Title | Words without mind. |
Publication Type | Journal Article |
Year of Publication | 1999 |
Authors | Schiff, N, Ribary U, Plum F, and Llinás R |
Journal | J Cogn Neurosci |
Volume | 11 |
Issue | 6 |
Pagination | 650-6 |
Date Published | 1999 Nov |
ISSN | 0898-929X |
Keywords | Acoustic Stimulation, Auditory Pathways, Brain, Female, Fingers, Fluorodeoxyglucose F18, Humans, Magnetic Resonance Imaging, Magnetoencephalography, Middle Aged, Persistent Vegetative State, Physical Stimulation, Tomography, Emission-Computed, Verbal Behavior |
Abstract | A woman (LR), unconscious for 20 years, spontaneously produces infrequent, isolated words unrelated to any environmental context. Fluorodeoxy-glucose-positron emission tomography (FDG-PET) imaging coregistered with magnetic resonance imaging (MRI) revealed a mean brain metabolism equivalent to deep anesthesia. Nevertheless, PET imaging demonstrated islands of modestly higher metabolism that included Broca's and Wernicke's areas. Functional brain imaging with magnetoencephalographic (MEG) imaging, a technique providing a temporal resolution of better than 1 msec, identified preserved dynamic patterns of spontaneous and evoked brain activity in response to sensory stimulation. Specifically, we examined spontaneous gamma-band activity (near 40 Hz) and its reset or modification during early auditory processing, a measure that correlated with human perception of sensory stimuli (Joliot, Ribary, & Llinás, 1994). Evidence of abnormal and incomplete gamma-band responses appeared in the left hemisphere only in response to auditory or somatosensory stimulation. MEG single-dipole reconstructions localized to the auditory cortex in the left hemisphere and overlapped with metabolically active regions identified by FDG-PET. The observation demonstrates that isolated neuronal groups may express well-defined fragments of activity in a severely damaged, unconscious brain. The motor fixed-action pattern character of her expressed words supports the notion of brain modularity in word generation. |
Alternate Journal | J Cogn Neurosci |
PubMed ID | 10601746 |
Submitted by mam2155 on January 7, 2014 - 10:53am