Name: measuring statistical learning across modalities and domains in school-aged children via an online platform and neuroimaging techniques
Uploaded: 2020-06-30T14:00:00
Description: Watch this Scientific Journal Video about Measuring Statistical Learning Across Modalities and Domains in School-Aged Children Via an Online Platform and Neuroimaging Techniques at JoVE.com

We thank Yoel Sanchez Araujo and Wendy Georgan for their contribution in the initial design of the web-based platform. We thank An Nguyen and Violet Kozloff for their work on improving the web-based statistical learning tasks, implementing the fMRI tasks, and piloting the tasks in adult participants. We thank Violet Kozloff and Parker Robbins for their contribution in assisting data collection in children. We thank Ibrahim Malik, John Christopher, Trevor Wigal, and Keith Schneider at the Center for Biological and Brain Imaging at the University of Delaware for their assistance in neuroimaging data collection. This work is funded in part by the National Institute on Deafness and other Communication Disorders (PI: Qi; NIH 1R21DC017576) and the National Science Foundation Directorate for Social, Behavioral &#38; Economic Sciences (PI: Schneider, Co-PI: Qi &#38; Golinkoff; NSF 1911462).

All participants gave written consent to participate and study was conducted in accordance with the Institutional Review Board.
1. Overview of the statistical learning paradigm utilized in the web-based protocol
<ol>
	<li>Include four tasks in the current paradigm: image (visual-nonlinguistic), letter (visual-linguistic), tone (auditory-nonlinguistic), and syllable (auditory-linguistic).
	<ol>
		<li>Construct stimuli for visual tasks using 12 standalone alien cartoon images (image) and 12 le...

The methods presented in the current protocol provide a multimodal paradigm for understanding the behavioral and neural indices of statistical learning across the course of development. The current design allows for the identification of individual differences in statistical learning ability across modalities and domains, which can be used for future investigation of the relationship between statistical learning and language development. Since an individuals&#8217; statistical learning ability is found to vary across dom...

Statistical learning is an elementary skill supporting the acquisition of rule-governed combinations in language inputs1. Successful statistical learning ability in infants predicts later language learning success2,3. Variability in statistical learning skills in school-aged children has also been associated with vocabulary4 and reading5,6. Difficulty in statistical learning has been proposed as one etiological mechanism underlying language impairment7. Despite the association between statistical learning and language outcomes in both neurotypical and atypical populations, the cognitive and the neural mechanisms underlying statistical learning remain poorly understood. In addition, previous literature has revealed that, within an individual, statistical learning ability is not uniform but independent across domains and modalities6,8,9. The developmental trajectory of statistical learning abilities may further vary across domains and modalities10. These findings emphasize the importance of assessing individual differences in statistical learning across multiple tasks throughout the course of development. However, the field first requires a more systematic investigation of the relationship between statistical learning and first language development. To address these questions, we apply innovative methods including a web-based testing platform11 that reaches a large number of children, and laboratory-based neuroimaging techniques (functional magnetic resonance imaging, or fMRI) that examine the real-time encoding of statistical information.
Standard measures of statistical learning begin with a familiarization phase and are followed by a two-alternative forced choice (2-AFC) task12,13. The familiarization phase introduces a continuous stream of stimuli embedded with statistical regularities, where some stimuli are more likely to co-occur than others. The presentation of these co-occurring stimuli follows a fixed temporal order. Participants are passively exposed to the stream during the familiarization phase, followed by a 2-AFC task that tests whether the participant successfully extracted the patterns. The 2-AFC accuracy task presents two consecutive sequences: one sequence has been presented to the participant during the familiarization phase, while the other is a novel sequence, or contains part of the sequence. Above-chance accuracy on the 2-AFC would indicate successful learning at the group level. Traditional behavioral tasks assessing statistical learning generally rely upon accuracy as the outcome measure of learning. However, accuracy fails to account for the natural learning of information as it unfolds in time. A measure of real-time learning is necessary to tap into the implicit learning process of statistical learning during which children are still encoding the regularities from the inputs14,15,16. Various adaptations across paradigms have been developed in an effort to move away from the 2-AFC measure, towards measures of on-line learning through behavioral responses during the exposure16. Studies utilizing these adaptations which measure reaction time during the exposure phase found they were related to post-learning accuracy17 with better test-retest reliability compared to that of the accuracy in adult learners18.
Neural measures are also foundational to our understanding of how learning unfolds over time, as the implicit process by which language learning occurs likely recruits different neural resources from those used once language is learned19. Neural measures also provide insights into differences in cognitive specializations underlying language ability across special populations20. How the condition contrast is designed in an fMRI study is crucial for how we interpret patterns of neural activation during learning. One common practice is to compare brain responses during the familiarization phase between sequences containing regular patterns versus those containing the same stimuli which are ordered randomly. However, previous research implementing such a random control condition found no evidence for learning in behavior, despite neural differences between structured and random sequences. This might be due to the interference of random sequences on learning of structured sequences, as both were constructed from the same stimuli21,22. Other fMRI studies which utilized backward speech or earlier learning blocks as the control condition confirmed learning took place behaviorally19,23. However, each of these paradigms introduced its own confounding factor, such as the effect of language processing for the former case and the effect of the experimental order for the latter case. Our paradigm uses the random sequence as the control condition but mitigates their interference on participants&#8217; learning of the structured sequences. Our fMRI paradigm also implements a mixed block/event-related design, which allows for the simultaneous modeling of transient trial-related and sustained task-related BOLD signals24. Lastly, and more broadly, neural measures allow for the measurement of learning in populations where eliciting an explicit behavioral response may be difficult (e.g., developmental and special populations)25.
The current protocol adopts a response time measure, in addition to traditional accuracy measures, and examines brain activation during the familiarization phase. The combination of these methods aims to provide a rich dataset for the investigation of real-time learning processes. The web-based platform offers a set of learning measures by including both response time during the exposure phase and accuracy of the 2-AFC task during the test phase. The neuroimaging protocol allows for the investigation of the underlying neural mechanisms supporting statistical learning across domains and modalities. While it is optimal to measure statistical learning within an individual using both the web-based and fMRI protocols, the tasks are designed so that they may be disseminated independently, and therefore, as two independent measures of statistical learning. The fMRI experiments included in the current protocol can help clarify how stimulus encoding, pattern extraction, and other constituent components of statistical learning are represented by particular brain regions and networks.

