Investigators at the Stanford University School of Medicine have shown that removing a matched set of molecules that typically help to regulate the brain’s capacity for forming and eliminating connections between nerve cells could substantially aid recovery from stroke even days after the event. In experiments with mice, the scientists demonstrated that when these molecules are not present, the mice’s ability to recover from induced strokes improved significantly.
cardiology
Friendly to a fault, yet tense: Personality traits traced in brain
A personality profile marked by overly gregarious yet anxious behavior is rooted in abnormal development of a circuit hub buried deep in the front center of the brain, say scientists at the National Institutes of Health. They used three different types of brain imaging to pinpoint the suspect brain area in people with Williams syndrome, a rare genetic disorder characterized by these behaviors. Matching the scans to scores on a personality rating scale revealed that the more an individual with Williams syndrome showed these personality/temperament traits, the more abnormalities there were in the brain structure, called the insula.
Discovery of hair-cell roots suggests the brain modulates sound sensitivity
The hair cells of the inner ear have a previously unknown “root” extension that may allow them to communicate with nerve cells and the brain to regulate sensitivity to sound vibrations and head position, researchers at the University of Illinois at Chicago College of Medicine have discovered. Their finding is reported online in advance of print in the Proceedings of the National Academy of Sciences.
Do you hear what I hear?
(Medical Xpress) — In both animals and humans, vocal signals used for communication contain a wide array of different sounds that are determined by the vibrational frequencies of vocal cords. For example, the pitch of someone’s voice, and how it changes as they are speaking, depends on a complex series of varying frequencies. Knowing how the brain sorts out these different frequencieswhich are called frequency-modulated (FM) sweepsis believed to be essential to understanding many hearing-related behaviors, like speech. Now, a pair of biologists at the California Institute of Technology (Caltech) has identified how and where the brain processes this type of sound signal.
Your brain on dye: Imaging neuronal voltage with fluorescent sensors and molecular wires
(Medical Xpress) — Optically monitoring the brain’s neuronal activity can be accomplished in several ways, including electrochromic dyes, hydrophobic anions, calcium imaging, or voltage-sensitive ion channels. Fluorescence imaging is an attractive method due to its ability to map the electrical activity and communication of multiple spatially resolved neurons. While this complements traditional electrophysiological measurements, historically fluorescent voltage imaging has been limited by the difficulty of developing sensors that give both large and fast responses to voltage changes. Recently, however, scientists in the Department of Pharmacology and other areas in the University of California at San Diego’s Howard Hughes Medical Institute have designed, synthesized, and implemented fluorescent sensors in the form of photo-induced electron transfer (PeT)-based molecular wire probes for voltage imaging in neurons. Moreover, they have used these so-called VoltageFluor sensors to perform single-trial detection of synaptic and action potentials in cultured hippocampal neurons and intact leech ganglia.