A number of MEG/EEG studies have shown modulation of endogenous sensorimotor (mu and beta) rhythm... more A number of MEG/EEG studies have shown modulation of endogenous sensorimotor (mu and beta) rhythms during the observation of hand movements. These modulations are similar to patterns that occur during execution of movement and it has been hypothesised that the neural substrates of these rhythms may play a role in action representation and understanding the actions of others. In this experiment we wished to determine whether similar responses would be obtained during the observation of oro-facial movements. Neuromagnetic recordings (151 channels, CTF Systems) were obtained from six healthy subjects while they (1) observed a video of an experimenter making oro-facial movements (2) imitated the same movements and (3) observed hand movements. Source scanning using synthetic aperture magnetometry (SAM) was used to find changes in source power between these active conditions compared to pre-stimulus control conditions where no movement occurred. SAM images were created with 5 mm resolutio...
Background: Although auditory processing is commonly found to be atypical in ASD, the precise nat... more Background: Although auditory processing is commonly found to be atypical in ASD, the precise nature of its relationship to language and communication difficulties in ASD is unclear. Some researchers argue that differences in low-level auditory perception have an early influence on speech perception (Oram Cardy et al 2005), contributing to language impairment in ASD. Others attribute language impairment and communicative deficits in ASD to reduced attention to speech (complex and rapidly changing social) stimuli (Ceponiene et al 2003, Dawson et al 2004, Kuhl et al 2005). In EEG studies, auditory discrimination and attention is typically measured using an auditory oddball paradigm in which infrequent deviant sounds occur within a train of standard speech or nonspeech sounds. Previously it has been reported that the Mismatch Negativity (MMN), an automatic pre-attentive change detection response, is atypical in ASD. However, the nature of this atypicality is inconsistent across studies...
Background / Purpose: Due to the limitations of neuroimaging methodologies, nearly all human stud... more Background / Purpose: Due to the limitations of neuroimaging methodologies, nearly all human studies of developmental brain function have been carried out with children older than four years of age, leaving a gap in the neuroscientific literature that has been termed “the missing neurobiology of cognitive development”. In the last several years work in our laboratory has addressed this gap using a novel magnetoencephalography (MEG) system customised for use with pre-schoolers in conjunction with experimental protocols designed to accommodate the capabilities and motivations of young children. Main conclusion: In the following we describe the child MEG instrument, experimental protocols, and data from recent MEG studies investigating perceptual, motor and cognitive brain function in healthy preschoolers.
Background: Various visual studies have indicated bottom-up and top-down processing difficulties ... more Background: Various visual studies have indicated bottom-up and top-down processing difficulties in Autistic Spectrum Disorder (ASD). If the auditory system is analogous to the visual system, then we would expect to see similar impairments in the auditory domain in bottom-up and top-down tasks. Time-shifted Dichotic Pitch (DP) (Dougherty et al., 1998) is an effective way to measure bottom-up and top-down mechanisms. Our previous research using DP demonstrated the presence of Object Related Negativity (ORN) and Positive 400 (P400) components in the auditory event related potential (AERP) (Hautus & Johnson, 2005). An ORN is elicited when two auditory objects are concurrently perceived – indexing perceptual segregation of concurrent sounds (Alain, Arnott & Picton, 2001; Hautus & Johnson, 2005; Johnson, Hautus, Duff & Clapp, 2007). The ORN occurs irrespective of attention and is driven by the sequence of the incoming auditory information (i.e. bottom-up) (Alain et al., 2001; Hautus & Jo...
The time to decide if a letter is normal or backwards (mirror-reversed) increases as the letter i... more The time to decide if a letter is normal or backwards (mirror-reversed) increases as the letter is rotated away from the upright. It is widely accepted that this increase in time reflects the mental rotation of the stimulus to the upright orientation in order to determine the mirror-normal status of the stimulus. Although response times tend to be longer for mirrored stimuli than for normal stimuli, the difference is constant across orientation. Little work has been focused on why mirror-image stimuli produce longer response times than normal stimuli. This study examines the question of whether or not mirrored stimuli are rotated in the picture plane at the same time as normal stimuli, and if so, why response times to mirrored stimuli are longer than that for normal stimuli. Both the behavioural and electrophysiological findings suggest that the mirrored stimuli are not only rotated in the picture plane, but that they are subsequently rotated to the normal view. It is this additiona...
Proceedings of the 9th Conference of the Australasian Society for Cognitive Science, 2010
Description Anticipatory postural adjustments (APA) are necessary for counteracting destabilizing... more Description Anticipatory postural adjustments (APA) are necessary for counteracting destabilizing forces induced by prime movements. The present study examined APA in a bimanual load-lifting task using simultaneous electroencephalography (EEG) and magnetoencephalography (MEG). A 1-kg weight placed on the left arm was either lifted by an experimenter (imposed condition) or by the subject (voluntary condition). In the imposed condition, inhibition of electromyographic (EMG) activity in the load-bearing muscle ( ...
