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1.
Brain Cogn ; 129: 9-15, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30579632

RESUMEN

The purpose of this study was to investigate the occurrence of an endogenously-evoked no-go N2b. Previous literature focused on the N2b being evoked by exogenous auditory stimuli. In this study, no-go stimuli were the absence of a gap in a 1000-ms noise burst (i.e., no-gap trials). ERPs were measured from 35 participants while performing a gap-detection task and passively listening to the same stimuli. Participants were asked to press a button when they heard a gap in the noise burst (go trials) and to withhold their button press when they did not perceive a gap in the noise burst (no-go trials). The current study's gap-detection task had predictable timing (gaps always occurred at 500 ms after noise burst onset) and high probability of gaps occurring (10:1); therefore, participants built up an expectancy that gaps would occur on most trials at 500 ms. For no-gap trials, this meant that a participant's expectancy was violated and thus a N2b-P3a response was generated. We found that all participants had N2b-P3a responses to no-gap trials. Overall, this study demonstrated that the no-go N2b-P3a response can be evoked by an endogenous signal in the form of the omission of an expected gap in noise.


Asunto(s)
Estimulación Acústica/métodos , Potenciales Relacionados con Evento P300/fisiología , Potenciales Evocados Auditivos/fisiología , Ruido , Adolescente , Adulto , Percepción Auditiva/fisiología , Electroencefalografía , Potenciales Evocados/fisiología , Femenino , Audición , Humanos , Masculino , Adulto Joven
2.
Pediatr Res ; 70(2): 171-5, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21544009

RESUMEN

Resting cortical activity is characterized by a distinct spectral peak in the alpha frequency range. Slowing of this oscillatory peak toward the upper theta-band has been associated with a variety of neurological and neuropsychiatric conditions and has been attributed to altered thalamocortical dynamics. Children born very preterm exhibit altered development of thalamocortical systems. To test the hypothesis that peak oscillatory frequency is slowed in children born very preterm, we recorded resting magnetoencephalography (MEG) from school age children born very preterm (≤ 32 wk gestation) without major intellectual or neurological impairment and age-matched full-term controls. Very preterm children exhibit a slowing of peak frequency toward the theta-band over bilateral frontal cortex, together with reduced alpha-band power over bilateral frontal and temporal cortex, suggesting that mildly dysrhythmic thalamocortical interactions may contribute to altered spontaneous cortical activity in children born very preterm.


Asunto(s)
Ritmo alfa/fisiología , Lóbulo Frontal/fisiología , Nacimiento Prematuro/fisiopatología , Lóbulo Temporal/fisiología , Tálamo/fisiología , Niño , Humanos , Magnetoencefalografía/métodos
3.
Brain Topogr ; 24(3-4): 271-8, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21499933

RESUMEN

This study investigated maturational differences of selective auditory attention effects on transient evoked responses and 40-Hz auditory steady-state responses between children and adults. Magnetoencephalography (MEG) was recorded from children and adults performing a task where they attended to 40-Hz amplitude-modulated (AM) tones of 1,200 Hz while ignoring 40-Hz AM tones of 800 Hz. By using standard dipole-modeling procedures, the N1m of the transient evoked fields and the 40-Hz ASSRs were localized to secondary and primary auditory cortices, respectively. Source waveforms for the transient evoked fields and ASSRs were reconstructed at these locations and compared between attended and unattended tones. Source waveforms revealed attention enhances the sustained negativity of the transient evoked responses in both adults and children around 250 and 400 ms. ASSRs were also found to be enhanced within this time range but only for adults. The results provide evidence for a limited role of attention modification of the 40-Hz ASSRs in children around the age of 12 years old. Because ASSRs are generated in a lower auditory processing stage as compared to the transient auditory evoked responses, findings from the present study could indicate that the maturation of attention progresses in top-to-bottom manner. These findings fit with the notion that as a person gains sensory experience selective gating of relevant from irrelevant information likely occurs at earlier and earlier processing levels in order to become more automatic and efficient.


