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Inter-regional brain communication and its disturbance in autism.

Schipul SE, Keller TA, Just MA - Front Syst Neurosci (2011)

Bottom Line: Specifically, the underconnectivity theory of autism postulates that individuals with autism have a reduced communication bandwidth between frontal and posterior cortical areas, which constrains the psychological processes that rely on the integrated functioning of frontal and posterior brain networks.It also summarizes the findings of disordered anatomical connectivity in autism, as measured by a variety of techniques, including distribution of white matter volumes and diffusion tensor imaging.We conclude with a discussion of the implications of these findings for autism and future directions for this line of research.

View Article: PubMed Central - PubMed

Affiliation: Center for Cognitive Brain Imaging, Department of Psychology, Carnegie Mellon University Pittsburgh, PA, USA.

ABSTRACT
In this review article, we summarize recent progress toward understanding disturbances in functional and anatomical brain connectivity in autism. Autism is a neurodevelopmental disorder affecting language, social interaction, and repetitive behaviors. Recent studies have suggested that limitations of frontal-posterior brain connectivity in autism underlie the varied set of deficits associated with this disorder. Specifically, the underconnectivity theory of autism postulates that individuals with autism have a reduced communication bandwidth between frontal and posterior cortical areas, which constrains the psychological processes that rely on the integrated functioning of frontal and posterior brain networks. This review summarizes the recent findings of reduced frontal-posterior functional connectivity (synchronization) in autism in a wide variety of high-level tasks, focusing on data from functional magnetic resonance imaging studies. It also summarizes the findings of disordered anatomical connectivity in autism, as measured by a variety of techniques, including distribution of white matter volumes and diffusion tensor imaging. We conclude with a discussion of the implications of these findings for autism and future directions for this line of research.

No MeSH data available.


Related in: MedlinePlus

This diagram depicts functional underconnectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The width of each connecting line represents the t-value of the difference in functional connectivity between the participants with autism and the neurotypical participants. Blue nodes are frontal regions and red nodes are posterior regions. The widest lines (reflecting the greatest group differences) are those connecting frontal and posterior regions. Data from Mason et al. (2008), with permission. MedFG, medial frontal gyrus; LIFG, left inferior frontal gyrus; RTPJ, right temporo-parietal junction; LMTG, left middle temporal gyrus; LMTGa, anterior left middle temporal gyrus.
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Figure 1: This diagram depicts functional underconnectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The width of each connecting line represents the t-value of the difference in functional connectivity between the participants with autism and the neurotypical participants. Blue nodes are frontal regions and red nodes are posterior regions. The widest lines (reflecting the greatest group differences) are those connecting frontal and posterior regions. Data from Mason et al. (2008), with permission. MedFG, medial frontal gyrus; LIFG, left inferior frontal gyrus; RTPJ, right temporo-parietal junction; LMTG, left middle temporal gyrus; LMTGa, anterior left middle temporal gyrus.

Mentions: Similar findings of lower functional connectivity in autism in relevant frontal and posterior areas have been reported in a wide variety of cognitive tasks. For example, in a passage comprehension task in which participants had to make inferences about the characters’ intentions, decreased functional connectivity in autism was found between frontal and parietal Theory of Mind areas, as well as between frontal language areas and parietal Theory of Mind areas (Mason et al., 2008). Figure 1 depicts the frontal–posterior underconnectivity in autism during this task (where line width corresponds to the group difference in functional connectivity). In a Tower of London task, decreased functional connectivity in autism was found between frontal and parietal working memory areas (Just et al., 2007). In a task which required participants to make inferences about the intentions of computer-animated geometric figures, individuals with autism had lower functional connectivity between frontal and posterior Theory of Mind areas (Kana et al., 2009). In a reading comprehension task with sentences of varying complexity, underconnectivity was found in autism between frontal and posterior areas involved in language comprehension and working memory (Just et al., 2004). In a working memory task with alphabetic characters, lower functional connectivity was reported between frontal and parietal working memory areas (Koshino et al., 2005). In a complex inhibition task, functional connectivity was lower in autism between the frontal inhibition network and the inferior parietal lobe (Kana et al., 2007). In a cognitive control task, lower functional connectivity was reported in ASD between the frontal executive system and several posterior regions in the brain, including parietal working memory areas and the visual cortex (Solomon et al., 2009). In the context of a working memory task with faces and houses (similar to that of Koshino et al., 2008, described above), lowered functional connectivity was found in ASD between the fusiform gyrus and the amygdala (both related to face processing), as well as between the fusiform gyrus and the posterior cingulate (Kleinhans et al., 2008). These studies collectively illustrate that functional underconnectivity has been observed in autism in a wide variety of frontal–posterior pairs. The communication between the members of each of these pairs is necessary for the integration of the multiple cognitive processes required for a given task. These findings support the underconnectivity theory's claim that decreased frontal–posterior connectivity in autism specifically affects behaviors that require the extensive coordinated functioning of frontal and posterior processing centers.


