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Hemispheric asymmetry in the maturation of the extrastriate checkerboard onset evoked potential
P Ossenblok1, J C De Munck, H J Wieringa
1The Netherlands Ophthalmic Research Institute, Amsterdam-Zuidoost.
Insights
The early positive peak in checkerboard evoked potentials (EPs) in older children originates from two sources: the striate cortex and extrastriate areas. Extrastriate activity shows right hemispheric dominance, aligning with developmental delays in the left hemisphere.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Visual Evoked Potentials
Background:
- Young children's checkerboard onset evoked potentials (EPs) show a striate-origin positive deflection that evolves into a negative-positive complex.
- An additional early positive peak emerges in the checkerboard onset EP, prompting investigation into its origin and development.
Purpose of the Study:
- To investigate the origin and developmental trajectory of the early positive deflection in checkerboard onset EPs.
- To identify the neural sources contributing to the pattern onset EP in children aged 9-16 years.
Main Methods:
- Studied checkerboard onset EPs in children aged 9-16 years.
- Utilized dipole source analysis to differentiate neural activity origins.
- Examined hemispheric asymmetry in extrastriate activity.
Main Results:
- Two distinct dipole sources were identified for the pattern onset EP in this age group.
- One source was localized to the striate cortex, while a second, extrastriate source accounted for the early positive deflection.
- Significant hemispheric asymmetry was observed, with the right extrastriate source strength exceeding the left.
Conclusions:
- The early positive deflection in checkerboard onset EPs arises from both striate and extrastriate cortical activity.
- Extrastriate activity demonstrates right hemispheric dominance, consistent with known developmental maturation differences between hemispheres.
- Findings support histological observations of delayed left extrastriate area maturation compared to the right.
Abstract:
Recently we have shown that the single positive deflection in the checkerboard onset evoked potential (EP) of young children of striate origin develops into a negative-positive complex. However, also an early positive peak becomes apparent in the checkerboard onset EP. To determine the origin and development of the activity underlying this early positive deflection we studied the checkerboard onset EPs in children of 9-16 years of age. It was found that for the children in this age group two different dipole sources are responsible for the activity underlying the pattern onset EP. One of the dipoles corresponds to the activity generated in the striate cortex, whereas a second dipole of extrastriate origin is responsible for the appearance of the early positive deflection. This extrastriate activity shows hemispheric asymmetry, i.e. the strength of the right hemispheric extrastriate source exceeds the strength of the left hemispheric source. These results are in accordance with histological studies of Conel (1939-1963) [The postnatal development of the human cerebral cortex (Vols 1-8). Cambridge, Mass.: Harvard Univ. Press] which show that the maturation of the extrastriate areas of the left hemisphere is delayed with respect to the right hemisphere.