Dendritic spines were quantified on terminal dendrites of medium spiny neurons (MSNs) in the nucleus accumbens core sub region of selectively-bred high- and low-responder rats following repeated cocaine treatment.
Drugs affect different people in different ways. Take cocaine for example. Not only does the drug have a stronger impact on the behavior of individuals with a particular genetic makeup, it also initiates more profound changes in their brains.
Researchers at the University of Michigan are studying brain plasticity in cocaine-treated rats after a period of abstinence. They’re studying how abstinence from the drug affects different types of rats – those with an “addictive personality” versus their less addicted cousins.
To determine the effects of cocaine abstinence on these two groups, the researchers studied specially bred lines of rats. One group was highly sensitive to cocaine, while the other group didn’t respond as strongly to the drug. Known as “high-responder rats” (bHR) and “low-responder rats” (bLR), the two groups reacted differently to the drug treatment, with bHR rats acting more agitated during cocaine treatment, and their brains displaying more pronounced plastic changes after a period of abstinence.
Continue reading “Researchers at the University of Michigan Analyze Spine Density in Addiction-Prone Rats with Neurolucida” »
A drawing of an L2 pyramidal neuron in the auditory cortex of a mouse brain rendered with Neurolucida. Biocytin-labeled neurons were visualized using the avidin:biotinylated horseradish peroxidase complex. Neurons were completely reconstructed in 3D with Neurolucida using an up-right Zeiss microscope with an oil immersion x100/1.4 numerical aperture objective.
Sensory stimuli are all around us. Street traffic zooms by. A neighbor waves “hello.” A co-worker taps away at his keyboard. Each sight, sound, and motion ignite action within our brains. But even without all these stimuli, the brain is always active.
Known as “spontaneous activity,” the activity happening inside the brain in the absence of direct stimuli follows a pattern of up and down states that scientists say is essential for processing sensory signals. Spontaneous activity may also be involved in memory.
Scientists from the Brain Research Center at the Third Military Medical University (Chongqing, China), the Center for Integrated Protein Science, SyNergy Cluster, and the Institute of Neuroscience at the Technical University of Munich (Germany) are working on figuring out how the activity occurring in the brain during “spontaneous activity” compares with what goes on during periods of sensory stimuli. Specifically, they’re looking at calcium signaling – an important element in synaptic activity during periods of both sensory stimuli and spontaneous activity, that helps neurons transmit information to other parts of the brain and body.
Continue reading “Scientists Use Neurolucida in Study of Calcium Signaling During Spontaneous Brain Activity” »
Life’s little pleasures often elude those suffering from depression, including rats, who show little interest in sugar water after experiencing stress. This behavior leads scientists to speculate that the illness might be characterized by a defect in the brain’s neural reward circuit.
Recent research focuses on a key element of this circuit – the nucleus accumbens (NAc), part of the brain region known as the ventral striatum, which is thought to regulate motivation and reward processing. In a new study of stress-induced depression in rats, researchers at the University of Minho in Braga, Portugal saw morphological changes in the dendrites of medium spiny neurons in the NAc, alongside disturbances in gene expression in this region. They also saw these changes reversed after administering antidepressants.
By using Neurolucida Explorer to analyze 3D reconstructions of medium spiny neurons generated with Neurolucida, the researchers observed longer than normal dendrites and greater spine density in the depressed rats. According to the paper, these findings contrast with studies of the hippocampus and prefrontal cortex, where chronic stress leads to shorter dendrites.
Continue reading “Scientists in Portugal Use Neurolucida Explorer to Analyze Neuroplasticity in Depression” »
Scientists hypothesize that seizures occur because brain cells fire in places they’re not supposed to. Dentate granule cells (DGCs), a type of neuron born throughout adulthood, sometimes migrate into a different region of the dentate gyrus, a part of the hippocampus. These abnormal newborn cells sprout axons called “mossy fibers” that form connections with neighboring DGCs in the inner molecular layer, causing synaptic changes that wouldn’t normally occur in healthy brains.
Much research has been done on this phenomenon, but neuroscientists still struggle to understand what exactly its relationship is with epilepsy.
