Digital Commons Network^™

Transcranial Magnetic Stimulation Of The Prefrontal Cortex In Awake Nonhuman Primates Evokes A Polysynaptic Neck Muscle Response That Reflects Oculomotor Activity At The Time Of Stimulation., Chao Gu, Brian D Corneil

Brain and Mind Institute Researchers' Publications

Transcranial magnetic stimulation (TMS) has emerged as an important technique in cognitive neuroscience, permitting causal inferences about the contribution of a given brain area to behavior. Despite widespread use, exactly how TMS influences neural activity throughout an interconnected network, and how such influences ultimately change behavior, remain unclear. The oculomotor system of nonhuman primates (NHPs) offers a potential animal model to bridge this gap. Here, based on results suggesting that neck muscle activity provides a sensitive indicator of oculomotor activation, we show that single pulses of TMS over the frontal eye fields (FEFs) in awake NHPs evoked rapid (within ∼25 …

Burning Pain Secondary To Clozapine Use: A Case Report., Bradley Linton, Rachel Fu, Penny A Macdonald, Hooman Ganjavi

Brain and Mind Institute Researchers' Publications

BACKGROUND: The first of the atypical antipsychotics introduced in the 1970s, clozapine remains the most efficacious neuroleptic to this day. However, serious and potentially fatal side effects have necessitated careful regular monitoring among prescribing clinicians. Some adverse effects (e.g. ischaemic bowel) remain under recognized, while newly identified adverse effects continue to be described in the literature.

CASE PRESENTATION: In this report, we describe a healthy 43-year old Caucasian male who experienced onset of a full body deep burning pain several months after the onset of treatment with clozapine. The pain worsened over time, ceased with cessation of treatment, and returned …

The Cost Of Moving Optimally: Kinematic Path Selection., Dinant A Kistemaker, Jeremy D Wong, Paul L Gribble

Brain and Mind Institute Researchers' Publications

It is currently unclear whether the brain plans movement kinematics explicitly or whether movement paths arise implicitly through optimization of a cost function that takes into account control and/or dynamic variables. Several cost functions are proposed in the literature that are very different in nature (e.g., control effort, torque change, and jerk), yet each can predict common movement characteristics. We set out to disentangle predictions of the different variables using a combination of modeling and empirical studies. Subjects performed goal-directed arm movements in a force field (FF) in combination with visual perturbations of seen hand position. This FF was designed …

Mirror Reversal And Visual Rotation Are Learned And Consolidated Via Separate Mechanisms: Recalibrating Or Learning De Novo?, Sebastian Telgen, Darius Parvin, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Motor learning tasks are often classified into adaptation tasks, which involve the recalibration of an existing control policy (the mapping that determines both feedforward and feedback commands), and skill-learning tasks, requiring the acquisition of new control policies. We show here that this distinction also applies to two different visuomotor transformations during reaching in humans: Mirror-reversal (left-right reversal over a mid-sagittal axis) of visual feedback versus rotation of visual feedback around the movement origin. During mirror-reversal learning, correct movement initiation (feedforward commands) and online corrections (feedback responses) were only generated at longer latencies. The earliest responses were directed into a nonmirrored …

Dopaminergic Therapy Affects Learning And Impulsivity In Parkinson's Disease., Nole M Hiebert, Ken N Seergobin, Andrew Vo, Hooman Ganjavi, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

OBJECTIVE: The aim was to examine the effect of dopaminergic medication on stimulus-response learning versus performing decisions based on learning.

METHOD: To see the effect of dopaminergic therapy on stimulus-response learning and response selection, participants with Parkinson's disease (PD) were either tested on and/or off their prescribed dose of dopaminergic therapy during different testing days. Forty participants with PD and 34 healthy controls completed the experiment on consecutive days. On Day 1, participants learned to associate abstract images with spoken, "right" or "left" responses via feedback (Session 1). On Day 2, participants recalled these responses (Session 2) and indicated the …

Developmental Stress, Condition, And Birdsong: A Case Study In Song Sparrows., Kim L Schmidt, Elizabeth A Macdougall-Shackleton, Shawn P Kubli, Scott A Macdougall-Shackleton

Brain and Mind Institute Researchers' Publications

Sexual-selection theory posits that ornaments and displays can reflect a signaler's condition, which in turn is affected both by recent and developmental conditions. Moreover, developmental conditions can induce correlations between sexually selected and other traits if both types of traits exhibit developmental phenotypic plasticity in response to stressors. Thus, sexually selected traits may reflect recent and/or developmental characteristics of signalers. Here, we review data on the relationships between birdsong, a sexually selected trait, and developmental and current condition of birds from a long-term study of a population of song sparrows (Melospiza melodia). Field studies of free-living birds indicate that the …

