Plasticity of the reading brain: Insights from isolated left and right hemispheres - PROJECT SUMMARY
Reading acquisition is most often accomplished during childhood with the benefit of both the left and right
hemispheres. Students who have undergone hemispherectomy surgery during early childhood must rely on a
single hemisphere for all functions and therefore establish reading brain systems using unique configurations
that are yet to be understood. While brain plasticity for reading has been examined via typical development,
developmental disabilities, and interventions, we lack insights into the potential of a single hemisphere to carry
reading functions despite evidence that the left and right hemisphere together play important roles in reading
ability. Children often acquire reading skills following hemispherectomy, underscoring the neuroplasticity
potential for establishing supporting brain systems. Our proposal examines the association between reading
outcomes and structural/functional brain targets in children relying on a left or right hemisphere compared to 1:1
matched typically developing peers. We focus on reading in the hemispherectomy community given the
opportunity to study a single hemisphere ethically and practically; because we lack sufficient understanding of
reading acquisition among these students that hampers their educational efforts; and to inform our understanding
of the potential of a single hemisphere for reading. This singular opportunity capitalizes on the largest convening
of this community that will be in our vicinity. Scientifically, this opportunity can improve our understanding of the
neuroplastic potential of a single hemisphere to support reading skills, identify unique or shared functions by
hemisphere, offer insights regarding acquired reading difficulty during childhood, and relate individual differences
in reading outcomes to brain structure and function. Practically, this information is crucial for developing effective
reading recommendations and practices for the hemispherectomy community as well as more broadly (e.g.,
those impacted by neurosurgery or acquired/developmental reading difficulties during childhood). Datasets will
include 40 students post-hemispherectomy (grades 1-12; ages 6-17) who will be recruited from a large convening
(July 2024) in Boston, and 40 typically developing (TD) 1:1 matched readers. We predict that reading scores will
be positively associated with (1) white matter properties of arcuate fasciculus (AF) and inferior longitudinal
fasciculus (ILF), key connectivity regions associated with reading skill, and (2) recruitment of the key left
hemisphere reading regions in left hemisphere-only and right hemisphere homologues in right hemisphere-only
participants. Our discovery of the neurocognitive basis of reading in hemispherectomy will offer a novel
consideration of plasticity with insights that can inform improved understanding of reading difficulties as well as
bring attention to proactive and preventative measures in support of children with reading difficulties. These
goals align with NIH's mission by examining the impact of learning disabilities (LDs) on reading, developing
knowledge about LDs in the hemispherectomy community, emphasizing prevention and early intervention, and
establishing and applying fundamental knowledge about the brain to optimize reading acquisition.
