Magnetoencephalographic (MEG) Evidence for Novel Metaphor Processing Among Schizophrenic Patients
Condition: Schizophrenia; Novel Metaphor
MeSH terms: Schizophrenia
Study type: Interventional

Summary: 
      The aim of this research is to investigate the neurolinguistic mechanisms underlying thought
      disorders among schizophrenic patients. In particular, it will investigate the
      neurolinguistic basis for loose association - a phenomena which this population is
      characterized by. Several researchers have previously suggested that loose associations among
      schizophrenic patients relate to a lack of inhibition in the automatic spread of activation
      mechanisms within semantic networks (e.g., Soriano, Jimenez, Roman, & Bajo, 2008). This
      research focuses on the relationship between I. the left-right hemisphere dynamic and II.
      semantic processing, among schizophrenic patients. The research follows Jung-Beeman's (2005)
      model which relates semantic associations, activation and inhibition processes to the
      functioning of the two cerebral hemispheres.

      Previous research suggests that, when compared to the neurotypical population, people with
      schizophrenia show a less defined - or even reversed - hemispheric lateralization pattern for
      semantic processing. This is linked to an impairment in language function in the left
      hemisphere, and to a language functions shift from left to right hemisphere (e.g., Crow,
      1997). The investigators assume that this unique lateralization pattern may cause a change in
      balance in the semantic activation and inhibition system among schizophrenic patients.

      As stated, one of the linguistic models that predicts how reduced left hemisphere dominancy
      will influence linguistic functioning is Jung-Beeman's (2005) bilateral model for language
      understanding. According to this model, the left hemisphere specializes in precise and fine
      semantic processing, while the right hemisphere specializes in coarse and abstract semantic
      processing. Building upon this distinction, our assumption is that schizophrenic patients
      experience a difficulty in fine semantic processing which is caused by functional impairment
      in the left hemisphere. It is our further assumption that coarse semantic processing -
      located in the right hemisphere - is relatively unimpaired. This change in the balance
      between the two processes may have direct implications on the associative semantic network
      among schizophrenic patients.

      In order to test this hypothesis, the current research will make use of a specific language
      expression type which involves fine and coarse semantic processing, and for which there is
      evidence for crucial right hemisphere involvement: novel metaphor processing. 10-20 adult
      schizophrenic patients will be presented with four different types of two word expressions:
      literal; conventional metaphor; novel metaphor and unrelated. The patients will have to
      decide as quickly and accurately as possible if the expression is meaningful or meaningless
      while their brain activity is recorded by a Magnetoencephalographic (MEG) device (which
      combines a high temporal resolution with the ability to localize the activity).

      Therefore, our main hypothesis is that schizophrenic patients will show a bilateral brain
      activity pattern when conducting semantic decisions, and that this pattern will be related to
      improved reaction times and accuracy when presented with novel metaphors than when presented
      with other types of expressions.
    


Intervention name(s): Magnetoencephalograph (MEG)
Intervention type(s): Device
Intervention description(s): Brain imaging device that records the magnetic fields in the brain.
Other intervention name(s): MAGNES STIMULUS, 4-D NEUROIMAGING, 9727 Pacific heights blvd., San Diego, CA 92121, USA.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Schizophrenia; Novel metaphor