Inter-regional brain communication and its disturbance in autism.

Schipul SE, Keller TA, Just MA - Front Syst Neurosci (2011)

This diagram depicts functional underconnectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The width of each connecting line represents the t-value of the difference in functional connectivity between the participants with autism and the neurotypical participants. Blue nodes are frontal regions and red nodes are posterior regions. The widest lines (reflecting the greatest group differences) are those connecting frontal and posterior regions. Data from Mason et al. (2008), with permission. MedFG, medial frontal gyrus; LIFG, left inferior frontal gyrus; RTPJ, right temporo-parietal junction; LMTG, left middle temporal gyrus; LMTGa, anterior left middle temporal gyrus.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3046360&req=5

Figure 1: This diagram depicts functional underconnectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The width of each connecting line represents the t-value of the difference in functional connectivity between the participants with autism and the neurotypical participants. Blue nodes are frontal regions and red nodes are posterior regions. The widest lines (reflecting the greatest group differences) are those connecting frontal and posterior regions. Data from Mason et al. (2008), with permission. MedFG, medial frontal gyrus; LIFG, left inferior frontal gyrus; RTPJ, right temporo-parietal junction; LMTG, left middle temporal gyrus; LMTGa, anterior left middle temporal gyrus.
Mentions: Similar findings of lower functional connectivity in autism in relevant frontal and posterior areas have been reported in a wide variety of cognitive tasks. For example, in a passage comprehension task in which participants had to make inferences about the characters’ intentions, decreased functional connectivity in autism was found between frontal and parietal Theory of Mind areas, as well as between frontal language areas and parietal Theory of Mind areas (Mason et al., 2008). Figure 1 depicts the frontal–posterior underconnectivity in autism during this task (where line width corresponds to the group difference in functional connectivity). In a Tower of London task, decreased functional connectivity in autism was found between frontal and parietal working memory areas (Just et al., 2007). In a task which required participants to make inferences about the intentions of computer-animated geometric figures, individuals with autism had lower functional connectivity between frontal and posterior Theory of Mind areas (Kana et al., 2009). In a reading comprehension task with sentences of varying complexity, underconnectivity was found in autism between frontal and posterior areas involved in language comprehension and working memory (Just et al., 2004). In a working memory task with alphabetic characters, lower functional connectivity was reported between frontal and parietal working memory areas (Koshino et al., 2005). In a complex inhibition task, functional connectivity was lower in autism between the frontal inhibition network and the inferior parietal lobe (Kana et al., 2007). In a cognitive control task, lower functional connectivity was reported in ASD between the frontal executive system and several posterior regions in the brain, including parietal working memory areas and the visual cortex (Solomon et al., 2009). In the context of a working memory task with faces and houses (similar to that of Koshino et al., 2008, described above), lowered functional connectivity was found in ASD between the fusiform gyrus and the amygdala (both related to face processing), as well as between the fusiform gyrus and the posterior cingulate (Kleinhans et al., 2008). These studies collectively illustrate that functional underconnectivity has been observed in autism in a wide variety of frontal–posterior pairs. The communication between the members of each of these pairs is necessary for the integration of the multiple cognitive processes required for a given task. These findings support the underconnectivity theory's claim that decreased frontal–posterior connectivity in autism specifically affects behaviors that require the extensive coordinated functioning of frontal and posterior processing centers.

Bottom Line: Specifically, the underconnectivity theory of autism postulates that individuals with autism have a reduced communication bandwidth between frontal and posterior cortical areas, which constrains the psychological processes that rely on the integrated functioning of frontal and posterior brain networks.It also summarizes the findings of disordered anatomical connectivity in autism, as measured by a variety of techniques, including distribution of white matter volumes and diffusion tensor imaging.We conclude with a discussion of the implications of these findings for autism and future directions for this line of research.

View Article: PubMed Central - PubMed

Affiliation: Center for Cognitive Brain Imaging, Department of Psychology, Carnegie Mellon University Pittsburgh, PA, USA.

ABSTRACT
In this review article, we summarize recent progress toward understanding disturbances in functional and anatomical brain connectivity in autism. Autism is a neurodevelopmental disorder affecting language, social interaction, and repetitive behaviors. Recent studies have suggested that limitations of frontal-posterior brain connectivity in autism underlie the varied set of deficits associated with this disorder. Specifically, the underconnectivity theory of autism postulates that individuals with autism have a reduced communication bandwidth between frontal and posterior cortical areas, which constrains the psychological processes that rely on the integrated functioning of frontal and posterior brain networks. This review summarizes the recent findings of reduced frontal-posterior functional connectivity (synchronization) in autism in a wide variety of high-level tasks, focusing on data from functional magnetic resonance imaging studies. It also summarizes the findings of disordered anatomical connectivity in autism, as measured by a variety of techniques, including distribution of white matter volumes and diffusion tensor imaging. We conclude with a discussion of the implications of these findings for autism and future directions for this line of research.

No MeSH data available.


Related in: MedlinePlus