Nicolas Robitaille - Academia.edu (original) (raw)

Papers by Nicolas Robitaille

Research paper thumbnail of Congenital Amusia Persists in the Developing Brain after Daily Music Listening

PLoS ONE, 2012

Congenital amusia is a neurodevelopmental disorder that affects about 3% of the adult population.... more Congenital amusia is a neurodevelopmental disorder that affects about 3% of the adult population. Adults experiencing this musical disorder in the absence of macroscopically visible brain injury are described as cases of congenital amusia under the assumption that the musical deficits have been present from birth. Here, we show that this disorder can be expressed in the developing brain. We found that (10-13 year-old) children exhibit a marked deficit in the detection of fine-grained pitch differences in both musical and acoustical context in comparison to their normally developing peers comparable in age and general intelligence. This behavioral deficit could be traced down to their abnormal P300 brain responses to the detection of subtle pitch changes. The altered pattern of electrical activity does not seem to arise from an anomalous functioning of the auditory cortex, because all early components of the brain potentials, the N100, the MMN, and the P200 appear normal. Rather, the brain and behavioral measures point to disrupted information propagation from the auditory cortex to other cortical regions. Furthermore, the behavioral and neural manifestations of the disorder remained unchanged after 4 weeks of daily musical listening. These results show that congenital amusia can be detected in childhood despite regular musical exposure and normal intellectual functioning.

Research paper thumbnail of When more is less: Extraction of summary statistics benefits from larger sets

Journal of Vision, 2011

Despite several processing limitations that have been identified in the visual system, research s... more Despite several processing limitations that have been identified in the visual system, research shows that statistical information about a set of objects could be perceived as accurately as the information about a single object. It has been suggested that extraction of summary statistics represents a different mode of visual processing, which employs a parallel mechanism free of capacity limitations. Here, we demonstrate, using reaction time measures, that increasing the number of stimuli in the set results in faster reaction times and better accuracy for estimating the mean tendency of a set. These results provide clear evidence that extraction of summary statistics relies on a distributed attention mode that operates across the whole display at once and that this process benefits from larger samples across which the summary statistics are calculated.

Research paper thumbnail of Études Des Marqueurs Physiologiques De La Mémoire Visuelle À Court Terme: Électrophysiologie, Magnétoencéphalographie et Imagerie Par Résonance Magnétique Fonctionnelle

Research paper thumbnail of On the control of visual spatial attention: evidence from human electrophysiology

Psychological Research, 2006

We used electrophysiological methods to track the deployment of visual spatial attention while ob... more We used electrophysiological methods to track the deployment of visual spatial attention while observers were engaged in concurrent central attentional processing, using a variant of the attentional blink paradigm. Two visual targets (T1, T2) were presented at a stimulus onset asynchrony of either 200 ms or 800 ms. T1 was a white digit among white letters presented on a dark background using rapid serial visual presentation at fixation. T2 was another digit that was presented to the left or right of fixation simultaneously with a distractor digit in the opposite visual field, each followed by a pattern mask. In each T2 display, one digit was red and one was green. Half of the subjects reported the red digit and ignored the green one, whereas the other half reported the green digit and ignored the red one. T1 and T2 were reported in one block of trials, and only T2 in another block (order counterbalanced across subjects). Accuracy of report of T2 was lower at short SOA than at long SOA when both T1 and T2 were reported, but was similar across SOA when only T2 was reported. The electrophysiological results focused on the N2pc component, which was used as an index of the locus of spatial attention. N2pc was reduced in amplitude when subjects reported T1, and particularly so at the short SOA. The results suggest that attention to T1 interfered with the deployment of visual spatial attention to T2.

