title: Compensatory networks to counteract the effects of ageing on language.
abstract: BACKGROUND
  Word-retrieval difficulties are a common consequence of healthy ageing and are associated with a reduction in asymmetrical recruitment of the dorsolateral prefrontal cortex (DLPFC), although the significance of this reduction has not yet been clarified. Using repetitive transcranial magnetic stimulation (rTMS) it has been demonstrated that an asymmetrical involvement of the DLPFC during action naming in young subjects, whereas bilateral involvement was shown in elderly participants. By using rTMS during a naming task in a group of elderly subjects, the aim of the present work was to investigate whether the magnitude of DLPFC asymmetry (left-right rTMS effect) during action naming correlates with task performance, proving the presence of a compensation strategy in some but not all elderly participants.
  
  
  METHODS
  We aimed to test if there was a correlation between DLPFC asymmetry (left-right rTMS effect) and naming performance in a group of elderly subjects.
  
  
  RESULTS
  The results show that rTMS affects action naming differently according to individual naming ability. In particular, the predominance of a left vs. right DLPFC effect was observed only in the low-performing older adults, while an asymmetric reduction was selectively shown in the high-performing group. Interestingly, high-performing older adults also displayed better performances on a phonemic fluency test.
  
  
  CONCLUSIONS
  The present data suggest that successful ageing is linked to less prefrontal asymmetry, an efficient strategy for counteracting age-related declines in cognitive function.
authors.affiliation: IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy. rmanenti@fatebenefratelli.it
authors.forename: Rosa
authors.initials: R
authors.lastname: Manenti
authors.forename: Michela
authors.initials: M
authors.lastname: Brambilla
authors.forename: Michela
authors.initials: M
authors.lastname: Petesi
authors.forename: Carlo
authors.initials: C
authors.lastname: Miniussi
authors.forename: Maria
authors.initials: M
authors.lastname: Cotelli
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D007807:Language Tests; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D050781:Transcranial Magnetic Stimulation