Weekly Neuroscience Update

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A team of neuroscientists from Göttingen and Tehran has shown. how our brain combines visual features to achieve a unified percept.

Research published in the journal Cerebral Cortex has shown that stronger functional connectivity—that is, communication among neurons in various networks of the brain—is linked to youthful memory in older adults. Those with superior memories—called superagers—have the strongest connectivity.

Scientists have found a link between brain’s emotion circuit and movement.

High-fat diets are not only bad for your waistline, they are also bad for your brain health. A new study reveals high-fat diets contribute to hypothalamic inflammation which occurs long before symptoms of obesity arise.

Patients with schizophrenia show increased brain activity in central areas of the brain, but lower activity in the temporal sulcus when hearing metaphors.

Researchers have developed a system that measures a patient’s pain level by analyzing brain activity from a portable neuroimaging device. The system could help doctors diagnose and treat pain in unconscious and noncommunicative patients, which could reduce the risk of chronic pain that can occur after surgery.

Finally this week, a new study reports maternal marijuana use may be detrimental to the brain development of children.

Weekly Neuroscience Update

EPNorth

A virtual reality world called EVA Park can improve the communication of those who have impaired speech and language following a stroke, according to research by academics at City University London. The study, which is published in PLOS ONE, is the first exploration of multi-user virtual reality in aphasia therapy and shows the potential for technology to play an important role in improving the everyday lives of people with the condition.

A new study will look at how brain connections mature and develop from childhood to adulthood.

Neurons communicate by sending chemical signals called neurotransmitters across synapses, specialized connections between two individual cells. This communication requires a delicate and intricate molecular architecture. A recent paper published in Nature has now shown that the structure of this intercellular space is more complicated than previously thought, and it probably helps boost the efficiency of the signaling.

A new long term study of young marijuana users tracks the brain’s response to reward over time. The findings indicate a lower response to reward in marijuana users.

Neuroscientists at the University of Pittsburgh have identified the neural networks that connect the cerebral cortex to the adrenal medulla, which is responsible for the body’s rapid response in stressful situations. These findings, reported in the online Early Edition of the journal Proceedings of the National Academy of Sciences (PNAS), provide evidence for the neural basis of a mind-body connection.

A new study provides insight into how overconfidence can lead to poor decision making.

Scientists have identified part of our brain that helps us learn to be good to other people. The discovery could help understanding of conditions like psychopathy where people’s behaviour is extremely antisocial.

Finally this week, researchers have developed a neurodevelopmental model of a rare genetic disorder that could help shed light on the workings of the human social brain.

 

Weekly Neuroscience Update

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Consciousness seems to work as continuous stream: one image or sound or smell or touch smoothly follows the other, providing us with a continuous image of the world around us. Image adapted from the EPFL press release.

 

Scientists propose a new way of understanding of how the brain processes unconscious information into our consciousness. According to the model, consciousness arises only in time intervals of up to 400 milliseconds, with gaps of unconsciousness in between.

A new study finds bursts of neural activity as the brain holds information in mind, overturns a long-held model.

Why do we sometimes decide to take risks and other times choose to play it safe? In a new study, researchers explored the neural mechanisms of one possible explanation: a contagion effect.

Using imagery is an effective way to improve memory and decrease certain types of false memories.

Scientists have developed an imaging process that for the first time, they say, can identify and track the progression of Alzheimer’s disease in people’s brains, even when there are no symptoms — a development that could lead to earlier diagnosis and treatment.

People prone to seeking stimulation and acting impulsively may have differences in the structure of their brains according to a study published in the Journal of Neuroscience. What’s more, those differences may predispose them to substance abuse.

In a recent study, researchers found evidence of a compromised dopamine system in heavy users of marijuana. Lower dopamine release was found in the striatum – a region of the brain that is involved in working memory, impulsive behavior, and attention. Previous studies have shown that addiction to other drugs of abuse, such as cocaine and heroin, have similar effects on dopamine release, but such evidence for cannabis was missing until now.

Finally this week an innovative collaboration between neuroscientists and developmental psychologists that investigated how infants’ brains process other people’s action provides the first evidence that directly links neural responses from the motor system to overt social behaviour in infants.

 

Your brain on cannabis

A recent article in the Irish Times exploring how a new, highly potent strain of cannabis now being grown in Ireland is more harmful than the drug’s benign image would suggest, prompted me to write about the topic this week.

Marijuana can hurt you

The marijuana problem is much bigger than previously recognized. It is the most widely used illicit drug in the world. Of the 5.6 million people suffering in the US, 62% are using marijuana and young people – some now as young as 12 years of age – represent 23% of the suffering population. The average age of initiation is decreasing while marijuana’s potency is increasing. With increasing potency and earlier use, marijuana poses a significant threat. It is no surprise then that of all teens in drug treatment, 62% have primary marijuana diagnosis. That number represents more young people in treatment than for alcohol and almost equal to the numbers from criminal justice and other sources

Route of administration

Marijuana (from the Mexican Spanish marihuana) also known as cannabis, is much more powerful today than it was 30 years ago. Marijuana is the herbal form of cannabis, and comprises the flowers, leaves and stalks of the mature female plant while hashish is the resinous, concentrated form of cannabis. Chemically, the major psychoactive compound in marijuana is Delta-9-tetrahydrocannabinol (Δ9-THC); it is one of 400 compounds in the plant The smoke also contains more than 150 other types of these cannabinoids such as cannabidiol (CBD), cannabinol (CBN), and tetrhydrocannabivarin (THCV), which can produce sensory effects unlike the psychoactive effects of THC. The pharmacology of marijuana is complex. The cannabinoids are vaporized (smoke) and then deeply inhaled. They are fatty compounds which rapidly cross from the lungs into the blood and tend to accumulate in specific regions of brain.

The psychological effects of marijuana – a Pandora’s Box

The immediate (acute) effects of marijuana include changes in time-sense, a loss of recent memory and impairment in attention. There is also a general difficulty expressing simple thoughts in words. Other effects include impaired motor skills, increase in hunger, nausea, dizziness, and  – depending on the personality of the person and the context in which it is taken – altered moods such as euphoria, a state of relaxation, panic, anxiety, tension, anger, confusion and – especially when eaten – an unpleasant sensation called depersonalization.

The effects on your body are not good either

Marijuana smoke contains more than 150 compounds many of which are cancer–causing so the respiratory system including the lungs suffer the most. Common symptoms include air obstruction, chronic cough, bronchitis, decreased tolerance to exercise and cancer. An increase in heart rate can aggravate existing cardiac conditions or high blood pressure (hypertension) – so don’t take this drug if you have a weak heart.

Definitely not good for your MOJO

Marijuana decreases blood testosterone levels, sperm count and motility. It also decreases sex-drive (libido) and impairs fertility as well as disrupting the female reproductive system which can impact pregnancy in adverse ways. The effect of the drug on the immune system is still unclear but recent studies in animals demonstrate that it impairs T helper cells – key cells in the immune system – which may increase the risk of cancer (by disrupting the cancer surveillance system).

In Part Two of Your Brain On Cannabis, we will take a closer look at the effects of marijuana on your brain, how the drug affects how you learn, how to counter the argument that it is a harmless drug, and if there is any scientific basis for using marijuana as medicine.