Research paper thumbnail of Short-term consolidation of visual patterns interferes with visuo-spatial attention: Converging evidence from human electrophysiology

Brain Research, 2007

In order to investigate the interplay between visuo-spatial attention and central attention, we v... more In order to investigate the interplay between visuo-spatial attention and central attention, we varied the relative probability (25% vs. 75%) of the responses to lateralized targets in an attentional blink paradigm. When the first target was associated with a less probable response, we observed a larger attentional blink, that is, a general reduction in accuracy for the second target. The efficiency of deployment of spatial attention to the second target was also reduced as a function of the response frequency for the first target. Both the N2pc, an event-related potential (ERP) associated with the deployment of attention in visual space, and the SPCN (sustained posterior contralateral negativity), an ERP associated with the maintenance of information in visual short-term memory, time-locked to T2 were significantly reduced when the first target was associated with a less frequent response.

Research paper thumbnail of Spatial attention freezes during the attention blink

Psychophysiology, 2006

A variant of the rapid serial visual presentation paradigm was used to display sequentially two l... more A variant of the rapid serial visual presentation paradigm was used to display sequentially two lateral sequences of stimuli, one to the left and one to the right of fixation, embedding two pairs of target stimuli, T1 and T2. T1 was composed of a pair of alphanumeric characters, and subjects had either to ignore T1 or to encode T1 for a delayed response. T2 was a lateral square of a prespecified color. The square had a small gap in one side, and the task for this stimulus was to report which side had the gap. When subjects were required to ignore T1, the T2-locked ERP produced a clear N2pc, that is, a greater negativity at electrode sites contralateral to the position occupied by T2. This N2pc was followed by a sustained posterior contralateral negativity (SPCN). When subjects were required to monitor T1 in addition to T2, both the N2pc and the SPCN components amplitude depended on the difficulty of the task associated with T1. If T1 was composed of digits that had to be encoded for a delayed same/different judgment, both the N2pc and the SPCN components were entirely suppressed. Although attenuated, such components were present when T1 was composed of a pair of symbols that subjects could disregard. The results suggest that a set of mechanisms subserving the allocation of attention in the spatial domain, resulting in the N2pc, suffer significant interference from concurrent cognitive operations required to encode information into visual short-term memory.

Research paper thumbnail of Attentional control and capture in the attentional blink paradigm: Evidence from human electrophysiology

European Journal of Cognitive Psychology, 2006

We studied attentional control mechanisms using electrophysiological methods, focusing on the N2p... more We studied attentional control mechanisms using electrophysiological methods, focusing on the N2pc event-related potential (ERP), to track the moment-bymoment deployment of visual spatial attention. Two digits (T 1 and T 2 , both red or both green, and masked, were embedded in a rapid serial visual presentation of letter distractors with an SOA of 200 ms or 800 ms. T 1 was at fixation, whereas T 2 was 38 to the left or right of fixation and presented with a concurrent equiluminant distractor digit in a different colour. T 1 and T 2 were reported in one block of trials, and only T 2 in another block (order counterbalanced). Accuracy for T 2 was lower at short SOA than at long SOA when both T1 and T2 were reported, suggesting an attentional blink (AB) effect. It was difficult to ignore T 1 because T 1 had the same colour as T 2 , producing a large deficit in T 2 accuracy at short SOA in the control condition. The amplitude of the N2pc ERP component was attenuated in the short-SOA condition relative to the long-SOA condition, both in the experimental and the control conditions, suggesting that T 1 involuntarily captured visual spatial attention and that while attention was deployed on T 1 , the processing of T 2 was significantly impaired.

Research paper thumbnail of On the control of visual spatial attention: evidence from human electrophysiology

Psychological Research, 2006

We used electrophysiological methods to track the deployment of visual spatial attention while ob... more We used electrophysiological methods to track the deployment of visual spatial attention while observers were engaged in concurrent central attentional processing, using a variant of the attentional blink paradigm. Two visual targets (T1, T2) were presented at a stimulus onset asynchrony of either 200 ms or 800 ms. T1 was a white digit among white letters presented on a dark background using rapid serial visual presentation at fixation. T2 was another digit that was presented to the left or right of fixation simultaneously with a distractor digit in the opposite visual field, each followed by a pattern mask. In each T2 display, one digit was red and one was green. Half of the subjects reported the red digit and ignored the green one, whereas the other half reported the green digit and ignored the red one. T1 and T2 were reported in one block of trials, and only T2 in another block (order counterbalanced across subjects). Accuracy of report of T2 was lower at short SOA than at long SOA when both T1 and T2 were reported, but was similar across SOA when only T2 was reported. The electrophysiological results focused on the N2pc component, which was used as an index of the locus of spatial attention. N2pc was reduced in amplitude when subjects reported T1, and particularly so at the short SOA. The results suggest that attention to T1 interfered with the deployment of visual spatial attention to T2.

