THE latest issue of Technology Review contains a photo essay by yours truly, called Time Travel Through the Brain, in which I look at how techniques used to investigate the brain have evolved during the 100 year history of modern neuroscience. The essay begins with a drawing by the great Spanish neuroanatomist Santiago Ramón y Cajal, who used the staining method discovered by Camillo Golgi to establish that nervous tissue is composed of cells, then goes on to describe more recent methods such as fibre tracing, Brainbow and various types of microscopy. This image from the piece graced the…
THE humble fruit fly (Drosophila melanogaster) has the ability to learn and remember, and to make predictions about the outcome of its behaviours on the basis of past experience. Compared to a human brain, that of the fruit fly  is relatively simple, containing approximately 250,000 cells. Even so, little is known about the anatomical basis of memory formation. The neural circuitry underlying memories in these insects has now been dissected. In an elegant new study published in the journal Cell,  researchers from the University of Oxford show that aversive memories are dependent on a tiny…
USING an inventive new method in which mice run through a virtual reality environment based on the video game Quake, researchers from Princeton University have made the first direct measurements of the cellular activity associated with spatial navigation. The method will allow for investigations of the neural circuitry underlying navigation, and should lead to a better understanding of how spatial information is encoded at the cellular level. In mice, spatial navigation involves at least four different cell types located in the hippocampus and surrounding regions. Place cells increase…
THINKING of and saying a word is something that most of us do effortlessly many times a day. This involves a number of steps - we must select the appropriate word, decide on the proper tense, and also pronounce it correctly. The neural computations underlying these tasks are highly complex, and whether the brain performs them all at the same time, or one after the other, has been a subject of debate. This debate has now apparently been settled, by a team of American researchers who had the rare opportunity to investigate language processing in conscious epileptic patients undergoing surgery…
ATHLETES who are on a winning streak often claim that they perceive their targets to be bigger than they actually are. After a run of birdies, for example, golfers sometimes say that the cup appeared to be the size of a bucket, and baseball players who have a hit a few home runs say that the ball is the size of a grapefruit. Conversely, targets are often reported to be smaller than they actually are by athletes who are performing badly. Research carried out in the past 5 years suggests that these are more than just anecdotes, and that performance in sports can actually affect perception. A…
THIS image by Dominik Paquet of Ludwig-Maximilians-Universität in Munich is one of the winners of the 2009 Nikon Small World Photomicrography competition. It's a confocal fluoresence microscopy image of zebrafish larvae expressing a mutant form of human Tau protein, which forms the neurofibrillary tangles that are a pathological hallmark of Alzheimer's Disease. The work is described in this recent paper. Below are two more images from the competition. This image of pyramidal cells in the mouse cerebral cortex was created by Celine Plachez of the University of Maryland School of Medicine.…
SECOND LIFE is an online "virtual world" which enables users to create a customised avatar, or digital persona, with which they can interact with each other. It has become incredibly popular since its launch just over 6 years ago, with millions of "residents" now using it regularly to meet others, socialize and even to have virtual sex. Second Life is now filled with virtual communities and institutions - it has businesses and universities, and its own virtual economy. Now, imagine a futuristic version of Second Life, in which avatars can transfer sensations to the bodies of their users.…
VISION is now well known to modulate the senses of touch and pain. Various studies have shown that looking at oneself being touched can enhance tactile acuity, so that one can discriminate between two pinpoints which would otherwise feel like a single sensation. And last year, researchers from the University of Oxford showed that using binoculars to make a limb look larger or smaller than it actually is can respectively enhance and diminish painful sensations. These phenomena occur because the brain fuses stimuli from different sensory systems to generate a coherent experience of bodily…
SEVERAL hundred species of fish have evolved the ability to generate electric fields, which they use to navigate, communicate and home in on prey. But this ability comes at a cost - the electric field is generated continuously throughout life, so consumes a great deal of energy, and it can also attract predators which are sensitive to it. Electrogenic fish species therefore utilize various strategies to save energy and to minimize the likelihood of being detected. Some generate irregular pulses of electrical discharges whose rate can be modulated; others can also modulate the strength of the…
REMOTE-CONTROLLED insects may sound like the stuff of science fiction, but they have already been under development for some time now. In 2006, for example, the Defense Advanced Research Projects Agency (DARPA, the Pentagon's research and development branch) launched the Hybrid Insect Micro-Electro-Mechanical Systems program, whose ultimate aim is to turn insects into unmanned aerial vehicles. Such projects provide proof of principle, but have met with limited success. Until now, that is. In the open access journal Frontiers in Integrative Neuroscience, a team of electrical engineers led by…
