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Nicotine Withdrawal Weakens Brain Connections Tied to Self Control Over Cigarette Cravings

High relapse rate in smokers may be explained by diminished connectivity among key brain networks.

People who try to quit smoking often say that kicking the habit makes the voice inside telling them to light up even louder, but why people succumb to those cravings so often has never been fully understood. Now, a new brain imaging study in this week’s JAMA Psychiatry from scientists in Penn Medicine and the National Institute on Drug Abuse (NIDA) Intramural Research Program shows how smokers suffering from nicotine withdrawal may have more trouble shifting from a key brain network—known as default mode, when people are in a so-called “introspective” or “self-referential” state— and into a control network, the so-called executive control network, that could help exert more conscious, self-control over cravings and to focus on quitting for good.

Read the full article Nicotine Withdrawal Weakens Brain Connections Tied to Self Control Over Cigarette Cravings at NeuroscienceNews.com.

The research is in JAMA Psychiatry. (full access paywall)

Research: “Large-Scale Brain Network Coupling Predicts Acute Nicotine Abstinence Effects on Craving and Cognitive Function” by Caryn Lerman, PhD; Hong Gu, PhD; James Loughead, PhD; Kosha Ruparel, MSE; Yihong Yang, PhD; and Elliot A. Stein, PhD in JAMA Psychiatry. doi:10.1001/jamapsychiatry.2013.4091

Ever So Slight Delay Improves Decision Making Accuracy

Read the full article Ever So Slight Delay Improves Decision Making Accuracy at NeuroscienceNews.com.

Findings could improve understanding of ADHD, schizophrenia, and other neuropsychiatric diseases.

Columbia University Medical Center (CUMC) researchers have found that decision-making accuracy can be improved by postponing the onset of a decision by a mere fraction of a second. The results could further our understanding of neuropsychiatric conditions characterized by abnormalities in cognitive function and lead to new training strategies to improve decision-making in high-stake environments. The study was published in the March 5 online issue of the journal PLoS One.

The research is in PLOS ONE. (full open access)

Research: “Humans Optimize Decision-Making by Delaying Decision Onset” by Tobias Teichert, Vincent P. Ferrera, and Jack Grinband in PLOS ONE. doi:10.1371/journal.pone.0089638

Why does the brain remember dreams?

Some people recall a dream every morning, whereas others rarely recall one. A team led by Perrine Ruby, an Inserm Research Fellow at the Lyon Neuroscience Research Center (Inserm/CNRS/Université Claude Bernard Lyon 1), has studied the brain activity of these two types of dreamers in order to understand the differences between them. In a study published in the journal Neuropsychopharmacology, the researchers show that the temporo-parietal junction, an information-processing hub in the brain, is more active in high dream recallers. Increased activity in this brain region might facilitate attention orienting toward external stimuli and promote intrasleep wakefulness, thereby facilitating the encoding of dreams in memory.

The reason for dreaming is still a mystery for the researchers who study the difference between “high dream recallers,” who recall dreams regularly, and “low dream recallers,” who recall dreams rarely. In January 2013 (work published in the journal Cerebral Cortex), the team led by Perrine Ruby, Inserm researcher at the Lyon Neuroscience Research Center, made the following two observations: “high dream recallers” have twice as many time of wakefulness during sleep as “low dream recallers” and their brains are more reactive to auditory stimuli during sleep and wakefulness. This increased brain reactivity may promote awakenings during the night, and may thus facilitate memorisation of dreams during brief periods of wakefulness.

In this new study, the research team sought to identify which areas of the brain differentiate high and low dream recallers. They used Positron Emission Tomography (PET) to measure the spontaneous brain activity of 41 volunteers during wakefulness and sleep. The volunteers were classified into 2 groups: 21 “high dream recallers” who recalled dreams 5.2 mornings  per week in average, and 20 “low dream recallers,” who reported 2 dreams per month in average. High dream recallers, both while awake and while asleep, showed stronger spontaneous brain activity in the medial prefrontal cortex (mPFC) and in the temporo-parietal junction (TPJ), an area of the brain involved in attention orienting toward external stimuli.

The South African neuropsychologist Mark Solms had observed in earlier studies that lesions in these two brain areas led to a cessation of dream recall.  The originality of the French team’s results is to show brain activity differences between high and low dream recallers during sleep and also during wakefulness.

Surface Characteristics Influence Cellular Growth on Semiconductor Material

Read the full article Surface Characteristics Influence Cellular Growth on Semiconductor Material at NeuroscienceNews.com.

Changing the texture and surface characteristics of a semiconductor material at the nanoscale can influence the way that neural cells grow on the material.

The finding stems from a study performed by researchers at North Carolina State University, the University of North Carolina at Chapel Hill and Purdue University, and may have utility for developing future neural implants.

