This study was supported by the Shandong Social Science Planning Fund [17CQRJ04], and Humanities and Social Sciences Foundation of Ministry of Education of China [18YJA740048].

The experiment was approved by the Ethics Committee of Beijing Foreign Studies University and it complied with the guideline for experiments with human subjects. All participants in the experiment provided written informed consent.
1. Stimuli Construction
<ol>
	<li>Construct experimental stimuli on the basis of the specific experimental questions. This protocol is intended to explore the effect of ageing on online sentence processing during reading, and as such, the visual stimuli used in the experiment are two types of RCs, namely SRCs and ORCs, which are the structures most frequently used in the studies of sentence processing by older adults.</li>
	<li>Prepare at least 24 experimental sentences with twelve sentences in each condition and at least 24 fillers that are of various length and structures. The number of fillers can be increased to up to three times of the experimental sentences. The experimental sentences should be counterbalanced across the two conditions. 
	NOTE: As our study focused on the processing of Mandarin sentences, all the sentences used in the experiment were in Mandarin Chinese. However, the protocol reported here may be also applicable to other languages.</li>
	<li>Plausibility rating: Invite at least 30 participants to rate the semantic plausibility of the experimental sentences using a five-point Likert scale with scores from &#39;&#39;1&#39;&#39; (the least plausible) to &#39;&#39;5&#39;&#39; (the most plausible). Make sure the group is similar to the participants in age, gender ratio and education. Make sure they do not take part in the subsequent experiment. Ensure the sentences used in the study are all semantically plausible (&#62;3) and semantic plausibility does not differ significantly between different experimental conditions. 
	NOTE: In our study, 15 older adults and 15 younger adults were invited to participate in the plausibility rating (Mage = 43.6, SD = 24.1; Female 16, Male 14).</li>
	<li>For each word in the experimental sentences, provide an ungrammatical alternative. In this way, prepare a pair of words for each segment of the sentences, with one of them being the grammatical continuation of the sentence and the other is not. Match the two alternatives in lexical frequency. Participants are expected to choose between the grammatically correct word and the grammatically incorrect one (See Figure 1 for sample sentences in English). An experimental sentence used in this study is shown in Figure 2.</li>
	<li>Randomization and design. Randomize the sentences and the positions of the two alternatives in the sentences before presenting them to participants. Find the Selection tab of the Property Page in the stimulus presentation software (see Table of Materials) and set the selection method to Random.
	<ol>
		<li>Divide the experiment into blocks with each lasting for no more than 10 min. 
		NOTE: In the study, the experiment consisted of two blocks with 24 sentences in each block. Each block lasted for about 5 min.</li>
		<li>Allow participants to have a break between two blocks. Breaks for about 5 min can be helpful for younger adults. Allow longer breaks for older adults to ensure they can recover from fatigue.</li>
	</ol>
	</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/60417/60417fig2b.jpg" /> 
Figure 2: Example of two experimental sentences. This figure shows that participants were presented two Chinese words in each frame and were required to choose the one which can grammatically continue the sentence. The words on the frame are Chinese characters&#160;with the English equivalents provided in parentheses. <a href="https://www.jove.com/files/ftp_upload/60417/60417fig2blarge.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
2. Participant Screening and Preparation for the Experiment
<ol>
	<li>Recruit participants who are native speakers of the language tested. Ensure participants have normal or corrected-to-normal vision. Invite at least 30 younger adults and 30 older adults. Match the two age groups in years of education and gender ratio.</li>
	<li>Ask participants whether they have had neurological, psychiatric or communication disorders before. Exclude the ones who report any history of these diseases.</li>
	<li>To ensure older participants recruited are cognitively healthy, have them complete the Global Deterioration Scale22 before the experiment as a way of screening. Exclude the participants who score above level two.</li>
	<li>Inform the participants that they should be free from exhaustion, hunger, illness or other conditions that make them uncomfortable on the day of the experiment.</li>
	<li>Invite the participants individually or in groups to the laboratory room.</li>
</ol>
3. Procedure
<ol>
	<li>Take participants to the laboratory room and instruct them to sit down at the computer workplaces.</li>
	<li>Ask the participants to read and sign the written informed consent forms. Exclude the participants who cannot provide informed consent for any reason.</li>
	<li>Provide verbal instructions to the participants to ensure they are clear about the requirements of the task. Ask participants to choose between the two words or phrases on the computer screen to form a grammatical continuation of the sentences. Inform them that their responses will be timed, so they are expected to respond as quickly and as accurately as possible.</li>
	<li>Provide the written instruction to the participants and ask them to read it carefully. Answer any questions participants may have about the instructions. Present the following message on paper or on computer screen in participants&#39; native language: 
	&#34;In this experiment, you will read a number of Chinese sentences. However, the sentences will be presented one word at a time. On each screen, two words will be presented and you need to choose the word which can grammatically continue the sentence as quickly as possible. If you choose the word on your left hand side, please press the F button on the keyboard and if you choose the word on the right, please press J. Please respond as quickly as possible. If you fail to respond in ten seconds, the next trial begins. If you have no further questions, press any key to start practice.&#34;</li>
	<li>Ask the participants to complete a small number of practice questions to ensure they understand how to perform the task. Provide participants with feedbacks after they have made their choices regarding which of the two phrases is the grammatical continuation of the sentence. To minimize the disturbance to the natural reading process, only provide feedback when incorrect answers are detected. The feedbacks are&#160;short phrases (&#34;incorrect&#34;) in the participants&#39; native language, which are visually presented on the computer screen.</li>
	<li>When participants complete the practice questions, ask them to make a choice as to whether they would like to redo the practice. If they press the button p on the keyboard, the practice session starts all over again and if they press the space bar, the practice session is over and the experimental session begins. Allow them to redo the practice as many times as possible until they are familiar with the procedures of the task. Provide them assistance whenever they encounter any difficulties during the practice session.</li>
	<li>Allow the participants to perform the required experimental task when they are clear about the experimental procedures.</li>
	<li>Present the items on the computer screen as black letters on a white background.</li>
	<li>Have participants read the items and for each segment, choose between the two words placed side by side on the screen with a press of the button on the keyboard (F button for the word on the left and J button for the word on the right).</li>
	<li>If participants choose the correct answer, present the next pair of words. When they choose a wrong answer, have the sentence terminate and have the next one appear.</li>
	<li>Administer the digital span task from the Wechsler Memory Scale23 to assess participants&#39; working memory span. Test participants individually.</li>
	<li>Ask participants to listen to a sequence of digits (1-9) that are presented auditorily at the rate of one digit per second.</li>
	<li>Ask participants to repeat the digit sequence in the same order.</li>
	<li>Start from short strings and increase the string length one digit at a time. Stop the test when participants make errors at two trials at a given length.</li>
	<li>Record participants&#39; responses on the record form. Use a digital recording device to record participants&#39; responses.</li>
	<li>Ask participants to complete the questionnaires about their background information, such as age, gender and years of education. Prepare participants&#39; payment during the questionnaire.</li>
	<li>Provide participants monetary compensation for their participation. 
	NOTE: In our experiment, each participant was paid 20 RMB (about USD$3) for their participation. The amount of payment may vary in different experiments. Other approaches can also be used to motivate participants such as rewards.</li>
</ol>
4. Data Analysis
<ol>
	<li>Obtain the RTs (ms) for each word in the sentences from the output files of the presentation software.</li>
	<li>Exclude the RTs for the trials that are responded incorrectly from data analysis. In order to reduce the influence of outliners on the results, exclude the RTs above three standard deviations from the means for each participant in each condition.</li>
	<li>Analyze the RTs for the regions of interest in the sentences, using repeated measures ANOVA with RTs as the dependent variable and age group (old, young), type of sentence (SRC, ORC) and region (1-6) as independent variables.</li>
</ol>

