Dendritic Spine Loss Reported in Schizophrenia and Bipolar Disorder

Golgi-stained human brain tissue from the dorsolateral prefrontal cortex.

Golgi-stained human brain tissue from the dorsolateral prefrontal cortex.

Schizophrenia and bipolar disorder are very different mental illnesses, but researchers are discovering evidence that the two disorders have some common pathologies. According to a recent study, a shared characteristic appears to be dendritic spine loss.

The researchers used Neurolucida to study pyramidal cells in human brain tissue from individuals with schizophrenia (n=14), individuals with bipolar disorder (n=9) and unaffected control participants (n=19). The pyramidal cells were located in the dorsolateral prefrontal cortex – a region that plays a key role in working memory. Bipolar patients showed significantly reduced spine density (10.5 percent) compared to control. Schizophrenic patients also showed lower spine density (6.5 percent), but this number just missed significance when compared to control patients. Individuals with both illnesses showed a lower number of spines per dendrite, as well as reduced dendritic length compared to controls.

To obtain these results, researchers analyzed 15 Golgi-stained pyramidal cells in each tissue sample. They used Neurolucida to reconstruct the longest dendrite on the pyramidal cells and to mark spines. After the researchers finished reconstructing the cells, Neurolucida provided them with important data about the dendrites and spines.

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Researchers at the University of Michigan Analyze Spine Density in Addiction-Prone Rats with Neurolucida

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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.

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