The Epidemic Of Mental And Neurological Health, Mohsyn I. Malik

Psychology Publications

This paper composes an image of modern mental and neurological health issues and looks to draw links to the current epidemic based on research and studies found online the internet and off-line. The goal is to examine what may be the underlying problem for a lot of these increases in mental health issues and neurodegenerative diseases and what are some promising clinical and sociocultural advances that may help. It explores problems such as the negative impact of the pharmaceutical giants, the increase in apathy in the work place and the general stigma towards mental disease. Through current research, the use …

Olanzapine-Induced Methylation Alters Cadherin Gene Families And Associated Pathways Implicated In Psychosis, Melkaye G. Melka, Christina A Castellani, Nagalingam Rajakumar, Richard O'Reilly, Shiva M Singh

Biology Publications

BACKGROUND: The complex aetiology of most mental disorders involves gene-environment interactions that may operate using epigenetic mechanisms particularly DNA methylation. It may explain many of the features seen in mental disorders including transmission, expression and antipsychotic treatment responses. This report deals with the assessment of DNA methylation in response to an antipsychotic drug (olanzapine) on brain (cerebellum and hippocampus), and liver as a non-neural reference in a rat model. The study focuses on the Cadherin/protocadherins encoded by a multi-gene family that serve as adhesion molecules and are involved in cell-cell communication in the mammalian brain. A number of these molecules …

Sharp Emergence Of Feature-Selective Sustained Activity Along The Dorsal Visual Pathway., Diego Mendoza-Halliday, Santiago Torres, Julio C Martinez-Trujillo

Brain and Mind Institute Researchers' Publications

Sustained activity encoding visual working memory representations has been observed in several cortical areas of primates. Where along the visual pathways this activity emerges remains unknown. Here we show in macaques that sustained spiking activity encoding memorized visual motion directions is absent in direction-selective neurons in early visual area middle temporal (MT). However, it is robustly present immediately downstream, in multimodal association area medial superior temporal (MST), as well as and in the lateral prefrontal cortex (LPFC). This sharp emergence of sustained activity along the dorsal visual pathway suggests a functional boundary between early visual areas, which encode sensory inputs, …

Human Premotor Areas Parse Sequences Into Their Spatial And Temporal Features., Katja Kornysheva, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Skilled performance is characterized by precise and flexible control of movement sequences in space and time. Recent theories suggest that integrated spatio-temporal trajectories are generated by intrinsic dynamics of motor and premotor networks. This contrasts with behavioural advantages that emerge when a trained spatial or temporal feature of sequences is transferred to a new spatio-temporal combination arguing for independent neural representations of these sequence features. We used a new fMRI pattern classification approach to identify brain regions with independent vs integrated representations. A distinct regional dissociation within motor areas was revealed: whereas only the contralateral primary motor cortex exhibited unique …

Sex Differences In Self-Regulation: An Evolutionary Perspective, Niki Hosseini-Kamkar, J. Bruce Morton

Psychology Publications

Bjorklund and Kipp (1996) provide an evolutionary framework predicting that there is a female advantage in inhibition and self-regulation due to differing selection pressures placed on males and females. The majority of the present review will summarize sex differences in self-regulation at the behavioral level. The neural and hormonal underpinnings of this potential sexual dimorphism will also be investigated and the results of the experiments summarized will be related to the hypothesis advanced by Bjorklund and Kipp (1996). Paradoxically, sex differences in self-regulation are more consistently reported in children prior to the onset of puberty. In adult cohorts, the results …

The Co-Occurrence Of Ptsd And Dissociation: Differentiating Severe Ptsd From Dissociative Ptsd, Cherie Amour, Karen-Inge Karstoft, Don Richardson

MacDonald Franklin OSI Research Centre

Purpose

A dissociative-posttraumatic stress disorder (PTSD) subtype has been included in the DSM-5. However, it is not yet clear whether certain socio-demographic characteristics or psychological/clinical constructs such as comorbid psychopathology differentiate between severe PTSD and dissociative-PTSD. The current study investigated the existence of a dissociative-PTSD subtype and explored whether a number of trauma and clinical covariates could differentiate between severe PTSD alone and dissociative-PTSD.