<ol><li>Obler, L. K., Nicholas, M., Albert, M. L., Woodward, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((On+comprehension+across+the+adult+lifespan%5BTitle%5D)+AND+%22Cortex%22%5BJournal%5D)">On comprehension across the adult lifespan.</a> Cortex. 21 (2), 273-280 (1985).</li>
<li>Zurif, E., Swinney, D., Prather, P., Wingfield, A., Brownell, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+allocation+of+memory+resources+during+sentence+comprehension%3A+Evidence+from+the+Elderly%5BTitle%5D)+AND+%22Journal+of+Psycholinguistic+Research%22%5BJournal%5D)">The allocation of memory resources during sentence comprehension: Evidence from the Elderly.</a> Journal of Psycholinguistic Research. 24 (3), 165-182 (1995).</li>
<li>Waters, G. S., Caplan, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Age%2C+working+memory%2C+and+on-line+syntactic+processing+in+sentence+comprehension%5BTitle%5D)+AND+%22Psychology+and+Aging%22%5BJournal%5D)">Age, working memory, and on-line syntactic processing in sentence comprehension.</a> Psychology and Aging. 16 (1), 128-144 (2001).</li>
<li>DeDe, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+of+animacy+on+processing+relative+clauses+in+older+and+younger+adults%5BTitle%5D)+AND+%22The+Quarterly+Journal+of+Experimental+Psychology%22%5BJournal%5D)">Effects of animacy on processing relative clauses in older and younger adults.</a> The Quarterly Journal of Experimental Psychology. 68 (3), 487-498 (2015).</li>
<li>Liu, X., Wang, W., Wang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Age+differences+in+the+effect+of+animacy+on+Mandarin+sentence+processing%5BTitle%5D)+AND+%22PeerJ%22%5BJournal%5D)">Age differences in the effect of animacy on Mandarin sentence processing.</a> PeerJ. 7, e6437(2019).</li>
<li>Gibson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Linguistic+complexity%3A+locality+of+syntactic+dependencies%5BTitle%5D)+AND+%22Cognition%22%5BJournal%5D)">Linguistic complexity: locality of syntactic dependencies.</a> Cognition. 68 (1), 1-76 (1998).</li>
<li>Gibson, E. The dependency locality theory: a distance-based theory of linguistic complexity. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aGibson%2C+E+%22Image%2C+Language%2C+Brain%22">Image, Language, Brain</a>. Miyashita, Y., Marantz, A., O'Neil, W. , MIT Press. Cambridge. 95-126 (2000).</li>
<li>Gibson, E., Ko, K. An integration-based theory of computational resources in sentence comprehension. Fourth Architectures and Mechanisms in Language Processing Conference. , University of Freiburg, Germany. (1998).</li>
<li>Hsiao, F., Gibson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Processing+relative+clauses+in+Chinese%5BTitle%5D)+AND+%22Cognition%22%5BJournal%5D)">Processing relative clauses in Chinese.</a> Cognition. 90 (1), 3-27 (2003).</li>
<li>Vasishth, S., Lewis, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Argument-head+distance+and+processing+complexity%3A+Explaining+both+locality+and+anti-locality+effects%5BTitle%5D)+AND+%22Language%22%5BJournal%5D)">Argument-head distance and processing complexity: Explaining both locality and anti-locality effects.</a> Language. 82 (4), 767-794 (2006).</li>
<li>He, W., Xu, N., Ji, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+of+Age+and+Location+in+Chinese+Relative+Clauses+Processing%5BTitle%5D)+AND+%22Journal+of+Psycholinguistic+Research%22%5BJournal%5D)">Effects of Age and Location in Chinese Relative Clauses Processing.</a> Journal of Psycholinguistic Research. 46 (5), 1-20 (2017).</li>
<li>Witzel, N., Witzel, J., Forster, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Comparisons+of+online+reading+paradigms%3A+Eye+tracking%2C+moving-window%2C+and+maze%5BTitle%5D)+AND+%22Journal+of+Psycholinguistic+Research%22%5BJournal%5D)">Comparisons of online reading paradigms: Eye tracking, moving-window, and maze.</a> Journal of Psycholinguistic Research. 41 (2), 105-128 (2012).</li>
<li>Rayner, K., Pollatsek, A. Eye movement control in reading. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aRayner%2C+K+%22Handbook+of+psycholinguistics%22">Handbook of psycholinguistics</a>. Traxler, M., Gernsbacher, M. , 2nd ed, Elsevier. Cambridge, MA. 609-653 (2006).</li>
<li>Rayner, K., Sereno, S. C. Eye movements in reading: Psycholinguistic studies. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aRayner%2C+K+%22Handbook+of+psycholinguistics%22">Handbook of psycholinguistics</a>. Gernsbacher, M. A. , 1st ed, Academic Press. San Diego, CA. 57-81 (1994).</li>
<li>Staub, A., Rayner, K. Eye movements and on-line comprehension processes. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aStaub%2C+A+%22The+Oxford+handbook+of+psycholinguistics%22">The Oxford handbook of psycholinguistics</a>. Gaskell, G. , Oxford University Press. Oxford, UK. 327-342 (2007).</li>
<li>Forster, K. I., Guerrera, C., Elliot, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+maze+task%3A+Measuring+forced+incremental+sentence+processing+time%5BTitle%5D)+AND+%22Behavior+Research+Methods%22%5BJournal%5D)">The maze task: Measuring forced incremental sentence processing time.</a> Behavior Research Methods. 41 (1), 163-171 (2009).</li>
<li>Nicol, J. L., Forster, K. I., Veres, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Subject-verb+agreement+processes+in+comprehension%5BTitle%5D)+AND+%22Journal+of+Memory+and+Language%22%5BJournal%5D)">Subject-verb agreement processes in comprehension.</a> Journal of Memory and Language. 36, 569587(1997).</li>
<li>Forster, K. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Using+a+maze+task+to+track+lexical+and+sentence+processing%5BTitle%5D)+AND+%22Mental+Lexicon%22%5BJournal%5D)">Using a maze task to track lexical and sentence processing.</a> Mental Lexicon. 5 (3), 347-357 (2010).</li>
<li>Qiao, X., Shen, L., Forster, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Relative+clause+processing+in+Mandarin%3A+Evidence+from+the+maze+task%5BTitle%5D)+AND+%22Language+and+Cognitive+Processes%22%5BJournal%5D)">Relative clause processing in Mandarin: Evidence from the maze task.</a> Language and Cognitive Processes. 27 (4), 611-630 (2002).</li>
<li>Caplan, D., DeDe, G., Waters, G., Michaud, J., Tripodis, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Effects+of+age%2C+speed+of+processing%2C+and+working+memory+on+comprehension+of+sentences+with+relative+clauses%5BTitle%5D)+AND+%22Psychology+and+Aging%22%5BJournal%5D)">Effects of age, speed of processing, and working memory on comprehension of sentences with relative clauses.</a> Psychology and Aging. 26 (2), 439-450 (2011).</li>
<li>Stine-Morrow, E. A., Ryan, S., Leonard, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Age+differences+in+on-line+syntactic+processing%5BTitle%5D)+AND+%22Experimental+Aging+Research%22%5BJournal%5D)">Age differences in on-line syntactic processing.</a> Experimental Aging Research. 26 (4), 315-322 (2000).</li>
<li>Reisberg, B., Ferris, S. H., de Leon, M. J., Crook, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+Global+Deterioration+Scale+for+assessment+of+primary+degenerative+dementia%5BTitle%5D)+AND+%22The+American+Journal+of+Psychiatry%22%5BJournal%5D)">The Global Deterioration Scale for assessment of primary degenerative dementia.</a> The American Journal of Psychiatry. 139, (1982).</li>
<li>Wechsler, D. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aWechsler%2C+D+%22Wechsler+memory+scale+-+Revised%22">Wechsler memory scale - Revised</a>. , Psychological Corporation. New York. (1987).</li>
</ol>