A number of MEG/EEG studies have shown modulation of endogenous sensorimotor (mu and beta) rhythm... more A number of MEG/EEG studies have shown modulation of endogenous sensorimotor (mu and beta) rhythms during the observation of hand movements. These modulations are similar to patterns that occur during execution of movement and it has been hypothesised that the neural substrates of these rhythms may play a role in action representation and understanding the actions of others. In this experiment we wished to determine whether similar responses would be obtained during the observation of oro-facial movements. Neuromagnetic recordings (151 channels, CTF Systems) were obtained from six healthy subjects while they (1) observed a video of an experimenter making oro-facial movements (2) imitated the same movements and (3) observed hand movements. Source scanning using synthetic aperture magnetometry (SAM) was used to find changes in source power between these active conditions compared to pre-stimulus control conditions where no movement occurred. SAM images were created with 5 mm resolutio...
Background: Although auditory processing is commonly found to be atypical in ASD, the precise nat... more Background: Although auditory processing is commonly found to be atypical in ASD, the precise nature of its relationship to language and communication difficulties in ASD is unclear. Some researchers argue that differences in low-level auditory perception have an early influence on speech perception (Oram Cardy et al 2005), contributing to language impairment in ASD. Others attribute language impairment and communicative deficits in ASD to reduced attention to speech (complex and rapidly changing social) stimuli (Ceponiene et al 2003, Dawson et al 2004, Kuhl et al 2005). In EEG studies, auditory discrimination and attention is typically measured using an auditory oddball paradigm in which infrequent deviant sounds occur within a train of standard speech or nonspeech sounds. Previously it has been reported that the Mismatch Negativity (MMN), an automatic pre-attentive change detection response, is atypical in ASD. However, the nature of this atypicality is inconsistent across studies...
Background / Purpose: Due to the limitations of neuroimaging methodologies, nearly all human stud... more Background / Purpose: Due to the limitations of neuroimaging methodologies, nearly all human studies of developmental brain function have been carried out with children older than four years of age, leaving a gap in the neuroscientific literature that has been termed “the missing neurobiology of cognitive development”. In the last several years work in our laboratory has addressed this gap using a novel magnetoencephalography (MEG) system customised for use with pre-schoolers in conjunction with experimental protocols designed to accommodate the capabilities and motivations of young children. Main conclusion: In the following we describe the child MEG instrument, experimental protocols, and data from recent MEG studies investigating perceptual, motor and cognitive brain function in healthy preschoolers.
Background: Various visual studies have indicated bottom-up and top-down processing difficulties ... more Background: Various visual studies have indicated bottom-up and top-down processing difficulties in Autistic Spectrum Disorder (ASD). If the auditory system is analogous to the visual system, then we would expect to see similar impairments in the auditory domain in bottom-up and top-down tasks. Time-shifted Dichotic Pitch (DP) (Dougherty et al., 1998) is an effective way to measure bottom-up and top-down mechanisms. Our previous research using DP demonstrated the presence of Object Related Negativity (ORN) and Positive 400 (P400) components in the auditory event related potential (AERP) (Hautus & Johnson, 2005). An ORN is elicited when two auditory objects are concurrently perceived – indexing perceptual segregation of concurrent sounds (Alain, Arnott & Picton, 2001; Hautus & Johnson, 2005; Johnson, Hautus, Duff & Clapp, 2007). The ORN occurs irrespective of attention and is driven by the sequence of the incoming auditory information (i.e. bottom-up) (Alain et al., 2001; Hautus & Jo...
The time to decide if a letter is normal or backwards (mirror-reversed) increases as the letter i... more The time to decide if a letter is normal or backwards (mirror-reversed) increases as the letter is rotated away from the upright. It is widely accepted that this increase in time reflects the mental rotation of the stimulus to the upright orientation in order to determine the mirror-normal status of the stimulus. Although response times tend to be longer for mirrored stimuli than for normal stimuli, the difference is constant across orientation. Little work has been focused on why mirror-image stimuli produce longer response times than normal stimuli. This study examines the question of whether or not mirrored stimuli are rotated in the picture plane at the same time as normal stimuli, and if so, why response times to mirrored stimuli are longer than that for normal stimuli. Both the behavioural and electrophysiological findings suggest that the mirrored stimuli are not only rotated in the picture plane, but that they are subsequently rotated to the normal view. It is this additiona...
Proceedings of the 9th Conference of the Australasian Society for Cognitive Science, 2010
Description Anticipatory postural adjustments (APA) are necessary for counteracting destabilizing... more Description Anticipatory postural adjustments (APA) are necessary for counteracting destabilizing forces induced by prime movements. The present study examined APA in a bimanual load-lifting task using simultaneous electroencephalography (EEG) and magnetoencephalography (MEG). A 1-kg weight placed on the left arm was either lifted by an experimenter (imposed condition) or by the subject (voluntary condition). In the imposed condition, inhibition of electromyographic (EMG) activity in the load-bearing muscle ( ...
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