Methods

The current study utilized a sample of 432 treatment seeking Canadian military veterans. Participants were assessed with the Clinician Administered PTSD Scale (CAPS) and self-report measures of traumatic life events, depression, and anxiety. CAPS severity …

Self-Injurious Behaviours Are Associated With Alterations In The Somatosensory System In Children With Autism Spectrum Disorder., Emma G Duerden, Dallas Card, S Wendy Roberts, Kathleen M Mak-Fan, M Mallar Chakravarty, Jason P Lerch, Margot J Taylor

Brain and Mind Institute Researchers' Publications

Children with autism spectrum disorder (ASD) frequently engage in self-injurious behaviours, often in the absence of reporting pain. Previous research suggests that altered pain sensitivity and repeated exposure to noxious stimuli are associated with morphological changes in somatosensory and limbic cortices. Further evidence from postmortem studies with self-injurious adults has indicated alterations in the structure and organization of the temporal lobes; however, the effect of self-injurious behaviour on cortical development in children with ASD has not yet been determined. Thirty children and adolescents (mean age = 10.6 ± 2.5 years; range 7-15 years; 29 males) with a clinical diagnosis of …

Continuous Executive Function Disruption Interferes With Application Of An Information Integration Categorization Strategy., Sarah J Miles, Kazunaga Matsuki, John Paul Minda

Brain and Mind Institute Researchers' Publications

Category learning is often characterized as being supported by two separate learning systems. A verbal system learns rule-defined (RD) categories that can be described using a verbal rule and relies on executive functions (EFs) to learn via hypothesis testing. A nonverbal system learns non-rule-defined (NRD) categories that cannot be described by a verbal rule and uses automatic, procedural learning. The verbal system is dominant in that adults tend to use it during initial learning but may switch to the nonverbal system when the verbal system is unsuccessful. The nonverbal system has traditionally been thought to operate independently of EFs, but …

Improving Trainee Psychiatrist’S Handover: Standard Setting And Audit, Arun Gupta, Ruth Bevan, Akshya Vasudev

Psychiatry Publications

No abstract provided.

Overt Responses During Covert Orienting., Brian D Corneil, Douglas P Munoz

Brain and Mind Institute Researchers' Publications

A distributed network of cortical and subcortical brain areas controls our oculomotor behavior. This network includes the superior colliculus (SC), which coordinates an ancient visual grasp reflex via outputs that ramify widely within the brainstem and spinal cord, accessing saccadic and other premotor and autonomic circuits. In this Review, we discuss recent results correlating subliminal SC activity in the absence of saccades with diverse components of the visual grasp reflex, including neck and limb muscle recruitment, pupil dilation, and microsaccade propensity. Such subtle manifestations of covert orienting are accessible in the motor periphery and may provide the next generation of …

Using Mand Training To Increase Vocalization Rates In Infants, Gabrielle Lee, Nicole Luke, Hye-Suk Leepark

Education Publications

The present study examined the effects of a mand training procedure on the rates of vocalizations in two infants. Both typically developing girls were less than six months old at the onset of the study. An ABCBC reversal design was employed to compare the rates of vocalizations in baseline conditions, a mand-training condition, and a differential reinforcement for other (DRO) condition. A state of deprivation was held constant for both infants across all three conditions in which neither infant was fed for one hour prior to the experimental session. The order of conditions was reversed for the second infant and …

Examining Dorsal Striatum In Cognitive Effort Using Parkinson's Disease And Fmri., Alex A Macdonald, Ken N Seergobin, Ruzbeh Tamjeedi, Adrian M Owen, Jean-Sebastien Provost, Oury Monchi, Hooman Ganjavi, Penny A Macdonald

Brain and Mind Institute Researchers' Publications

OBJECTIVE: Understanding cognition mediated by the striatum can clarify cognitive deficits in Parkinson's disease (PD). Previously, we claimed that dorsal striatum (DS) mediates cognitive flexibility. To refute the possibility that variation in cognitive effort confounded our observations, we reexamined our data to dissociate cognitive flexibility from effort. PD provides a model for exploring DS-mediated functions. In PD, dopamine-producing cells supplying DS are significantly degenerated. DS-mediated functions are impaired off and improved on dopamine replacement medication. Functional magnetic resonance imaging (fMRI) can confirm striatum-mediated functions.

