Neuroscience

Several studies have demonstrated that the primary active constituent of cannabis, delta-9-tetrahydrocannabinol induces transient psychosis-like effects in healthy subjects similar to those observed in schizophrenia. However, the mechanisms underlying these effects are not clear. A new study reports that delta-9-tetrahydrocannabinol increases random neural activity, termed neural noise, in the brains of healthy human subjects. The findings suggest that increased neural noise may play a role in the psychosis-like effects of cannabis. "At doses roughly equivalent to half or a single joint,…

Scientists believe they have resolved a decades-long debate about how the brain is modified when an animal learns. Using newly developed tools for manipulating specific populations of neurons, the researchers have for the first time observed direct evidence of synaptic plasticity -- changes in the strength of connections between neurons -- in the fruit fly brain while flies are learning. Due to the relative simplicity of fruit fly neural anatomy -- there are just two synapses separating odor-detecting antenna from an olfactory-memory brain center called the mushroom body -- the diminutive…

Machado-Josephdisease (MJD) is a hereditary neurodegenerative disorder that destroys the brainareas involved in muscle control. Although the disease is clearly caused by a mutationin the ATXN3 gene - resulting in an abnormal ataxin-3 protein that forms toxic aggregatesin the brain - the mechanism how MJD develops is unclear. And despite decadesof research no cure or treatment has been found. But now a study in the journal Brain by researchers from Universityof Coimbra in Portugal used a new approach to this old problem, and discovereda way to revert the disease’s neural damage and its…

In comparison to other organs, the human brain has the highest energy requirements. Nerve cells cover their high energy demand with glucose and lactate and a new report shows for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells.  The supply of energy for nerve cells and the particular role of lactic acid (lactate) has been a matter of intense research for many years. A hypothesis from the 1990's postulates, that a well-orchestrated collaboration between two cell types, astrocytes and neurons, is the basis of brain energy…

The upside to modern cancer treatment, like chemotherapy, is obvious; people are living more, and living longer. The downside is that some food tastes terrible.  Chemotherapy, by design, kills all fast-growing cells in the body. As cancer cells die, so do all the healthy fast-growing cells, including the cells responsible for hair growth and taste buds. So your hair falls out and everything tastes metallic. "Here they are, critically ill, needing good nutrition more than ever, and they can't enjoy food? It's beyond unfair," said Dan Han, a psychologist at the University of Kentucky.…

Noisy gymnasiums, restaurants where conversations are nearly impossible, and concert halls less than perfect for the music are all engineering problems. What does that have to do with emotions? Perhaps a lot. Penn State acoustical engineers are using functional MRI, measuring brain activity by sensing changes in blood flow in the brain, to better understand room acoustics and the emotions they can cause. Michelle Vigeant, assistant professor of acoustics and architectural engineering at Penn State, and Martin S. Lawless, Ph.D. student in acoustics, are looking at the emotional response to…

If you are apathetic, it would be a surprise to know your brain is making more effort, but a new study finds that some people traditionally perceived as lazy have a biology problem and not an attitude one. Forty healthy volunteers completed a questionnaire that scored them on how motivated they were. They were then asked to play a game in which they were made offers, each with a different level of reward and physical effort required to win the reward. Unsurprisingly, offers with high rewards requiring low effort were usually accepted, while low rewards requiring high effort were less popular…

Because light travels far faster than sound, we see distant events before we hear them. Perhaps as a child you learned to count the seconds between a lightning flash and the sound of thunder to estimate its distance.  A new paper says that our brains can also detect and process sound delays that are too short to be noticed consciously. And they found that we use even that unconscious information to fine tune what our eyes see when estimating distances to nearby events.  "Much of the world around us is audiovisual," said Duje Tadin, associate professor of brain and cognitive sciences…

In a new study, infants remained calm twice as long when listening to a song as when listening to speech. The study involved thirty healthy infants aged between six and nine months. Humans like music biologically, according to one hypothesis. In adults and older children, this "entrainment" may be displayed by behaviors such as foot-tapping, head-nodding, or drumming.  "Emotional self-control is obviously not developed in infants, and we believe singing helps babies and children develop this capacity," says Professor Isabelle Peretz of the  University of Montreal. "Infants…

Early life stress is a major risk factor for later episodes of depression. In fact, adults who are abused or neglected as children are almost twice as likely to experience depression.  Scientific research into this link has revealed that the increased risk following such childhood adversity is associated with sensitization of the brain circuits involved with processing threat and driving the stress response. More recently, research has begun to demonstrate that in parallel to this stress sensitization, there may also be diminished processing of reward in the brain and associated…