Research paper thumbnail of Short-term consolidation of visual patterns interferes with visuo-spatial attention: Converging evidence from human electrophysiology

Brain Research, 2007

In order to investigate the interplay between visuo-spatial attention and central attention, we v... more In order to investigate the interplay between visuo-spatial attention and central attention, we varied the relative probability (25% vs. 75%) of the responses to lateralized targets in an attentional blink paradigm. When the first target was associated with a less probable response, we observed a larger attentional blink, that is, a general reduction in accuracy for the second target. The efficiency of deployment of spatial attention to the second target was also reduced as a function of the response frequency for the first target. Both the N2pc, an event-related potential (ERP) associated with the deployment of attention in visual space, and the SPCN (sustained posterior contralateral negativity), an ERP associated with the maintenance of information in visual short-term memory, time-locked to T2 were significantly reduced when the first target was associated with a less frequent response.

Research paper thumbnail of Attentional control and capture in the attentional blink paradigm: Evidence from human electrophysiology

European Journal of Cognitive Psychology, 2006

We studied attentional control mechanisms using electrophysiological methods, focusing on the N2p... more We studied attentional control mechanisms using electrophysiological methods, focusing on the N2pc event-related potential (ERP), to track the moment-bymoment deployment of visual spatial attention. Two digits (T 1 and T 2 , both red or both green, and masked, were embedded in a rapid serial visual presentation of letter distractors with an SOA of 200 ms or 800 ms. T 1 was at fixation, whereas T 2 was 38 to the left or right of fixation and presented with a concurrent equiluminant distractor digit in a different colour. T 1 and T 2 were reported in one block of trials, and only T 2 in another block (order counterbalanced). Accuracy for T 2 was lower at short SOA than at long SOA when both T1 and T2 were reported, suggesting an attentional blink (AB) effect. It was difficult to ignore T 1 because T 1 had the same colour as T 2 , producing a large deficit in T 2 accuracy at short SOA in the control condition. The amplitude of the N2pc ERP component was attenuated in the short-SOA condition relative to the long-SOA condition, both in the experimental and the control conditions, suggesting that T 1 involuntarily captured visual spatial attention and that while attention was deployed on T 1 , the processing of T 2 was significantly impaired.

Research paper thumbnail of Attending to pitch information inhibits processing of pitch information: the curious case of amusia

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 4, 2015

In normal listeners, the tonal rules of music guide musical expectancy. In a minority of individu... more In normal listeners, the tonal rules of music guide musical expectancy. In a minority of individuals, known as amusics, the processing of tonality is disordered, which results in severe musical deficits. It has been shown that the tonal rules of music are neurally encoded, but not consciously available in amusics. Previous neurophysiological studies have not explicitly controlled the level of attention in tasks where participants ignored the tonal structure of the stimuli. Here, we test whether access to tonal knowledge can be demonstrated in congenital amusia when attention is controlled. Electric brain responses were recorded while asking participants to detect an individually adjusted near-threshold click in a melody. In half the melodies, a note was inserted that violated the tonal rules of music. In a second task, participants were presented with the same melodies but were required to detect the tonal deviation. Both tasks required sustained attention, thus conscious access to ...

