Sylvia M L Cox

• Ph.D.
• Research Associate at McGill University

Background Adolescent alcohol use is the norm, but only some develop a substance use disorder (SUD). The most common vulnerability traits are characterized by diverse externalizing (EXT) behaviors (e.g., poor impulse-control and emotion regulation). Preliminary studies suggest that this increased risk may be influenced by altered mesocorticolimbic...

Background Adolescent alcohol use is the norm, but only some develop a substance use disorder. The increased risk might reflect heightened mesocorticolimbic responses to reward‐related cues but results published to date have been inconsistent. Methods Young social drinkers (age 18.5 ± 0.6 y.o.) who have been followed since birth were recruited fro...

Addictions are thought to be fostered by the emergence of poorly regulated mesocorticolimbic responses to drug‐related cues. The development and persistence of these responses might be promoted by altered glutamate transmission, including changes to type 5 metabotropic glutamate receptors (mGluR5s). Unknown, however, is when these changes arise and...

The Personality Inventory for DSM-5-Brief Form (PID-5-BF) is a relatively novel measure assessing maladaptive personality traits. We examined whether PID-5-BF traits are associated with non-personality measures of wellbeing in N = 661 Canadian adults in the community. Depression, anxiety, and perceived stress measures were obtained, as were indices...

The brain is composed of disparate neural populations that communicate and interact with one another. Although fiber bundles, similarities in molecular architecture, and synchronized neural activity all reflect how brain regions potentially interact with one another, a comprehensive study of how all these interregional relationships jointly reflect...

Neurotransmitter receptors support the propagation of signals in the human brain. How receptor systems are situated within macro-scale neuroanatomy and how they shape emergent function remain poorly understood, and there exists no comprehensive atlas of receptors. Here we collate positron emission tomography data from more than 1,200 healthy indivi...

Neurotransmitter receptors support the propagation of signals in the human brain. How receptor systems are situated within macroscale neuroanatomy and how they shape emergent function remains poorly understood, and there exists no comprehensive atlas of receptors. Here we collate positron emission tomography scans in >1,200 healthy individuals to c...

Neurotransmitter receptors support the propagation of signals in the human brain. How receptor systems are situated within macroscale neuroanatomy and how they shape emergent function remains poorly understood, and there exists no comprehensive atlas of receptors. Here we collate positron emission tomography scans in >1,200 healthy individuals to c...

Commonly comorbid early onset psychiatric disorders might reflect the varying expression of overlapping risk factors. The mediating processes remain poorly understood, but three factors show some promise: adolescent externalizing traits, early life adversity, and midbrain dopamine autoreceptors. To investigate whether these features acquire greater...

Stimulant drug-paired cues can acquire the ability to activate mesocorticolimbic pathways and lead to new bouts of drug use. Studies in laboratory animals suggest that these effects are augmented by progressively greater drug use histories, impulsive personality traits, and acute drug ingestion. As a preliminary test of these hypotheses in humans,...

This chapter describes the use of positron emission tomography (PET) for in vivo imaging of brain regional type 5 metabotropic glutamate (mGlu5) receptors. Two mGlu5 PET tracers have been well-validated, [¹¹C]ABP688 and [¹⁸F]FPEB. They have been used, in laboratory animals and humans, to study diverse illnesses including Parkinson’s disease, Alzhei...

Objective: Only a minority of drug and alcohol users develops a substance use disorder. Previous studies suggest that this differential vulnerability commonly reflects a developmental trajectory characterized by diverse externalizing behaviors. In this study, we examined the relation between child and adolescent externalizing behaviors and adolesc...

This study sought to examine if mental health issues, namely depression and anxiety symptoms, and loneliness were experienced differently according to various demographic groups during the COVID-19 pandemic (i.e., a societal stressor). An online survey, comprising demographic questions and questionnaires on depression, anxiety and loneliness sympto...

The excitatory neurotransmitter glutamate has been implicated in experience-dependent neuroplasticity and drug-seeking behaviors. Type 5 metabotropic glutamate (mGlu5) receptors might be particularly important. They are critically involved in synaptic plasticity and their availability has been reported to be lower in people with alcohol, tobacco, a...

The neurobiological traits that confer risk for addictions remain poorly understood. However, dopaminergic function throughout the prefrontal cortex, limbic system, and upper brainstem has been implicated in behavioral features that influence addiction vulnerability, including poor impulse control and altered sensitivity to rewards and punishments...

Objective Recently identified mutations of the axon guidance molecule receptor gene, DCC, present an opportunity to investigate, in living human brain, mechanisms affecting neural connectivity and the basis of mirror movements, involuntary contralateral responses that mirror voluntary unilateral actions. We hypothesized that haploinsufficient DCC+/...

Purpose The purpose of this study was to assess, in a large sample of healthy young adults, sex differences in the binding potential of [¹¹C]ABP688, a positron emission tomography (PET) tracer selective for the metabotropic glutamate type 5 (mGlu5) receptor. Methods High resolution [¹¹C]ABP688 PET scans were acquired in 74 healthy volunteers (25 m...

Purpose To determine how the low-affinity (Z)-isomer of the radiotracer [¹¹C]ABP688 affects binding potential values in vivo in humans. Methods High-resolution [¹¹C]ABP688 PET scans were acquired on 74 healthy volunteers (25 male, 49 female, mean age 20 ± 3.0). The relative contents of (E)- and (Z)-isomers were determined prior to injection using...

