Hightech Research on Reading Comprehension: Current Neuroscience on Text Comprehension Processes

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High-tech Research on Reading Comprehension
Current Neuroscience on Text Comprehension
Processes

• George G. Hruby, Ph.D.
• Utah State University

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Target of Presentation

• Comprehending comprehension
• Comprehending brain research on comprehension

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Overview

• Brief review of the technologies for brain study
• Brief review of the difficulties related to these
  technologies
• Brief review of current neuroscience relatable to
  reading comprehension

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Event-related Potential (ERP)

• EEG, MEG
• Tracks electro-magnetic field changes in brain as
  correlate to neural activation
• EM fluctuations are the result of 100s of
  thousands of dendrites firing in unison
• Requires numerous trials to average out the
  target responses from spontaneous and spurious
  firing and EM noise

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ERP Challenges

• Brain-waves are our brain thinking!
• No evidence that neural signaling is symbolic
• EM fluctuations are the result of chemical action
  of the cell -- not of electrical current flowing
  through wires
• Variability across trials very high
• Significance of some data uncertain

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Vascular Imaging

• PET, fMRI
• Tracks blood flow, or glucose or oxygen uptake,
  as a correlate of neural activity
• Blood flow is then compared by subtraction
  between two different conditions
• Results are manipulated for overlay, averaged
  across subjects, outliers rejected, and noise
  reduced

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Vascular Imaging Challenges

• Resulting image is a statistical chart
• Not a picture of a/the brain in action
• Localization of activation is as much the result
  of baseline choice for comparison as choice of
  experimental condition
• All cells need blood to function most in the
  brain are glial cells, not neurons
• Neurotransmitter concentrations may dilate blood
  vessels

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Vascular Imaging Challenges

• Images artificially expunge individual variation
  giving false sense of consistency
• Do not always match ERP localizations
• Multiple functions can be localized in the same
  area
• Neo-phrenology, Blobology (Lieberman)
• The brain does NOT light up!

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Electrode Assay

• Area chosen for its ostensible function
• Individual cells monitored for activity under a
  variety of conditions
• Strong correlates with activation noted
• Brains dissected to determine just what was being
  monitored
• Neural structure is mapped
• Some cells are very functionally precise

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Electrode Assay Challenges

• Cannot be used on healthy humans
• No definitive wiring map neurons grow into
  functional connections uniquely
• Role of individual neurons as regulatory systems
  not well understood
• Mirror neurons interesting but perhaps over-hyped

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Manipulation Studies

• tDCS, rTMS
• Originally developed for therapeutic purposes
• Sends pulse(s) of E/M current/field into a
  specific brain area
• Effects on behavior monitored
• Relatively new for brain study

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Other Methods

• Lesion studies
• Biochemical analysis
• Cellular imaging
• Micro-anatomy (e.g., SPECT)
• Computer modeling
• Systems modeling

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Other Methods

• Lesion studies
• Biochemical analysis
• Cellular imaging
• Micro-anatomy (e.g., SPECT)
• Computer modeling
• Systems modeling

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General Challenges

• Brain activity changes with use
• Literally grows with experience
• High activation indicates effort
• Things done with ease show little activation
• So relationship of brain activity to function not
  intuitive
• Necessary conditions rarely sufficient
• Few meta-analyses

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Neuroscience Findings

• Comprehension processes do not just build on one
  another, they co-regulate
• Subcortical systems and motor areas involved in
  language processing
• Skill development first builds in parietal lobe
  and shifts to other areas later
• Presumption of pattern and anticipation of
  pattern completion important for proactive
  behavior and comprehension

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Neuroscience Implications

• Language development is not automatic (i.e.,
  natural)
• Emotion is important in meaning
• Syntactic and semantic processing are important
  in language comprehension
• Discourse modality and narrative structure affect
  syntactic and semantic processing

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Neuroscience Inspiration

• Language reception is about recognizing sound
  categories
• Sound categories identified through
  larger-grained sound contours and assumptions
  about the physiological requirements for making
  them
• Mirror-neurons allow us to presume the intention
  of those actions
• Johannes Müller

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Caveats

• The brain does not read
• You do
• Strictly speaking, there is no such thing as
  neuroscience on reading
• Only research on classroom practices can give us
  research-based recommendations for practice

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Thank you!

• George G. Hruby
• Utah State University

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