Research paper thumbnail of Associations and dissociations among electrophysiological indices of visual spatial attention and short-term memory: Evidence from EEG/ERPs and MEG

Research paper thumbnail of Induced oscillatory activity during retention in visual short-term memory

Research paper thumbnail of Electromagnetic explorations of the temporal dynamics of visual short-term memory

Research paper thumbnail of MUSICAL TRAINING IN TEENAGERS WITH CONGENITAL AMUSIA

Research paper thumbnail of Masking reduces P3 amplitude but not P3 latency: implications for the attentional blink paradigm

Research paper thumbnail of Stimulus intensity affects the latency but not the amplitude of the N2pc

NeuroReport, 2007

The N2pc component of the event-related potential (ERP) is an index of visual-spatial attention. ... more The N2pc component of the event-related potential (ERP) is an index of visual-spatial attention. It is not clear whether the N2pc reflects pure top-down attentional activity or an interaction of top-down activity with bottom-up sensory activity. Here, we manipulated stimulus intensity of the items composing the target display. Although the amplitude of the P1 component increased monotonically with increasing stimulus intensity, the amplitude of the N2pc did not vary with stimulus intensity. Instead, the onset latency of the N2pc was delayed for weaker stimuli, suggesting that the strength of the selection cue (target color) influenced the moment at which attention was deployed. The results reveal one way in which early sensory ERP amplitude differences are converted into later latency differences.

Research paper thumbnail of Backward masking during rapid serial visual presentation affects the amplitude but not the latency of the P3 event-related potential

Psychophysiology, 2010

Masking of the first target in the attentional blink (AB) paradigm increases the magnitude of the... more Masking of the first target in the attentional blink (AB) paradigm increases the magnitude of the AB relative to when the first target is not masked. We examined the underlying causes of this effect in an experiment in which a single target was presented in a rapid visual serial presentation stream. The P3 to the target was isolated by subtracting infrequent target category trials from frequent target category trials. The item immediately trailing the target (i.e., the mask) was present in the masked condition and replaced by a blank screen in the not-masked condition, reproducing conditions known to modulate the AB. Masking the target significantly reduced the amplitude of the target-locked P3 but had no effect on P3 latency. Results are discussed in relation to previous findings in the AB literature.

Research paper thumbnail of Bilateral parietal and contralateral responses during maintenance of unilaterally encoded objects in visual short-term memory: Evidence from magnetoencephalography

Psychophysiology, 2009

A component of the event-related magnetic field (ERMF) response was observed in magnetoencephalog... more A component of the event-related magnetic field (ERMF) response was observed in magnetoencephalographic signals recorded during the maintenance of information in visual short-term memory (VSTM). This sustained posterior contralateral magnetic (SPCM) field is likely the magnetic equivalent of the sustained posterior contralateral negativity (SPCN) found in electrophysiology. Magnetoencephalography data showed, at the sensor level, a bilateral activation over the parietal cortex that increased in amplitude for higher memory load. Others sensors, also over the parietal cortex, showed an activation pattern similar to the SPCN with higher activation for the hemisphere contralateral to the visual field from which visual information was encoded. These two activation patterns suggest that the SPCN and SPCM are generated by a network of cortical sources that includes bilateral parietal loci, likely intra-parietal/intraoccipital cortex, and contralateral parietal sources.

Research paper thumbnail of Spatial attention freezes during the attention blink

Psychophysiology, 2006

A variant of the rapid serial visual presentation paradigm was used to display sequentially two l... more A variant of the rapid serial visual presentation paradigm was used to display sequentially two lateral sequences of stimuli, one to the left and one to the right of fixation, embedding two pairs of target stimuli, T1 and T2. T1 was composed of a pair of alphanumeric characters, and subjects had either to ignore T1 or to encode T1 for a delayed response. T2 was a lateral square of a prespecified color. The square had a small gap in one side, and the task for this stimulus was to report which side had the gap. When subjects were required to ignore T1, the T2-locked ERP produced a clear N2pc, that is, a greater negativity at electrode sites contralateral to the position occupied by T2. This N2pc was followed by a sustained posterior contralateral negativity (SPCN). When subjects were required to monitor T1 in addition to T2, both the N2pc and the SPCN components amplitude depended on the difficulty of the task associated with T1. If T1 was composed of digits that had to be encoded for a delayed same/different judgment, both the N2pc and the SPCN components were entirely suppressed. Although attenuated, such components were present when T1 was composed of a pair of symbols that subjects could disregard. The results suggest that a set of mechanisms subserving the allocation of attention in the spatial domain, resulting in the N2pc, suffer significant interference from concurrent cognitive operations required to encode information into visual short-term memory.