The cover image, by Kelly Smart et al., is based on the Research Article Test–retest variability of [11C]ABP688 estimates of metabotropic glutamate receptor subtype 5 availability in humans, DOI: 10.1002/syn.22041.

Background [¹¹C]ABP688 is a positron emission tomography (PET) radioligand that binds selectively to metabotropic glutamate type 5 receptors (mGluR5). The use of this tracer has identified receptor binding changes in clinical populations, and has been informative in drug occupancy studies. However, previous studies have found significant increases...

It has been proposed that the acquisition of drug seeking is related to the development of conditioned dopamine responses in the ventral striatum. As drug use continues and becomes habit-like, conditioned responses have been shown to shift to the dorsal striatum. Here, using the PET [11C]raclopride method and highly personalized cocaine cues, we re...

Background Novelty-seeking (NS) and impulsive personality traits have been proposed to reflect an interplay between fronto-cortical and limbic systems, including the limbic striatum (LS). Although neuroimaging studies have provided some evidence for this, most are comprised of small samples and many report surprisingly large effects given the chall...

Excel table containing the dataset used in the analyses outlined in this manuscript. (XLSX)

Background: Accumulating evidence indicates that drug-related cues can induce dopamine (DA) release in the striatum of substance abusers. Whether these same cues provoke DA release in the human prefrontal cortex remains unknown. Methods: We used high-resolution positron emission tomography with [18F]fallypride to measure cortical and striatal DA...

Background Only a minority of drug and alcohol users develops a substance use disorder (SUD). Cross-sectional studies suggest that this differential vulnerability commonly reflects a developmental trajectory characterized by diverse externalizing behaviors. Here, we examined the relationship between these features and substance use in a prospective...

Chapter 1: Understanding the Risk Factors for Substance Abuse There are multiple developmental pathways to substance use disorders, with the risk factors that can start an individual down one of these pathways ranging from the genetic to the sociocultural. Because these factors tend to cluster and can vary with age, disentangling their unique contr...

Chapter 1: Understanding the Risk Factors for Substance Abuse There are multiple developmental pathways to substance use disorders, with the risk factors that can start an individual down one of these pathways ranging from the genetic to the sociocultural. Because these factors tend to cluster and can vary with age, disentangling their unique contr...

Drug related cues are potent triggers for relapse in people with cocaine dependence. Dopamine release within a limbic network of striatum, amygdala and hippocampus has been implicated in animal studies, but in humans it has only been possible to measure effects in the striatum. The objective here was to measure drug cue-induced dopamine release in...

Effects of lowered serotonin transmission on cocaine-induced striatal dopamine response: PET [¹¹C]raclopride study in humans. BJP, 199, 391–397. Figure 3 (p. 394): blue diamonds should be labelled ‘BAL+cocaine’. Online Table DS1, the headings of columns five and six for parts (b) to (d) should read: (b) ‘BPND values on nutritionally balanced amino...

Low serotonin transmission is thought to increase susceptibility to a wide range of substance use disorders and impulsive traits. To investigate the effects of lowered serotonin on cocaine-induced (1.0 mg/kg cocaine, self-administered intranasally) dopamine responses and drug craving. In non-dependent cocaine users, serotonin transmission was reduc...

Few pharmacological treatments for alcohol dependence are available. Moreover, the best supported treatment, naltrexone hydrochloride, appears to work for only some. To investigate potential predictors of these differential responses, 40 social drinkers (20 women) were administered 6 days of treatment with naltrexone vs. placebo in a double-blind,...

The effect of self-administered cocaine on extracellular dopamine (DA) levels has not been measured in humans. Ten nondependent cocaine users underwent positron emission tomography [11C]raclopride scans following intranasal self-administration of cocaine hydrochloride (1.0 mg/kg) and placebo powder. Compared with placebo, intranasal cocaine self-ad...

A previous paper reported high susceptibility to spatial migration (allochiria) of tactile stimuli in about 25% of healthy individuals (High Error subjects). When synchronous stimuli touched the two hands, if the unattended stimulus was temporally modulated when the attended one was not (and was thus more salient than the latter), it "migrated" to...

Serotonin (5-HT) is well known to affect the motivational properties of stimuli predictive of rewards as well as the inhibitory control of behavior. Here, central 5-HT depletion was induced by the acute tryptophan (TRP) depletion (ATD) procedure in young healthy volunteers to examine the role of 5-HT in motivated action and prepotent response inhib...

A great deal of human behavior and motivation is based on the intrinsic emotional significance of rewarding or aversive events, as well as on the associations formed between such emotional events and concurrent environmental stimuli. Recent functional neuroimaging studies have implicated the ventral striatum, orbitofrontal cortex (OFC), and amygdal...

The presence of the head in an MRI scanner leads to inhomogeneities in the magnetic field. These cause the 'susceptibility artifacts' of image distortion and signal dropout. In this paper, we evaluate a technique called passive shimming, which has the potential to reduce field inhomogeneities and the resultant artifacts. A piece of a magnetically a...

Migration of tactile sensation was found to occur very frequently in about 25% of normal people (High Error subjects) and very infrequently in others. When synchronous stimuli touched the two hands, if the unattended stimulus was modulated when the attended one was not (and was thus more salient) it "migrated" to the attended hand and fused with or...

Recent studies in rats have suggested that the amygdala and the dorsal striatum may be differentially involved in the formation of stimulus-reward associations and stimulus-response associations, respectively. In a recent study in humans, conditioned preference learning deficits were observed in a group of patients with damage to the amygdala forma...