Gamma activity modulated by naming of ambiguous and unambiguous images: intracranial recording.
Clin Neurophysiol
; 126(1): 17-26, 2015 Jan.
Article
em En
| MEDLINE
| ID: mdl-24815577
ABSTRACT
OBJECTIVE:
Humans sometimes need to recognize objects based on vague and ambiguous silhouettes. Recognition of such images may require an intuitive guess. We determined the spatial-temporal characteristics of intracranially-recorded gamma activity (at 50-120Hz) augmented differentially by naming of ambiguous and unambiguous images.METHODS:
We studied 10 patients who underwent epilepsy surgery. Ambiguous and unambiguous images were presented during extraoperative electrocorticography recording, and patients were instructed to overtly name the object as it is first perceived.RESULTS:
Both naming tasks were commonly associated with gamma-augmentation sequentially involving the occipital and occipital-temporal regions, bilaterally, within 200ms after the onset of image presentation. Naming of ambiguous images elicited gamma-augmentation specifically involving portions of the inferior-frontal, orbitofrontal, and inferior-parietal regions at 400ms and after. Unambiguous images were associated with more intense gamma-augmentation in portions of the occipital and occipital-temporal regions.CONCLUSIONS:
Frontal-parietal gamma-augmentation specific to ambiguous images may reflect the additional cortical processing involved in exerting intuitive guess. Occipital gamma-augmentation enhanced during naming of unambiguous images can be explained by visual processing of stimuli with richer detail.SIGNIFICANCE:
Our results support the theoretical model that guessing processes in visual domain occur following the accumulation of sensory evidence resulting from the bottom-up processing in the occipital-temporal visual pathways.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Estimulação Luminosa
/
Lobo Temporal
/
Mapeamento Encefálico
/
Eletroencefalografia
/
Ritmo Gama
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Lobo Occipital
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Adolescent
/
Adult
/
Child
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Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Clin Neurophysiol
Assunto da revista:
NEUROLOGIA
/
PSICOFISIOLOGIA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Estados Unidos