The authors declare that they have no competing interests.

In this study, a maze task was used to find the exact location for the effect of ageing on sentence processing. The study examined how older adults and younger adults differentially processed Chinese SRCs and ORCs. In the task, participants were instructed to read a sentence by choosing between two alternatives, only one of which was the grammatical continuation of the sentence. They were required to make the choice as quickly and as accurately as possible. If participants chose the correct alternatives in the sequence, ...

Sentence processing is an essential process for human beings to comprehend sentences in natural languages. It requires integrating incoming words into the existing sentential structures and establishes relationships between words in the sentence in a way which conforms to the grammatical constraints. As sentence processing is a resource-demanding process, older adults tend to encounter difficulties due to the age-related decline in working memory. Previous studies have found that older adults have great difficulties in comprehending and processing sentences with complex syntactic structures such as relative clauses (RCs): &#34;The reporter whom the senator attacked admitted error&#34;1. Most previous studies focused on RCs to investigate the effect of ageing on sentence processing. Compared with younger adults, older adults have lower accuracy and efficiency in RC comprehension. However, despite the extensive studies on RC processing by older adults, it is still not clear which parts of RCs are more difficult to process for older adults as they read sentences word by word. Zurif et al. (1995) found that older adults had greater difficulty at the RC verbs (&#34;attacked&#34;) as they were less efficient to assign the patient roles to the objects of the verbs (&#34;reporter&#34;)2. However, some studies suggest that older adults did not perform differently from the younger controls at any particular region. Rather the difficulties occurred when participants finished reading the entire sentences3. Still, several other studies found that older adults performed less efficiently than younger adults at the RC subjects (&#34;the senator&#34;) and verbs (&#34;attacked&#34;)4,5. In other words, the precise locations of the processing difficulties for older adults have not yet been clearly identified.
Sentence processing is an incremental process that requires sufficient cognitive resources. According to the Dependency Locality Theory (DLT)6,7, the processing difficulties or costs in sentence processing are determined by the distance between the incoming word and the dependent word to which it is attached and thus the costs may vary at different regions in the sentence. The processing costs increase when the distance between the word and its dependent is longer. Therefore, due to the decline of working memory in older adults, they may encounter greater difficulties than younger adults at the words that are located far away from their dependents and are cognitively more costly, such as the verbs (&#39;attacked&#39;) of object RCs. Although the DLT was supported by prior work8,9, it has also been challenged by a number of studies10. The study of the precise locations of the processing difficulties in older and younger adults can test the validity of the DLT and help us to understand the relationships between sentence processing and cognitive resources. It can also provide a fine-grained picture of how ageing might influence online sentence processing.
Previous studies on the effect of ageing on sentence processing during reading have mostly adopted self-paced reading5,11, self-paced listening4 and cross-modal priming2. As an online measure, cross-modal priming tasks can be used to probe the activation of syntactic or lexical information in sentence processing. However, this task can only reveal the processing performance at a certain word or phrase and thus it does not allow us to measure participants&#39; performance at different segments of the sentence to identify where their processing difficulties are mainly located. Actually, so far there has been only one study which used the cross-modal priming task to examine the age-related decline in sentence processing. Zurif et al. (1995) discovered that older adults encountered greater difficulty in processing English object RCs at the verb regions when the distance between gaps and fillers was longer2. The study suggested that there was an age-related decline in RC processing as a result of the lack of working memory resources2. However, due to methodological constraints, the study failed to provide information regarding the processing difficulty at other regions of RCs.
As one of the most frequently used approaches in the research into the effect of ageing on sentence processing, self-paced reading (SPR) tasks require participants to read sentences word by word by pressing a specific button. Participants indicate with a press of the button that they have finished reading the word on the screen and then the next word appear, replacing the previous one. The participants repeat this procedure until all words of the sentence are presented, at which point they are required to answer a comprehension question related to the meaning of the sentences they have just read. Reading times (RTs) are recorded and used to measure the processing difficulties for each sentence segment and responses to the sentence-final questions are used to measure the accuracy of sentence comprehension. SPR tasks differ significantly from natural reading because only one word is allowed to be displayed at a time and regressive eye movements are not possible12. The unnatural aspect of SPR tasks has the advantage of reducing the number of strategies used by participants and thus the interference of processing strategies on participants&#39; performance can be minimized. Therefore, SPR tasks are helpful for researchers to identify the processing difficulties related to processing every word in the sentences. The major problem with SPR tasks is that they cannot ensure accurate measurement of RTs as participants may delay button-pushing to memorize the sentences or speed up button-pushing to buffer each region for later construction in the sentences12.
Apart from SPR tasks, eye-tracking has also been frequently used in studies on sentence processing13,14,15. In eye-tracking experiments, full sentences are presented to participants and they are asked to read them naturally. The duration and location of eye fixations and regressions are recorded. The advantage of eye-tracking is that it allows for natural reading and puts little constraints on how participants read sentences12. However, the naturalness of eye-tracking also makes it difficult for researchers to assess the exact processing costs because participants might adopt a wide variety of reading strategies such as skimming or word-by-word reading12. Therefore, we are not clear whether the fixation location and duration reflect processing difficulties or the application of certain reading strategies.
