John F Connolly

• PhD
• Emeritus Professor Cognitive & Clinical Neuroscience at McMaster University

Background/Objectives: Coma prognosis is challenging, as patient presentation can be misleading or uninformative when using behavioral assessments only. Event-related potentials have been shown to provide valuable information about a patient’s chance of survival and emergence from coma. Our prior work revealed that the mismatch negativity (MMN) in...

BACKGROUND Our research team developed evidence-based Return to Activity and Return to School protocols for youths with concussion which are based on the Sports Concussion Consensus statements and the main management strategy for concussion recovery. OBJECTIVE It is important to determine if youth with concussion adhere to these protocols before e...

Background Concussion, or mild traumatic brain injury, is a growing public health concern, affecting approximately 1.2% of the population annually. Among children aged 1‐17 years, concussion had the highest weighted prevalence compared to other injury types, highlighting the importance of addressing this issue among the youth population. Objective...

Introduction: Concussive and sub-concussive blows are commonly sustained during contact sports. Through a detailed neuroimaging analysis, this pilot study aimed to determine if a history of sport-related concussions exacerbated cognitive decline later in life. It was hypothesized that clinical health assessments and magnetic resonance imaging (MRI)...

The mismatch negativity (MMN) is considered the electrophysiological change-detection response of the brain, and therefore a valuable clinical tool for monitoring functional changes associated with return to consciousness after severe brain injury. Using an auditory multi-deviant oddball paradigm, we tracked auditory MMN responses in seventeen heal...

A consistent limitation when designing event-related potential paradigms and interpreting results is a lack of consideration of the multivariate factors that affect their elicitation and detection in behaviorally unresponsive individuals. This paper provides a retrospective commentary on three factors that influence the presence and morphology of l...

Functional magnetic resonance imaging (fMRI) has identified dysfunctional network dynamics underlying a number of psychopathologies, including post-traumatic stress disorder, depression and schizophrenia. There is tremendous potential for the development of network-based clinical biomarkers to better characterize these disorders. However, to realiz...

In the United States, approximately 2.53 million people sustain a concussion each year. Relative to adults, youth show greater cognitive deficits following concussion and a longer recovery. An accurate and reliable imaging method is needed to determine injury severity and symptom resolution. The primary objective of this study was to characterize c...

Objectives: The N2b is an event-related potential (ERP) component thought to index higher-order executive function. While the impact of concussion on executive functioning is frequently discussed in the literature, limited research has been done on the role of N2b in evaluating executive functioning in patients with concussion. The aims of this rev...

Objective The present study sought to determine: 1) whether concussed adolescents exhibited deficits in neurocognitive functioning as reflected by neurophysiological alterations; 2) if neurophysiological alterations could be linked to supplementary data such as the number of previous concussions and days since injury; and 3) if deficits in psycholo...

The current literature presents a discordant view of mild traumatic brain injury and its effects on the human brain. This dissonance has often been attributed to heterogeneities in study populations, etiology, acuteness, experimental paradigms, and/or testing modalities. To investigate the progression of mild traumatic brain injury in the human bra...

The paramount importance of research design and research methodologies within the shared space of neurology, clinical neurophysiology, and cognitive neuroscience serves as the theme around which a range of topics is presented. After a tour of historical figures of human electrophysiology and electroencephalography (EEG), the discussion turns to eve...

Objective: The need to have a pediatric-specific concussion management protocol on Return to School (RTS) and Return to Activity (RTA) after concussion has been recognized internationally. The first step to evaluate the protocol effectiveness is to establish whether children and youth are adhering to these recommendations. The objective of this st...

Concussion has been shown to leave the afflicted with significant cognitive and neurobehavioural deficits. The persistence of these deficits and their link to neurophysiological indices of cognition, as measured by event-related potentials (ERP) using electroencephalography (EEG), remains restricted to population level analyses that limit their uti...

There has been increased effort to understand the neurophysiological effects of concussion aimed to move diagnosis and identification beyond current subjective behavioural assessments that suffer from poor sensitivity. Recent evidence suggests that event-related potentials (ERPs) measured with electroencephalography (EEG) are persistent neurophysio...