<table>
	<tbody>
		<tr>
			<td>4 Button Inline Response Device</td>
			<td>Cambridge Research Systems</td>
			<td>SKU: N1348</td>
			<td>An fMRI reponse pad used for measuring in-scanner response time</td>
		</tr>
		<tr>
			<td>Short/Slim Canal Tips</td>
			<td>Comply Foam</td>
			<td>SKU: 40-15028-11</td>
			<td>Short &#38; slim in-ear canal tips are recommended for children to protect hearing and allow for them to hear the stimuli while in the scanner.</td>
		</tr>
		<tr>
			<td>jsPsych</td>
			<td>jsPsych</td>
			<td>https://www.jspsych.org/</td>
			<td>jsPsych is a JavaScript library for running behavioral experiments in a web browser.</td>
		</tr>
		<tr>
			<td>Speech Synthesizer</td>
			<td>Praat</td>
			<td>Version 6.1.14</td>
			<td>This program is an artificial speech synthesizer which was used to create the syllable stimuli.</td>
		</tr>
		<tr>
			<td>Web-based statistical learning tasks</td>
			<td>Zenodo</td>
			<td>http://doi.org/10.5281/zenodo.3820620 (2020).</td>
			<td>All web-based statistical learning tasks are available for free access on Zenodo.</td>
		</tr>
	</tbody>
</table>

measuring statistical learning across modalities and domains in school-aged children via an online platform and neuroimaging techniques

Statistical learning, a fundamental skill to extract regularities in the environment, is often considered a core supporting mechanism of the first language development. While many studies of statistical learning are conducted within a single domain or modality, recent evidence suggests that this skill may differ based on the context in which the stimuli are presented. In addition, few studies investigate learning as it unfolds in real-time, rather focusing on the outcome of learning. In this protocol, we describe an approach for identifying the cognitive and neural basis of statistical learning, within an individual, across domains (linguistic vs. non-linguistic) and sensory modalities (visual and auditory). The tasks are designed to cast as little cognitive demand as possible on participants, making it ideal for young school-aged children and special populations. The web-based nature of the behavioral tasks offers a unique opportunity for us to reach more representative populations nationwide, to estimate effect sizes with greater precision, and to contribute to open and reproducible research. The neural measures provided by the functional magnetic resonance imaging (fMRI) task can inform researchers about the neural mechanisms engaged during statistical learning, and how these may differ across individuals on the basis of domain or modality. Finally, both tasks allow for the measurement of real-time learning, as changes in reaction time to a target stimulus is tracked across the exposure period. The main limitation of using this protocol relates to the hour-long duration of the experiment. Children might need to complete all four statistical learning tasks in multiple sittings. Therefore, the web-based platform is designed with this limitation in mind so that tasks may be disseminated individually. This methodology will allow users to investigate how the process of statistical learning unfolds across and within domains and modalities in children from different developmental backgrounds.

Web-based Behavioral Results 
Given the current protocol is designed for easy dissemination with developmental populations, we have included preliminary web-based results based on data from 22 developing school-aged children (Mean (M) age = 9.3 years, Standard Deviation (SD) age = 2.04 years, range = 6.2-12.6 years, 13 girls). In the web-based statistical learning task, children performed significantly better than 0.5 chance-level on all conditions, indicating successful statistical learning at the ...

Watch this Scientific Journal Video about Measuring Statistical Learning Across Modalities and Domains in School-Aged Children Via an Online Platform and Neuroimaging Techniques at JoVE.com

Measuring Statistical Learning Across Modalities and Domains in School-Aged Children Via an Online Platform and Neuroimaging Techniques

Presented here is a protocol introducing a set of child-friendly statistical learning tasks geared towards examining children&#8217;s learning of temporal statistical patterns across domains and sensory modalities. The developed tasks collect behavioral data using the web-based platform and task-based functional magnetic resonance imaging (fMRI) data for examining neural engagement during statistical learning.

