auditory pathway

Scientists Outline How Brain Separates Relevant & Irrelevant Information

Imagine yourself sitting in a noisy café trying to read. To focus on the book at hand, you need to ignore the surrounding chatter and clattering of cups, with your brain filtering out the irrelevant stimuli coming through your ears and “gating” in the relevant ones in your vision—words on a page.

In a new paper in the journal Nature Communications, New York University researchers offer a new theory, based on a computational model, on how the brain separates relevant from irrelevant information in these and other circumstances.

“It is critical to our everyday life that our brain processes the most important information out of everything presented to us,” explains Xiao-Jing Wang, Global Professor of Neural Science at NYU and NYU Shanghai and the paper’s senior author. “Within an extremely complicated neural circuit in the brain, there must be a gating mechanism to route relevant information to the right place at the right time.”

The analysis focuses on inhibitory neurons—the brain’s traffic cops that help ensure proper neurological responses to incoming stimuli by suppressing other neurons and working to balance excitatory neurons, which aim to stimulate neuronal activity.

“Our model uses a fundamental element of the brain circuit, involving multiple types of inhibitory neurons, to achieve this goal,” Wang adds. “Our computational model shows that inhibitory neurons can enable a neural circuit to gate in specific pathways of information while filtering out the rest.”

In their analysis, led by Guangyu Robert Yang, a doctoral candidate in Wang’s lab, the researchers devised a model that maps out a more complicated role for inhibitory neurons than had previously been suggested.

Of particular interest to the team was a specific subtype of inhibitory neurons that targets the excitatory neurons’ dendrites—components of a neuron where inputs from other neurons are located. These dendrite-targeting inhibitory neurons are labeled by a biological marker called somatostatin and can be studied selectively by experimentalists. The researchers proposed that they not only control the overall inputs to a neuron, but also the inputs from individual pathways—for example, the visual or auditory pathways converging onto a neuron.

“This was thought to be difficult because the connections from inhibitory neurons to excitatory neurons appeared dense and unstructured,” observes Yang. “Thus a surprising finding from our study is that the precision required for pathway-specific gating can be realized by inhibitory neurons.”

The study’s authors used computational models to show that even with the seemingly random connections, these dendrite-targeting neurons can gate individual pathways by aligning with excitatory inputs through different pathways. They showed that this alignment can be realized through synaptic plasticity—a brain mechanism for learning through experience.

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USUALLY JJBA SCIENCE LOGIC FAILS DON’T BOTHER ME BUT THIS ONE MADE ME LAUGH A LOT oMFG

Kakyoin did not need to damage any blood vessel because if their stands can enter nerves as a well, merely entering the auditory nerve would have made the Lovers fight so much shorter LOL

EDIT: Even if you don’t know the auditory nervous pathway it literally is the most straightforward route to the brainstem idk why Kakyoin took the scenic route GG

The language of senses

Sight, touch and hearing are our windows to the world: these sensory channels send a constant flow of information to the brain, which acts to sort out and integrate these signals, allowing us to perceive the world and interact with our environment. But how do these sensory pathways emerge during development? Do they share a common structure, or, on the contrary, do they emerge independently, each with its specific features? By identifying gene expression signatures common to sight, touch and hearing, neuroscientists at the University of Geneva (UNIGE), Switzerland, discovered a sensory “lingua franca” which facilitates the brain’s interpretation and integration of sensory input. These results, to be read in Nature, pave the way towards a better understanding of perception and communication disorders.

The ability to detect and sort various kinds of stimuli is essential to interact with surrounding objects and people, and to communicate correctly. Indeed, social interaction deficits in people living with autism appear to be partly due difficulties in detecting and interpreting sensory signals. But how does the brain interpret and integrate the stimuli sent by our five senses? It is this very question which Denis Jabaudon, Professor at UNIGE Faculty of Medicine and his team have addressed. ‘We studied the genetic structure of tactile, visual and auditory pathways in mice,’ explains Laura Frangeul, the study first author. ‘By observing neuronal gene expression in these distinct pathways during development, we detected common patterns, as if an underlying genetic language was bringing them together.’

A common language with tailored modulations

The Geneva neuroscientists’ results thus reveal that during development, the various sensory pathways initially share a common gene expression structure, which then adapts to the activity of the organ attached to each sense. ‘This process only takes a few days in mice but could take up to several months in human beings, whose development is much longer and very sensitive to the environment,’ underlines Denis Jabaudon.

This genetic ‘lingua franca’ therefore allows the various sensory pathways to be built according to a similar architecture regardless of their very different functions. It is this shared language that allows the brain to accurately interpret stimuli coming from different sources, and to compose a coherent representation of their combined meaning.

Constant and necessary interactions

Sharing the same building plan also explains how various pathways can mutually balance out, for example when touch or hearing become highly over-developed in people born blind. This discovery also explains why sensory interferences, including synesthesias and hallucinations, can occur in people suffering from neurodevelopmental disorders such as autism or schizophrenia.

Denis Jabaudon concludes: ‘Our results allow us to better understand how the brain circuits which build our representation of the world assemble during development. We are now able to examine how these findings could be put to use to repair them when they fail.’