There was always this awareness of the relationship between brain and behavior, but it wasn’t very well understood — the 1980s corresponded to a proliferation of effective ways of measuring brain activity through MRI/CAT/PET scans/EEG. Now that there's a whole array of ways to look at the brain:

Neurological perspective of LD:

• Systematic differences between neurons (fewer neural connections in people with dyslexia -- decreased performance)
• Anatomical differences in terms of number of connections and degree of specialization (and laterality) in brain

Neuropsychological perspective:

Instead of measuring brain activity, measure behavior/performance on tasks that are likely to be affected by regions of the brain that are deficient

• Wisconsin card sort task: how quickly do you notice that the pattern changes? you have to come up with a new pattern to explain
• By themselves, these tests are not useful diagnoses but they are good supplemental approaches

Unconscious tasks (task that can be performed while sleeping): you put on headphones and listen to a series of sounds (simple syllables like 6000 “ba”’s) while watching a subtitle movie

• Lasts ~250 milliseconds
• 200 milliseconds are steady state syllables (no articulation necessary for the vowel) and clusters of frequency
• First 50 milliseconds (1/20th of a second), you have to distinguish the consonant (whether it’s “ba” or “da”)
  • Pick up formant transitions (bigger picture: allows us to distinguish words)
• Brain activity is measured at auditory brain stem (coming out of cochlea, it’s the first synapse)
• People with LD have lower brain activity:
  • Brain signal is reduced; magnitude of response is muted/lessened; firing less
  • This task primarily diagnoses kids with reading problems (specifically with troubles decoding)
• Can measure this in sleeping infants — has the potential to identify kids at risk for later language based learning disabilities far before they’re expected to read or write or do math!

Cognitive perspective: