Anatomy & Physiology Fundamentals Flashcards

Which brain imaging technique measures changes in blood oxygenation levels (BOLD signal) to infer neural activity and is widely used in dyslexia research?

Answer: fMRI (functional magnetic resonance imaging)

fMRI measures the BOLD (blood-oxygen-level-dependent) signal, which reflects local increases in oxygenated blood flow that accompany neural activity, making it the standard neuroimaging tool in dyslexia research.

Diffusion tensor imaging (DTI) studies in dyslexia most often report abnormalities in which white matter tract?

Answer: Left arcuate fasciculus and left superior longitudinal fasciculus

DTI studies consistently show reduced fractional anisotropy (FA) in the left arcuate fasciculus and associated superior longitudinal fasciculus in individuals with dyslexia, reflecting less organized white matter connectivity.

The supramarginal gyrus, part of the inferior parietal lobule, contributes to reading by supporting:

Answer: Phonological awareness and phoneme manipulation

The supramarginal gyrus in the left inferior parietal lobule is involved in phonological awareness and short-term phonological memory, both critical for reading acquisition.

How does the dorsal stream ('where/how' pathway) contribute to reading, distinct from the ventral stream?

Answer: The dorsal stream supports grapheme-phoneme conversion and attentional letter-by-letter processing

The dorsal stream (occipitoparietal) supports the attentional, analytical processing of print including grapheme-to-phoneme conversion, while the ventral stream handles automatic whole-word recognition.

A student who reverses letters such as 'b' and 'd' in writing is most likely demonstrating a deficit in:

Answer: Directional/spatial encoding and orthographic memory for letter orientation

Letter reversals reflect difficulty with the spatial/directional encoding required to distinguish mirror-image letters, representing an orthographic memory challenge rather than a phonological one.

Which of the following best describes the role of the prefrontal cortex in reading difficulties?

Answer: It supports executive functions like working memory and cognitive control that compensate for decoding deficits

The prefrontal cortex supports executive functions including working memory, attention, and cognitive control; individuals with dyslexia often recruit it more heavily as a compensatory strategy during reading.

The phonological deficit theory of dyslexia proposes that the core neurobiological impairment lies in:

Answer: Disrupted representation or processing of speech sounds in perisylvian language areas

The phonological deficit theory holds that dyslexia stems from imprecise or unstable phonological representations in perisylvian cortex, making it difficult to map graphemes to phonemes.