Research paper thumbnail of Congenital Amusia Persists in the Developing Brain after Daily Music Listening

PLoS ONE, 2012

Congenital amusia is a neurodevelopmental disorder that affects about 3% of the adult population.... more Congenital amusia is a neurodevelopmental disorder that affects about 3% of the adult population. Adults experiencing this musical disorder in the absence of macroscopically visible brain injury are described as cases of congenital amusia under the assumption that the musical deficits have been present from birth. Here, we show that this disorder can be expressed in the developing brain. We found that (10-13 year-old) children exhibit a marked deficit in the detection of fine-grained pitch differences in both musical and acoustical context in comparison to their normally developing peers comparable in age and general intelligence. This behavioral deficit could be traced down to their abnormal P300 brain responses to the detection of subtle pitch changes. The altered pattern of electrical activity does not seem to arise from an anomalous functioning of the auditory cortex, because all early components of the brain potentials, the N100, the MMN, and the P200 appear normal. Rather, the brain and behavioral measures point to disrupted information propagation from the auditory cortex to other cortical regions. Furthermore, the behavioral and neural manifestations of the disorder remained unchanged after 4 weeks of daily musical listening. These results show that congenital amusia can be detected in childhood despite regular musical exposure and normal intellectual functioning.

Research paper thumbnail of When more is less: Extraction of summary statistics benefits from larger sets

Journal of Vision, 2011

Despite several processing limitations that have been identified in the visual system, research s... more Despite several processing limitations that have been identified in the visual system, research shows that statistical information about a set of objects could be perceived as accurately as the information about a single object. It has been suggested that extraction of summary statistics represents a different mode of visual processing, which employs a parallel mechanism free of capacity limitations. Here, we demonstrate, using reaction time measures, that increasing the number of stimuli in the set results in faster reaction times and better accuracy for estimating the mean tendency of a set. These results provide clear evidence that extraction of summary statistics relies on a distributed attention mode that operates across the whole display at once and that this process benefits from larger samples across which the summary statistics are calculated.

Research paper thumbnail of Études Des Marqueurs Physiologiques De La Mémoire Visuelle À Court Terme: Électrophysiologie, Magnétoencéphalographie et Imagerie Par Résonance Magnétique Fonctionnelle

Research paper thumbnail of On the control of visual spatial attention: evidence from human electrophysiology

Psychological Research, 2006

We used electrophysiological methods to track the deployment of visual spatial attention while ob... more We used electrophysiological methods to track the deployment of visual spatial attention while observers were engaged in concurrent central attentional processing, using a variant of the attentional blink paradigm. Two visual targets (T1, T2) were presented at a stimulus onset asynchrony of either 200 ms or 800 ms. T1 was a white digit among white letters presented on a dark background using rapid serial visual presentation at fixation. T2 was another digit that was presented to the left or right of fixation simultaneously with a distractor digit in the opposite visual field, each followed by a pattern mask. In each T2 display, one digit was red and one was green. Half of the subjects reported the red digit and ignored the green one, whereas the other half reported the green digit and ignored the red one. T1 and T2 were reported in one block of trials, and only T2 in another block (order counterbalanced across subjects). Accuracy of report of T2 was lower at short SOA than at long SOA when both T1 and T2 were reported, but was similar across SOA when only T2 was reported. The electrophysiological results focused on the N2pc component, which was used as an index of the locus of spatial attention. N2pc was reduced in amplitude when subjects reported T1, and particularly so at the short SOA. The results suggest that attention to T1 interfered with the deployment of visual spatial attention to T2.

Research paper thumbnail of Short-term consolidation of visual patterns interferes with visuo-spatial attention: Converging evidence from human electrophysiology

Brain Research, 2007

In order to investigate the interplay between visuo-spatial attention and central attention, we v... more In order to investigate the interplay between visuo-spatial attention and central attention, we varied the relative probability (25% vs. 75%) of the responses to lateralized targets in an attentional blink paradigm. When the first target was associated with a less probable response, we observed a larger attentional blink, that is, a general reduction in accuracy for the second target. The efficiency of deployment of spatial attention to the second target was also reduced as a function of the response frequency for the first target. Both the N2pc, an event-related potential (ERP) associated with the deployment of attention in visual space, and the SPCN (sustained posterior contralateral negativity), an ERP associated with the maintenance of information in visual short-term memory, time-locked to T2 were significantly reduced when the first target was associated with a less frequent response.

Research paper thumbnail of Spatial attention freezes during the attention blink

Psychophysiology, 2006

A variant of the rapid serial visual presentation paradigm was used to display sequentially two l... more A variant of the rapid serial visual presentation paradigm was used to display sequentially two lateral sequences of stimuli, one to the left and one to the right of fixation, embedding two pairs of target stimuli, T1 and T2. T1 was composed of a pair of alphanumeric characters, and subjects had either to ignore T1 or to encode T1 for a delayed response. T2 was a lateral square of a prespecified color. The square had a small gap in one side, and the task for this stimulus was to report which side had the gap. When subjects were required to ignore T1, the T2-locked ERP produced a clear N2pc, that is, a greater negativity at electrode sites contralateral to the position occupied by T2. This N2pc was followed by a sustained posterior contralateral negativity (SPCN). When subjects were required to monitor T1 in addition to T2, both the N2pc and the SPCN components amplitude depended on the difficulty of the task associated with T1. If T1 was composed of digits that had to be encoded for a delayed same/different judgment, both the N2pc and the SPCN components were entirely suppressed. Although attenuated, such components were present when T1 was composed of a pair of symbols that subjects could disregard. The results suggest that a set of mechanisms subserving the allocation of attention in the spatial domain, resulting in the N2pc, suffer significant interference from concurrent cognitive operations required to encode information into visual short-term memory.

Research paper thumbnail of Attentional control and capture in the attentional blink paradigm: Evidence from human electrophysiology

European Journal of Cognitive Psychology, 2006

We studied attentional control mechanisms using electrophysiological methods, focusing on the N2p... more We studied attentional control mechanisms using electrophysiological methods, focusing on the N2pc event-related potential (ERP), to track the moment-bymoment deployment of visual spatial attention. Two digits (T 1 and T 2 , both red or both green, and masked, were embedded in a rapid serial visual presentation of letter distractors with an SOA of 200 ms or 800 ms. T 1 was at fixation, whereas T 2 was 38 to the left or right of fixation and presented with a concurrent equiluminant distractor digit in a different colour. T 1 and T 2 were reported in one block of trials, and only T 2 in another block (order counterbalanced). Accuracy for T 2 was lower at short SOA than at long SOA when both T1 and T2 were reported, suggesting an attentional blink (AB) effect. It was difficult to ignore T 1 because T 1 had the same colour as T 2 , producing a large deficit in T 2 accuracy at short SOA in the control condition. The amplitude of the N2pc ERP component was attenuated in the short-SOA condition relative to the long-SOA condition, both in the experimental and the control conditions, suggesting that T 1 involuntarily captured visual spatial attention and that while attention was deployed on T 1 , the processing of T 2 was significantly impaired.

Research paper thumbnail of On the control of visual spatial attention: evidence from human electrophysiology

Psychological Research, 2006

We used electrophysiological methods to track the deployment of visual spatial attention while ob... more We used electrophysiological methods to track the deployment of visual spatial attention while observers were engaged in concurrent central attentional processing, using a variant of the attentional blink paradigm. Two visual targets (T1, T2) were presented at a stimulus onset asynchrony of either 200 ms or 800 ms. T1 was a white digit among white letters presented on a dark background using rapid serial visual presentation at fixation. T2 was another digit that was presented to the left or right of fixation simultaneously with a distractor digit in the opposite visual field, each followed by a pattern mask. In each T2 display, one digit was red and one was green. Half of the subjects reported the red digit and ignored the green one, whereas the other half reported the green digit and ignored the red one. T1 and T2 were reported in one block of trials, and only T2 in another block (order counterbalanced across subjects). Accuracy of report of T2 was lower at short SOA than at long SOA when both T1 and T2 were reported, but was similar across SOA when only T2 was reported. The electrophysiological results focused on the N2pc component, which was used as an index of the locus of spatial attention. N2pc was reduced in amplitude when subjects reported T1, and particularly so at the short SOA. The results suggest that attention to T1 interfered with the deployment of visual spatial attention to T2.