Asunto(s)
Envejecimiento/fisiología , Atención/fisiología , Corteza Auditiva/fisiología , Potenciales Evocados Auditivos/fisiología , Magnetoencefalografía , Estimulación Acústica , Vías Auditivas/fisiología , Mapeo Encefálico , Niño , Femenino , Humanos , Masculino , Neuroimagen/métodos , Análisis y Desempeño de Tareas , Adulto Joven
4.
Clin Neurophysiol ; 120(3): 497-504, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19138878

RESUMEN

OBJECTIVE: To investigate the neural sources and associated changes in oscillatory activity involved in auditory attention and memory updating processing using spatially filtered magnetoencephalography. METHODS: We recorded magnetic responses during an auditory oddball task in 12 normal subjects. Synthetic aperture magnetometry (SAM)-permutation analysis was used to visualize the multiple brain regions associated with event-related magnetic fields (ERFs), and event-related oscillations during target detection processing. RESULTS: SAM-permutation results showed the topographical distribution of N1m over the bilateral primary auditory cortex. Post-stimulus delta (1.5-4 Hz) activity sources, likely related to the P300 slow-waveform, were distributed over the right frontocentral and parietal regions. Source locations of theta (4-8 Hz) and alpha (8-13 Hz) event-related synchronization (ERS) were identified over the dorsolateral and medial prefrontal cortex. We visualized bilateral central-Rolandic suppresions for mu (8-15 Hz), beta (15-30 Hz), and low-gamma (30-60 Hz) activities, more dominant in the hemisphere contralateral to the moving hand (button-pressing in response to target stimuli). CONCLUSIONS: Prefrontal theta and alpha ERS, and frontocentral-parietal delta ERS are functionally engaged in auditory attention and memory updating process. SIGNIFICANCE: Spatially filtered MEG is valuable for detection and source localization of task-related changes in the ongoing oscillatory activity during oddball tasks.


Asunto(s)
Atención/fisiología , Relojes Biológicos/fisiología , Corteza Cerebral/fisiología , Potenciales Evocados/fisiología , Magnetoencefalografía/métodos , Memoria/fisiología , Estimulación Acústica , Adulto , Corteza Cerebral/anatomía & histología , Cognición/fisiología , Femenino , Lateralidad Funcional/fisiología , Humanos , Masculino , Red Nerviosa/anatomía & histología , Red Nerviosa/fisiología , Vías Nerviosas/anatomía & histología , Vías Nerviosas/fisiología , Pruebas Neuropsicológicas , Procesamiento de Señales Asistido por Computador , Localización de Sonidos/fisiología
5.
Neuropsychology ; 22(3): 293-300, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18444707

RESUMEN

Past research suggests a link between socioeconomic status (SES) and brain processes in children, but direct evidence from neuroimaging is scarce. The authors investigated the relationships among SES, performance, and the neural correlates of auditory selective attention, by comparing event-related potentials (ERPs) in lower- and higher-SES preadolescent children during a task in which they attended to two types of pure tones but ignored two other types. Our hypothesis was that, at comparable performance levels, higher-SES children ignore distracters (the unattended, irrelevant tones) while lower-SES children attend equally to distracters and to targets (the attended, relevant tones). The authors found that ERP waveform differences between attended and unattended tones (Nd, difference negativity) were significant in the higher-SES but not in the lower-SES group. However, the groups did not differ in reaction times or accuracy. Electroencephalographic power analysis revealed a differential pattern of theta activity concomitant with irrelevant tones for the two groups, indicating that although they performed similarly the children from these groups recruited different neural processes. Lower-SES children, the authors suggest, deployed supplementary resources to also attend to irrelevant information.


Asunto(s)
Atención/fisiología , Potenciales Evocados Auditivos/fisiología , Clase Social , Estimulación Acústica/métodos , Adolescente , Mapeo Encefálico , Niño , Electroencefalografía , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Análisis Espectral
6.
J Cogn Neurosci ; 20(6): 1030-42, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18211239

RESUMEN

It is well known that previous perceptual experiences alter subsequent perception, but the details of the neural underpinnings of this general phenomenon are still sketchy. Here, we ask whether previous experiences with an item (such as seeing a person's face) leads to the alteration of the neural correlates related to processing of the item as such, or whether it creates additional associative connections between such substrates and those activated during prior experience. To address this question, we used magnetoencephalography (MEG) to identify neural changes accompanying subjects' viewing of unfamiliar versus famous faces and hearing the names of unfamiliar versus famous names. We were interested in the nature of the involvement of auditory brain regions in the viewing of faces, and in the involvement of visual regions in the hearing of names. Evoked responses from MEG recordings for the names and faces conditions were localized to auditory and visual cortices, respectively. Unsurprisingly, peak activation strength of evoked responses was larger for famous versus nonfamous names within the superior temporal gyrus (STG), and was similar for famous and nonfamous faces in the occipital cortex. More relevant to the issue of experience on perception, peak activation strength in the STG was larger for viewed famous versus nonfamous faces, and peak activation within the occipital cortex was larger for heard famous versus nonfamous names. Critically, these experience-related responses were present within 150-250 msec of stimulus onset. These findings support the hypothesis that prior experiences may influence processing of faces and names such that perception encompasses more than what is imparted on the senses.


