We have learned that zebrafish have much more in common with humans than meets the eye, which is why they have become a “go-to” model in neuroscience research. But one obvious difference remains: we walk and they swim, which means movement in 3 dimensions. So while video tracking from one camera angle (e.g. above) can give us a lot of information about the movement of humans (or rodents), all the information from the third dimension (depth) is entirely missed from single camera tracking.
By now, we are all familiar with the zebrafish as a model species. It has many advantages over rodent models and thus has complemented and/or replaced many studies that use the traditional mouse or rat. But today, let’s talk about another fish: the Japanese medaka (Oryzias latipes). It has much in common with the zebrafish, such as external embryogenesis and transparency in early life stages, and genetically speaking is also complementary to zebrafish (see Porazinski et al., 2011).
Characterizing postoperative cognitive dysfunction with a novel rat-model.This week we have a guest post by Iris Hovens. She has done some really interesting research into the consequences of surgery in terms of reduced memory and concentration problems. This is especially a concern for elderly people. We are very happy that Iris has so kindly agreed to write about her research on our blog. At the end of this post, you will also find a link to a free white paper about this research! Thank you, Iris!
In the Netherlands, yearly more than 400.000 patients aged over 60 undergo surgery. Although the surgeries are aimed at improving health and well-being, ten percent of these older surgery patients will develop dementia-like symptoms, such as reduced memory and concentration and problems with planning and information processing. This postoperative cognitive dysfunction (POCD) seriously affects the life of patients and their near friends and relatives, as it is associated with a reduced quality of life, increased dependency on social care and an increased risk of lasting mental and functional disability.
Translation in POCD researchThe last decades many human and animal studies have been performed with the aim to understand POCD and its underlying mechanisms . As the cognitive symptoms of POCD can vary widely among patients, human studies investigating the incidence and risk-factors have usually defined POCD as a persisting cognitive decline in general. In contrast, mechanistic research in animals has focused on a simplified model of POCD investigating the effects of surgery on one specific brain region, the hippocampus, and the cognitive function related to this region, spatial learning and memory. These studies have greatly contributed to our understanding of POCD. For example, we now have strong evidence that inflammatory processes that result from surgical trauma may play a key role in POCD development. However, the large differences in the view on POCD may hamper translation of animal studies into clinical practice.
A new rat-model for POCD
The aim of my PhD project was to develop a new model for POCD in rats to aid translation and gain more insight in the mechanisms underlying POCD. The model we developed made use of abdominal surgery in male rats, mimicking the effects of major abdominal surgery in humans. To be able to measure several aspects of cognition and mood related behavior in different time-windows of interest after surgery, we developed a compact behavioral test protocol (5 days, see figure). For this protocol we chose behavioral tests that could be performed quickly and of which the execution and analysis could be easily standardized using Ethovision software: An open field test to measure interest and anxiety, the novel object test and location recognition test to measure object recognition and spatial recognition, and the Morris water maze test to measure spatial learning, memory and cognitive flexibility. Additionally, we analyzed markers for inflammation and neuronal functioning in the blood and in brain regions critically associated with cognitive performance: hippocampus for spatial learning and memory; prefrontal cortex for object memory; and striatum for cognitive flexibility .
Sexual selection can lead to fascinating phenomena. We are all familiar with the fabulous color display of male peacocks to attract females. Less well known, but definitely not less interesting, are stalk-eyed flies. Due to the fact that the females strongly prefer males with wideset eyes, the males have developed eyes on stalks that can be larger than their bodies. And did you know that the Irish elk developed antlers through sexual selection that span over two-and-a-half meters? Some people believe that the males with antlers this large could hardly move through the forest, which may have led to the species’ extinction. It’s no wonder that sexual preference is so well-studied with so many hypotheses formulated in relation to it.
In a recent blog post, we talked about letting animals walk freely in gait research.
At Noldus, we strongly believe that this is the way to go in gait research, so our CatWalk XT system makes use of free gait. This is consistent with the constant feedback from, and collaborations with, scientists who actually perform gait, locomotor, or pain research.
Mouse models have proven to be essential in discovering the neurological underpinnings of diseases and to the development of a deeper understanding of genotype-phenotype relations. Behavioral phenotyping of these mice is very important, evidenced by the variety of tests that have been described in literature. Unfortunately, many of these tests are susceptible to bias, for example, testing in a novel environment. Bias can also result from handling animals prior to the tests, which can induce artificial behaviors that confound results.
When children lack information, they make up stories by adding up their own guesses. Their imagination can run wild: all elephants are pink, right? This kind of reasoning is undesirable when trying to explain a rare disorder of a sister or brother. Guesswork may result in incorrect illness explanations and might cause related miscommunication or behavioral problems. When we learn more about how siblings describe illnesses, we might be able to appropriately assist family counselors and parents.
Aphids are small insects that pierce plant leaves and suck out their contents. They can cause considerable crop damage. Although they inflict limited physical destruction to the plant, aphids commonly infect plants with viruses, which can destroy complete harvests .
Aggressive behavior is typically adaptive for most species in the animal kingdom. Examples of this can be seen in maternal aggression to protect one’s young, and defense of a home territory; both of these contribute to the survival of an individual, and the species as a whole. But how is aggressive behavior mediated in the brain? Recent work indicates that the hippocampus in general, and the CA2 region in particular, is a crucial neural component in mediating social recognition and aggression. What CA2-specific mechanisms allow for such regulation?
By using video and audio recordings in education, students and educators can receive, and benefit from, direct feedback.
Students are raised with TV and internet and are accustomed to interacting with images and videos. They are used to receiving information by watching short movie clips. On a daily basis, students find themselves browsing YouTube for information (and for fun, of course). In training and simulation situations including, for example, a simulated nurse-patient interaction, students can learn a lot. Recent research  tells us that it is important to first deal with emotions in a medical encounter before trying to convey an important message, such as a treatment plan.