In this study, we adopted a maze task16,17, which can solve these problems with SPR tasks, eyetracking and cross-modal priming tasks. A maze task is a more updated reading paradigm and an adaptation of self-paced reading tasks. The task is an approach adopted in psycholinguistic experiments to record RTs as participants read sentences word by word. In the tasks, participants are required to read a sentence by making a choice between two alternatives for each segment of the sentence16. The procedure of a maze task is demonstrated in Figure 1.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/60417/60417fig1.jpg" /> 
Figure 1: A sample display of the sequential frames in a maze sentence. The figure shows that there are two alternative words in each frame, only one of which can continue the sentence. <a href="https://www.jove.com/files/ftp_upload/60417/60417fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
If the first word of the sentence is the, which is followed by the pair cat and on, the participants are expected to choose cat by pressing a button to indicate that the word on the left is the grammatical continuation of the sentence. When the next pair of words (to and ate) is presented, the participants are expected to choose ate because it can serve as the verb of the sentence. This procedure is repeated until they arrive at the end of the sentence. In case they make a mistake, the current trial will be terminated, and the next trial starts. An online demonstration of the maze task provided by Kenneth Forster can be found at http://www.u.arizona.edu/~kforster/MAZE.
The maze task is a highly constrained experimental paradigm in which participants are not permitted to look ahead or back to the previous section of the sentence18,19. Each word must be integrated with the existing structure before participants can proceed to read the following word. This method requires participants to process the sentences very carefully and accurately and it reduces the processing strategies available to participants. It allows us to make an objective measurement of RTs in online sentence comprehension. Moreover, the maze task is more sensitive to the processing costs associated with integrating words into sentences12,16, as it places unusual constraints on the processing strategies available to the participants. In this sense, the maze task is particularly suitable for the studies of sentence processing by older adults. Due to their richer language experience, older adults tend to adopt various compensation strategies such as prediction to make their performance comparable with younger adults4. These strategies make the age differences in sentence processing less noticeable. In a maze task, if participants make a response prematurely, they will be forced to respond randomly at the next frame and thus, they are most likely to make an error. Therefore, the task does not allow participants to make predictions and the effect measured by the task is unanticipated in nature. By reducing the number of sentence processing strategies available to older adults12,16, the maze task allows for more objective assessment of the processing difficulties of older adults during sentence reading.
The maze task was utilized in our study to pinpoint the processing difficulties for older adults in sentence comprehension and to localize the effect of ageing. As older adults generally have slower speed of processing and longer reading times than younger adults, most previous studies evaluated the effect of ageing by measuring the extent to which the effect of syntactic complexity or processing cost is modulated by age, a common practice in the research into the effect of ageing on sentence processing. Most studies chose to use object relative clauses (ORCs) and subject relative clauses (SRCs) as the experimental stimuli as they represent syntactically more complex structures and less complex structures, as exemplified below. Therefore, in this study, we also examined the effect of ageing by evaluating the influence of age on the processing difference between SRCs and ORCs.
a. Subject relative clause, SRC: The girl who chased the boy was wearing a hat. 
b. Object relative clause, ORC: The girl whom the boy chased was wearing a hat.
According to Gibson&#39;s Dependency Locality Theory6,7, sentence (b) is more difficult to process than sentence (a) as there are higher storage costs and integration costs involved in (b) to assign patient role to the head noun girl. By comparing participants&#39; performance in processing SRCs and ORCs, we are able to find out how they process sentences with different cognitive burdens. However, previous studies are divided with regard to their interpretation of the effect of syntactic complexity. Some studies maintained that if the effect of sentence complexity is exacerbated in older adults, it suggests that older adults are more sensitive to processing costs than younger adults3,20. Therefore, the amplified effect of sentence complexity is regarded as the evidence for age-related decline in sentence processing. Other studies, however, proposed that an effect of sentence complexity indicated that older adults are capable of allocating cognitive recourses to sentence processing and thus it should be viewed as a sign for the preservation of sentence processing ability in older adults21. The two lines of research are divergent in their interpretation of the effect of sentence complexity mainly because the experimental methods used in these studies such as SPR or cross-modal priming cannot tell us whether older adults actually use their working memory resources to integrate the words into the previous sections of the sentence or they cannot integrate the words due to the lack of working memory recourses. The maze task can provide a perfect solution to this problem because participants are forced to integrate the words into the previous structures in this task. Therefore, it is safe to say that the RTs obtained from the maze task represent the actual processing costs or processing difficulty in sentence processing. The maze task provides an effective means to explore sentence processing by older adults. Qiao, Shen and Forster (2002) used the maze task to examine the processing of Mandarin RCs and discovered that this technique was highly sensitive to sentence complexity effect in the processing of Mandarin subject- and object-extracted RCs19. The study indicates that the maze task is applicable to the research which is intended to localize the experimental effect in Mandarin sentence processing or lexical processing.

