Neuroscience

The number of individuals who are obese and suffer with its associated health problems has continued to rise, even being called an epidemic.

Is it genetics?  The dream of cheap food finally being realized? Or are we slaves to marketing?

Researchers from Yale University School of Medicine and the University of Southern California say they have visualized differences in the way that the brains of obese and non-obese individuals respond to visual cues of high-calorie foods.  They see those foods differently.

A study on activity in a the parahippocampal cortex (PHC) found people will remember a visual scene when the brain is more active.

The PHC, which has previously been linked to recollection of visual scenes, wraps around the hippocampus, a part of the brain critical for memory formation. However, this NeuroImage study is the first to investigate how PHC activity before a scene was presented would affect how well the scene was remembered. 

In patients with seriously altered states of consciousness, there is also the puzzle about dreaming.   Do ‘vegetative’ patients (also known in clunkier, politically correct fashion as patients in a state of unresponsive wakefulness) or minimally conscious state patients experience normal sleep?  Electrophysiological studies have been no help so the hypothesis is if the vegetative state opens no conscious door onto the external world, the state of minimal consciousness for its part assumes a residual consciousness of the environment, certainly fluctuating but real.

Most of us don’t have a problem attributing emotions to primates, dogs, horses and other vertebrates. But what about invertebrates? That seems less obvious. They have smaller, less complex brains, but is that enough to boldly claim they have no emotions? Of course, studying animal emotions is a precarious business. Studying human emotions has already proven difficult enough, and in animals it is bound to be a lot harder.

One way to go about it, is to take a look at so-called cognitive biases, biases in the processing of information that are typical of negative affective states. An example of this is the pessimistic bias, an increased expectation of punishment, greater attention to potential threats and a tendency to interpret ambiguous stimuli as if they were threats.

For the crowd watching an Illinois high school football game last fall, it was a sickening feeling watching one of their Unity High School cornerbacks collapse to the ground after delivering a heads-down tackle on an opposing running back (see video here.) 

For Steven Broglio, an assistant professor of kinesiology at the University of Michigan, it was a mixed feeling of concern and curiosity as to the extent of the injury.  Since 2007, Broglio has been collecting data on the violent collisions that occur in high school football and their contribution to concussions and other head injuries.

The brain is quite complex (talking about an understatement), with its billions of neurons with many connections between them. These neurons and their connections form an intricate three-dimensional structure which forms the seat for cognition, awareness and much more. Its intricacy, however, also makes mapping it a daunting challenge. Nevertheless, there are some research groups that have put themselves to the task (for example, the Human Brain Project).

Age does  a lot of things to us. And to our brains, which shrink when we grow older. Those incredibly complex neural networks inside our skulls not only shrink, but they also become more susceptible to scourges such as dementia and Alzheimer’s disease. People who do not suffer from these cognitive dysfunctions, also show aging effects in their brains, such as the accumulation of amyloid-beta plaques.

To trace the evolutionary roots of the aging brain, researchers have previously investigated whether similar effects occur in the brains of rhesus monkeys (which diverged from the ‘human lineage’ about 30 million years ago). These primates showed only very limited effects of age in their brains. So, the mystery remained.

A perhaps somewhat lugubrious study, published in PLoS ONE, set out to investigate whether decapitation is a humane method of euthanasia in small animals, such as rats and birds. To do this, they used 22 rats that were decapitated while an EEG was recorded. Of these rats, 9 were awake and 8 were anesthetized (5 rats lost the electrodes during the experiment).

Not surprisingly, the EEG lost power fast and globally and decreased to about half the initial value in about 4 seconds after the decapitation. Where the EEG markedly differed between both groups before the ‘death sentence’ was carried out, it did not appear different post decapitation.  The authors present two hypotheses to explain this phenomenon:

New neurological research, using, of course, the ever-popular giant axon of squid, shows that neurons are pretty darn clever at picking signal out of noise. And what's more, they're sensitive to context:
Neurons are often compared to transistors on a computer, which search for and respond to one specific pattern, but it turns out that neurons are more complex than that. They can search for more than one signal at the same time, and their choice of signal depends on what else is competing for their attention.
Take that, transistors! Neurons are way smarter than you.

Well, at least squid neurons are.