Tag: Neural-networks

Scientists identify neural pathways behind visual perceptual decision-making

Scientists at the National Eye Institute (NEI) have found that neurons in the superior colliculus are key players in allowing us to detect visual objects and events. This structure doesn’t help us recognize what the specific object or event is; instead, it’s the part of the brain that decides something is there at all. 
In this study researchers used an “accumulator threshold model” to study how neuronal activity in the superior colliculus relates to behavior. By comparing brain activity recorded from the right and left superior colliculi at the same time, the researchers were able to predict whether an animal was seeing an event. The findings were published today in the journal Nature Neuroscience.
This new study shows that process of deciding that an object is present or that an event has occurred in the visual field – is handled by the superior colliculus. The process of deciding to take an action (a behavior, like avoiding a chair) based on information received from the senses (like visual information) is known as “perceptual decision-making”. Most research into perceptual decision-making – in humans, non-human primates, or in other animals – uses mathematical models to describe a relationship between a stimulus shown to an animal (like moving dots, changes in color, or appearance of objects) and the animal’s behavior. But because visual information processing in the brain is highly complex, scientists have struggled to demonstrate that these mathematical models accurately mimic a biological process happening in the brain during decision-making.
Citation: James P. Herman, Leor N. Katz, and Richard J. Krauzlis. “Midbrain Activity Can Explain Perceptual Decisions during an Attention Task.” Nature Neuroscience 21, no. 12 (2018): 1651-655. doi:10.1038/s41593-018-0271-5.

Understanding “social brain” neural networks in autistic children

A team of researchers from the University of Geneva (UNIGE), Switzerland, studies how neural networks develop in brains of toddlers with autism. Their findings are published in the journal eLife.

As infants grow, they start reacting and responding to social cues like human gestures, voices, and faces. During this time their social brain develops. “Social brain” is part of the brain neural networks that respond to social cues.  It is well known that infants with Autism Spectrum Disorder (ASD) have lower attention and sensitivity during the first year and this is thought to ultimately influence normal development of neural networks related to the social brain.

Each dot represents the gaze position for an individual child watching the movie. The blue dots on the left represent the typically developing toddlers. The red dots represent toddlers with Autism Spectrum Disorders (ASD).
Credit: University of Geneva.

The study results show that therapies and interventions targeting children at an early age to develop the ability to respond to social cues could rewire neural networks of the brain when the brain is still elastic and programmable.

Dr Holger Sperdin, Postdoctoral Research Associate at the UNIGE’s Faculty of Medicine and lead author of the study, explains what he and his team set out to discover: “As toddlers with Autism Spectrum Disorder (ASD) have less preferential attention for social cues, we hypothesised that when we showed them moving social images, they would demonstrate differences in both the way they visually explore these images and in the way their brain networks process social information, compared with typically developing toddlers.”

The research team used electroencephalography (EEG) to monitor the children’s brain activity, and powerful eye-tracking technology to observe their eye gaze while they watched movies featuring human social interactions. They found that the children with Autism Spectrum Disorder (ASD) had different gaze patterns while watching the movies to the typically developing infants and that this was accompanied by alterations in neural networks and information flow in the brain.

In those with Autism Spectrum Disorder (ASD), the team also observed what is known as ‘increased driving’ in two specific frequencies of brain waves alpha and theta as well as high levels of connectivity between nerve cells in certain regions in the brain. The theta brainwave frequency and the regions of the brain affected are both known to be important components of the “social brain”, and the alpha frequency is important for visual attention.

These findings represent the first evidence that differences in the visual exploration of images coincide with changes in connectivity between critical regions of the social brain in very young children with Autism Spectrum Disorder (ASD). Brain regions generating these brainwave frequencies may, therefore, develop differently in children with Autism Spectrum Disorder (ASD) compared with their typically developing peers.

“Our results show for the first time the presence of alterations in information flow from brain areas involved in social cue processing in toddlers and pre-schoolers with Autism Spectrum Disorders (ASD),” concludes senior author Professor Marie Schaer, Assistant Professor at the University of Geneva, Switzerland. “These alterations within regions of the social brain are present at early stages of Autism Spectrum Disorder (ASD) and justify further investigation into whether therapeutic interventions targeting social orienting skills may help to remediate social brain development during this critical stage when neural plasticity is still possible.”

Citation: Sperdin, Holger Franz, Ana Coito, Nada Kojovic, Tonia Anahi Rihs, Reem Kais Jan, Martina Franchini, Gijs Plomp, Serge Vulliemoz, Stephan Eliez, Christoph Martin Michel, and Marie Schaer. “Early alterations of social brain networks in young children with autism.” ELife 7 (2018). doi:10.7554/elife.31670.

Adapted from press release by the University of Geneva.

Understanding "social brain" neural networks in autistic children

A team of researchers from the University of Geneva (UNIGE), Switzerland, studies how neural networks develop in brains of toddlers with autism. Their findings are published in the journal eLife.

As infants grow, they start reacting and responding to social cues like human gestures, voices, and faces. During this time their social brain develops. “Social brain” is part of the brain neural networks that respond to social cues.  It is well known that infants with Autism Spectrum Disorder (ASD) have lower attention and sensitivity during the first year and this is thought to ultimately influence normal development of neural networks related to the social brain.