<table><tbody><tr><td>Computers</td><td>N/A</td><td>N/A</td><td>Used to present stimuli and record subjects&#039; responses.</td></tr><tr><td>E-prime</td><td>PST</td><td>2.0.8.22</td><td>Stimulus presentation software</td></tr><tr><td>The Digital Working Memory Span Test</td><td>N/A</td><td>N/A</td><td>Used to assess subjects&#039; working memory span. From Wechsler (1987).</td></tr><tr><td>The Global Deterioration Scale (GDS)</td><td>N/A</td><td>N/A</td><td>Used to assess subjects&#039; general cognitive status. From Reisberg, Ferris, de Leon and Crook (1988)</td></tr></tbody></table>

an experimental paradigm for measuring the effects of ageing on sentence processing

Previous studies have found that older adults have greater difficulties in processing syntactically complex sentences than younger adults. However, the exact regions where the difficulties arise have not been fully identified. In this study, a maze task was implemented to investigate how older adults and younger adults differentially processed two types of sentences with different levels of syntactic complexity, namely subject relative clauses and object relative clauses. Participants were asked to choose between two alternatives at each segment of the sentences. The task required participants to engage in a strictly incremental mode of processing. The reading times for each segment were recorded, allowing the quantification of the difficulty of sentence reading. The task allowed us to identify the exact locations of the processing difficulty and thus facilitate a more accurate assessment of the age-related decline in sentence processing. The results indicate that the effect of ageing was found mainly at the head nouns, but not at other regions of the sentences, a finding which suggests that the maze task is an effective method to identify the exact location of the ageing effect on sentence processing. The implications of this experimental paradigm for investigating the effect of ageing on sentence processing are discussed.

This study is intended to examine the effect of ageing on online sentence processing using a maze task. The RTs for each segment in the sentences are used to indicate the processing difficulty. In this study, we explored how a group of older adults (Mage = 65.2, SD = 3.04, Range = 59 -74) and younger adults (Mage = 19.1, SD = 1.04, Range = 18-23) differentially processed Mandarin SRCs and ORCs. The two age groups were matched in education (Mold = 12.8, SD ...

