CALT Neurobiology of Reading and Dyslexia 5

Question 1

Which gene has been most extensively linked to neuronal migration anomalies and susceptibility to dyslexia in GWAS and candidate gene studies?

Accepted Answer

DCDC2

Answer

DCDC2, located on chromosome 6p, is one of the most replicated dyslexia candidate genes and is thought to affect neuronal migration in reading-relevant cortical areas.

Question 2

Cortical ectopias and neuronal migration anomalies found post-mortem in brains of individuals with dyslexia are most densely concentrated in which region?

Accepted Answer

Left perisylvian language regions

Answer

Post-mortem studies by Galaburda and colleagues found microgyria and ectopias predominantly in left perisylvian regions critical for language and reading.

Question 3

Functional MRI studies comparing dyslexic and typical readers during rhyme judgment tasks most reliably show underactivation in which region?

Accepted Answer

Left temporoparietal junction

Answer

The left temporoparietal junction (including the angular gyrus and supramarginal gyrus) is consistently underactivated in dyslexic readers during phonological tasks like rhyme judgment.

Question 4

The 'dual-route' model of reading predicts that individuals with phonological dyslexia have a selective deficit in which reading pathway?

Accepted Answer

Sublexical phonological route for nonword decoding

Answer

Phonological dyslexia is characterized by a specific breakdown of the sublexical route, impairing the ability to decode unfamiliar words and pseudowords by letter-sound rules.

Question 5

Diffusion tensor imaging (DTI) studies most consistently reveal reduced fractional anisotropy in dyslexic readers within which white matter tract?

Accepted Answer

Left arcuate fasciculus and superior longitudinal fasciculus

Answer

Reduced fractional anisotropy—indicating less coherent white matter microstructure—is most reliably found in the left arcuate and superior longitudinal fasciculi in dyslexic readers.

CALT - Certified Academic Language Therapist Practice Test

CALT - Certified Academic Language Therapist Practice Test

CALT Neurobiology of Reading and Dyslexia 5