Each dot represents the gaze position for an individual child watching the movie. The blue dots on the left represent the typically developing toddlers. The red dots represent toddlers with Autism Spectrum Disorders (ASD).
Credit: University of Geneva.

The study results show that therapies and interventions targeting children at an early age to develop the ability to respond to social cues could rewire neural networks of the brain when the brain is still elastic and programmable.

Dr Holger Sperdin, Postdoctoral Research Associate at the UNIGE’s Faculty of Medicine and lead author of the study, explains what he and his team set out to discover: “As toddlers with Autism Spectrum Disorder (ASD) have less preferential attention for social cues, we hypothesised that when we showed them moving social images, they would demonstrate differences in both the way they visually explore these images and in the way their brain networks process social information, compared with typically developing toddlers.”

The research team used electroencephalography (EEG) to monitor the children’s brain activity, and powerful eye-tracking technology to observe their eye gaze while they watched movies featuring human social interactions. They found that the children with Autism Spectrum Disorder (ASD) had different gaze patterns while watching the movies to the typically developing infants and that this was accompanied by alterations in neural networks and information flow in the brain.

In those with Autism Spectrum Disorder (ASD), the team also observed what is known as ‘increased driving’ in two specific frequencies of brain waves alpha and theta as well as high levels of connectivity between nerve cells in certain regions in the brain. The theta brainwave frequency and the regions of the brain affected are both known to be important components of the “social brain”, and the alpha frequency is important for visual attention.

These findings represent the first evidence that differences in the visual exploration of images coincide with changes in connectivity between critical regions of the social brain in very young children with Autism Spectrum Disorder (ASD). Brain regions generating these brainwave frequencies may, therefore, develop differently in children with Autism Spectrum Disorder (ASD) compared with their typically developing peers.

“Our results show for the first time the presence of alterations in information flow from brain areas involved in social cue processing in toddlers and pre-schoolers with Autism Spectrum Disorders (ASD),” concludes senior author Professor Marie Schaer, Assistant Professor at the University of Geneva, Switzerland. “These alterations within regions of the social brain are present at early stages of Autism Spectrum Disorder (ASD) and justify further investigation into whether therapeutic interventions targeting social orienting skills may help to remediate social brain development during this critical stage when neural plasticity is still possible.”

Citation: Sperdin, Holger Franz, Ana Coito, Nada Kojovic, Tonia Anahi Rihs, Reem Kais Jan, Martina Franchini, Gijs Plomp, Serge Vulliemoz, Stephan Eliez, Christoph Martin Michel, and Marie Schaer. “Early alterations of social brain networks in young children with autism.” ELife 7 (2018). doi:10.7554/elife.31670.

Adapted from press release by the University of Geneva.

MESO-BRAIN stem cell research project to develop 3D nanoprinting techniques to replicate neural networks

Aston University heading up major €3.3m stem cell research project to develop 3D nanoprinting techniques that could replicate brain’s neural networks.

Aston University has launched MESO-BRAIN, a major stem cell research project which it hopes will develop three-dimensional (3D) nanoprinting techniques that can be used to replicate the brain’s neural networks.

The cornerstone of the MESO-BRAIN project will be its use of pluripotent stem cells generated from adult human cells that have been turned into brain cells, which will form neural networks with specific biological architectures. Advanced imaging and detection technologies developed in the project will be used to report on the activity of these networks in real time.

Credit: Ashton University
Such technology would mark a new era of medical and neuroscience research which would see screening and testing conducted using physiologically relevant 3D living human neural networks. In the future, this could potentially be used to generate networks capable of replacing damaged areas in the brains of those suffering from Parkinson’s disease, dementia or other brain trauma.
The MESO-BRAIN initiative, which will span three years, received €3.3million of funding from the European Commission as part of its prestigious Future and Emerging Technology (FET) scheme. Aston University is leading the project, with partners from industry and higher education across Europe: Axol Bioscience Ltd, Laser Zentrum Hannover, The Institute of Photonic Sciences, University of Barcelona and Kite Innovations. This unique partnership brings together stem cell biologists, neuroscientists, photonics experts and physicists.

Head of the MESO-BRAIN project, Professor Edik Rafailov, said: “What we’re hoping to achieve with this project has, until recently, been the stuff of science-fiction.

“If we can use 3D nanoprinting to improve the connection of neurons in an area of the brain which has been damaged, we will be in a position to develop much more effective ways to treat those with dementia or brain injuries.

“To date, attempts to replicate and reproduce cells in this way have only ever delivered 2D tissues or poorly defined 3D tissues that do not resemble structures found within the human body. The new form of printing we are aiming to develop promises to change this. The MESO-BRAIN project could improve hundreds of thousands of lives.”

Dr Eric Hill, Programme Director for MSc Stem cells and Regenerative Medicine at Aston University, commented: “This research carries the potential to enable us to recreate brain structures in a dish. This will allow us to understand how brain networks form during development and provide tools that will help us understand how these networks are affected in diseases such as Alzheimer’s disease.”

Adapted from press release by Ashton University.