in sensory and motor cortex, from the lab of Carl Petersen in Lausanne.
The contributor breaking down the paper for the neuroscience group is Eric Thomson, a post-doctoral fellow at Duke University in the lab of Miguel Nicolelis. I want to thank Eric for his participation in this new endeavor.
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How many neurons are required for learning and memory? None, according to Saigusa et al., who report basic learning behavior in unicellular amoebae in a recent article in Physical Review Letters.
The amoeba Physarum polycephalum is sensitive to environmental conditions. At room temperature, Physarum move at a constant rate. However, dry air slows the rate of Physarum movement.
The authors puffed dry air on Physarum once an hour for three hours. On the fourth hour, Physarum slowed down, even when no puff of air was delivered. Subsequent hours without air puffs slowly extinguished the periodic slowing of Physarum movement. However, one dry air puff six hours later reactivated the hourly behavior pattern.
These behaviors are consistent with rudimentary learning in higher organisms. Do these data indicate that unicellular organisms can learn? Physarum, like other organisms, have precise biological rhythms set by cellular oscillators. So, Physarum may be particularly sensitive to events occuring at regular intervals, and their periodic slow-down may represent the setting of a biological rhythm. However, rhythms alone do not explain extinction of the behavior in the absence of additional dry air puffs.
Do these data indicate a potential origin for learning, or do they indicate that our definition of learning in complex organisms is too simplistic? I'm a bit torn.
Answers in Genesis, a self-described Christianity-defending ministry dedicated to enabling Christians to defend their faith and to proclaim the gospel of Jesus Christ effectively, recently launched a new publication, Answers Research Journal. Their mission:
Addressing the need to disseminate the vast fields of research conducted by creationist experts in theology, history, archaeology, anthropology, biology, geology, astronomy, and other disciplines of science, Answers Research Journal will provide scientists and students the results of cutting-edge research that demonstrates the validity of the young-earth model, the global Flood, the non-evolutionary origin of “created kinds,” and other evidences that are consistent with the biblical account of origins.
As their parental organization teaches, "facts" don't speak for themselves, but must be interpreted. All I can say is..........Wow.
The work submitted to this journal will be peer-reviewed and hopes to encourage Christians with the latest and best research providing the truth from "the perspective of the recent Creation and the global Flood within a biblical framework."
Best of all, this is an open-access journal, so you can feel free to peruse the three papers that have been reviewed and published for Volume 1:
1. Proceedings of the Microbe Forum
2. Microbes and the Days of Creation
3. Catastrophic Granite Formation (In the spirit of full disclosure, the third paper is actually by the Editor-in Chief)
I'm going to refrain from giving an opinion, so as not to bias your views of the journal, although I STRONGLY encourage you to give me your opinion below. Happy reading!
Everyone has had that awkward moment at a cocktail party or at the lunch table:
You: Congratulations on the little one; she's beautiful! When was she born?
New mother: Thank you, thank you. Well, let's see, I've kind of lost track, but with today being January 14 and her birthday being December 17...
You: Oh, so she's already 5 weeks old then. Wow!
New Mother: Uhh...no. She is exactly 28 days old.
Although mistaken mental math has embarrassed us all, we humans still reign supreme in the nonverbal representation of numerical values, right? A new study in PLoS aimed to find out by directly comparing rhesus monkeys and college students on the same arithmetic task.
Many studies have previously established that other animals use a similar cognitive process as humans to nonverbally represent numerical values, but have only tested for the ability to order values according to the amount, as opposed to adding them together, which would require a mental transformation of the value.
Here, the authors directly compared the nonverbal arithmetic abilities of monkeys and adult humans using the same task and stimuli. Macaques and college students were presented with two sets of dots on a touch screen monitor, separated by a delay. Subjects were then required to choose between two new arrays: one with a number of dots equal to the sum of the first two sets, and a second, which contained a different number of dots. Monkeys could not only adequately perform this task (completing a wide range of addition problems), but with enough practice, could also correctly solve novel problems that were never used during training.
Based on modeling results and correlation analyses of the data, the authors determined that both human and nonhuman primates seem to use a primitive mathematical function that utilizes an analog representation of numerical values, with performance in both species limited by the ratio between the numerical values of the choice stimuli.
From the authors:
Numerical addition is a component of the primitive, language-independent set of numerical capacities that has a common evolutionary origin among primates, including humans. More broadly, our data demonstrate that the ability to combine mental representations, which is a characteristic of sophisticated aspects of human cognition, is a capacity that nonhuman animals use within the numerical domain.
So what was the result of the competition? Well, the college students outperformed the macaques, earning an "A" with a 94% accuracy rate, while the monkeys only managed a "C" (76% accurate). But the monkeys shouldn't feel too bad about losing; after all, they were competing against students at Duke.
I apologize for the blatant promotion, but I wanted to bring your attention to a new forum designed to spur on discussion involving interesting neuroscience papers. I categorized this under "What's new in NN?", except here, the "NN" is different: Nature Network. This platform has been around for some time now, but I am new to it. I recommend that you check out the site, as it aims to connect scientists on both the local and global levels (but unless you are in Boston or London, the local part is still being rolled out).
In the Neuroscience group, we are starting an online journal club featuring interesting papers from any journal for discussion. These journal clubs will be written up by experts in each respective field (except those that I do; I am going to fake my way through whatever topics don't get covered by the experts...). These experts will be students and post-docs discussing somebody else's work, in the classic spirit of a journal club.
This forum is designed to teach the non-specialist about certain neuroscience sub-fields in which they may have some interest, as well as to feature important findings that very well may pertain to the current work of the specialist. Hopefully, the discussion will include the following (and more): questions being asked regarding the data or conclusions of the study; inquiries made as to how to successfully implement particular methodologies; reasons given for why additional data would help the authors solidify their conclusions; suggestions floated as to what the next steps should be in the follow-up experiments.
We will try to get one posted once a week or once every two weeks; hopefully we can at least meet the latter goal. As usual, suggestions and comments on this proposal are welcome, and if you would like to participate or suggest a paper, feel free to contact me directly.
A new policy in the Journal of Neuroscience demonstrates the current push towards open access publication. Researchers can pay to have their article freely available immediately upon publication, starting with all articles submitted as of January 1, 2008. It is interesting, because J Neurosci words the new policy a bit like an experiment, essentially telling the authors and funding agencies to put their money where their mouth is. If they want open access, as many are calling for, they can help support it. Hopefully we can return to this policy in 6 months or so to see how many authors took this option, and who funded those choosing to "pay for play."
Well, now, it has been a nice long break since the last post, but time to get this blog rolling again here in 2008. Let's start light, while I finish cooking up the stuff I want to discuss. Let's return to a request I buried in a previous post that received no response:
With regards to moving on, I have plenty of ideas for new discussions, but would also like to offer up the concept of "reader-generated content." If I receive enough participation, I'm willing to discuss what you find interesting as often as you send me promising topics. For now, let's set the modest goal of one reader-selected topic every 2 weeks, and go from there. If you would rather keep your communications and ideas private, feel free to email me at 'Actionpotential' at natureny dot com.
This can take any form, including a nomination for a new study that you think might stimulate conversation, or for clarification on a Nature Neuroscience paper that was recently published (I especially encourage the non-scientist readers to take us up on this offer!).
In addition, if you haven't noticed, we have been working on a modest facelift of the blog homepage, with more organization and categorization. I'd love to hear any feedback on any of these new aspects and will take any other suggestions that might make the blog more user-friendly. Here's looking towards a captivating survey of neuroscience in 2008!