Posts tagged hippocampus
Articles and news from the latest research reports.
Tuning a piano also tunes the brain, say researchers who have seen structural changes within the brains of professional piano tuners.
Researchers at University College London and Newcastle University found listening to two notes played simultaneously makes the brain adapt. Brain scans revealed highly specific changes in the hippocampus, which governs memory and navigation. These correlated with the number of years tuners had been doing this job.
The Wellcome Trust researchers used magnetic resonance imaging to compare the brains of 19 professional piano tuners - who play two notes simultaneously to make them pitch-perfect - and 19 other people. What they saw was highly specific changes in both the grey matter - the nerve cells where information processing takes place - and the white matter - the nerve connections - within the brains of the piano tuners.
Investigator Sundeep Teki said: “We already know that musical training can correlate with structural changes, but our group of professionals offered a rare opportunity to examine the ability of the brain to adapt over time to a very specialised form of listening.”
Other researchers have noted similar hippocampal changes in taxi drivers as they build up detailed information needed to find their way around London’s labyrinth of streets. Prof Tim Griffiths, who led the latest study, published in Neuroscience, said: “There has been little work on the role of the hippocampus in auditory analysis. “Our study is consistent with a form of navigation in pitch space as opposed to the more accepted role in spatial navigation.”
Unlocking a major secret of the brain
McGill researchers uncover crucial link between hippocampus and prefrontal cortex
A clue to understanding certain cognitive and mental disorders may involve two parts of the brain which were previously thought to have independent functions, according to a McGill University team of researchers led by Prof. Yogita Chudasama, of the Laboratory of Brain and Behavior, Department of Psychology. The McGill team discovered a critical interaction between two prominent brain areas: the hippocampus, a well-known memory structure made famous by Dr. Brenda Milner’s patient H.M., and the prefrontal cortex, which is involved in decision-making and inhibiting inappropriate behaviours.
“We had always thought that the hippocampus and the prefrontal cortex functioned independently,” says Prof. Chudasama. “Our latest study provides the first indication that that is not the case.”
The team’s finding, just published in the Journal of Neuroscience, reveals a critical interaction between these two brain areas and the control of behavior, and may advance the treatment of some cognitive and mental disorders including schizophrenia, and depression. The interaction between the hippocampus and the prefrontal cortex shows that brain circuits function not just as specific parts of the brain, but are linked together and work as a system.
“Although the prefrontal cortex has long been known to be the driving force that steers our behavior, pushing us to make good decisions and withhold improper actions, it turns out that it can’t do this unless it interacts with the hippocampus,” added Prof. Chudasama. “We found that when we prevented these two structures from communicating with each other, like humans with compulsive disorders, rats persisted with behaviours that were not good for them; they didn’t correct their errant behaviours and could not control their natural urges.
The ability to control impulsive urges or inhibit our actions allows us to interact normally in personal or social situations, and this type of behaviour depends on the normal interaction of the hippocampus and the prefrontal cortex. This result provides a means for understanding the neural basis for social and cognitive deficits in disorders of brain and behaviour, such as those with frontotemporal dementia”, concludes Prof. Chudasama.
This image depicts stem cells (green) and neuronal nuclei (red) in the hippocampus, a brain structure crucial for cognitive function.
(Credit: Grigori Enikolopov and Ann-Shyn Chiang)
The World’s Most Famous Brain
In the summer of 1953, Henry Gustav Molaison (1926-2008) underwent brain surgery to contain epileptic seizures that had become critically debilitating. The intervention brought some relief from convulsions, but these positive results were overshadowed by an astonishing and indelible side effect. Soon after the operation, it became apparent that he could no longer recognize hospital staff, he did not remember the way home, he did not remember newspaper articles he had just read, nor the crossword puzzles he had solved; otherwise, he was completely normal. Since the time of the surgery, more than five decades of scrupulous neuropsychological research examined the nature of patient H.M.’s amnesia which proved to be both persistent and remarkably selective.
The goal of our project is to provide a window into the brain of the man who helped establish the scientific study of memory and unfailingly forgot the enormously generous contribution he made to medical research.
Synapses are modified through learning. Up until now, scientists believed that a particular form of synaptic plasticity in the brain’s hippocampus was responsible for learning spatial relations. This was based on a receptor type for the neurotransmitter glutamate: the NMDA receptor. Researchers at the Max Planck Institute for Medical Research in Heidelberg and Oxford University have now observed that mice develop a spatial memory, even when the NMDA receptor-transmitted plasticity is switched off in parts of their hippocampus. However, if these mice have to resolve a conflict while getting their bearings, they are not successful in resolving it; the hippocampal NMDA receptors are clearly needed to detect or resolve the conflict. This has led the researchers involved in this experiment to refute a central tenet of neuroscience regarding the function of hippocampal NMDA receptor-transmitted plasticity in spatial learning.
Cajal’s histological preparations and drawings showing some contributions to glial cells. (A) Fibrous astrocyte in the white matter of adult brain (formalin-uranium nitrate and gold-sublimated chloride); (B) Protoplasmic astrocyte in an adult brain (silver carbonate (del Rio) and formalin-uranium nitrate); (C) Twin astrocytes in the human hippocampus (formalin-uranium nitrate); (D) Fibrous astrocytes from the white substance of adult brain (Golgi methods); (E) Olygodendrocytes (ammoniacal silver oxide and Nissl); (F) Microglia cells (ammoniacal silver oxide, reduced silver nitrate and silver carbonate (del Rio) methods).