ERP lab



There are two major research projects currently underway. These are:

Aging and the Neural Architecture Supporting Perceptual Organization of Speech

Sponsor: Natural Sciences and Engineering Research Council of Canada

Aging and the Neural Architecture Supporting Perceptual Organization of Speech

Sponsors: Canadian Institutes of Health Research

Each of these projects consists of multiple experiments. Some of the experiments currently underway include:

Neural Correlates of Change Deafness – Kristina Backer, Claude Alain

Change deafness is the auditory analogue of change blindness, or the failure to detect salient changes in a complex auditory scene. In a typical change deafness paradigm, two auditory scenes (comprised of 3 or more sounds) are played one after another, and some aspect within the second scene is changed (e.g. a sound changes location or is removed, etc.). Often, this change goes unnoticed. Both attentional and working memory accounts have been independently proposed to explain change deafness. In the current study, an attentional cue will be manipulated to further explore: 1) the extent to which change deafness arises from a working memory failure and 2) the interaction between memory and attention with respect to change deafness.

Neural correlates of ineffective study and effective retrieval – Alice Kim, Claude Alain, and Endel Tulving

Recent research has produced a surprising finding: standard conditions of repeated studying are essentially useless for long-term retention after an item’s initial recall; instead, repeated testing is a critical factor. Although the facilitative role of testing (retrieval) for long-term retention is not altogether a new finding, this is the first time that the ineffectiveness of repeated studying has been demonstrated so strikingly. As yet there is no explanation for why repeated testing, but not repeated studying, leads to better long-term retention. To examine further this phenomenon of “useless study and useful testing” we will first replicate the behavioural effects of repeated studying and repeated testing and then measure the neural signatures of repeated studying and repeated testing using the event-related potential methodology.

Pitch-Encoding Differences Between Tone and Non-Tone Language-Speaking Musicians With and Without Absolute Pitch – Claude Alain, Stefanie Hutka

This study was the first to examine pitch-encoding in tone (Mandarin and Cantonese) and non-tone language (English) speaking musicians with and without absolute pitch (AP) (n=32). AP is the ability to label pitches without a reference pitch. Though AP is generally a rare ability, research suggests that development of AP may be facilitated by speaking a tone language (Deutsch et al., 2006). Neuroimaging studies suggest that language-related areas are activated when AP musicians process musical stimuli. I hypothesized that AP musicians, and particularly, tone-language-speakers with AP, would demonstrate greater accuracy and faster response times than both non-tone language speaking musicians with AP and without AP, on two audio-visual encoding tasks. Significant differences between AP and no-AP groups were found for both musical and non-musical stimuli, suggesting that individuals with AP may encode and combine audio-visual information more effectively than those without AP. A marginal significant interaction was found for tone-language and reaction time (but not accuracy) for encoding musical stimuli across tasks. Reference: Deutsch, D., Henthorn, T., Marvin, E., & Xu, H. (2006). Absolute pitch among Americans and Chinese conservatory students: Prevalence differences and evidence for a speech- related critical period. Acoustical Society of America, 119(2), 719-722.

Neuroimaging studies of auditory perception and attention: Attentional consequences of harmonic mistuning — Ada W. S. Leung and Claude Alain

In order to perform concurrent sound segregation successfully, the auditory system often bases on the harmonic relations between components of a physical sound source. This mechanism, though believed to be dependent on low level processes that take place along the ascending auditory pathways, have recently been found sensitive to attention. However, the extent to which attention is deployed and how it is allocated during the sound segregation process is still unknown. The present study aimed to explicitly test the deployment of attention during processing of complex sounds. A series of experiments are conducted to examine whether attention allocated to mistuned harmonic can improve or hinder gap detection. Since gap detection is an attention demanding task, examining the gap detection performance allows us to evaluate the attentional deployment to the mistuned harmonic. Several experiments are designed to manipulate the degree of mistuning and the duration of the gap. The idea is that the attention being drawn to the mistuned harmonic might compete with that required to detect the gap and hence jeopardize gap detection. Both behavioral data and event-related potentials will be recorded for analysis.

Sleep, Consolidation and Experience-Based Changes in Performance and Neuromagnetic Brain – Claude Alain, Bernhard Ross, Kuang Da Zhu

Sleep has been shown to be important in the consolidation of newly acquired skills in visual, motor and auditory domains. Previous studies have found training-related changes in auditory perceptual learning in N1 and P2 with the latter possibly indexing slow-learning process that is dependent on sleep. In this experiment, participants will learn over multiple sessions to identify two simultaneously presented vowels that differ in frequency. We will manipulate time of testing (TOD) for each session to better understand the role of sleep in auditory learning as measured behaviourally and using magnetoencephalography (MEG).

Neuroimaging studies of auditory perception and attention: MEG study for auditory attentional blink – Dawei Shen and Claude Alain

The AB occurs when two targets are to be identified among distractors in a rapid serial auditory (or visual) presentation stream. In this situation, correct identification of the first target (target) may produce a deficit in processing the second target (probe), and this effect lasts several hundred milliseconds. In previous studies, the auditory attentional blink mainly concerned the influence of bottom –up factors (e.g., SOA and effects of distractors). At present, we investigate the influence of top-down factors on the auditory AB by using magnetoencephalography (MEG) technique in order to further discover the nature of the auditory AB.