THE vegetative and minimally conscious states are examples of what are referred to as disorders of consciousness. Patients in these conditions are more or less oblivious to goings-on in their surroundings - they exhibit few, if any, signs of conscious awareness, and are usually unable to communicate in any way. It is, therefore, extremely difficult to establish what these patients are experiencing, and the consciousness disorders are among the least understood, and most commonly misdiagnosed, conditions in medicine. Although technologies such as functional neuorimaging have enabled…
LANGUAGE contains many sayings which link our feelings and behaviour towards others to temperature. We might, for example, hold "warm feelings" for somebody, and extend them a "warm welcome", while giving somebody else "the cold shoulder" or "an icy stare". Why is that we have so many metaphors which relate temperature to social distance? According to George Lakoff, a professor of cognitive science and linguistics at the University of California, Berkeley, we judge others on the basis of warmth because abstract concepts, such as affection, are firmly grounded in bodily sensations. There is…
A paper by researchers from Princeton University, just published in the open access journal PLoS One, describes a new virus-based technique for probing the connections between neurons while simultaneously monitoring their activity in live animals. Various methods are available for studying the activity of neurons and how they are connected to one another, but examining the co-ordinated activity of multiple nerve cells in neural circuits has, until now, posed a big challenge, because none of them can monitor both activity and connectivity at the same time. The earliest method for tracing…
THIS short film clip shows two images of the same scene. Watch it carefully, and see if you can spot the subtle differences between them. As you watch, your eyes will dart back and forth across the images, so that you can perceive the most important features. And even though you might not be consciously aware of the differences, your brain will have picked up on them. This implicit form of remembering is referred to as relational memory; in this case, the brain is encoding the perceptual associations between items in the image. And recent studies have shown that relational memory…
THE retina has an inverted structure which seems ill-suited to its function: the rod and cone cells, which are sensitive to light, and which convert light energy into electrical impulses, point backwards and are located at the back of the retina, so that light entering the eye has to pass through several layers of irregularly organized cells before it reaches them. The retina also contains nerve fibres which are positioned perpendicular to the path of light entering the eye, and many of the structures in the upper cell layers have a diameter similar to that of the wavelength of visible light…
THIS weird and wonderful creature is the star-nosed mole (Condylura cristata), a small, semi-aquatic mammal which inhabits the low wetlands of eastern North America. Like other moles, it ekes out an existence in a network of narrow underground tunnels, and digs shallow surface tunnels where it forages for insects, worms and molluscs. Living as it does in almost complete darkness, the star-nosed mole has poorly developed eyes, and is virtually blind. Instead, it relies heavily on its remarkable star-shaped nose. This organ enables the star-nosed mole to decide whether something is edible with…
AS Seed's Featured Blogger of the week, I have written a short article about the Human Connectome Project, in response to a news story on the magazine's website, called Mapping the brain's highways, by Azeen Ghorayshi. Several weeks ago, the National Institutes of Health announced the Human Connectome Project, an ambitious $30 million five-year initiative, which aims to map the connectivity of the human brain. Is this feasible? In short, the answer is no. The idea that a complete connectivity map of the whole brain can be achieved within five years is unrealistic, and producing a…
NOT so long ago, the idea that birds might possess some form of what we call intelligence seemed quite ridiculous. Yet this view has changed dramatically in recent years, with numerous studies showing that some bird species are capable of complex cognition. Members of one family of birds in particular - the Corvidae, which includes crows, rooks and ravens - have an ability to make and use tools which is at least as sophisticated as that of chimpanzees. Two new studies, published this week, provide yet more demonstrations of the remarkable cognitive abilities of this group of birds. One shows…
RESEARCHERS at the University of California, Berkeley have developed a microscope attachment which enables a standard mobile phone with a camera to be used for high-resolution clinical microscopy. Daniel Fletcher and his colleagues describe the CellScope in a paper published today in the open access journal PLoS One, and demonstrate that it can be used to capture high quality bright field images of the malaria parasite and sickle blood cells, as well as fluorescence images of cells infected with the bacterium that causes tuberculosis. The device could potentially become an important tool for…
BATS use sonar, or echolocation, to navigate complex environments, and also to forage and then accurately pinpoint the flying insects on which they prey. Insects in turn have evolved various counter-measures to evade capture. Some species have ears which are in tune to the echolocation signals, while others are capable of performing complex evasive flight maneuvers in response to the clicks produced by attacking bats. Tiger moths have evolved the ability to produce ultrasonic clicks in response to attacking bats. However, the function of these clicks was unclear, although decades of research…