Current models of spoken word recognition have been predominantly based on studies of Indo-European languages. As a result, less is known about the recognition processes involved in the perception of tonal languages (e.g., Mandarin Chinese), and the role of lexical tone in speech perception. One view is that words in tonal languages are processed p...

Introduction: Coma is a deep state of unconsciousness that can be caused by a variety of clinical conditions. Traditional tests for coma outcome prediction are based mainly on a set of clinical observations. Recently, certain event-related potentials (ERPs), which are transient electroencephalogram (EEG) responses to auditory, visual or tactile sti...

Objective: Recent studies demonstrate that sports-related concussions can have negative consequences on long-term brain health. The goal of the present study was to determine whether retired Canadian Football League (CFL) athletes with a history of concussions exhibit alterations in neurocognitive functioning, along with changes in physical, socia...

Mismatch Negativity (MMN) is a component of the event-related potential (ERP) that is elicited through an odd-ball paradigm. The existence of the MMN in a coma patient has a good correlation with coma emergence; however, this component can be difficult to detect. Previously, MMN detection was based on visual inspection of the averaged ERPs by a ski...

Generally, prognostication of coma outcome currently combines behavioral, reflex, and possibly neuroimaging tests that are interpreted by an attending physician. Electroencephalography, particularly, event-related brain potentials (ERP) have received attention due to evidence demonstrating the positive predictive value of certain ERP including the...

Grand average difference waveforms of the oddball mismatch MMN and corresponding peak topographic maps. The mean difference response for the younger adult (blue) and older adult (orange) groups are plotted for the (A) Mid Frontal, (B) Mid Central, and (C) Mid Parietal ROIs. Dashed colored lines indicate the mean group latency from individually scor...

Grand average waveforms at all ROIs to a list of Common First Names, the Subject’s Own Name, and a list of Non-salient Other Words and their corresponding peak topographic maps within the Subject’s Own Name paradigm. The younger adult group’s average responses in the (A) Mid Frontal, (C) Mid Central, (E) Mid Parietal ROIs, and the older adult group...

Grand average waveforms to the familiar and unfamiliar novels and corresponding peak topographic maps within the oddball mismatch. The mean responses to the familiar novel (FN) for younger adults (blue) and older adults (green), and the unfamiliar novel (UFN) for younger adults (orange) and older adults (red) groups are plotted for the (A) Mid Fron...

Grand average waveforms at all ROIs to Congruent, Incongruent, Nonword, and Pseudoword target words and their corresponding peak topographic maps within the word-word priming paradigm. The younger adult group’s average responses in the (A) Mid Frontal, (C) Mid Central, (E) Mid Parietal ROIs, and the older adult group’s average responses in the (B)...

Grand average waveforms at all ROIs to a list of Common First Names, the Subject’s Own Name, and a list of Non-salient Other Words and their corresponding peak topographic maps within the Subject’s Own Name paradigm with the behavioral manipulation. The active condition average responses in the (A) Mid Frontal, (C) Mid Central, (E) Mid Parietal ROI...

Grand average waveforms at all ROIs to Congruent, Incongruent, Low Probability, and Phonological Foil terminal words and their corresponding peak topographic maps within the semantic violation sentences paradigm. The younger adult group’s average responses in the (A) Mid Frontal, (C) Mid Central, (E) Mid Parietal ROIs, and the older adult group’s a...

Grand average difference waveforms of the pattern violation mismatch MMN to the first and second deviants and corresponding peak topographic maps. The mean difference response to the first and second deviants for the young adult and older adult groups are plotted for the (A) Mid Frontal, (B) Mid Central, and (C) Mid Parietal ROIs. Young adult first...

Grand average waveforms at all ROIs to Congruent, Incongruent, Low Probability, and Phonological Foil terminal words and their corresponding peak topographic maps within the semantic violation sentences paradigm with the behavioral manipulation. The active condition average responses in the (A) Mid Frontal, (C) Mid Central, (E) Mid Parietal ROIs, a...

Grand average waveforms at all ROIs to Congruent, Incongruent, Nonword, and Pseudoword target words and their corresponding peak topographic maps within the word-word priming paradigm with the behavioral manipulation. The active condition average responses in the (A) Mid Frontal, (C) Mid Central, (E) Mid Parietal ROIs, and the passive condition ave...

fMRI and EEG during mental imagery provide alternative methods of detecting awareness in patients with disorders of consciousness (DOC) without reliance on behaviour. Because using fMRI in patients with DOC is difficult, studies increasingly employ EEG. However, there has been no verification that these modalities provide converging information at...

Background Conventional imaging techniques are unable to detect abnormalities in the brain following mild traumatic brain injury (mTBI). Yet patients with mTBI typically show delayed response on neuropsychological evaluation. Because fractal geometry represents complexity, we explored its utility in measuring temporal fluctuations of brain resting...

It has been demonstrated repeatedly that mild traumatic brain injury (mTBI) (concussion) results in neurological deficits (Dupuis et al, 2000; De Beaumont et al, 2007; Covassin et al, 2008). Moreover, individuals diagnosed with a concussion often suffer from prolonged physical, cognitive, and emotional/behavioral symptoms referred to as post-concus...

Abstract: Introduction/Background: Event Related Potential (ERP) analysis of Electroencephalography (EEG) data has been widely used in research on language, cognition, and pathology. The high dimensionality of a typical EEG/ERP dataset makes it a time-consuming prospect to properly analyze, explore, and validate knowledge without a particular restr...

Accurate and fast detection of event related potential (ERP) components is an unresolved issue in neuroscience and critical health care. Mismatch negativity (MMN) is a component of the ERP to an odd stimulus in a sequence of identical stimuli which has good correlation with coma awakening. All of the previous studies for MMN detection are based on...

Up to 40% of individuals with unresponsive wakefulness syndrome (UWS) actually might be conscious. Recent attempts to detect covert consciousness in behaviorally unresponsive patients via neurophysiological patterns are limited by the need to compare data from brain-injured patients to healthy controls. In this report, we pilot an alternative withi...

We found effects of coarticulatory violations on all three components studied. This suggests that the N100 and P200 are not solely perceptual responses, but may also be taken to reflect early steps in phonological processing. Furthermore,what appeared to be the phonological mapping negativity (PMN) was shown to be modulated by the type of coarticul...

We collected EEG data from both Health Controls (HC) and Concussed Adolescents (CA) and found significantly delayed Mismatch Negativity (MMN) latencies to frequency and intensity “deviant” tones in the CA group, while no significant amplitude differences to any of the ”deviant” stimuli (intensity, frequency and duration) were found between the grou...

Event Related Potential (ERP) analysis of Electroencephalography (EEG) data has been widely used in research on language, cognition, and pathology. The high dimensionality (time x channel x condition) of a typical EEG/ERP dataset makes it a time-consuming prospect to properly analyze, explore, and validate knowledge without a particular restricted...

As a sentence unfolds, semantic information accumulated from the surrounding context facilitates the comprehension of upcoming speech. Previous neurolinguistic research has revealed that word recognition is sensitive to prior contextual information that is present in the wider linguistic discourse. The current research used ERPs to investigate whet...

Background There is converging evidence for the notion that pain affects a broad range of attentional domains. This study investigated the influence of pain on the involuntary capture of attention as indexed by the P3a component in the event-related potential derived from the electroencephalogram.Methods Participants performed in an auditory oddbal...

Electroencephalography data recorded during functional magnetic resonance imaging acquisition are subject to large cardiac-related artifacts that must be corrected during postprocessing. This study compared two widely used ballistocardiogram (BCG) correction algorithms as implemented in two software programs. Reduction of BCG amplitude, correlation...

The N400 component is commonly associated with the detection of linguistic incongruity. A few studies have shown that the N400 can also be elicited by non-linguistic stimuli. Different spatiotemporal patterns were observed between the typical Linguistic N400 and the Non-linguistic N400, suggesting distinct brain generators. The aim of this study wa...

HARRISON, A. H., and J. F. Connolly. Finding a way in: A review and practical evaluation of fMRI and EEG in disorders of consciousness. NEUROSCI BIOBEHAV REV XX(X) XXX-XXX, 2013. Diagnoses and assessments of cognitive function in disorders of consciousness (DOC) are notoriously prone to error due to their reliance on behavioural measures. As a resu...

The level of co-activation between brain regions can be measured by resting-state functional magnetic resonance imaging (rs-fMRI). These studies are all done while subjects quietly lay awake with eyes open inside the MRI. We are interested in exercise induced brain effects and recent fMRI work has shown brain activation during a cycling ergometer p...

