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Free keywords:
Goal-directed behavior; Social-motivational behavior; Nucleus accumbens; Vertex-wise shape analysis
Abstract:
Purpose:
Neuroimaging studies in persistent developmental stuttering repeatedly report altered
basal ganglia functions. Together with thalamus and cerebellum, these structures mediate
sensorimotor functions and thus represent a plausible link b
etween stuttering and
neuroanatomy. However, stuttering is a complex, multifactorial disorder. Besides sensorimotor
functions, emotional and social
-motivational factors constitute major aspects of the disorder.
Here, we investigated cortical and subcortica
l grey matter regions
to study whether persistent
developmental stuttering is also linked to alterations of limbic structures.
Methods:
The study included 33 right-handed participants who stutter and 34 right-handed
control participants matched for sex, age, and education. Structural images were acquired using
magnetic resonance imaging to estimate volumetric characteristics of the nucleus accumbens,
hippocampus, amygdala, pallidum, putamen,
caudate nucleus, and thalamus.
Results:
Volumetric comparisons and vertex
-based shape comparisons revealed structural
differences. The right nucleus accumbens was larger
in participants who stutter compared to
controls.
Conclusion:
Recent theories of basal ganglia functions suggest that the nucleus accumbens is
a motivation-to-movement interface. A speaker intends to reach communicative goals, but
stuttering can derail these efforts. It is therefore highly plausible to find alterations in the
motivation-to
-movement interface in stuttering. While behavioral studies of stuttering sought to
find links between the limbic and sensorimotor system, we provide the first neuroimaging
evidence of alterations in the limbic system. Thus, our findings might initialize a unified
neurobiological framework of persistent developmental stuttering that integrates sensorimotor
and social
-motivational neuroanatomical circuitries.
