Biomedical subjects

Craig J Gonsalvez

Publications and source records attributed to Craig J Gonsalvez.

5 recordsLinked to original sources

PubMed2006

Event-related potentials during an emotional Stroop task.

Emotional Stroop tasks have gained wide interest in scientific literature in the last two decades. Although no direct measure of attention is employed, these studies infer the presence of preferential processing of threatening information based on reaction time (RT) impairment in a competing task. Because event-related potential (ERP) measures are sensitive to both the extent (amplitude) and speed (latency) of cerebral processing, they are valuable tools with which to examine more directly the claim that threatening stimuli are associated with enhanced attention. Twenty-two students rated a pool of words to identify those that were personally disturbing. Two word types (threat and neutral) were then compared in two tasks (color relevant, in which the color ink of words was identified, and word relevant in which words were classified as threatening or not). No emotional Stroop effect was observed in terms of longer RTs to identify the colors of threat words. ERP results provided valuable information about threat processing which was not observed with behavioral measures. Threat content was associated with larger P2 amplitude in the right than left hemisphere, and larger P3 amplitude, across tasks. The results indicate strong evidence for enhanced processing of threat-related stimuli in healthy individuals. It is concluded that ERPs are a sensitive measure of processes underlying emotional Stroop performance, which can be used to elucidate attentional biases in healthy and clinical populations.

Adolescent↗

PubMed2004

Suppression of P50 evoked potential component, schizotypal beliefs and smoking.

Suppression of the P50 component of the evoked potential is an electrophysiological index of sensory gating that is blunted in schizophrenia spectrum disorders. Although P50 suppression is thought to be related to symptomatology, this is yet to be shown. The failure to demonstrate this relation has led some to argue that P50 suppression and symptomatology are not related. However, a possible confound has recently been corroborated [i.e., chronic smoking is related to superior P50 suppression [Crawford et al., Neuroscience Letters 317 (2002) 151]], and a relation has been found in questionnaire-defined individuals with indications of schizotypy [i.e., psychometric schizotypy is related to poor P50 suppression [Croft et al., Biological Psychiatry 50 (2001) 441]]. The present study attempted to replicate and extend both studies by examining P50 suppression, smoking histories, psychometric schizotypy and NEO Five-Factor Inventory (NEO-V) scores in 37 healthy participants. Replicating Crawford et al., P50 suppression was better in the heavier smokers. Providing a partial replication of Croft et al., P50 suppression was inversely related to schizotypy scores in participants who smoked little or not at all; however, P50 suppression was positively related to schizotypy in heavier smokers. Covarying for age and NEO-V scale scores had little effect on these relations. The findings provide evidence of important confounds that would limit our ability to detect P50 suppression/symptom relations in schizophrenia.

Adolescent↗

PubMed2004

Differential relations between heart rate and skin conductance, and public speaking anxiety.

The present pilot study tested whether the lack of consistent findings of relations between autonomic nervous system (ANS) activity and non-clinical levels of public speaking anxiety (PSA) can be explained by methodology. An ambulatory protocol was utilised to test whether the interaction of belief structure with each of an undergraduate student speaker's heart rate and skin conductance level predicted state speech anxiety better than their linear summation. Results suggest that in a non-clinical population, the interaction of ANS activity and belief structure is an important determinant of PSA, and may account for variable findings in the literature.

Adult↗

PubMed2002

Response inhibition deficits in obsessive-compulsive disorder.

Difficulty inhibiting irrelevant information may play a central role in the aetiology of obsessive-compulsive disorder (OCD). The aim of the present study was to determine whether OCD subjects (n=20) exhibit deficits in behavioural and cognitive inhibition compared with a clinical control group diagnosed with panic disorder (n=20). All subjects were administered a Go/Nogo task (a measure of behavioural inhibition) and a Stroop test (a measure of cognitive inhibition). OCD subjects made more commission errors on the Go/Nogo task, and they made more errors and displayed longer reaction times on the interference trial of the Stroop task. Trends towards correlations were observed between OCD severity scores and Stroop reaction time, where the more severe the OCD symptoms the faster was the response. No correlations between clinical symptomatology or subject demographics and the Go/Nogo task were observed. It was demonstrated that OCD subjects exhibit deficits in behavioural and cognitive inhibition, which together may underlie the repetitive symptomatic behaviours of the disorder, such as compulsions and obsessions.

Adolescent↗

PubMedDate not supplied

Executive functions in obsessive-compulsive disorder: state or trait deficits?

OBJECTIVE: Despite the neuropsychology literature providing reliable evidence of impaired executive functions in obsessive-compulsive disorder (OCD), to date it has not been determined whether these deficits are trait-related (independent of symptomatology) or state-dependent (dependent on symptomatology). The current research examines the executive functions in OCD in a comprehensive manner and, for the first time, assesses the stability of these deficits over the developmental course of the disorder. METHOD: Using a cross-sectional design, Study 1 examined the executive functions (set shifting, inhibition, planning, verbal fluency and working memory) in 60 subjects (20 actively Symptomatic OCD, 20 Remitted OCD and 20 Panic Disorder). Using a longitudinal design, Study 2 reassessed a subsample of OCD subjects (participants in Study 1) once they reached remitted status. RESULTS: Study 1 found that the OCD groups exhibited deficits in set shifting and inhibition relative to Panic Disorder controls; however, no deficits were observed in planning, verbal fluency or working memory. There were no differences found between the Symptomatic and Remitted OCD groups on any of the executive function measures. Study 2 found that the identified executive function deficits in individuals were stable over time and remained unchanged despite symptom remittance. CONCLUSION: Current results confirm the presence of specific executive function deficits in OCD, and indicate that these deficits are trait-like in nature.

Adult↗