The research is in Acta Biomaterialia. (full access paywall)

Research: “Surface topography and chemistry shape cellular behavior on wide band-gap semiconductors” by Lauren E. Bain, Ramon Collazo, Shu-han Hsu, Nicole Pfiester Latham, Michael J. Manfra, and Albena Ivanisevic in Acta Biomaterialia. doi:10.1016/j.actbio.2014.02.038

06 February 2014

Tuning In

Imagine you’re at a party. All around you guests are chatting and music is playing. But you’re only interested in hearing the person next to you. Fortunately, the brain is equipped with mechanisms that help to tune out this background noise and allow us to focus on specific sounds. Yet very little is known about how this actually works. These traces show how a ferret’s hearing system – surprisingly similar to our own – responds to speech in an increasingly noisy environment (top to bottom). The coloured traces on the left represent the sound itself, while the other peaks are patterns of nerve activity in different parts of the brain that process sound. They reveal that the background noise gets ‘tuned out’ gradually as the signals get closer to the main part of the brain (furthest right), revealing more about how we cope with noisy situations.

Written by Kat Arney

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Making your brain social

In many people with autism and other neurodevelopmental disorders, different parts of the brain don’t talk to each other very well. Scientists have now identified, for the first time, a way in which this decreased functional connectivity can come about. In a study published online today in Nature Neuroscience, scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, and collaborators at the Istituto Italiano di Tecnologia (IIT), in Rovereto, and La Sapienza University in Rome, demonstrate that it can be caused by cells called microglia failing to trim connections between neurons.

“We show that a deficit in microglia during development can have widespread and long-lasting effects on brain wiring and behaviour,” says Cornelius Gross, who led the study. “It leads to weak brain connectivity, decreased social behaviour, and increased repetitive behaviour, all hallmarks of autism.”

The findings indicate that, by trimming surplus connections in the developing brain, microglia allow the remaining links to grow stronger, like high-speed fibre-optic cables carrying strong signals between brain regions. But if these cells fail to do their job at that crucial stage of development, those brain regions are left with a weaker communication network, which in turn has lifelong effects on behaviour.

Yang Zhan, a postdoctoral fellow in Gross’ lab at EMBL, analysed the strength of connections between different areas of brain in mice that were genetically engineered to have fewer microglia during development. Working with Alessandro Gozzi’s lab at IIT and Davide Ragozzino at La Sapienza University, the EMBL scientists combined this approach with high-resolution fMRI (functional Magnetic Resonance Imaging) scans of the mice’s brains, taking full advantage of a novel technique developed at IIT, which enables scientists to obtain detailed, three-dimensional maps of the brain’s functional connections. The team found that mice with fewer microglia had weaker connections between neurons, and less cross-talk between different brain regions. When Rosa Paolicelli, a PhD student in Gross’ lab, studied the mice’s behaviour, she discovered that mice with fewer microglia and decreased connectivity displayed behaviours commonly associated with autism spectrum disorders. These mice spent more time repeatedly grooming themselves, and avoided social interactions.

Your Brain Is Fine-Tuning Its Wiring Throughout Your Life

The white matter microstructure, the communication pathways of the brain, continues to develop/mature as one ages. Studies link age-related differences in white matter microstructure to specific cognitive abilities in childhood and adulthood.

Most prior studies, however, did not include individuals from the entire life span or evaluated a limited section of white matter tracts. This knowledge gap prompted a new study published this week in Biological Psychiatry.

Dr. Bart Peters, of the Zucker Hillside Hospital, and his colleagues investigated the relationship of age and neurocognitive performance to nine white matter tracts from childhood to late adulthood.

To accomplish this, they recruited 296 healthy volunteers who ranged from 8 to 68 years of age. The participants completed a comprehensive battery of tests designed to measure their cognitive functioning, including speed, attention, memory, and learning. They also underwent a non-invasive diffusion tensor imaging scan, a technology that allowed the researchers to create maps of the 9 major white matter tracts under investigation.

The combination of this data allowed them to identify the neurocognitive correlates of each white matter tract in relation to its unique aging pattern.

They found that, from childhood into early adulthood, differences in fractional anisotropy – a measure of connectivity – of the cingulum were associated with executive functioning, whereas fractional anisotropy of the inferior fronto-occipital fasciculus was associated with visual learning and global cognitive performance via speed of processing.

"Our study identified key brain circuits that develop during adolescence and young adulthood that are associated with the growth of learning, memory and planning abilities. These findings suggest that young people may not have full capacity of these functions until these connections have completed their normal trajectory of maturation beyond adolescence," explained Peters.

"Our brain is changing throughout our lives. These changes underlie the capacities that emerge and are refined through adulthood," commented Dr. John Krystal, Editor of Biological Psychiatry. “There are clues that the steps that we take to preserve our medical health and stimulate our minds also serve to further refine and maintain these connections. For good reasons, attending to brain health is increasingly a focus of healthy aging.”

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