Research paper thumbnail of Short-term consolidation of visual patterns interferes with visuo-spatial attention: Converging evidence from human electrophysiology

Brain Research, 2007

In order to investigate the interplay between visuo-spatial attention and central attention, we v... more In order to investigate the interplay between visuo-spatial attention and central attention, we varied the relative probability (25% vs. 75%) of the responses to lateralized targets in an attentional blink paradigm. When the first target was associated with a less probable response, we observed a larger attentional blink, that is, a general reduction in accuracy for the second target. The efficiency of deployment of spatial attention to the second target was also reduced as a function of the response frequency for the first target. Both the N2pc, an event-related potential (ERP) associated with the deployment of attention in visual space, and the SPCN (sustained posterior contralateral negativity), an ERP associated with the maintenance of information in visual short-term memory, time-locked to T2 were significantly reduced when the first target was associated with a less frequent response.

Research paper thumbnail of Attentional control and capture in the attentional blink paradigm: Evidence from human electrophysiology

European Journal of Cognitive Psychology, 2006

We studied attentional control mechanisms using electrophysiological methods, focusing on the N2p... more We studied attentional control mechanisms using electrophysiological methods, focusing on the N2pc event-related potential (ERP), to track the moment-bymoment deployment of visual spatial attention. Two digits (T 1 and T 2 , both red or both green, and masked, were embedded in a rapid serial visual presentation of letter distractors with an SOA of 200 ms or 800 ms. T 1 was at fixation, whereas T 2 was 38 to the left or right of fixation and presented with a concurrent equiluminant distractor digit in a different colour. T 1 and T 2 were reported in one block of trials, and only T 2 in another block (order counterbalanced). Accuracy for T 2 was lower at short SOA than at long SOA when both T1 and T2 were reported, suggesting an attentional blink (AB) effect. It was difficult to ignore T 1 because T 1 had the same colour as T 2 , producing a large deficit in T 2 accuracy at short SOA in the control condition. The amplitude of the N2pc ERP component was attenuated in the short-SOA condition relative to the long-SOA condition, both in the experimental and the control conditions, suggesting that T 1 involuntarily captured visual spatial attention and that while attention was deployed on T 1 , the processing of T 2 was significantly impaired.

Research paper thumbnail of Attending to pitch information inhibits processing of pitch information: the curious case of amusia

The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 4, 2015

In normal listeners, the tonal rules of music guide musical expectancy. In a minority of individu... more In normal listeners, the tonal rules of music guide musical expectancy. In a minority of individuals, known as amusics, the processing of tonality is disordered, which results in severe musical deficits. It has been shown that the tonal rules of music are neurally encoded, but not consciously available in amusics. Previous neurophysiological studies have not explicitly controlled the level of attention in tasks where participants ignored the tonal structure of the stimuli. Here, we test whether access to tonal knowledge can be demonstrated in congenital amusia when attention is controlled. Electric brain responses were recorded while asking participants to detect an individually adjusted near-threshold click in a melody. In half the melodies, a note was inserted that violated the tonal rules of music. In a second task, participants were presented with the same melodies but were required to detect the tonal deviation. Both tasks required sustained attention, thus conscious access to ...

