PMID- 23001709
OWN - NLM
STAT- MEDLINE
DCOM- 20130528
LR  - 20151119
IS  - 1875-8908 (Electronic)
IS  - 1387-2877 (Linking)
VI  - 33
IP  - 2
DP  - 2013
TI  - Altered parietal-motor connections in Alzheimer's disease patients.
PG  - 525-33
LID - 10.3233/JAD-2012-121144 [doi]
AB  - Alzheimer's disease (AD) is characterized by altered functional cortico-cortical 
      connectivity likely due to loss of afferent and efferent connections between 
      different cortical areas. Here we explored parieto-frontal functional 
      connectivity in 15 AD patients and 12 healthy control subjects by means of 
      bifocal transcranial magnetic stimulation (TMS). Conditioning stimuli were 
      applied over the right posterior parietal cortex (PPC) at different intensities 
      (90% and 110% of resting motor threshold, RMT). Motor evoked potentials (MEPs) 
      were then recorded from the ipsilateral primary motor cortex at different 
      interstimulus intervals (ISIs) ranging between 2 and 15 ms. Results showed that 
      in healthy subjects, a conditioning TMS pulse applied over the ipsilateral PPC at 
      90%, but not at 110%, of RMT intensity was able to increase the excitability of 
      the right M1. This functional interaction peaked at ISI = 6 ms. Conversely, in AD 
      patients the facilitatory pattern of parieto-motor connections was evident only 
      when TMS was delivered at an intensity of 110% of RMT with a peak at ISI = 8 ms. 
      Moreover in AD patients, treatment with cholinesterase inhibitors did not induce 
      any significant modification in the strength of the connection. In subsequent 
      analyses, we found that, in AD patients, the effects induced by PPC conditioning 
      at 110% RMT correlated with neuropsychological measures of episodic memory and 
      executive functions, implying that patients with better cognitive performance had 
      less impaired connectivity. Our findings reveal that parieto-frontal 
      cortico-cortical functional connectivity is altered in AD patients, providing 
      further evidence for a disconnection-based interpretation of AD symptoms.
FAU - Bonni, Sonia
AU  - Bonni S
AD  - IRCCS Fondazione Santa Lucia, Rome, Italy.
FAU - Lupo, Federica
AU  - Lupo F
FAU - Lo Gerfo, Emanuele
AU  - Lo Gerfo E
FAU - Martorana, Alessandro
AU  - Martorana A
FAU - Perri, Roberta
AU  - Perri R
FAU - Caltagirone, Carlo
AU  - Caltagirone C
FAU - Koch, Giacomo
AU  - Koch G
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - J Alzheimers Dis
JT  - Journal of Alzheimer's disease : JAD
JID - 9814863
RN  - 0 (Cholinesterase Inhibitors)
RN  - 0 (Phenylcarbamates)
RN  - PKI06M3IW0 (Rivastigmine)
SB  - IM
MH  - Aged
MH  - Aged, 80 and over
MH  - Alzheimer Disease/drug therapy/*pathology/physiopathology
MH  - Cholinesterase Inhibitors/therapeutic use
MH  - Efferent Pathways/*pathology/physiopathology
MH  - Evoked Potentials, Motor/*physiology
MH  - Female
MH  - Humans
MH  - Male
MH  - Motor Cortex/*pathology/physiopathology
MH  - Neuropsychological Tests
MH  - Parietal Lobe/*pathology/physiopathology
MH  - Phenylcarbamates/therapeutic use
MH  - Rivastigmine
MH  - Transcranial Magnetic Stimulation
EDAT- 2012/09/25 06:00
MHDA- 2013/05/29 06:00
CRDT- 2012/09/25 06:00
PHST- 2012/09/25 06:00 [entrez]
PHST- 2012/09/25 06:00 [pubmed]
PHST- 2013/05/29 06:00 [medline]
AID - 314X510216M20430 [pii]
AID - 10.3233/JAD-2012-121144 [doi]
PST - ppublish
SO  - J Alzheimers Dis. 2013;33(2):525-33. doi: 10.3233/JAD-2012-121144.