A new study by researchers at the Cincinnati Children’s Hospital Medical Center validates hypotheses about the role of abnormal DGCs in epilepsy. In their study of a transgenic mouse model of temporal lobe epilepsy (TLE), the scientists observed a relationship between the presence of deviant DGCs and seizure frequency.
Continue reading “Cincinnati Scientists Use Neurolucida in Epilepsy Study” »
The placenta delivers nutrients from a mother’s blood to a developing fetus. It also produces hormones that help the baby grow during its forty or so weeks in utero. But the placenta’s powerhouse abilities don’t end there. The organ provides a wealth of information about the infant’s future health, allowing doctors to make predictions about whether or not the child will develop autism or, later in life, heart disease.
A recent study conducted at the Ludwig-Maximilians-University in Munich, Germany offers new insights into the relationship between the placenta and postnatal health.
Continue reading “Munich Scientists Analyze Placenta Morphometry with Stereo Investigator” »
If one area isn’t working, another part can step in. Plasticity is one of the brain’s most beautiful attributes. Recent research has documented the organ’s ability to compensate in the face of damage, and now a new study identifies a key region for compensation when the damage occurs in the hippocampus.
The region is the medial prefrontal cortex (mPFC). It’s an integral part of the hippocampal-prefrontal-amygdala circuit involved with memory formation – specifically with contextual fear memories. In their study, published last month in Proceedings of the National Academy of Sciences, researchers at the University of California, Los Angeles identify a microcircuit in the mPFC that can encode memories when the dorsal hippocampus is damaged.
Continue reading “UCLA Scientists Count Cells with Stereo Investigator in Study Identifying Compensating Regions in Brain Damage” »
Obstetricians and midwifes have long hailed the benefits of folic acid during pregnancy. Now new research offers evidence that choline is another important nutrient for the developing fetus. Found in foods like eggs and cauliflower, choline is known to aid healthy liver function. But in the past few years, studies have shown that the nutrient also plays a role in brain development. One recent study by Velasquez and colleagues claims that increased choline during pregnancy may offer a possible therapy for Down syndrome.
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According to scientists at the Hotchkiss Brain Institute in Calgary, Canada, there is evidence for increased neurogenesis in adult mice reared by two parents. Their study also describes other interesting findings, such as the fact that increased neurogenesis persists in the next generation, or that the effects of differences in rearing affect males and females differently.
Continue reading “Study Links Increased Touch to Enhanced Neurogenesis in Adult Mice; Stereo Investigator Used for Quantification” »
Researchers at the Waisman Center (University of Wisconsin-Madison) just took a big step in their quest to develop regenerative medicines for treating Parkinson’s, Alzheimer’s, and other neurodegenerative diseases. They used human embryonic stem cells to restore memory and learning in disabled mice.
The study, published last month in Nature Biotechnology, “is the first to show that human stem cells can successfully implant themselves in the brain and then heal neurological deficits,” senior author Su-Chun Zhang told the University of Wisconsin-Madison news department.
Continue reading “Wisconsin Scientists Use Stereo Investigator to Quantify Neurons Formed From Stem Cells” »
A baby makes eye contact with a passing stranger and his social development begins. Unable to resist the infant’s smile, the stranger smiles back and the baby starts to learn about human emotion through facial expression. But some babies, especially those on the autism spectrum, don’t make eye contact. What compels these tiny humans to avoid the eyes of people around them? Scientists specializing in developmental disabilities say the flocculus, a brain region in the cerebellum integral to eye movement control, may play a role in atypical gaze.
In their study of the postmortem brains of 12 autistic subjects and 10 control subjects, the research team, led by Dr. Jerzy Wegiel of the New York State Institute for Basic Research in Developmental Disabilities, in Staten Island, saw abnormally large flocculi in eight autistic subjects. According to the study, published last month in Brain Research, seven of these subjects exhibited “poor, very poor, or no eye contact” during the course of their lives.
Continue reading “Researchers Use Stereo Investigator to Identify Abnormalities in Autistic Brains” »