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Editorial
. 2004 Mar;127(Pt 3):457-9.
doi: 10.1093/brain/awh113.

Functional neuroimaging of schizophrenia: from a genetic predisposition to the emergence of symptoms

Paul C Fletcher
Editorial

Functional neuroimaging of schizophrenia: from a genetic predisposition to the emergence of symptoms

Paul C Fletcher. Brain. 2004 Mar.
No abstract available

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Figures

Fig. 1
Fig. 1
Proposed explanation for the pattern of regional activity (anterior cingulate/medial frontal, thalamus and cerebellum) in at-risk subjects. Whalley et al. observed that, with increasing task difficulty, at-risk subjects showed an attenuated response in these regions. This attenuation was more pronounced in asymptomatic at-risk subjects. (i) One possibility is that these regions show inverted U responses to task difficulty and that the genetic predisposition to schizophrenia is accompanied by a leftward shift in response [greater for symptomatic (Risk +) than asymptomatic (Risk −) individuals]. The overlaid box represents the suggested scope of the task demands used by Whalley et al., and shows the profile of difficulty-dependent activity change that might be predicted for each of the three groups. (ii) Predicted profiles of demand-dependent activity for the three groups of subjects. While, at this level of cognitive demand, incremental increases in difficulty in control subjects may be met by an increase in activity, if there is indeed a leftward shift of an inverted U function for the at-risk subjects, this would result in a difficulty dependent decrease in activity. Further, if the presence of symptoms (Risk +) was associated with a greater leftward shift, the magnitude of decrease across the four levels of difficulty would be less, due to a bottoming-out effect. The consequence of this would be a stronger negative effect for Risk − than Risk +. (iii) The pattern of regression for the three groups of subjects (units arbitrary) if the above assumptions are true. As can be seen, the main difference would be between the controls and the at-risk subjects without symptoms (Risk −). This is the effect that was indeed observed by Whalley et al. in their Fig. 4.
See this image and copyright information in PMC

Comment on

References

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