Physicists negate century-old assumption regarding neurons and brain activity

December 21, 2017, Bar-Ilan University
The old scheme for a neuron functioning as an excitable unit (left), and the new one with left/right/down sensitivities (right) Credit: Prof. Ido Kanter

Neurons are the basic computational building blocks that compose our brain. Their number is approximately one Tera (trillion), similar to Tera-bits in midsize hard discs. According to the neuronal computational scheme, which has been used for over a century, each neuron functions as a centralized excitable element. The neuron accumulates its incoming electrical signals from connecting neurons through several terminals, and generates a short electrical pulse, known as a spike, when its threshold is reached.

Using new types of experiments on neuronal cultures, a group of scientists, led by Prof. Ido Kanter, of the Department of Physics at Bar-Ilan University, has demonstrated that this century-old assumption regarding brain activity is mistaken.

In an article published today in the journal Scientific Reports, the researchers go against conventional wisdom to show that each neuron functions as a collection of excitable elements, where each excitable element is sensitive to the directionality of the origin of the input signal. Two weak inputs from different directions (e.g., "left" and "right") will not sum up to generate a spike, while a strong input from "left" will generate a different spike waveform than that from the "right".

"We reached this conclusion using a new experimental setup, but in principle these results could have been discovered using technology that has existed since the 1980s. The belief that has been rooted in the scientific world for 100 years resulted in this delay of several decades," said Prof. Kanter and his team of researchers, including Shira Sardi, Roni Vardi, Anton Sheinin, and Amir Goldental.

The new results call for a re-examination of neuronal functionalities beyond the traditional framework and, in particular, for an examination into the origin of degenerative diseases. Neurons which are incapable of differentiating between "left" and "right"—similar to distortions in the entire human body—might be a starting point for discovering the origin of these diseases.

The new realization for the computational scheme of a neuron calls into question the spike sorting technique which is at the center of activity of hundreds of laboratories and thousands of scientific studies in neuroscience. This method was mainly invented to overcome the technological barrier to measure the activity from many simultaneously, using the assumption that each neuron tends to fire spikes of a particular waveform which serves as its own electrical signature. However, this assumption, which resulted from enormous scientific efforts and resources, is now questioned by the work of Kanter's lab.

Explore further: Neuron types in brain are defined by gene activity shaping their communication patterns

More information: Shira Sardi et al, New Types of Experiments Reveal that a Neuron Functions as Multiple Independent Threshold Units, Scientific Reports (2017). DOI: 10.1038/s41598-017-18363-1

Related Stories

Neuron types in brain are defined by gene activity shaping their communication patterns

September 21, 2017
In a major step forward in research, scientists at Cold Spring Harbor Laboratory (CSHL) today publish in Cell a discovery about the molecular-genetic basis of neuronal cell types. Neurons are the basic building blocks that ...

Brain is 10 times more active than previously measured, researchers find

March 9, 2017
A new UCLA study could change scientists' understanding of how the brain works—and could lead to new approaches for treating neurological disorders and for developing computers that "think" more like humans.

Optogenetics captures neuronal transmission in live mammalian brain

December 24, 2014
Swiss scientists have used a cutting-edge method to stimulate neurons with light. They have successfully recorded synaptic transmission between neurons in a live animal for the first time.

Static synapses on a moving structure: Mind the gap!

July 22, 2015
In biology, stability is important. From body temperature to blood pressure and sugar levels, our body ensures that these remain within reasonable limits and do not reach potentially damaging extremes. Neurons in the brain ...

Researchers shed light on how our eyes process visual cues

June 7, 2017
The mystery of how human eyes compute the direction of moving light has been made clearer by scientists at The University of Queensland.

Recommended for you

Sensitive babies become altruistic toddlers

September 25, 2018
Our responsiveness to seeing others in distress accounts for variability in helping behavior from early in development, according to a study published September 25 in the open-access journal PLOS Biology by Tobias Grossmann ...

Immune cell pruning of dopamine receptors may modulate behavioral changes in adolescence

September 25, 2018
A study by MassGeneral Hospital for Children (MGHfC) researchers finds that the immune cells of the brain called microglia play a crucial role in brain development during adolescence, but that role is different in males and ...

Scientists reverse a sensory impairment in mice with autism

September 25, 2018
Using a genetic technique that allows certain neurons in the brain to be switched on or off, UCLA scientists reversed a sensory impairment in mice with symptoms of autism, enabling them to learn a sensory task as quickly ...

Why it doesn't get dark when you blink

September 25, 2018
People blink every five seconds. During this brief moment, no light falls on the retina, yet people continue to observe a stable picture of the environment with no intervals of darkness. Caspar Schwiedrzik and Sandrin Sudmann, ...

Researchers identify new cause of brain bleeds

September 25, 2018
A team of researchers including UCI project scientist Rachita Sumbria, Ph.D. and UCI neurologist Mark J. Fisher, MD have provided, for the first time, evidence that blood deposits in the brain may not require a blood vessel ...

Lung inflammation from childhood asthma linked with later anxiety

September 25, 2018
Persistent lung inflammation may be one possible explanation for why having asthma during childhood increases your risk for developing anxiety later in life, according to Penn State researchers.

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

thingumbobesquire
2.5 / 5 (2) Dec 21, 2017
Connectionist neurological models are reductionist nonsensical claptrap. http://thingumbob...tal.html
LaPortaMA
not rated yet Dec 21, 2017
So, statistically, are we pretty sure Ido Kantor is right, or is this editoral sensaitonalism?
RobertKarlStonjek
5 / 5 (1) Dec 21, 2017
Neurons are not similar to computer bits or even shift registers but to fairly simple cores (CPU Cores) that are able to perform a number of fairly simple functions. All neurons are in the 'ON' state (polarised) when not firing, a continuous 'OFF' state only occurs when the neuron dies.
baudrunner
5 / 5 (1) Dec 21, 2017
This study negates nothing. It only refines our thinking about the way that neurons behave and communicate.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.