METHODS: Twenty-two PD patients, off-on dopaminergic medication, and 22 healthy age-matched controls performed a number selection …

Mental Health Of University Students: Perspectives For Intervention And Prevention: An Indo-Canadian Collaborative Project, Amresh Srivastava, Rahel Eynan, Ravi Shah, Laxaman Dutt, Shubhangi Parkar, Tss Rao, Dp Giridhar, Rakesh Bhandari, Nagesh Bhandari, Paul Link

Data and Test Instruments

Purpose: The study aimed to determine the levels of psychological distress of university students and examine teachers’ awareness and opinions concerning suicide prevention. Methods: The study used a two-phase, sequential mixed-method approach of converging quantitative and qualitative methodologies. In the quantitative study the 1a2-item General Health Questionnaire (GHQ-12) was used to measure psychological wellbeing in a student sample ( n=110 ). The qualitative study consisted of a focus group with students (n=200) and faculty members. (n=25). Results: The scores for the sample ranged between 0- 33 with a mean score of 10.25 (SD= 6.14). The majority of respondents (70.6%) endorsed …

A New Brief Scale To Assess Suicidality: Scale For Impact Of Suicidality-Management, Assessment And Planning Of Care (Sis-Map- Brief Scanner), Amresh Srivastava, Megan Johnston, Miky Kaushal, Robbie Campbell, Charles Nelson

Data and Test Instruments

Purpose: In this study we examine merit of a short version (Brief Interview Screener (SIS-MAP-scn )of a previously developed and validated 108 item scale, known as ‘ Scale for Impact of Suicidality-Management, Assessment and Planning of Care ( SIS MAP), for rapid assessment in challenging clinical settings e.g. primary care and emergency room. Background: Generally suicide risk is assessed clinically and structured assessments optimize the direction for decision-making across various settings e.g. inpatient care, emergency rooms and crisis centers. We believe that measures with accurate and valid information should be based upon multifactorial risk-constituent domains, e.g. biological, social, psychological, environmental …

A Method For Investigating Age-Related Differences In The Functional Connectivity Of Cognitive Control Networks Associated With Dimensional Change Card Sort Performance, Bianca Debenedictis, J. Bruce Morton

Paediatrics Publications

The ability to adjust behavior to sudden changes in the environment develops gradually in childhood and adolescence. For example, in the Dimensional Change Card Sort task, participants switch from sorting cards one way, such as shape, to sorting them a different way, such as color. Adjusting behavior in this way exacts a small performance cost, or switch cost, such that responses are typically slower and more error-prone on switch trials in which the sorting rule changes as compared to repeat trials in which the sorting rule remains the same. The ability to flexibly adjust behavior is often said to develop …

Effector-Independent Motor Sequence Representations Exist In Extrinsic And Intrinsic Reference Frames., Tobias Wiestler, Sheena Waters-Metenier, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Many daily activities rely on the ability to produce meaningful sequences of movements. Motor sequences can be learned in an effector-specific fashion (such that benefits of training are restricted to the trained hand) or an effector-independent manner (meaning that learning also facilitates performance with the untrained hand). Effector-independent knowledge can be represented in extrinsic/world-centered or in intrinsic/body-centered coordinates. Here, we used functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis to determine the distribution of intrinsic and extrinsic finger sequence representations across the human neocortex. Participants practiced four sequences with one hand for 4 d, and then performed these sequences …

A Dedicated Binding Mechanism For The Visual Control Of Movement., Alexandra Reichenbach, David W Franklin, Peter Zatka-Haas, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

The human motor system is remarkably proficient in the online control of visually guided movements, adjusting to changes in the visual scene within 100 ms [1-3]. This is achieved through a set of highly automatic processes [4] translating visual information into representations suitable for motor control [5, 6]. For this to be accomplished, visual information pertaining to target and hand need to be identified and linked to the appropriate internal representations during the movement. Meanwhile, other visual information must be filtered out, which is especially demanding in visually cluttered natural environments. If selection of relevant sensory information for online control …

Gene Co-Citation Networks Associated With Worker Sterility In Honey Bees., Emma Kate Mullen, Mark Daley, Alanna Gabrielle Backx, Graham James Thompson

Brain and Mind Institute Researchers' Publications

BACKGROUND: The evolution of reproductive self-sacrifice is well understood from kin theory, yet our understanding of how actual genes influence the expression of reproductive altruism is only beginning to take shape. As a model in the molecular study of social behaviour, the honey bee Apis mellifera has yielded hundreds of genes associated in their expression with differences in reproductive status of females, including genes directly associated with sterility, yet there has not been an attempt to link these candidates into functional networks that explain how workers regulate sterility in the presence of queen pheromone. In this study we use available …

Cardiovascular And Psychiatric Morbidity In Obstructive Sleep Apnea (Osa) With Insomnia (Sleep Apnea Plus) Versus Obstructive Sleep Apnea Without Insomnia: A Case-Control Study From A Nationally Representative Us Sample, Madhulika A. Gupta, Katie Knapp

