Specific forms of neural activity associated with tactile space awareness.
Left tactile extinction, in which a left tactile stimulus fails to access consciousness only when a right stimulus is presented simultaneously, offers a model for studying tactile awareness from its transitory absence. Pairs of transcranial magnetic stimuli (TMS) on the parietal cortex inhibit contralateral tactile perception when separated by an interval of 1 ms. We have applied this technique on the left parietal cortex of right brain damaged (RBD) patients and normal subjects and have shown a selective lack of paired TMS inhibitory effects on right tactile perception of patients during bimanual stimulation. TMS effects were normal during unimanual right stimulation. These results suggest the presence of a specific pattern of inhibitory/excitatory interactions in parietal brain areas as critical for tactile awareness.
Oliveri
Massimiliano
M
Fondazione S. Lucia IRCCS, Via Ardeatina, 306, 00179 Rome, Italy.
Rossini
Paolo Maria
PM
Filippi
Maria Maddalena
MM
Traversa
Raimondo
R
Cicinelli
Paola
P
Caltagirone
Carlo
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001288:Attention / Q000502:physiology; D001930:Brain Injuries / Q000473:pathology / Q000503:physiopathology*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005108:Extinction, Psychological / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D006987:Hypesthesia / Q000473:pathology / Q000503:physiopathology*; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology; D010296:Parietal Lobe / Q000293:injuries / Q000473:pathology / Q000503:physiopathology*; D010468:Perceptual Disorders / Q000473:pathology / Q000503:physiopathology*; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D014110:Touch / Q000502:physiology*