Depression specifically impairs the ability to learn how to actively avoid unpleasant events, though it does not affect avoidance behavior once learned.
Category: neuroscience – Page 4
Neuroscientists show for first time that precise timing of nerve signals determines how brain processes information
It has long been known that the brain preferentially processes information that we focus our attention on—a classic example is the so-called cocktail party effect.
“In an environment full of voices, music, and background noise, the brain manages to concentrate on a single voice. The other noises are not objectively quieter, but are perceived less strongly at that moment,” explains brain researcher Dr. Eric Drebitz from the University of Bremen.
The brain focuses its processing on the information that is currently relevant—in this case, the voice of the conversation partner—while other signals are received but not forwarded and processed to the same extent.
Comprehensive molecular atlas of human hippocampus maps cell subtypes and organization
The hippocampus is an important brain region known to support various cognitive (i.e., mental) processes, including the encoding and retrieval of memories, learning, decision-making and the regulation of emotional states. While extensive research has tried to delineate the structure, functions and organization of the hippocampus, the cell types contained within it and their connections with other neurons have not yet been fully mapped out.
Over the past decades, available methods for studying cell subpopulations, the expressions of genes within them and their connectivity have become increasingly advanced. One of these methods, known as spatially resolved transcriptomics, works by measuring the expression of genes in cells while preserving their arrangement in space. Another called single-nucleus RNA-sequencing (snRNA-seq), allows scientists to examine RNA molecules inside individual cell nuclei to detect differences between them and categorize cells into different subtypes.
Researchers at Johns Hopkins Bloomberg School of Public Health, the Lieber Institute for Brain Development and Johns Hopkins School of Medicine recently used a combination of these two experimental techniques to examine cells in tissue extracted from the hippocampus. Their paper, published in Nature Neuroscience, introduces a comprehensive molecular atlas of the hippocampus that maps different cell subtypes and their organization.
Depression linked to presence of immune cells in the brain’s protective layer
Immune cells released from bone marrow in the skull in response to chronic stress and adversity could play a key role in symptoms of depression and anxiety, say researchers.
The discovery—found in a study in mice—sheds light on the role that inflammation can play in mood disorders and could help in the search for new treatments, in particular for those individuals for whom current treatments are ineffective.
Around 1 billion people will be diagnosed with a mood disorder such as depression or anxiety at some point in their life. While there may be many underlying causes, chronic inflammation —when the body’s immune system stays active for a long time, even when there is no infection or injury to fight—has been linked to depression. This suggests that the immune system may play an important role in the development of mood disorders.
Exploring criminal behavior in patients with dementia
A suspected perpetrator who can barely remember his name, several traffic violations committed by a woman in her mid-fifties who is completely unreasonable and doesn’t understand her behavior—should such cases be brought before a court? And how does the state deal with people who commit acts of violence without meaning to?
Those questions come to mind if one hears those examples from everyday clinical praxis with persons suffering from dementia. Neurodegenerative diseases might affect several functions of the brain, ranging from memory in Alzheimer’s disease to behavior, such as in behavioral variant frontotemporal dementia, and to sensorimotor function in Parkinson’s disease.
One of the most interesting consequences of these alterations is the fact that persons affected by these diseases might develop criminal risk behavior like harassment, traffic violation, theft or even behavior causing harm to other people or animals, even as the first disease sign.
How pediatric brain tumors grow: Blocking a chemical messenger could offer new route to treatment
The most common type of brain tumor in children, pilocytic astrocytoma (PA), accounts for about 15% of all pediatric brain tumors. Although this type of tumor is usually not life-threatening, the unchecked growth of tumor cells can disrupt normal brain development and function.
Current treatments focus mainly on removing the tumor cells, but recent studies have shown that non-cancerous cells, such as nerve cells, also play a role in brain tumor formation and growth, suggesting novel approaches to treating these cancers.
Scientists have long known that a nerve cell signaling chemical called glutamate can increase the growth of cancers throughout the body, but despite years of investigation, they haven’t figured out exactly how this happens, or how to stop it.