The study of how words are represented and processed in the mind has served as a meeting ground for research in psychology, linguistics, and neuroscience. Right now, this domain of study is in the midst of astonishing developments. At the core of these developments are the methodological and analytic advancements that have enabled researchers to ad...

We present MINEMO (Minimal Information for Neural ElectroMagnetic Ontologies), a checklist for the description of event-related potentials (ERP) studies. MINEMO extends MINI (Minimal Information for Neuroscience Investigations)to the ERP domain. Checklist terms are explicated in NEMO, a formal ontology that is designed to support ERP data sharing a...

The field of neuroimaging has experienced a tremendous boom due to technological advances in the last ten years and this is also reflected in the electroencephalography / event-related potentials (EEG/ERP) method. This contribution provides an overview of the main EEG/ERP hardware systems and software development currently on the market and the ben...

Up to 25% of children with autism are labeled nonverbal with the implication that they can neither produce nor comprehend language and may have a restricted and limited cognitive life. In many situations these judgments are based on psychological assessments and behavioral observations only. This proof of principle study draws from experience succe...

Several studies have explored the processing specificity of music and speech, but only a few have addressed the processing autonomy of their fundamental components: pitch and phonemes. Here, we examined the additivity of the mismatch negativity (MMN) indexing the early interactions between vowels and pitch when sung. Event-related potentials (ERPs)...

In clinical neurology, a comprehensive understanding of consciousness has been regarded as an abstract concept--best left to philosophers. However, times are changing and the need to clinically assess consciousness is increasingly becoming a real-world, practical challenge. Current methods for evaluating altered levels of consciousness are highly r...

This paper describes recommended methods for the use of event-related brain potentials (ERPs) in clinical research and reviews applications to a variety of psychiatric and neurological disorders. Techniques are presented for eliciting, recording, and quantifying three major cognitive components with confirmed clinical utility: mismatch negativity (...

This study investigated eyewitness identification using ERPs. Twenty participants completed two eyewitness lineup tasks (standard and deception conditions). For the standard condition, participants tried to accurately identify the culprit, whereas in the deception condition, they were asked to deceptively conceal their recognition of the culprit. I...

The present study was designed to investigate the electrophysiological consequences of a mismatch between initial phoneme expectations and the actual spoken input. Participants were presented with a word/nonword prompt with the instruction to delete the initial sound (e.g., snap without the /s/; snoth without the /s/) and determine the resulting se...

Why bother recording event-related brain potentials (ERP) in language studies? What is their " added value? " We attempt to answer these questions by providing an overview of recent ERP work investigating word segmentation and phonological analysis during speech processing, semantic integration mechanisms, syn-tactic processing, and the analysis of...

This study sought to determine if recognition/familiarity memory can be measured using event-related potentials (ERP) in response to a computer-adapted version of a commonly used non-verbal memory assessment instrument. If successful, resulting ERP would further our knowledge of the neurophysiology of recognition memory and could be used in a cogni...

This study investigated the use of event-related brain potentials (ERPs) as a neurophysiological measure of eyewitness identification accuracy during a lineup task (ERP-lineup). Time delay between viewing the crime and completing the ERP-lineup (no-delay, 1-h delay and 1-week delay conditions) and culprit presence or absence were also manipulated....

Communication difficulties are a common consequence of brain injury and neuropathological processes. Equally common is the inability to assess intellectual functioning in many communication-impaired populations because the aphasia and physical disability of such patients prevents measurable performance on traditionally administered tests of mental...

Event-related brain potentials (ERPs) were recorded during a computerized and modified version of the Digit Span Backwards (DB) task from the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). The modified DB version (ERP-DB task) was divided into two sections of 2, 4, 6 and 8 digits in length (Group 1) and 3, 5 and 7 digits in length (Gro...

Previous research has found that pain can exert a disruptive effect on cognitive processing. This experiment was conducted to extend previous research with participants with chronic pain. This report examines pain's effects on early processing of auditory stimulus differences using the Mismatch Negativity (MMN) in healthy participants while they ex...

This study investigated the effectiveness of an ERP-compatible Digit Span Backward (ERP-DB) task to determine working memory abilities in healthy participants. Participants were administered both the standard digit span backward and ERP-DB tasks. The ERP-DB task was divided into two sections, consisting of 2, 4, 6 and 8 (Group 1) and 3, 5, and 7 (G...

