synapses

The large, multisite California-based study examined associations between specific classes of pesticides, including organophosphates, pyrethroids and carbamates, applied during the study participants’ pregnancies and later diagnoses of autism and developmental delay in their offspring. “This study validates the results of earlier research that has reported associations between having a child with autism and prenatal exposure to agricultural chemicals in California,” said lead study author Janie F. Shelton, a UC Davis graduate student who now consults with the United Nations. “While we still must investigate whether certain sub-groups are more vulnerable to exposures to these compounds than others, the message is very clear: Women who are pregnant should take special care to avoid contact with agricultural chemicals whenever possible.”

Three key proteins – KCC2, Neto2 and GluK2 – required for inhibitory and excitatory synaptic communication. KCC2 is required for inhibitory impulses, GluK2 is a receptor for the main excitatory transmitter glutamate, and Neto2 is an auxiliary protein that interacts with both KCC2 and GluK2. The discovery of the complex of three proteins is pathbreaking as it was previously believed that KCC2 and GluK2 were in separate compartments of the cell and acted independently of each other.

Researchers at NYU Langone Medical Center show for the first time that sleep after learning encourages the growth of dendritic spines, the tiny protrusions from brain cells that connect to other brain cells and facilitate the passage of information across synapses, the junctions at which brain cells meet. Moreover, the activity of brain cells during deep sleep, or slow-wave sleep, after learning is critical for such growth.

Researchers at Albert Einstein College of Medicine of Yeshiva University used advanced imaging techniques to provide a window into how the brain makes memories. These insights into the molecular basis of memory were made possible by a technological tour de force never before achieved in animals: a mouse model developed at Einstein in which molecules crucial to making memories were given fluorescent “tags” so they could be observed traveling in real time in living brain cells.

Learning and memory are made possible by the incessant reorganization of nerve connections in the brain. Both processes are based on targeted modifications of the functional interfaces between nerve cells – the so-called synapses – which alter their form, molecular composition and functional properties. In effect, connections between cells that are frequently co-activated together are progressively altered so that they respond to subsequent signals more rapidly and more strongly. This way, information can be encoded in patterns of synaptic activity and promptly recalled when needed. The converse is also true: learned behaviors can be lost by disuse, because inactive synapses are themselves less likely to transmit an incoming impulse, leading to the decay of such connections.

The gene is a likely player in the aging process in the brain, the researchers say. Additionally, in demonstrating the usefulness of the new method, the discovery paves the way for faster progress toward identifying genes involved in complex mental illnesses such as autism and schizophrenia — as well as potential drugs for such conditions.

But in the past few years, the glia cells – particularly the tiny microglia that make up about one-tenth of the brain cells – have been shown to play critical roles both in the healthy and in the diseased brain.

New research by UC San Francisco scientists shows that one of the brain’s fundamental self-protection mechanisms depends on coordinated, finely calibrated teamwork among neurons and non-neural cells knows as glial cells, which until fairly recently were thought to be mere support cells for neurons.

Due to the simultaneous strengthening of all of the synapses of the affected neurons, major reductions in the neuronal activity can be normalised again with surprising speed. The relatively stable activity level thereby achieved is an essential prerequisite for maintaining a healthy, adaptable brain.