Research paper thumbnail of Associations and dissociations among electrophysiological indices of visual spatial attention and short-term memory: Evidence from EEG/ERPs and MEG

Research paper thumbnail of Induced oscillatory activity during retention in visual short-term memory

Research paper thumbnail of Electromagnetic explorations of the temporal dynamics of visual short-term memory

Research paper thumbnail of MUSICAL TRAINING IN TEENAGERS WITH CONGENITAL AMUSIA

Research paper thumbnail of Masking reduces P3 amplitude but not P3 latency: implications for the attentional blink paradigm

Research paper thumbnail of Stimulus intensity affects the latency but not the amplitude of the N2pc

NeuroReport, 2007

The N2pc component of the event-related potential (ERP) is an index of visual-spatial attention. ... more The N2pc component of the event-related potential (ERP) is an index of visual-spatial attention. It is not clear whether the N2pc reflects pure top-down attentional activity or an interaction of top-down activity with bottom-up sensory activity. Here, we manipulated stimulus intensity of the items composing the target display. Although the amplitude of the P1 component increased monotonically with increasing stimulus intensity, the amplitude of the N2pc did not vary with stimulus intensity. Instead, the onset latency of the N2pc was delayed for weaker stimuli, suggesting that the strength of the selection cue (target color) influenced the moment at which attention was deployed. The results reveal one way in which early sensory ERP amplitude differences are converted into later latency differences.

Research paper thumbnail of Backward masking during rapid serial visual presentation affects the amplitude but not the latency of the P3 event-related potential

Psychophysiology, 2010

Masking of the first target in the attentional blink (AB) paradigm increases the magnitude of the... more Masking of the first target in the attentional blink (AB) paradigm increases the magnitude of the AB relative to when the first target is not masked. We examined the underlying causes of this effect in an experiment in which a single target was presented in a rapid visual serial presentation stream. The P3 to the target was isolated by subtracting infrequent target category trials from frequent target category trials. The item immediately trailing the target (i.e., the mask) was present in the masked condition and replaced by a blank screen in the not-masked condition, reproducing conditions known to modulate the AB. Masking the target significantly reduced the amplitude of the target-locked P3 but had no effect on P3 latency. Results are discussed in relation to previous findings in the AB literature.

Research paper thumbnail of Bilateral parietal and contralateral responses during maintenance of unilaterally encoded objects in visual short-term memory: Evidence from magnetoencephalography

Psychophysiology, 2009

A component of the event-related magnetic field (ERMF) response was observed in magnetoencephalog... more A component of the event-related magnetic field (ERMF) response was observed in magnetoencephalographic signals recorded during the maintenance of information in visual short-term memory (VSTM). This sustained posterior contralateral magnetic (SPCM) field is likely the magnetic equivalent of the sustained posterior contralateral negativity (SPCN) found in electrophysiology. Magnetoencephalography data showed, at the sensor level, a bilateral activation over the parietal cortex that increased in amplitude for higher memory load. Others sensors, also over the parietal cortex, showed an activation pattern similar to the SPCN with higher activation for the hemisphere contralateral to the visual field from which visual information was encoded. These two activation patterns suggest that the SPCN and SPCM are generated by a network of cortical sources that includes bilateral parietal loci, likely intra-parietal/intraoccipital cortex, and contralateral parietal sources.

Research paper thumbnail of Spatial attention freezes during the attention blink

Psychophysiology, 2006

A variant of the rapid serial visual presentation paradigm was used to display sequentially two l... more A variant of the rapid serial visual presentation paradigm was used to display sequentially two lateral sequences of stimuli, one to the left and one to the right of fixation, embedding two pairs of target stimuli, T1 and T2. T1 was composed of a pair of alphanumeric characters, and subjects had either to ignore T1 or to encode T1 for a delayed response. T2 was a lateral square of a prespecified color. The square had a small gap in one side, and the task for this stimulus was to report which side had the gap. When subjects were required to ignore T1, the T2-locked ERP produced a clear N2pc, that is, a greater negativity at electrode sites contralateral to the position occupied by T2. This N2pc was followed by a sustained posterior contralateral negativity (SPCN). When subjects were required to monitor T1 in addition to T2, both the N2pc and the SPCN components amplitude depended on the difficulty of the task associated with T1. If T1 was composed of digits that had to be encoded for a delayed same/different judgment, both the N2pc and the SPCN components were entirely suppressed. Although attenuated, such components were present when T1 was composed of a pair of symbols that subjects could disregard. The results suggest that a set of mechanisms subserving the allocation of attention in the spatial domain, resulting in the N2pc, suffer significant interference from concurrent cognitive operations required to encode information into visual short-term memory.