Neuroscience article. https://academic.oup.com/cercor/article/20/8/1937/404725 <
ID: 129308 • Letter: N
Question
Neuroscience article. https://academic.oup.com/cercor/article/20/8/1937/404725 <-- Link
Semantic, Factual, and Social Language Comprehension in Adolescents with Autism: An FMRI Study
I have already typed down what I thought were the key points, but I just got it directly from the text instead of actually understanding. Can you please read the article and/or my notes and help me understand the methods/tasks and the results/discussion? Please explain in simple terms. All this neuroscience jargon is confusing me. Thank you!
Introduction/Brief Overview
Language deficits in high-functioning autism is characterized by pragmatic and semantic deficits.
People with autism have a reduced tendency to integrate information
Because the left and right inferior frontal (LIF and RIF) regions are implicated with integration of speaker information, world knowledge, and semantic knowledge, they hypothesized that abnormal functioning of the LIF and RIF regions might contribute to pragmatic and semantic language deficits in autism.
Brain activation of sixteen 12- to 18-year-old, high functioning autistic participants was measured with functional magnetic resonance imaging during sentence comprehension and compared with that of 26 matched individuals
The content of the pragmatic sentence was congruent or incongruent with respect to the speaker characteristics (male/female, child/adult, and upper class/lower class).
The semantic- and world-knowledge sentences were congruent or incongruent with respect to semantic expectancies and factual expectancies about the world, respectively.
In the semantic-knowledge and world-knowledge condition, activation of the LIF region did not differ between groups.
In sentences that require integration of speaker information, the autism group showed abnormally reduced activation of the LIF region.
These results suggest that people with autism may recruit the LIF region in a different manner in tasks that demand integration of social information.
Materials and Methods
Participants
Two groups participated in the study: 30 adolescents with high functioning autism and 31 matched, typically developing (TD) adolescents.
All participants were Caucasian adolescents from 12 to 18 years old.
Exclusion criteria were left handedness, IQ (total, verbal, or performance) lower than 85, any general medical condition affecting brain function, neurologic disorders, and substance abuse.
Due to excessive head movements during MRI data acquisition, defined as a translation of more than one voxel in either direction, 5 sessions from the control group and 14 sessions from the autism group were excluded from further analysis so that 16 participants with autism and 26 TD participants were entered in the final analysis.
The participants with autism were recruited from referrals to Karakter Child and Adolescent Psychiatry University Center in Nijmegen. Control participants were recruited through local schools.
Data Acquisition
FMRI data was acquired on a 1.5-T Siemens Sonata whole-body scanner.
The auditory stimuli were presented through headphones, and the visual stimuli were projected onto a translucent screen that participants could view through a mirror mounted on the head coil.
Functional images were acquired using a gradient echo planar imaging sequence (time re
FMRI Stimuli Paradigm
In a separate session prior to the MRI scanning procedure, all participants practiced the experimental paradigm in a dummy scanner to get adjusted to the scanner environment. To make sure that the participants focused their attention on the auditory stimuli without enforcing explicit processing of the sentence meaning, participants were asked to perform a task that was orthogonal to the experimental conditions of interest. That is, the task entailed pushing a button upon hearing the target condition, that is, sentences that only contained pseudowords. All participants were able to master the experimental task in the practice session without mistakes. The sentences used in the practice session were different from those in the actual experiment.
The MRI scanning was done in 2 30-min runs with a 30-min break in between. Spoken sentences were presented in a pseudorandomized event-related design, with an interstimulus interval jittered in 0.5-s steps from 8.2 to 9.7 s after each sentence during which an asterisk was shown. The participants were asked to attentively listen to all sentences and to press a button whenever they heard a sentence that contained pseudowords.
Apart from the target condition, 80 pairs of sentences that differed only with respect to the speaker voice (male/female, child/adult, upper class/lower class; referred to as speaker-identity condition), 36 triplets of sentences that differed only with respect to one critical word (no anomaly; semantic anomaly; and world-knowledge anomaly) and 36 speech-like noise fragments matched on spectral and temporal properties with an average duration of 3.0 s were used (referred to as noise condition). The critical words were matched on word frequency, average length, and word class. The sentences were recorded in a sound studio by a total of 26 actors, 2 of whom were children.
The speaker-identity sentences were utterances in which sentence meaning did or did not voice-based expectations about speaker’s age, gender, or social background.
Example - “I have a very large tattoo on my back” spoken in an upper class and a lower-class accent; “Every morning, I drink a cup of coffee at breakfast” spoken by a child and an adult; “If I only I looked like Britney Spears in her latest video” spoken by a male and a female.
For this condition, there were 40 sentences that were congruent and 40 sentences that were incongruent with the speaker’s gender; 20 sentences that were congruent, and 20 sentences that were incongruent with speaker’s age; 20 sentences that were congruent and 20 sentences that were incongruent with speaker’s social status. They counterbalanced the sentences pairs over the participants so that only one sentence of each pair was played per participant.
