title: Damage to the medial motor system in stroke patients with motor neglect.
abstract: OBJECTIVE
  Motor neglect (MN) is a clinically important condition whereby patients with unilateral brain lesions fail to move their contralateral limbs, despite normal muscle strength, reflexes, and sensation. MN has been associated with various lesion sites, including the parietal and frontal cortex, the internal capsule, the lenticulostriate nuclei, and the thalamus. In the present study, we explored the hypothesis that MN depends on a dysfunction of the medial motor system by performing a detailed anatomical analysis in four patients with MN.
  
  
  METHODS
  Ten patients participated in the study: four with MN, four with left visual neglect but without MN, and three patients with left hemiplegia without MN. We used specific scales for clinical and neuropsychological assessment. We drew the lesion borders directly onto the original brain images of each patient, and plotted the lesions on anatomical atlases for gray and white matter.
  
  
  RESULTS
  Lesion locations were highly heterogeneous in our MN patients, and included frontal and parietal sites, basal ganglia, and white matter. The only consistently damaged structure across all MN patients was the cingulum bundle, a major pathway of the medial motor system important for motor initiative, and a key connection with limbic structures crucial for motivational aspects of actions. Three MN patients with additional damage to lateral fronto-parietal networks had also signs of contralesional visual neglect. The cingulum bundle was intact in all the control patients with visual neglect or hemiplegia.
  
  
  CONCLUSIONS
  Cingulum damage may induce MN through unilateral dysfunction of the medial motor system. Additional lateral fronto-parietal dysfunction can result in the association with visual neglect.
authors: Inserm UMR-S 1127, UPMC-Paris 6, CNRS UMR 7225, Brain and Spine Institute, Groupe Hospitalier Pitié-Salpêtrière Paris, France ; Fédération de Neurologie, IM2A, AP-HP, Groupe Hospitalier Pitié-Salpêtrière Paris, France ; Department of Psychology, Catholic University Milan, Italy.
authors: Raffaella
authors: R
authors: Migliaccio
authors: Inserm UMR-S 1127, UPMC-Paris 6, CNRS UMR 7225, Brain and Spine Institute, Groupe Hospitalier Pitié-Salpêtrière Paris, France.
authors: Florence
authors: F
authors: Bouhali
authors: Inserm UMR-S 1127, UPMC-Paris 6, CNRS UMR 7225, Brain and Spine Institute, Groupe Hospitalier Pitié-Salpêtrière Paris, France ; AP-HP, Service de Médecine Physique et Réadaptation, Groupe Hospitalier Pitié-Salpêtrière Paris, France.
authors: Federica
authors: F
authors: Rastelli
authors: Fédération de Neurologie, IM2A, AP-HP, Groupe Hospitalier Pitié-Salpêtrière Paris, France.
authors: Sophie
authors: S
authors: Ferrieux
authors: Fédération de Neurologie, IM2A, AP-HP, Groupe Hospitalier Pitié-Salpêtrière Paris, France.
authors: Celine
authors: C
authors: Arbizu
authors: AP-HP, Service de Médecine Physique et Réadaptation, Groupe Hospitalier Pitié-Salpêtrière Paris, France.
authors: Stephane
authors: S
authors: Vincent
authors: AP-HP, Service de Médecine Physique et Réadaptation, Groupe Hospitalier Pitié-Salpêtrière Paris, France ; ER 06, UPMC, Service de MPR, Groupe Hospitalier Pitié-Salpêtrière Paris, France.
authors: Pascale
authors: P
authors: Pradat-Diehl
authors: Inserm UMR-S 1127, UPMC-Paris 6, CNRS UMR 7225, Brain and Spine Institute, Groupe Hospitalier Pitié-Salpêtrière Paris, France ; Department of Psychology, Catholic University Milan, Italy.
authors: Paolo
authors: P
authors: Bartolomeo
keywords: cingulum bundle; medial motor system; motor neglect; parieto-frontal network; visual neglect