Asunto(s)
Percepción Auditiva/fisiología , Aprendizaje/fisiología , Percepción Visual/fisiología , Estimulación Acústica , Adulto , Señales (Psicología) , Interpretación Estadística de Datos , Cara , Femenino , Humanos , Imagen por Resonancia Magnética , Magnetoencefalografía , Masculino , Estimulación Luminosa , Disposición en Psicología , Lóbulo Temporal/fisiología
7.
Neurosci Lett ; 399(1-2): 61-6, 2006 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-16507333

RESUMEN

In this study, we investigated changes in cortical oscillations following congruent and incongruent grapheme-phoneme stimuli. Hiragana graphemes and phonemes were simultaneously presented as congruent or incongruent audiovisual stimuli to native Japanese-speaking participants. The discriminative reaction time was 57 ms shorter for congruent than incongruent stimuli. Analysis of MEG responses using synthetic aperture magnetometry (SAM) revealed that congruent stimuli evoked larger 2-10 Hz activity in the left auditory cortex within the first 250 ms after stimulus onset, and smaller 2-16 Hz activity in bilateral visual cortices between 250 and 500 ms. These results indicate that congruent visual input can modify cortical activity in the left auditory cortex.


Asunto(s)
Corteza Auditiva/fisiología , Reconocimiento Visual de Modelos , Percepción del Habla , Corteza Visual/fisiología , Estimulación Acústica , Mapeo Encefálico , Femenino , Humanos , Magnetoencefalografía , Masculino , Estimulación Luminosa
8.
Neuroimage ; 20(2): 995-1005, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14568469

RESUMEN

In this study we applied synthetic aperture magnetometry (SAM) to investigate active cortical areas associated with magnetically recorded transient and steady-state auditory evoked responses. For transient evoked responses, SAM images reveal an activated volume of cortical tissue within the lateral aspect of the superior temporal plane. The volume of cortical activation for steady-state responses was located more medially than that for transient evoked responses. Additionally, SAM also reveals a small overlap of activated areas between transient and steady-state evoked responses, which has not be demonstrated when using equivalent current dipole (ECD) source modeling. Source waveforms from SAM and ECD analyses show comparable temporal information. Results from this study suggest that SAM is a useful technique for imaging cortical structures involved in processing perceptual information.


Asunto(s)
Corteza Auditiva/fisiología , Magnetoencefalografía , Estimulación Acústica , Adulto , Algoritmos , Mapeo Encefálico , Interpretación Estadística de Datos , Femenino , Humanos , Masculino , Modelos Neurológicos , Lóbulo Temporal/fisiología
9.
Brain Topogr ; 15(2): 69-86, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12537303

RESUMEN

The objective of this study was to localize the intracerebral generators for auditory steady-state responses. The stimulus was a continuous 1000-Hz tone presented to the right or left ear at 70 dBSPL. The tone was sinusoidally amplitude-modulated to a depth of 100% at 12, 39, or 88 Hz. Responses recorded from 47 electrodes on the head were transformed into the frequency domain. Brain electrical source analysis treated the real and imaginary components of the response in the frequency domain as independent samples. The latency of the source activity was estimated from the phase of the source waveform. The main source model contained a midline brainstem generator with two components (one vertical and lateral) and cortical sources in the left and right supratemporal plane, each containing tangential and radial components. At 88 Hz, the largest activity occurred in the brainstem and subsequent cortical activity was minor. At 39 Hz, the initial brainstem component remained and significant activity also occurred in the cortical sources, with the tangential activity being larger than the radial. The 12-Hz responses were small, but suggested combined activation of both brainstem and cortical sources. Estimated latencies decreased for all source waveforms as modulation frequency increased and were shorter for the brainstem compared to cortical sources. These results suggest that the whole auditory nervous system is activated by modulated tones, with the cortex being more sensitive to slower modulation frequencies.


Asunto(s)
Estimulación Acústica , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología , Percepción Sonora/fisiología , Adolescente , Adulto , Análisis de Varianza , Corteza Cerebral/fisiología , Oído/fisiología , Electrodos , Electroencefalografía , Femenino , Lateralidad Funcional , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Emisiones Otoacústicas Espontáneas/fisiología , Tiempo de Reacción , Localización de Sonidos , Factores de Tiempo
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