The world knowledge and semantic-knowledge sentences were piloted among 90 12-year-old, high-school children to ensure that they knew the world knowledge and semantic knowledge referred to in the sentences. Only those sentences that could be understood and explained correctly (for the semantic-knowledge condition) or appreciated for their veridicality (in the world-knowledge condition) were used in the experiment. Examples were “Dutch trains are sour” (semantic anomaly) and “Dutch trains are white.” The last sentence comprises a world-knowledge anomaly because it is a well-known fact among Dutch people that Dutch trains are yellow. In the example, the third sentence of the triplet was “Dutch trains are yellow” containing no anomaly. In the current experiment, 36 triplets (world-knowledge anomaly, semantic-knowledge anomaly and no anomaly) of sentences were used. These sentences were also counterbalanced over participants.
Results
ROI Results
To test their hypotheses about integration of speaker identity, they first tested the speaker-incongruent greater than speaker-congruent contrast in the control group.
As they hypothesized, both the LIFG (-54, 26, 14) and the RIFG (50, 34, 12) were significantly activated.
The autism group, however, failed to activate those ROIs in the speaker-identity contrast.
In the inverse contrast (congruent greater than incongruent), neither group activated any ROI.
In the direct group comparison, the LIFG (-54, 26, 14) was significantly more activated in the control group, whereas the RIFG did not yield significant differences.
Second, they tested world knowledge greater than correct sentence contrast.
Whole-Brain Results - for the whole-brain analysis, tested the same contrasts as the ROI analyses
First, tested the speaker-identity condition. In this condition, speaker-incongruent and speaker-congruent sentences were contrasted.
Greater activation for speaker-incongruent than speaker-congruent sentences were observed in the control group in the left and right precuneus and cuneus.
Conversely speaker-congruent vs. speaker-incongruent sentences showed greater activation in the right supramarginal, right superior, middle and inferior temporal gyrus, the right superior-frontal gyrus, as well as in the right anterior cingulate cortex and the superior orbital gyrus in controls
Second, tested the world-knowledge condition. In this condition, sentences at odds with well-known facts were contrasted with factually correct sentences.
The control group showed distinct activation of language association areas, including the left middle and superior temporal gyrus, the LIFG, and RIF regions were activated but the temporal regions and the cerebellum were not.
Third , tested the semantic-knowledge condition.
In the control group, the activation pattern for sentences that contained semantic anomalies contrasted against correct sentences, mirrored the activation pattern for the world-knowledge anomalies: distinct activation of the language association regions (left superior and middle temporal gyrus and LIFG) and the contralateral cerebellum.
In the autism group, the LIFG was activated, but the temporal areas were not.
In contrast to the world-knowledge condition, the RIFG was not activated.
However, direct group comparison did not reveal significant differences.
Fourth, tested the speech vs. noise condition.
When sentences were contrasted against noise that resembled the temporal and spectral characteristics of speech, a large number of voxels were significant both in the autism and the control group.
Behavioral Results
After the scanning sessions, all participants underwent an extensive exit interview in which they were asked to state whether they had heard odd sentences.
All participants were able to describe the experimental manipulation for world knowledge, semantic knowledge, and speaker inferences and mentioned all three types of incongruencies spontaneously (e.g., world knowledge, semantic knowledge, and speaker inference).
Specifically, all participants in both groups could give at least one example of an utterance with a world-knowledge incongruency and a semantic-knowledge incongruency.
Speaker inference sentences: All participants in both groups could give at least one example of an utterance in which the speaker’s gender was incongruent with the speakers utterance. This was also the case for the speaker’s age.
Finally, 18/26 (69%) controls vs 10/16 (63%) participants with autism could give at least one example of an utterance in which the sentence meaning did not match voice-based expectations about speaker’s social status.
Thus, for both groups, the social status anomalies were least salient and to a similar extent in both groups. The behavioral data therefore suggest that the autism group was as able to identify world knowledge, semantic knowledge, and speaker inference incongruencies as the control group and that observed FMRI differences cannot be attributed to behavioral differences.
Discussion
They compared brain activation patterns in high-functioning adolescents with autism and well-matched control subjects during sentence processing. F
For the social contrasts, only the speaker differed so that the content of the sentence was in line (speaker congruent) or at odds (speaker incongruent) with voice-based inferences of the speaker’s age, gender, or social class.
For the semantic-knowledge and world-knowledge contrasts, sentences differed only for one critical word that was at odds or in line with knowledge about language or the world.
The first main finding was that although the autism group showed activation of the LIF region and the posterior-superior temporal region during world knowledge, semantic knowledge, and noise contrasts, the LIF region showed reduced activation in the autism group during the social contrasts compared with the control group. Thus, the integrative demand imposed by the socially incongruent sentences led to an increased activation of the LIF region in the control group only.
The second main finding was that left extrastriate visual regions were involved during auditory language comprehension in the autism group. During the world-knowledge anomaly condition, the autism group showed a reduced activation of the extrastriate area, whereas during a different condition (sentence vs. speech-like noise), the same region was activated. This activation pattern also been observed during single-word processing, in which autistic participants had to make semantic judgements.