Watch this Scientific Journal Video about An Experimental Paradigm for Measuring the Effects of Ageing on Sentence Processing at JoVE.com

An Experimental Paradigm for Measuring the Effects of Ageing on Sentence Processing

Here, we present a protocol to examine the age-related decline in sentence processing using a maze task that allowed us to localize the processing difficulty at each word of the sentences during reading.

Previous studies have found that older adults have greater difficulties in processing syntactically complex sentences than younger adults. However, the ...

an-experimental-paradigm-for-measuring-effects-ageing-on-sentence

Research

JoVE Journal

Behavior

5.6K Views.  Beijing Foreign Studies University. Dit protocol biedt een effectief middel voor het onderzoeken van de experimentele effecten van online zinsverwerking in verschillende leeftijdsgroepen en kan de problemen met het bijhouden van advertenties in zelfstudietaken overwinnen. Met behulp van deze techniek kunnen we de leestijden van elk segment nauwkeurig meten in de zinnen, waardoor we de verwerkingsmoeheid in zinsbegrip nauwkeurig kunnen lokaliseren. Het aantonen van de procedure zal Liu Chong zijn, een student van mijn afdeling.

Video: An Experimental Paradigm for Measuring the Effects of Ageing on Sentence Processing

Assessment of Age-related Changes in Cognitive Functions Using EmoCogMeter, a Novel Tablet-computer Based Approach

The main goal of this study was to assess the usability of a tablet-computer-based application (EmoCogMeter) in investigating the effects of age on cognitive functions across the lifespan in a sample of 378 healthy subjects (age range 18-89 years). Consistent with previous findings we found an age-related cognitive decline across a wide range of neuropsychological domains (memory, attention, executive functions), thereby proving the usability of our tablet-based application. Regardless of prior computer experience, subjects of all age groups were able to perform the tasks without instruction or feedback from an experimenter. Increased motivation and compliance proved to be beneficial for task performance, thereby potentially increasing the validity of the results. Our promising findings underline the great clinical and practical potential of a tablet-based application for detection and monitoring of cognitive dysfunction.

We tested the usability of a tablet-computer-based application (EmoCogMeter) in investigating the effects of age on cognition. Results show an age-related cognitive decline, thereby proving the usability of our application. Findings underline the great clinical and practical potential of a tablet-based application for detection and monitoring of cognitive dysfunction.

The main goal of this study was to assess the usability of a tablet-computer-based application (EmoCogMeter) in investigating the effects of age on ...

A Method for Investigating Age-related Differences in the Functional Connectivity of Cognitive Control Networks Associated with Dimensional Change Card Sort Performance

The ability to adjust behavior to sudden changes in the environment develops gradually in childhood and adolescence. For example, in the Dimensional Change Card Sort task, participants switch from sorting cards one way, such as shape, to sorting them a different way, such as color. Adjusting behavior in this way exacts a small performance cost, or switch cost, such that responses are typically slower and more error-prone on switch trials in which the sorting rule changes as compared to repeat trials in which the sorting rule remains the same. The ability to flexibly adjust behavior is often said to develop gradually, in part because behavioral costs such as switch costs typically decrease with increasing age. Why aspects of higher-order cognition, such as behavioral flexibility, develop so gradually remains an open question. One hypothesis is that these changes occur in association with functional changes in broad-scale cognitive control networks. On this view, complex mental operations, such as switching, involve rapid interactions between several distributed brain regions, including those that update and maintain task rules, re-orient attention, and select behaviors. With development, functional connections between these regions strengthen, leading to faster and more efficient switching operations. The current video describes a method of testing this hypothesis through the collection and multivariate analysis of fMRI data from participants of different ages.

This video presents a method of examining age-related changes in functional connectivity of cognitive control networks engaged by targeted tasks/processes. The technique is based on multi-variate analysis of fMRI data.

The ability to adjust behavior to sudden changes in the environment develops gradually in childhood and adolescence. For example, in the Dimensional ...

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease

Our laboratory uses event-related EEG potentials (ERPs) to understand and support behavioral investigations of episodic memory in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). Whereas behavioral data inform us about the patients' performance, ERPs allow us to record discrete changes in brain activity. Further, ERPs can give us insight into the onset, duration, and interaction of independent cognitive processes associated with memory retrieval. In patient populations, these types of studies are used to examine which aspects of memory are impaired and which remain relatively intact compared to a control population. The methodology for collecting ERP data from a vulnerable patient population while these participants perform a recognition memory task is reviewed. This protocol includes participant preparation, quality assurance, data acquisition, and data analysis. In addition to basic setup and acquisition, we will also demonstrate localization techniques to obtain greater spatial resolution and source localization using high-density (128 channel) electrode arrays.

The methodology for collecting high-density event-related potential data while patients with Alzheimer's disease perform a recognition memory task is reviewed. This protocol will include subject preparation, quality assurance, data acquisition, and data analysis.

Our laboratory uses event-related EEG potentials (ERPs) to understand and support behavioral investigations of episodic memory in patients with amnestic ...