The effects of working memory (WM) on the semantic N400 response were studied using high-resolution event-related brain potentials (ERPs). Participants were presented with semantically related sentence pairs and the terminal word congruence was varied in the second sentence. WM load was varied for the sentence pairs using a modified fan procedure [...

The behaviourally unresponsive patient, unable to exhibit the presence of cognition, constitutes a conundrum for health care specialists. Prognostic uncertainty impedes accurate management decisions and the application of ethical principles. An early, reliable prognosis is highly desirable. In this review investigations studying comatose patients w...

The goal of the present study was to delineate phonology's role in silent reading using event-related brain potential (ERP) techniques. Terminal endings of high cloze sentences were manipulated in four conditions in which the terminal word was: (1) the high cloze ending and thus orthographically, phonologically and semantically congruent (e.g., The...

The spatio-temporal dynamics of cortical activation underlying auditory word recognition, particularly its phonological stage, was studied with whole-head magnetoencephalography (MEG). Subjects performed a visuo-auditory priming task known to evoke the phonological mismatch negativity (PMN) response that is elicited by violations of phonological ex...

We studied the fan effect of verbal working memory using functional magnetic resonance imaging (fMRI). Participants were presented with a sentence-pair matching task that described semantic relationships (e.g. classroom-school). Working memory load and semantic processing were manipulated by increasing the number of sentences to be remembered and v...

Clinical assessment of the unresponsive patient is limited to examination of brainstem reflexes and simple motor responses to stimulation. It is thus difficult, especially if brainstem functions are intact, to give early, accurate prognostic information on comatose patients. Neurochemical tests and imaging have not been validated and have significa...

Phonological and semantic processing was studied using high-resolution event-related brain potentials (ERPs) during a sentence-matching task to investigate the spatial distribution of the phonological mismatch negativity (PMN) and the N400 response. It was hypothesized that the two components were spatially separable and that the activity matched p...

Event-related potentials were used as an adjunct to behavioral and self-report measures to examine the impact of pain in a short-term memory-scanning task. P3 amplitude was reduced and a frontal slow wave was increased during pain regardless of the number of items in memory. Results are discussed in terms of pain affecting an attention-switch mecha...

To investigate the effect of chronic pain on processes that generate the mismatch negativity (MMN). Twelve participants with a diagnosis of chronic intractable pain were tested before and after pain treatment. During testing, event-related potentials were recorded while participants performed tasks of varying difficulty. The amplitude of the MMN wa...

The electroencephalogram (EEG) reflects the electrical activity in the brain on the surface of scalp. A major challenge in this field is the localization of sources in the brain responsible for eliciting the EEG signal measured at the scalp. In order to estimate the location of these sources, one must correctly model the sources, i.e., dipoles, as...

Several studies have identified a negativity [the phonological mismatch negativity (PMN)] preceding the N400 during auditory sentence comprehension. The present study investigated whether the PMN reflects a prelexical or lexical stage of spoken word recognition. Event-related brain potentials (ERPs) were recorded to investigate phonological process...

Event-related brain potentials (ERPs) were used to assess language function after stroke and demonstrate that it is possible to adapt neuropsychological tests to evaluate neurocognitive function using ERPs. Prior ERP assessment work has focused on language in both healthy individuals and case studies of aphasic neurotrauma patients. The objective o...

The objective of this study was to find the event-related brain potential (ERP) waveform features and parameters that maximize the correlation between the ERP components and behavioral performance on a neuropsychological test of language comprehension (PPVT-R) in order to develop an electrophysiological diagnostic technique that can be used in the...

Objective: Event-related brain potentials (ERPs) were used to assess language function after stroke and demonstrate that it is possible to adapt neuropsychological tests to evaluate neurocognitive function using ERPs. Prior ERP assessment work has focused on language in both healthy individuals and case studies of aphasic neurotrauma patients. The...

We used magnetoencephalography to elucidate the cortical activation associated with the segmentation of spoken words in nonreading-impaired and dyslexic adults. The subjects listened to binaurally presented sentences where the sentence-ending words were either semantically appropriate or inappropriate to the preceding sentence context. Half of the...