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"In the study, Prof. Fried observed the neural activity in the brains of 13 epilepsy patients, as the patients watched clips from TV shows like Seinfeld and The Simpsons. A short while after, the test subjects were asked to describe what they remembered from the video clips. During recall, the exact same neurons that had fired while viewing a clip fired once again while the subject was recalling it. Soon, the researchers were able to predict what clip the subjects would recall just by looking at the neurons that lit up seconds before the recall experience was vocalized."

"Cdk5 therefore appears to be crucial only for later stages of the maturation of newborn neurons. The authors suggest that the improper connections formed by these cells could interfere with information processing in the hippocampus. However, they did not carry out any behavioural tests to explore the consequences of blocking cdk5 activity. This would be an interesting thing to do next, given the recent discovery that new neurons are needed for new memories. Nevertheless, the new findings could have important implications for the use of stem cells in cell replacement therapies for neurological diseases, as they suggest that cells would have to be transplanted accurately into specific locations in order to be effective. " (Neurophilosophy)

If I were a sociologist of science, I would jump on mirror neurons - they are the perfect object if you want to study a scientific controversy today.

"Social scientists are often concerned about the importation of poorly understood concepts from the hard sciences into "softer" fields like anthropology or sociology. In my view, the story of mirror neurons shows that the reverse also happens: scores of brilliant neuroscientists were set to work on entities celebrated and, one might say, partly invented because they allowed neuroscience to relate to social concepts, like imitation, culture, and art. Once it got started, the story was one of mutual seduction. The disenchantment, if it takes place at all, may take years. Will the speculative bubble burst? "

From a single fertilised egg of about 0.14 millimetres in diameter, to an adult human being, the neurophysiology of development of the brain and nervous system is nothing short of remarkable. We are born with around 100 billion neurons, and the development of the brain continues long after birth, with dendrites of some neurons in the neocortex continuing to grow well into old age

In laying down the neural circuitry of the developing brain, billions of neurons must first migrate to their correct destinations and then form complex synaptic connections with their new neighbors.

During the development of the brain, young neurones need to form connections with other cells. But equally important, they need to avoid making connections with themselves.

"Based on recent findings from neuroscience we can plausibly deduce that the mirror neurons of the viewer were engaged by these images of others suffering. The appeal was to the public's awakened sense of compassion and revulsion toward graphic depictions of the wholesale violence, barbarity, and torture routinely practiced on these Atlantic voyages. Rediker notes that the images would instantaneously "make the viewer identify and sympathize with the 'injured Africans' on the lower deck of the ship . . ." while also producing a sense of moral outrage (p. 315, Olson, 2008)."

"Now a recent breakthrough by the Cambridge neuroscientist and geneticist Seth Grant may provide a third possibility. In a report published in the June 2008 issue of Nature Neuroscience, Grant and his colleagues analyzed synapses in organisms of increasing evolutionary complexity, from single-celled organisms to vertebrates. They found that more advanced organisms also had more complex synapses, allowing neurons to communicate in more complicated ways." Seed

The picture of agency presented here is one well worth pursuing. Murphy and Brown have not presented us with a view that is defensible, both because it is far too sketchy to be properly assessed, and because many of the claims made will no doubt turn out to be false. However, the general outlines of the view are plausible, and there is a rich research agenda here. Perhaps future work will see some of the details worked out, and the gaps filled. (Neil Levy)