Medicine

Preparation of Acute Hippocampal Slices from Rats and Transgenic Mice for the Study of Synaptic Alterations during Aging and Amyloid Pathology

The rodent hippocampal slice preparation is perhaps the most broadly used tool for investigating mammalian synaptic function and plasticity. The hippocampus can be extracted quickly and easily from rats and mice and slices remain viable for hours in oxygenated artificial cerebrospinal fluid. Moreover, basic electrophysisologic techniques are easily applied to the investigation of synaptic function in hippocampal slices and have provided some of the best biomarkers for cognitive impairments. The hippocampal slice is especially popular for the study of synaptic plasticity mechanisms involved in learning and memory. Changes in the induction of long-term potentiation and depression (LTP and LTD) of synaptic efficacy in hippocampal slices (or lack thereof) are frequently used to describe the neurologic phenotype of cognitively-impaired animals and/or to evaluate the mechanism of action of nootropic compounds. This article outlines the procedures we use for preparing hippocampal slices from rats and transgenic mice for the study of synaptic alterations associated with brain aging and Alzheimer's disease (AD)1-3. Use of aged rats and AD model mice can present a unique set of challenges to researchers accustomed to using younger rats and/or mice in their research. Aged rats have thicker skulls and tougher connective tissue than younger rats and mice, which can delay brain extraction and/or dissection and consequently negate or exaggerate real age-differences in synaptic function and plasticity. Aging and amyloid pathology may also exacerbate hippocampal damage sustained during the dissection procedure, again complicating any inferences drawn from physiologic assessment. Here, we discuss the steps taken during the dissection procedure to minimize these problems. Examples of synaptic responses acquired in "healthy" and "unhealthy" slices from rats and mice are provided, as well as representative synaptic plasticity experiments. The possible impact of other methodological factors on synaptic function in these animal models (e.g. recording solution components, stimulation parameters) are also discussed. While the focus of this article is on the use of aged rats and transgenic mice, novices to slice physiology should find enough detail here to get started on their own studies, using a variety of rodent models.

This article outlines procedures for preparing hippocampal slices from rats and transgenic mice for the study of synaptic alterations associated with brain aging and age-related neurodegenerative diseases, such as Alzheimer&#x2019;s disease.

The rodent hippocampal slice preparation is perhaps the most broadly used tool for investigating mammalian synaptic function and plasticity. The ...

Neuroscience

A Cognitive Paradigm to Investigate Interference in Working Memory by Distractions and Interruptions

Goal-directed behavior is often impaired by interference from the external environment, either in the form of distraction by irrelevant information that one attempts to ignore, or by interrupting information that demands attention as part of another (secondary) task goal. Both forms of external interference have been shown to detrimentally impact the ability to maintain information in working memory (WM). Emerging evidence suggests that these different types of external interference exert different effects on behavior and may be mediated by distinct neural mechanisms. Better characterizing the distinct neuro-behavioral impact of irrelevant distractions versus attended interruptions is essential for advancing an understanding of top-down attention, resolution of external interference, and how these abilities become degraded in healthy aging and in neuropsychiatric conditions. This manuscript describes a novel cognitive paradigm developed the Gazzaley lab that has now been modified into several distinct versions used to elucidate behavioral and neural correlates of interference, by to-be-ignored distractors versus to-be-attended interruptors. Details are provided on variants of this paradigm for investigating interference in visual and auditory modalities, at multiple levels of stimulus complexity, and with experimental timing optimized for electroencephalography (EEG) or functional magnetic resonance imaging (fMRI) studies. In addition, data from younger and older adult participants obtained using this paradigm is reviewed and discussed in the context of its relationship with the broader literatures on external interference and age-related neuro-behavioral changes in resolving interference in working memory.

A novel cognitive paradigm is developed to elucidate behavioral and neural correlates of interference by to-be-ignored distractors versus interference by to-be-attended interruptors during a working memory task. In this manuscript, several variants of this paradigm are detailed, and data obtained with this paradigm in younger/older adult participants is reviewed.

Goal-directed behavior is often impaired by interference from the external environment, either in the form of distraction by irrelevant information that ...

Automated, Long-term Behavioral Assay for Cognitive Functions in Multiple Genetic Models of Alzheimer's Disease, Using IntelliCage

Multiple factors&#8212;such as aging and genes&#8212;are frequently associated with cognitive decline. Genetically modified mouse models of cognitive decline, such as Alzheimer&#39;s disease (AD), have become a promising tool to elucidate the underlying mechanisms and promote the therapeutic advances. An important step is the validation and characterization of expected behavioral abnormality in the models, in the case of AD, cognitive decline. The long-term behavioral investigations of laboratory animals to study the effect of aging demand substantial efforts from researchers. The IntelliCage system is a high-throughput and cost-effective test battery for mice that eliminates the need for daily human handling. Here, we describe how the system is utilized in the long-term phenotyping of a genetic Alzheimer&#39;s disease model, specifically focusing on the cognitive functions. The experiment employs repeated battery of tests that assess spatial learning and executive functions. This cost-effective age-dependent phenotyping allows us to identify the transient and/or permanent effects of genes on various cognitive aspects.

This paper describes a protocol for cognitive assessments for genetic models of the Alzheimer&#39;s disease using the IntelliCage system, which is a high throughput automated behavioral monitoring system with operant conditioning.

Multiple factors&#8212;such as aging and genes&#8212;are frequently associated with cognitive decline. Genetically modified mouse models of cognitive ...

