TYPICAL AND ATYPICAL DEVELOPMENT OF BRAIN NETWORKS IN CHILDREN USING EEG/Оценка типичного и атипичного развития нервных связей у детей методами EEG
Аннотация
Тема: Typical and atypical development of brain networks in children using EEG (Оценка типичного и атипичного развития нервных связей у детей методами EEG) by Despoina Tsolisou (Тсолису Деспина)
Top-down control of the visual cortex facilitates voluntary visual attention and the “collection” of relevant visual information that allows the child to learn. In adults, visual top-down control is performed with the prefrontal cortex manipulating the activity of visual cortex via the frontoparietal network (FPAN). In fact, the increase of frontocentral theta activity is suggested to indicate the activation of the anterior part of FPAN, and the decrease of alpha activity the visual network activation. Nevertheless, their relationship and the cognitive role of theta remains under investigation. On the other hand, infants demonstrate a more widespread brain activity as their networks are still under development. It is notable that impairment of top-down control and
inability to suppress irrelevant visual information has been connected with neurodevelopmental disorders such ADHD and learning difficulties. Thus, finding a biomarker for visual top-down control can be useful for the diagnosis of early weaknesses or impairments that could lead to
deceased cognitive development.
We recruited 28 5-months-old and 28 14-months-old healthy children and performed EEG (3 visual conditions; baseline, adults, objects) and Bayley-III test (Cognitive Scale). Our first hypothesis was that the 5month group will show widespread theta (3-6 Hz) synchronization and alpha (6-9 Hz) desynchronization from baseline to active visual conditions. Our second hypothesis was that the 14-month group will show localized theta synchronization and alpha desynchronization in the frontal and parieto-occipital areas respectively from baseline to active-states. Our third hypothesis was that the power increase from baseline to active-state for the two age groups will be higher for the second visual condition (adult narrating nursery rhymes). Our fourth hypothesis was that 14-month will show frontal-posterior theta-alpha inverse linear relationship in contrast with the 5month group. Our fifth hypothesis was that the participants with higher cognitive scores (≥115) will demonstrate localized inverse linear relationship between their frontocentral (PFC and premotor cortex and supplementary motor cortex) theta power and parieto-occipital (parietal and occipital cortex) alpha power.
We found that 5-months-old infants showed a statistical significant posterior theta increase (right parietal (PC) and left occipital cortex (OC)) and central-posterior alpha decrease (right somatosensory (SMC), right OC and left PCs) during visual attention and particularly while
watching objects. At the same time, we found a decrease of theta in the right temporal region in response to active visual stimuli, something that contradicts the previous theory. Although, it is notable that the role of theta in attention is less clear than that of alpha rhythm. Then, in the
14month group we found that during visual attention (objects), theta activity increased in the right and left PFC, left temporal (TC) and left SMC, while alpha activity decreased in the right OC, left TC and right PC. The lack of direct relationship of frontocentral theta and posterior alpha rhythm after linear regression with adjusted p-value may indicate the continuation of FPAN development, especially its frontal part as studies have argued that the developmental processes in PFC start peaking after the first postnatal year.
In the end, our results showed that after the first postnatal year, theta and alpha activity become more organized in more frontocentral and posterior areas respectively, possibly indicating the development of FPAN and the increase of frontal activation. Thus overall, it is clear that young children demonstrate from early on an adult-like theta-alpha pattern in response to visual stimuli, with some different characteristics, indicating the immature state of FPAN and visual top-down control. Further studies with larger sample and with more age groups may clarify even more this association, along with their connection with cognitive abilities. Also, non-linear metrics may be more appropriate for the study of brain network communication instead of linear ones.
Key-words: top-down control, frontoparietal network, theta activity, alpha activity
Top-down control of the visual cortex facilitates voluntary visual attention and the “collection” of relevant visual information that allows the child to learn. In adults, visual top-down control is performed with the prefrontal cortex manipulating the activity of visual cortex via the frontoparietal network (FPAN). In fact, the increase of frontocentral theta activity is suggested to indicate the activation of the anterior part of FPAN, and the decrease of alpha activity the visual network activation. Nevertheless, their relationship and the cognitive role of theta remains under investigation. On the other hand, infants demonstrate a more widespread brain activity as their networks are still under development. It is notable that impairment of top-down control and
inability to suppress irrelevant visual information has been connected with neurodevelopmental disorders such ADHD and learning difficulties. Thus, finding a biomarker for visual top-down control can be useful for the diagnosis of early weaknesses or impairments that could lead to
deceased cognitive development.
We recruited 28 5-months-old and 28 14-months-old healthy children and performed EEG (3 visual conditions; baseline, adults, objects) and Bayley-III test (Cognitive Scale). Our first hypothesis was that the 5month group will show widespread theta (3-6 Hz) synchronization and alpha (6-9 Hz) desynchronization from baseline to active visual conditions. Our second hypothesis was that the 14-month group will show localized theta synchronization and alpha desynchronization in the frontal and parieto-occipital areas respectively from baseline to active-states. Our third hypothesis was that the power increase from baseline to active-state for the two age groups will be higher for the second visual condition (adult narrating nursery rhymes). Our fourth hypothesis was that 14-month will show frontal-posterior theta-alpha inverse linear relationship in contrast with the 5month group. Our fifth hypothesis was that the participants with higher cognitive scores (≥115) will demonstrate localized inverse linear relationship between their frontocentral (PFC and premotor cortex and supplementary motor cortex) theta power and parieto-occipital (parietal and occipital cortex) alpha power.
We found that 5-months-old infants showed a statistical significant posterior theta increase (right parietal (PC) and left occipital cortex (OC)) and central-posterior alpha decrease (right somatosensory (SMC), right OC and left PCs) during visual attention and particularly while
watching objects. At the same time, we found a decrease of theta in the right temporal region in response to active visual stimuli, something that contradicts the previous theory. Although, it is notable that the role of theta in attention is less clear than that of alpha rhythm. Then, in the
14month group we found that during visual attention (objects), theta activity increased in the right and left PFC, left temporal (TC) and left SMC, while alpha activity decreased in the right OC, left TC and right PC. The lack of direct relationship of frontocentral theta and posterior alpha rhythm after linear regression with adjusted p-value may indicate the continuation of FPAN development, especially its frontal part as studies have argued that the developmental processes in PFC start peaking after the first postnatal year.
In the end, our results showed that after the first postnatal year, theta and alpha activity become more organized in more frontocentral and posterior areas respectively, possibly indicating the development of FPAN and the increase of frontal activation. Thus overall, it is clear that young children demonstrate from early on an adult-like theta-alpha pattern in response to visual stimuli, with some different characteristics, indicating the immature state of FPAN and visual top-down control. Further studies with larger sample and with more age groups may clarify even more this association, along with their connection with cognitive abilities. Also, non-linear metrics may be more appropriate for the study of brain network communication instead of linear ones.
Key-words: top-down control, frontoparietal network, theta activity, alpha activity