Poster A138, Saturday, March 25, 5:00 – 7:00 pm, Pacific Concourse
Are there ripple effects from focal brain lesions to intact neural tissue?
Yuan Tao1, Jeremy Purcell1, Brenda Rapp1; 1Johns Hopkins University
The remote effects of focal brain lesions (termed “diaschisis” in the neurological literature) have long been interesting for clinical reasons and for understanding neural connectivity and modularity. Neuroimaging methods provide important opportunities to examine this topic and recent studies report remote effects of focal lesions. However, this work has largely involved modelling rather than studies of brain lesioned individuals. Given the neural response variability in healthy individuals, an important challenge is to evaluate the integrity of activation patterns at the individual subject level. In this study, we examined neural responses to face processing in 12 individuals who suffered left hemisphere strokes. The lesions affected left frontal, parietal or superior temporal areas, preserving the bilateral ventral temporal regions typically recruited in face processing, allowing us to examine activation patterns in these areas. Data analysis showed that the contrast of face > scenes in 17 individual controls yielded reliable activation in the right Fusiform and Occipital Face Areas and (less consistent) activation of their left hemisphere homologues. Seven of the brain-lesioned individuals showed normal activation patterns across the two hemispheres, with five exhibiting somewhat weaker activations. Overall, the finding of normal response patterns indicates that disruption of remote areas is not a necessary consequence of brain injury, indicating some degree of modular organization. Understanding the circumstances under which focal lesions may affect remote intact neural tissue remains an important topic that will require examining other measures of neural integrity including connectivity, lesion characteristics, and the functional relationship between lesioned and distant areas.
Topic Area: OTHER