Exploring eye movement analysis as a measure of selective visual attention in brain injured individuals.

PRIMARY OBJECTIVE: To investigate the utility of using a new method of assessment for deficits in selective visual attention (SVA). METHODS AND PROCEDURES: An independent groups design compared six participants with brain injuries with six participants from a non-brain injured control group. The Sensomotoric Instruments Eye Movement system with remote eye-tracking device (eye camera) and two sets of eight stimuli were employed to determine if the camera would be a sensitive discriminator of SVA in these groups. MAIN OUTCOMES AND RESULTS: The attention profile displayed by the brain injured group showed that they were slower, made more errors, were less accurate and more indecisive than the control group. CONCLUSIONS: The utility of eye movement analysis as an assessment method was established, with implications for rehabilitation requiring further development.

Public attitudes towards survivors of brain injury.

PRIMARY OBJECTIVE: To explore the effects of religious identity, gender and socioeconomic status (SES) on public attitudes towards survivors of brain injury. RESEARCH DESIGN: An independent groups design was used to compare the attitudes of Northern Irish participants. METHODS AND PROCEDURES: The participants were asked to complete a modified form of the Community Attitudes to Mental Illness scale. The new questionnaire replaced the original scales' emphasis on mental illness with that of brain injury. Complete data was available for 179 participants for the religious identity and gender analysis and 124 for gender and SES. Analyses of variance were conducted on these variables. OUTCOMES AND RESULTS: Significant differences between male and female attitudes were found along with significant interactions between religious identity and gender and SES and gender. CONCLUSIONS: Religious, economic and gender-based divisions in society affect attitudes towards survivors of brain injury.

Social networks as support interventions following traumatic brain injury.

The social network and social support needs of people following traumatic brain injury (TBI) are considerable and related to both health outcomes and community integration. We review what is known of the structure of social networks following TBI and explore the relationship of these networks to social support and health. Social network interventions in TBI are described and discussed. Empirically based suggestions are given for the development of interventions based on culturally sensitive programmes which develop social networks and support in a naturalistic manner.

Classification of opioid and 5-hydroxytryptamine receptors by means of discriminative drug effects.

Behavioural studies can help to validate, modify and refine schemes for classifying receptors that are developed from electrophysiological and biochemical experiments. Drug discrimination constitutes one family of behavioural techniques that is being extensively used for studying subtypes of receptors, mainly because the methods often have remarkably high pharmacological specificity but can be applied to agents from a diverse range of classes. This article reviews briefly studies on agents acting through opioid and 5-hydroxytryptamine systems, where the results of the behavioural studies are very largely consistent with findings from other approaches. Many drugs used in such work have limited selectivity for putative subtypes of receptor, but little is known about how such compound pharmacological stimuli are processed in drug discrimination experiments. The characteristics of the discriminative stimuli produced by a mixture of drugs are discussed with respect to implications for effects of single drugs with multiple actions. Based on these initial experiments on discrimination of a mixture of nicotine and midazolam, it appears that the components of a compound pharmacological stimulus may be perceived and processed independently.

Discriminative stimulus effects of a nicotine-midazolam mixture in rats.

Rats were trained to discriminate the effects of nicotine (0.4 mg/kg SC) plus midazolam (0.2 mg/kg SC) from those of saline in a two-bar operant conditioning procedure involving a tandem schedule of food reinforcement. After discrimination training, the component drugs of the mixture produced very considerable amounts of drug-appropriate responding when given separately. Mecamylamine and Ro 15-1788 only slightly attenuated the discriminative response to the mixture when given separately, but completely blocked the response when administered together. In different groups of rats trained to discriminate nicotine or midazolam separately from saline, neither drug appreciably altered the dose-response curve for the other, suggesting a minimal role for pharmacological interactions when effects of mixtures were assessed. The results suggest that the two components of a compound drug-produced stimulus can be perceived separately rather than being blended into a homogenous entity. Knowledge of the characteristics of compound drug-produced stimuli may aid interpretation of the discriminative effects of single drugs with wide spectra of action.

Midazolam cue in rats: effects of drugs acting on GABA and 5-hydroxytryptamine systems, anticonvulsants and sedatives.

The discriminative stimulus effect of midazolam, a short-acting benzodiazepine, was used for testing the effects of related drugs including agents thought to act at different sites in the proposed benzodiazepine receptor complex. Rats were trained in a standard two- bar operant conditioning procedure with food reinforcers delivered on a tandem schedule. The 0.4 mg/kg dose of midazolam used for training was well discriminated, typically yielding about 95% correct responding. There was no generalization to the GABA agonists muscimol and THIP, to the 5-HT antagonists cyproheptadine and methergoline, to buspirone, CGS 9896, ethanol, Ro 5-4864, promethazine, phenytoin sodium or sodium valproate. Muscimol and THIP also failed to potentiate the effects of midazolam. The GABA antagonist bicuculline weakly attenuated the discriminative effect of midazolam without impairing generalization to pentobarbitone, whereas the benzodiazepine inverse agonist FG 7142 did not attenuate the effect of midazolam. The results provide additional evidence for the notable specificity of the midazolam cue but do little to link the behavioural effects of benzodiazepines to GABA or 5- HT systems. Perhaps the potency, efficacy or selectivity of the GABA agonists was inadequate to produce the expected results. Only the effects of bicuculline, and those reported previously for picrotoxin, provided some support for the hypothesis that midazolam cue is mediated by the GABA system.