New insights into difficulties in skill acquisition autism versus dyslexia
Is the cerebellum - the source of slow-update in autism?
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Our predictions about how physical and social situations are based on our past experiences, both recent and more distant, and different populations integrate these experiences differently across time. Researchers in the NeuroCompSkill project are exploring the idea that people with autism update their predictions differently to those with dyslexia, as Professor Merav Ahissar explains. Many of the conversations we have in our everyday lives develop along broadly familiar lines, and often we are able to anticipate the utterances of family and friends before the words even leave their mouths. This is the result of our ability to form predictions about how social situations are likely to develop, based on integration of information from past experiences. “This is an automatic, implicit process. We integrate things that have happened recently, as well as information about things that have happened over longer timeframes,” says Merav Ahissar, Professor of Brain Sciences at ELSC Centre of the Hebrew University of Jerusalem. Evidence suggests that highfunctioning autistic people put less weight on relatively recent events in this process, which limits their ability to form predictions and communicate effectively in social situations, which require fast online updating of predictions at the sub-second level.
NeuroCompSkill project As Principal Investigator of the ERC-backed NeuroCompSkill project, Professor Ahissar is now exploring how autistic people absorb information from the surrounding environment in daily life, and contrasting this group with dyslexic populations. While people with autism are slow in setting predictions, people with dyslexia experience a rapid decay of their implicit memory, which then affects their proficiency with their native language. “This affects reading and writing skills, and the way that people put phrases together,” explains Professor Ahissar. Together with her colleagues in the project, Professor Ahissar is now contrasting the slow updating of autism with
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the fast decay of dyslexia, based on neural evidence from studies of a phenomenon called neural adaptation. “If you present a particular stimulus to an individual, and shortly afterwards you present the same stimulus again, the subsequent response will be smaller than the first. This shows that
the neurons have adapted,” she says. “We think of this as a form of implicit memory since it is evoked by external stimuli rather than by intentional recall. If you present a very different stimulus, you will not see this reduction in response, indicating stimulusspecificity of this memory.” As long as the active system that responds to stimuli remembers the first event, then the response will be smaller when it is repeated, to a point where there may not be any response at all in some people. The aim for Professor Ahissar now is to use this phenomenon to investigate how long this implicit memory is active in different populations. “We measure how long this neural adaptation lasts in the general population, in people with autism, and in people with dyslexia,” she outlines. Part of this research involves recording responses to stimuli from the auditory cortex of the skull, and researchers have found variations in the adaptation time across different populations. “In people with dyslexia the adaptation is short, and the repetition of a stimuli within a short period can be like an entirely new event,” continues Professor Ahissar. “We can also see that this adaptation is correlated with updating. People with dyslexia update their predictions quickly, whereas people with autism update more slowly.” A further aspect of the project’s research involves investigating people’s motor updating. It is still an open question whether perceptual predictions and motor plans are updated together. One would think they should be coordinated, so that if a target moves, people’s reaching plans will need to be updated online. To test whether updating motor plans is also slowed in autism - perhaps explaining the nature of motor difficulties that many people
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with autism experience - Ahissar’s group tested how people synchronise their own movements with external stimuli. To simplify the experimental question, they measured synchronizing finger tapping to an external metronome with a fixed beat of two beats per second. Autistic people tend to have difficulties in synchronising, a topic that Professor Ahissar is exploring in the project. “We can measure whether you tap in an accurate manner, and the extent to which there is any variability, namely – precise manner” she explains. “We study the sources of this variability and find that it is due to an online problem in online error correction. When they do not synchronize well, their correction is very partial.” The project team are also conducting research into a task that can be performed across different species, and is known to be very challenging for people with autism. In this task people are asked to place a finger on
mechanisms behind these updating processes are not particularly well understood in the general population. Working with large populations will help researchers build a fuller picture in this respect, and shed new light on differences in sub-populations. “We need to understand variability in the general population,” acknowledges Professor Ahissar. It’s now possible to use internet-based assessments to gather data on large numbers of people, yet people may not necessarily behave in the same way at home as they would in the lab, an issue Professor Ahissar is taking into account in her research. “We’re trying to replicate the mental context of the lab, and we have established reliable protocols,” she says. “In the first round, we saw that people who had previous experience of participating in lab-based research produced the same results at home, but people who are less familiar with the lab environment did not.”
If you present a particular stimulus to an individual, and shortly afterwards you present the same stimulus again, the subsequent response will be smaller than the first. This shows that the neurons have adapted. an iPad, then to move it towards a target upon a certain signal. “When the light changes to green you can start moving. The light turns off pretty rapidly, so you have to move to the target quickly,” outlines Professor Ahissar. Occasionally the target jumps to a different position, and researchers are able to measure how quickly people are able to update their direction of movement, with clear results. “People have to update their motor perception to the new position very quickly. We consistently find that people with autism are slower in updating their movement direction,” says Professor Ahissar. “The question then arises; what is it that is difficult for them to update? Is it due to reduced intake of external stimuli, due to slower integration of these stimuli, or to slower changes in motor commands? This needs further study,” she says.
Autism and dyslexia This research is focused primarily on specific sub-populations, namely people with autism and people with dyslexia, yet the brain
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Researchers are tweaking the protocols to get study participants in the right frame of mind, so that results gained from online assessments are of the same quality and rigour as those from the lab-based work. This will then allow researchers to work with much bigger populations, while Professor Ahissar is also interested in working with young people, although some changes will need to be made. “It’s not obvious how these tasks would be performed by younger people, and we anticipate that we will need to make certain adaptations and modifications to keep children interested,” she says. This research could lead to a deeper understanding of how we acquire communication skills, which holds wider relevance to teaching. “This could eventually lead to a better teaching environment. It’s about understanding when you should be explicit, what kind of information needs to be repeated, and when intervals should be introduced. You might want to provide more temporally spaced conditions in some circumstances,” outlines Professor Ahissar.
Neurocompskill Learning to talk: A neuro-computational look at verbal and non-verbal communication skills
Project Objectives
Researchers in the NeuroCompSkill project is using a neurocomputational framework to investigate how people with autism integrate information from past experiences and comparing them with dyslexic populations. This research will shed new light on how people acquire certain social skills and open up new insights into developmental disorders.
Project Funding
This project has received funding from the European Research Council (ERC) - EXCELLENT SCIENCE research and innovation programme under Grant agreement ID: 833694.
Contact Details
Project Coordinator, Professor Merav Ahissar The Edmond and Lily Safra Center for Brain Sciences The Suzanne and Charles Goodman Brain Sciences Building, Level 1, Room 1103, Edmond J. Safra Campus, The Hebrew University of Jerusalem, 9190401 T: +972-2-5883409 E: msmerava@gmail.com : @MeravAhissar W: https://elsc.huji.ac.il/people-directory/ faculty-members/merav-ahissar/
Professor Merav Ahissar
Merav Ahissar is Professor of Brain Sciences at the ELSC Centre of the Hebrew University of Jerusalem. The main focus of her lab is on understanding the neurocognitive mechanisms that underlie skill acquisition. She conducts research into both dyslexia and autism, and is interested in the dynamics of using recent history in autism.
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