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Category: neuroscience – Page 6

Brain network active at birth linked to social behavior later in life

Paying less attention to faces is one of the key markers of autism spectrum disorder. But while researchers have begun to uncover the brain network that supports processing of social stimuli such as faces, gaze, and speech, little is known about how and when it begins to develop.

In a new study, Yale researchers have now found that this network is already quite active at birth or shortly thereafter, a finding that provides insight into the that underlie social behaviors later in life.

The study was published in Biological Psychiatry Global Open Science.

High-density brain probe reveals distinctive electrical patterns of cell types during behavior

Trying to document how single brain cells participate in networks that govern behavior is a daunting task. Brain probes called Neuropixels, which feature high-density silicon arrays, have enabled scientists to collect electrophysiological data of this nature from a variety of animals. These include fish, reptiles, rodents and primates, as well as humans.

Neuropixels, which come in several versions, record from hundreds to thousands of neurons simultaneously. Neurons are nerve cells that receive, process and transmit information.

While the data collected has led to insights on the neural basis of perception and decision-making, those probes cannot sample fine-scale brain structures. They also are limited in resolving (separately distinguishing) the electrical fields around individual brain cells.

Minimally invasive implantation of scalable high-density cortical microelectrode arrays for multimodal neural decoding and stimulation

To elicit VEPs, the eyelid corresponding to the stimulated retina was retracted temporarily while periodic 50 ms flashes were generated at 1 Hz from an array of white light-emitting diodes (LEDs). Neural response waveforms were temporally aligned to the stimulus onset. VEPs were calculated as the time-aligned averaged signals over 150 trials.

Electrical stimulation at the cortical surface was applied at one of the 200 µm electrodes, controlled by the Intan Technologies RHS controller and RHX software. Charge-balanced, biphasic, cathodic-first, 200 µs pulses of 100 µA peak current were delivered at 0.25 Hz. The evoked potentials were recorded over a series of trials. During analysis, for each trial and electrode, the Hjorth ‘activity’ of each trial was computed as the variance of the signal from 200 ms to 2,000 ms post-stimulation, and the average activity was taken over 40 trials.

A 1,024-channel array was placed over the sensorimotor cortex on each hemisphere following carefully sized bilateral craniectomies. Two Intan 1,024-channel RHD controllers were used to record from both arrays simultaneously.

Early intake of the antidepressant fluoxetine alters brain development in rats, study finds

Past neuroscience studies have consistently showed the profound effects of early life experiences on the brain’s wiring, particularly on the formation of the junctions that enable communication between neurons (i.e., synapses). The influence of early life experiences was found to be particularly pronounced during so-called sensitive periods (SPs), windows of time during which the brain’s plasticity (i.e., its ability to form or reorganize neural connections) is heightened.

Experimental evidence suggests that these periods of heightened brain plasticity are regulated by specialized neurons that release the inhibitory neurotransmitter GABA (gamma-aminobutyric acid). So-called parvalbumin-positive (PV+) interneurons have been found to play a central role in the unfolding of SPs, as their gradual enclosure into protective structures was linked to the conclusion of these periods.

Researchers at University of Milan and University of Helsinki recently carried out a study exploring the effects of early exposure to the widely prescribed antidepressant fluoxetine (FLX) on the regulation of SPs in rats. Their findings, published in Molecular Psychiatry, suggest that exposure to fluoxetine during gestation, pregnancy or breastfeeding could influence the and behavior of rat pups later in life.

Mapping RNA-protein ‘chats’ could uncover new treatments for cancer and brain disease

Bioengineers at the University of California San Diego have developed a powerful new technology that can map the entire network of RNA-protein interactions inside human cells—an achievement that could offer new strategies for treating diseases ranging from cancer to Alzheimer’s.

RNA-protein interactions regulate many essential processes in cells, from turning genes on and off to responding to stress. But until now, scientists could only capture small subsets of these interactions, leaving much of the cellular “conversation” hidden.

“This technology is like a wiring map of the cell’s conversations,” said Sheng Zhong, professor in the Shu Chien-Gene Lay Department of Bioengineering at the UC San Diego Jacobs School of Engineering, who led the study published in Nature Biotechnology.

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