1. Presented by: Vanessa Wong Corbetta et al.

2.  Inability to pay attention to space  Most common cause is stroke  Caused by focal injury to temporoparietal cortex or ventral frontal cortex  Damage in right hemisphere and neglects left side of space

4.  Local injury hypothesis  Injury to a brain area causes behaviour deficits that reflect local dysfunction of neurons at the site of injury  Distributed injury hypothesis  Lesion causes dysfunction in other nodes of a functional brain network, impairing processes other than those mediated by neurons at the site of injury

5.  Does the distributed injury hypothesis apply to spatial neglect? Hypothesis: Recovery is associated with a normalization of activity in attention networks

6.  11 participants (3 females, 8 males, M=60 years)  All with unilateral (right side) stroke with no damage to visual field areas and are representative of the most common lesion sites in neglect  All underwent standard rehabilitation for at least 3 months  Tested at acute(~4 weeks) and chronic (~39weeks) recovery stage

7. fMRI

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11. Independent  Valid cue or Invalid cue  Left or right visual field  Acute or chronic stage Dependent  Reaction time  Accuracy

12. Significant recovery from acute to chronic stage  Decrease in rightward processing bias  Greater improvement in reaction time for left than right visual field targeting  Improvement in attentional reorientating  Less reaction time and more hit rates in targeting invalid cues

14.  Failed to support the local injury hypothesis  Supported the distributed injury hypothesis  Recovery correlates with reactivation and rebalancing of normal activity within network

15.  Small sample size (N=11)  Even though all patients have clinical neglect, different areas of brain are damaged

16.  Strengths  Brain scans and graphs  In depth description of brain regions  Clearly presented the results found  Well organized  Short and concise  Weakness  Little detail on the rehabilitation

17.  The distributed impairment principle can likely be applicable to aphasia or sensory- motor deficits  Re-examination of localization of anatomical basis and functional information on specific neuropsychological disorders

18. Corbetta, M., Kincade, M.J., Lewis, C., Znyder, A.Z. & Sapir, A. (2005). Neural basis and recovery of spatial attention deficits in spatial neglect. Nature Neuroscience, 8 (11), 1603-1610.