Paediatrics Publications

Purpose: To evaluate cardiovascular and psychiatric morbidity in patient visits with obstructive sleep apnea (OSA) with insomnia (OSA+Insomnia) versus OSA without insomnia (OSA-Insomnia) in a nationally representative US sample. Methods: A retrospective case-control study of epidemiologic databases (National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey) representing an estimated ± standard error (SE) 62,253,910±5,274,747 (unweighted count = 7234) patient visits with diagnosis of OSA from 1995-2010, was conducted. An estimated 3,994,104±791,386 (unweighted count = 658) were classified as OSA+Insomnia and an estimated 58,259,80664,849,800 (unweighted count = 6576) as OSA-Insomnia. Logistic regression analysis was carried out using OSA+Insomnia …

Investigating The Relation Between Striatal Volume And Iq., Penny A Macdonald, Hooman Ganjavi, D Louis Collins, Alan C Evans, Sherif Karama

Brain and Mind Institute Researchers' Publications

The volume of the input region of the basal ganglia, the striatum, is reduced with aging and in a number of conditions associated with cognitive impairment. The aim of the current study was to investigate the relation between the volume of striatum and general cognitive ability in a sample of 303 healthy children that were sampled to be representative of the population of the United States. Correlations between the WASI-IQ and the left striatum, composed of the caudate nucleus and putamen, were significant. When these data were analyzed separately for male and female children, positive correlations were significant for the …

Activation Of Mglur2/3 Receptors In The Ventro-Rostral Prefrontal Cortex Reverses Sensorimotor Gating Deficits Induced By Systemic Nmda Receptor Antagonists., Bridget Valsamis, Michael Chang, Marei Typlt, Susanne Schmid

Brain and Mind Institute Researchers' Publications

Prepulse inhibition (PPI) of acoustic startle is an operational measure of sensorimotor gating, which is disrupted in schizophrenia. NMDA receptor (NMDAR) antagonist induced PPI disruption has become an important pharmacological model for schizophrenia; however, knowledge of the underlying mechanism remains incomplete. This study examines the role of NMDAR in the caudal pontine reticular nucleus (PnC) and the medial prefrontal cortex (mPFC) in NMDARs antagonist induced PPI deficits, as well as the NMDA receptor subtypes involved. We administered the NMDA antagonist MK-801 locally into the caudal pontine reticular formation (PnC), where the PPI mediating pathway converges with the primary startle pathway, …

Bihemispheric Transcranial Direct Current Stimulation Enhances Effector-Independent Representations Of Motor Synergy And Sequence Learning., Sheena Waters-Metenier, Masud Husain, Tobias Wiestler, Jörn Diedrichsen

Brain and Mind Institute Researchers' Publications

Complex manual tasks-everything from buttoning up a shirt to playing the piano-fundamentally involve two components: (1) generating specific patterns of muscle activity (here, termed "synergies"); and (2) stringing these into purposeful sequences. Although transcranial direct current stimulation (tDCS) of the primary motor cortex (M1) has been found to increase the learning of motor sequences, it is unknown whether it can similarly facilitate motor synergy learning. Here, we determined the effects of tDCS on the learning of motor synergies using a novel hand configuration task that required the production of difficult muscular activation patterns. Bihemispheric tDCS was applied to M1 of …

Allocating Structure To Function: The Strong Links Between Neuroplasticity And Natural Selection, Michael Anderson, Barbara L. Finlay

Brain and Mind Institute Researchers' Publications

A central question in brain evolution is how species-typical behaviors, and the neural function-structure mappings supporting them, can be acquired and inherited. Advocates of brain modularity, in its different incarnations across scientific subfields, argue that natural selection must target domain-dedicated, separately modifiable neural subsystems, resulting in genetically-specified functional modules. In such modular systems, specification of neuron number and functional connectivity are necessarily linked. Mounting evidence, however, from allometric, developmental, comparative, systems-physiological, neuroimaging and neurological studies suggests that brain elements are used and reused in multiple functional systems. This variable allocation can be seen in short-term neuromodulation, in neuroplasticity over the …

Gold Mining On Mayan-Mam Territory: Social Unravelling, Discord And Distress In The Western Highlands Of Guatemala, C. Susana Caxaj, Helene Berman, Colleen Varcoe, Susan L. Ray, Jean Paul Restoulec

Paediatrics Publications

This article examines the influence of a large-scale mining operation on the health of the community of San Miguel Ixtahuacán, Guatemala. An anti-colonial narrative approach informed by participatory action research principles was employed. Data collection included focus groups and one-on-one interviews from August to November of 2011. Over this period, we interviewed 15 Mam Mayan men and 41 women (n=56) between the ages of 18 and 64 including health care workers, educators, spiritual leaders, agricultural workers and previous mine employees from 13 villages within the municipality. Participants' accounts pointed to community health experiences of social unravelling characterized by overlapping narratives …