Examining Online Syntactic Processing of Spoken Complex Sentences in Chinese Using Dual-Modal Interference Tasks

Working memory (WM) plays a central role in the comprehension of complex sentences. Its function in the processing of spoken complex sentences is especially evident because spoken complex sentence processing is memory-intensive. The dual-modal interference paradigm has been used to examine how the WM system is involved in complex syntactic processing. This article presents two exemplar experiments involving auditory processing with either intra- or extrasentential interferences. In the first experiment, auditory stimuli [spoken-Chinese relative clause (RC) sentences with two syntactic types: subject-gapped (SRC) vs. object-gapped (ORC)] are interfered with via a visually presented lexical decision task within a sentence and manipulated using three different interference timepoints. In the second experiment, the same auditory stimuli, presented via an auditory window moving technique, are interfered with via a visually presented digital recall task beyond the sentence and manipulated using three digital memory loads. By assessing how the primary task of comprehending the RC sentences is affected by the secondary task, we can tackle the controversial issue concerning Chinese RC processing asymmetry. Our results reveal different patterns of RC processing compared to those reported in previous studies. Experiment 1 manifests no clear RC processing advantages in either SRC or ORC; however, a preference for ORC is observed at the ends of sentences, and a preference for SRC is found at the main verb site. Likewise, Experiment 2 presents a dynamic pattern. Under a no-digit load, SRCs show processing advantages in the RC marker region. However, under higher-digit-load interference, ORCs show processing advantages in the same region. These results lead to the conjecture that no obvious or intrinsic processing asymmetry exists in the processing of Chinese RCs. Using the approach of assessing specific interference during syntactic processing, these experiments demonstrate future research applications that explore the processing metrics of spoken sentences involving working memory.

Here, we present a protocol employing dual-modal interference tasks to examine online processing of spoken-Chinese relative clause sentences. Two exemplar experiments involving auditory processing with intra- and extrasentential interferences are described. The paradigm provides a methodology for addressing the nature of working memory and its effects on sentence processing.

Working memory (WM) plays a central role in the comprehension of complex sentences. Its function in the processing of spoken complex sentences is ...

Lexical Decision Task for Studying Written Word Recognition in Adults with and without Dementia or Mild Cognitive Impairment

Older adults are slower at recognizing visual objects than younger adults. The same is true for recognizing that a letter string is a real word. People with Alzheimer&#39;s disease (AD) or Mild Cognitive Impairment (MCI) demonstrate even longer responses in written word recognition than elderly controls. Despite the general tendency towards slower recognition in aging and neurocognitive disorders, certain characteristics of words influence word recognition speed regardless of age or neuropathology (e.g., a word&#8217;s frequency of use). We present here a protocol for examining the influence of lexical characteristics on word recognition response times in a simple lexical decision experiment administered to younger and older adults and people with MCI or AD. In this experiment, participants are asked to decide as quickly and accurately as possible whether a given letter string is an actual word or not. We also describe mixed-effects models and principal components analysis that can be used to detect the influence of different types of lexical variables or individual characteristics of participants on word recognition speed.

This article describes how to implement a simple lexical decision experiment to assess written word recognition in neurologically healthy participants and in individuals with dementia and cognitive decline. We also provide a detailed description of reaction time analysis using principal components analysis (PCA) and mixed-effects modeling.

Older adults are slower at recognizing visual objects than younger adults. The same is true for recognizing that a letter string is a real word. People ...

Highlighting and Reducing the Impact of Negative Aging Stereotypes During Older Adults' Cognitive Testing

As life expectancy increases, aging has become a major health challenge, resulting in a huge effort to better discriminate between normal and pathological cognitive decline. It is thus essential that cognitive tests and their administration are as fair as possible. However, an important source of bias during cognitive testing comes from negative aging stereotypes that can impair the memory performance of older adults and inflate age differences on cognitive tasks. The fear of confirming negative aging stereotypes creates an extra pressure among older adults which interferes with their intellectual functioning and leads them to perform below their true abilities. Here, we present a protocol that highlights simple but efficient interventions to alleviate this age-based stereotype threat effect. The first study showed that simply informing older participants about the presence of younger participants (threat condition) led older adults to underperform on a standardized memory test compared with younger participants, and that this performance difference was eliminated when the test was presented as age-fair (reduced-threat condition). The second study replicated these findings on short cognitive tests used to screen for predementia in clinical settings and showed that teaching older adults about stereotype threat inoculated them against its effects. These results provide useful recommendations about how to improve older adults' memory assessment both in Iab studies and in clinical settings.

Here, we present a protocol designed to show how negative aging stereotypes can impair memory performance of older adults during cognitive testing and how to reduce this deleterious effect. This method can help older people to perform at an optimal level during testing in both lab studies and clinical settings.

As life expectancy increases, aging has become a major health challenge, resulting in a huge effort to better discriminate between normal and pathological ...

Experimental Paradigm for Measuring the Effect of Induced Emotion on Grammar Learning

Previous studies have found that emotion has significant influence on the learning of foreign language vocabulary and textual comprehension. However, little attention has been given to the effect of induced emotion on grammar learning. This research examined the influence of positive induced emotion on the learning of Japanese grammatical rules among a group of learners with Chinese as their native language, using a semi-artificial language (i.e. Chipanese), which combines the grammatical rules of Japanese and the vocabulary of Chinese. Music was used to invoke positive emotional conditions in participants. Participants were required to learn Chipanese sentences in a training session through practice and then a grammaticality judgment task was administered to measure learning outcomes. We found that participants in positive emotional states performed less accurately and efficiently than those in the control group. The findings suggest that the protocol is effective in identifying the effect of positive induced emotion on grammar learning. The implications of this experimental paradigm for investigating foreign language learning are discussed.

Here, we present a protocol to measure the effect of positive induced emotion on grammar learning in foreign language learners using a semi-artificial language that integrates the grammatical rules of a foreign language with the lexicon of the learners&#39; native language.

Previous studies have found that emotion has significant influence on the learning of foreign language vocabulary and textual comprehension. However, ...

An Experimental Paradigm for Measuring the Effects of Ageing on Sentence Processing

Samenvatting

Meer video's verkennen