Because the LIF region subserves integration processes that extend beyond semantic-knowledge and world-knowledge categories, we hypothesized that individuals with autism would show a reduced activation in the LIF region in the social condition. which was what they found.
In addition, they found no activation in the autism group in the social condition, either in the ROI or in the whole-brain analysis. Apparently, in the autism group, speaker-congruent vs. speaker-incongruent sentences do not lead to differential activation.
In the control group, we found RIFG and LIFG activation for the speaker-incongruent greater than speaker-congruent contrast. For the opposite contrast, large, mainly right-sided areas became active in the control group, including the medial frontal cortex (MFC), temporal areas and the precuneus.
As they hypothesized, the semantic and world-knowledge anomaly condition did not show any differential activation in the LIFG between the groups. Both the autism and control group showed robust LIFG activation, suggesting that integration of incongruent words (semantic) and integration of “facts” at odds with the current state of the world (e.g., false statements) increased activation in the LIFG in both groups in equal amounts. It would therefore appear that the activation of the LIFG and the RIFG is only reduced under certain circumstances in autism.
Explanation / Answer
Note: This response is in UK English, please paste the response to MS Word and you should be able to spot discrepancies easily
(Answer) Since you need an explanation, I will be conversational throughout the answer and not really prosaic. If you need this for an assignment, you may have to polish it up a bit.
I have read the article you have linked, it basically talks about the three perceptions or points of view of language and how adolescent autistic kids pick up language. There is the factual language, which is basically memorising words without much attention to the actual meanings. Then there is the semantic language which focuses more on the meaning of words. Finally, there is the social language which is pretty self-explanatory. It is when the autistic child is able to hold a meaningful social conversation.
What the article suggests is that autistic kids are able to memorise words easily. But, a proper comprehension of those words is difficult for them. For example, you can tell a subject about the words “salt” and “salty.” They will memorise it and speak out the words easily. You can explain the meaning of the word “salty” (in terms of taste and not personality) for hours. But the child will not understand you even if they listen intently.
However, when you take a pinch of salt and show it to the child and say “salt.” They now understand what the word salt really means. Furthermore, when you feed the child a pinch of salt and say “salty”, they now understand the meaning of salty.
During this experiment, regions of the brain known as LIF and RIF (left and right inferior frontal) kick into action. These regions are responsible for regulating information like world and semantic knowledge, speaker information etc.
But in an autistic child, it may take a little longer and a few more teaching exercises for them to understand “salt” and “salty.” This is because the LIF and RIF have defects because of their condition.
What the article says is that if there is a defect in one of the blades of a fan, the room may not be as cool. The research attempts to understand how different the cooling of a room with a defected fan really is? Even though we know it is different from a regular fan, the researchers try to understand the difference a little better.
From what I read about the experiment, it is pretty straightforward. Firstly the doctors had the challenge of monitoring brain functions while conducting the actual language test. So they conducted 2 tests per child. This is because the children were shaking their head frequently in the machine and the doctors wanted to get the children used to the machine first. In the first test, a fake machine is used and the real MRI machine is used in the 2nd test.
What they did was, they put a button inside the machine and spoke sentences to the children. These were fake or made up sentences. The children had to press the button upon some kind of recognition of those words. (The study doesn’t really mention what degree of recognition was needed for the kids to press the button for those words.)
The results show that most children recognised words and pressed the button successfully. But when the speaker was changed from male to female or any such thing, they did not always press the button. Perhaps they recognised the sound of the words or the speakers and not always the true feeling or understanding associated with that word.
One of the criteria was that they made odd people speak odd or incorrect sentences. Example, a man saying, “I wish I looked like Britney Spears.” Or a child saying, “I go to the office.”
To check the child’s world knowledge, they spoke incorrect facts like, “a chessboard has pink squares.”
The results: The autistic children failed to see the folly when a child spoke the sentence, “I go to the Office.” (These sentences are examples; the results are better detailed in the study with empirical values.)
I recommend that you try and understand this part better. (First, tested the speaker-identity condition. In this condition, speaker-incongruent and speaker-congruent sentences were contrasted.
Greater activation for speaker-incongruent than speaker-congruent sentences were observed in the control group in the left and right precuneus and cuneus.
Conversely speaker-congruent vs. speaker-incongruent sentences showed greater activation in the right supramarginal, right superior, middle and inferior temporal gyrus, the right superior-frontal gyrus, as well as in the right anterior cingulate cortex and the superior orbital gyrus in controls)
If you have trouble with it, I recommend that you look at a model of a brain or understand the function of each part of the brain mentioned in the parenthesis I have pasted above.
In fact, I recommend that throughout your semester, you should make a list of all these neurological terms and organs and write in 2 or 3 lines about their function. Make a rudimentary dictionary if you need. You will be able to understand it all better.
63% of autistic children found some or the other errors that were placed in sentences. But from the study, they found that these autistic children are able to connect the dots only under certain conditions or when they are probably comfortable enough to understand or focus on such faults in the sentences. This probably makes them more like normal children than we assume they are.
If you read the paper again, you may understand it better. If you have any other doubts, please comment below.