Effects of multiple source characteristics on word and speaker recognition: An ERP study – Sandra Campeanu, Dr. Fergus Craik and Dr. Claude Alain

Context reinstatement has been shown to facilitate word and source recognition. In an auditory ERP experiment, participants performed both recognition tasks with words spoken in four voices. Two voice parameters varied between speakers, with the possibility that none, one or two of these parameters was congruent between study and test. Results indicate that reinstating the study voice at test facilitates both word and speaker memory, compared with no benefit when only one voice parameter is similar. This implies that voices are encoded as acoustic patterns rather than as the sum of their vocal attributes. ERPs revealed, in addition to three expected memory-related modulations, a pre-recollection positivity associated with this reinstatement benefit in both tests. This positivity, likely reflecting acoustic recognition, occurred at 400ms over parietal regions in the word test and started as early as 120ms and 175ms over right frontal and right temporal areas, respectively, in the speaker test.

Speaker Identity in Memory: Exploring the Nature of Voice Reinstatement at Test – Sandra Campeanu, Dr. Fergus Craik, Dr. Claude Alain

In a previous study we found evidence that voice information is encoded as a whole, rather than as the sum of its acoustic parts. In a follow-up study we are now investigating the effect of attention allocation on the representation of voice in memory, both implicitly and explicitly. The purpose of this work is to discern whether voices, like faces, are distinctively processed by their corresponding sensory system.

Dissociable Changes in Auditory Evoked Responses for Speech Identification Performance and Task Repetition – Boaz Ben-David, Sandra Campeanu, Kelly Tremblay and Claude Alain

Auditory perceptual learning, which is accompanied by rapid changes in sensory and response pathways, is a fundamental process central to speech perception, yet the neural mechanisms underlying auditory learning remain poorly understood. Here, we report rapid physiological changes in the human auditory system that coincide with learning. During a one hour test session, participants learned to identify two consonant-vowel syllables that differed in voice-onset-time (VOT). They also carried out a simple tone identification task to determine if changes in auditory evoked potentials were specific to the trained speech cue or whether they simply reflect task repetition. The ability to identify the speech sounds improved from the first to the fourth block of trials as revealed by higher d prime while beta measures remained constant throughout the experiment. This behavioural improvement coincided with a decrease in N1 and P2 amplitude and these learning-related changes differed from those observed during tone identification task, which did not yield changes in performance. Training-induced changes in sensory evoked responses were followed by a decreased in sustained activity over the parietal regions that was specific to the speech sounds. The results are consistent with a top-down non-specific attention effect on neural activity during learning, as well as a more learning-specific modulation, which is coincident with behavioural improvements in speech identification.

Scientists:

Research Associates:

  • Dr. Michael (Sasha) John
  • Dr. Stephen Arnott

Current Post-doctoral Fellows:

  • Dr. Takako Fujioka
  • Dr. Dawei Shen
  • Dr. Ada Leung

Graduate Students:

  • Alice Kim
  • Benjamin Zendel
  • Sandra Campeanu
  • Kuang da Zhu
  • Kristina Backer
  • Stefanie Hutka
  • Nasim Shams

Lab Managers/Research Assistants:

  • Yu He
  • Claire Salloum

Recent Graduates and Undergraduates:

(click the link to see where they are now!)

Associated Researchers:

  • Dr. Brian Levine’s Lab:
    • Nadine Richard
    • Wayne Khuu
    • Priya Kumar
  • Dr. Randy McIntosh’s Lab:
    • Maria Tassopolous
    • Tanya Brown
    • Hongye Wang
  • Dr. Cheryl Grady’s Lab
  • Dr. Joel Snyder
  • Dr. Bruce Schneider

There are currently three electroencephalography systems used in the ERP (Event-Related Potentials) labs – Neuroscan, Biosemi, and MASTER.  Neuroscan and Biosemi are multi-channel recordings using a special cap containing electrodes to record the signal from your brain.

Capping Procedure using the Neuroscan System:

Capping Procedure using the Biosemi System:

Electrode Placement for the MASTER System:

The MASTER (multiple auditory steady-state response) system uses three electrodes to collect data about your hearing.

Steve Aiken:

 Dalhousie University


Hilmi Dajani:

University of Ottawa


Ben Dyson:

 University of Ottawa


Jeni Mangels:

 Cognitive Neuroscience Lab


Heather E. McNeely:

 Schizophrenia Service


David Purcell:

 School of Communication Sciences and Disorders

 National Centre for Audiology


Bruce Schneider:

Human Communication Laboratory


Joel Snyder:

 Auditory Cognitive Neuroscience Laboratory


David Stapells:

 School of Audiology and Speech Sciences


Affiliations:


Suppliers:

Biosemi

  • 76 channel Biosemi system

Compumedics Neuroscan Compumedics USA Ltd

  • 64 and 128 channel Neuroscan systems with Synamp 1
  • 64 channel Neuroscan system with Synamp 2

Electrocap International 1011 West Lexington Rd.

  • 64 channel cap
  • 128 channel cap

Electromedical Instruments

  • audiometers
  • calibrations
  • insert earphone tips

Etymotic

Grass Telefactor Canada

  • Impedance meters
  • Gold Electodes
  • Analysis software for EEG/ERP