Statistical learning, a fundamental skill to extract regularities in the environment, is often considered a core supporting mechanism of the first ...

The ability to extract patterns from inputs is foundational for language and cognitive development. The technique can address whether the remarkable heterogeneity of statistical learning in children is explained by domain general or domain specific mechanisms. Our protocol allows for the measurement of statistical learning across domains and modalities within individuals, is child-friendly and combines web-based behavioral with lab-based neuroimaging techniques.This method will provide insight into the learning frameworks of language development. If applied in special populations, our protocol may also advance our understanding of language learning difficulties. We are in the process of making our tasks accessible to the research community on Zenodo and GitHub.We encourage other researchers to reproduce our tasks once they become available. To perform a web-based protocol, first navigate to the web-based statistical learning paradigm. For the syllable task, introduce the participant to an alien and its favorite word in its alien language.Doe.Inform the participant that they will listen to the alien's language and to remember to press the space bar whenever they hear the favorite word. Have the participant complete a practice trial before the familiarization phase, in which they must press the space bar as soon as the alien's favorite word is heard. During the test phase, instruct the participant to select one of the two sequences that sound more familiar.The target sequence will be presented in the familiarization phase. Klaptoo the foil sequence will not have been previously presented. Klaptoo In the tone task, inform the participant that they will have to keep track of the alien favorite note in its folk song.The test phase will follow the same design as the syllable task. In the image task, informed the participant that they will have to keep track of a special alien as a group of aliens lineup to enter a space ship. During the test phase present both targets in the familiarization phase and foil triplets not seen before to the participant in pairs.In the letter task informed the participant that they will have to keep track of the aliens favorite sign. As the alien holds up signs for a parade. To help participants especially children become comfortable in scanner practice the MRI scanning session with a mock scanner.Introduce the participant to the mock scanner or brain camera and to their scan buddy. Explain that the purpose of the scan buddy is to keep them company and to help them if they need anything. The scan buddy will also gently remind the participant to keep still if too much motion is detected by the camera.Introduce the participant to the statistical learning paradigm and have them complete a brief portion of the task on a computer. After completing the task, help the participant into the mock scanner and play child-friendly videos to help them acclimate to the sound and video. When the participant is ready, play a few prerecorded scanner or sound clips to prepare them for the noises produced by the real MRI.During this time, have the participant practice staying still and working with the scan buddy. When the participant is comfortable with the mock scanner confirmed that the FMRI data collection protocol is appropriately set up on the MRI acquisition computer. Have the participant lie comfortably on the bed of the MRI scanner with headphones that protect their ears from the scanner noise and a response pad in their hand.Place additional padding around the participant's head to ensure limited head motion during the data collection and give the participant the option of a scan buddy. Give the participant a squeeze ball to use to notify if they are distressed or need to stop and place the head coil over the participant's head. After aligning the participant in the scanning bed register a new participant in the acquisition computer and choose the correct scanning protocol.Insert the scanning bed and participant into the bore of the MRI and show a movie to the participant while acquiring a structural MRI scan. To have the participant perform an auditory task use an Intercom system connected to their headphones to inform the participant. Now we are going to play a button pressing game.You will hear the aliens, say words and play music remember to press the button on the response pad whenever you hear the sound you're listening for. After giving the instructions, start the paradigm on the presentation computer to allow the acquisition of the auditory statistical learning data. For a visual task inform the participant.Now, you're going to see the pictures of the aliens and the letters. Whenever you see the pictures that you're looking for press the button on your response pads. After giving the instructions start the paradigm on the presentation computer to acquire the visual statistical learning data.Once the participant has completed the paradigm stop the MRI, safely remove the participant from inside the scanner and remove the head coil. In the web based statistical learning task. Children performed significantly better than a 0.5 chance level on all conditions indicating successful statistical learning at the group level.The mean reaction time slope was negative and significantly below zero in the syllable condition and marginally significant in the letter condition suggesting a faster acceleration of the target detection during the familiarization phase in the linguistic tasks. The mean reaction time slope was not significantly different from zero in the image or the tone condition despite evidence of learning in the offline measures of accuracy. Here preliminary FMRI results based on data from nine developing school aged children who completed auditory and visual statistical learning tasks are shown.When comparing structured blocks to random blocks significant clusters were observed across a variety of brain regions, depending on the stimulus type. These results suggest that the current task design is sensitive to detecting learning induced hemodynamic changes in children's brains. Representative findings in adults indicate that the structured sequences are learnable supported by a significantly quicker response time in the structured condition, compared to the random condition in all of the in scanner tasks with the exception of the tone task.We encourage researchers, to include other individual difference measures to better understand how variability and statistical learning across domains and modalities relates to higher level processes. This protocol is a first step towards delineating how individual differences in statistical learning may account for variation in language outcomes in both typical and atypical development.

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