Correlated variability and its attentional modulation depend on anatomical connectivity.

Visual cortical neurons show variability in their responses to repeated presentations of a stimulus and a portion of this variability is shared across neurons. Attention may enhance visual perception by reducing shared spiking variability. However, shared variability and its attentional modulation are not consistent within or across cortical areas, and depend on additional factors such as neuronal type. A critical factor that has not been tested is actual anatomical connectivity. We measured spike count correlations among pairs of simultaneously recorded neurons in the primary visual cortex (V1) for which anatomical connectivity was inferred from spiking cross-correlations. Neurons were recorded in monkeys performing a contrast-change discrimination task requiring covert shifts in visual spatial attention. Accordingly, spike count correlations were compared across trials in which attention was directed toward or away from the visual stimulus overlapping recorded neuronal receptive fields. Consistent with prior findings, attention did not significantly alter spike count correlations among random pairings of unconnected V1 neurons. However, V1 neurons connected via excitatory synapses showed a significant reduction in spike count correlations with attention. Interestingly, V1 neurons connected via inhibitory synapses demonstrated high spike count correlations overall that were not modulated by attention. Correlated variability in excitatory circuits also depended upon neuronal tuning for contrast, the task-relevant stimulus feature. These results indicate that shared variability depends on the type of connectivity in neuronal circuits. Also, attention significantly reduces shared variability in excitatory circuits, even when attention effects on randomly sampled neurons within the same area are weak.

Family violence experts in the criminal court: the need to fill the void.

This paper describes the role of family violence expert evidence and argues for the need for adequately trained and experienced specialists to provide that evidence within the criminal jurisdiction of the District Court and High Court in Aotearoa New Zealand. Court processes for the criminal jurisdiction were reviewed to consider the roles and the requirements of expert witnesses in cases of family violence. Given the lack of expert witness training in Aotearoa New Zealand, components of best practice in other jurisdictions, including examples of international expert witness skills and knowledge were sought. Unique skills and experience are necessary for an accurate description of a history of family violence. Experience working with survivors and offenders provides an understanding of the nature and dynamics of violence experienced within a relationship and allows experts to address myths and misconceptions, particularly in relation to the effective nature of the current family violence safety system. Without a contemporary, comprehensive understanding of family violence across police prosecution, judges and lawyers, expert evidence from trained and experienced specialists is required. To enhance the educative role of family violence expert evidence, such evidence should be called by the Court.

Attention differentially modulates multiunit activity in the lateral geniculate nucleus and V1 of macaque monkeys.

Attention promotes the selection of behaviorally relevant sensory signals from the barrage of sensory information available. Visual attention modulates the gain of neuronal activity in all visual brain areas examined, although magnitudes of gain modulations vary across areas. For example, attention gain magnitudes in the dorsal lateral geniculate nucleus (LGN) and primary visual cortex (V1) vary tremendously across fMRI measurements in humans and electrophysiological recordings in behaving monkeys. We sought to determine whether these discrepancies are due simply to differences in species or measurement, or more nuanced properties unique to each visual brain area. We also explored whether robust and consistent attention effects, comparable to those measured in humans with fMRI, are observable in the LGN or V1 of monkeys. We measured attentional modulation of multiunit activity in the LGN and V1 of macaque monkeys engaged in a contrast change detection task requiring shifts in covert visual spatial attention. Rigorous analyses of LGN and V1 multiunit activity revealed robust and consistent attentional facilitation throughout V1, with magnitudes comparable to those observed with fMRI. Interestingly, attentional modulation in the LGN was consistently negligible. These findings demonstrate that discrepancies in attention effects are not simply due to species or measurement differences. We also examined whether attention effects correlated with the feature selectivity of recorded multiunits. Distinct relationships suggest that attentional modulation of multiunit activity depends upon the unique structure and function of visual brain areas.

Thinking Slow More Quickly: Development of Integrated Illness Scripts to Support Cognitively Integrated Learning and Improve Clinical Decision-Making.

Illness scripts describe the mental model used by experienced clinicians to store and recall condition-specific knowledge when making clinical decisions. Studies demonstrate that novice clinicians struggle to develop and apply strong illness scripts. We developed the Integrated Illness Script and Mechanism of Disease (IIS-MOD) map framework to address this challenge.

Changes in Local Network Activity Approximated by Reverse Spike-Triggered Local Field Potentials Predict the Focus of Attention.

The effects of visual spatial attention on neuronal firing rates have been well characterized for neurons throughout the visual processing hierarchy. Interestingly, the mechanisms by which attention generates more or fewer spikes in response to a visual stimulus remain unknown. One possibility is that attention boosts the likelihood that synaptic inputs to a neuron result in spikes. We performed a novel analysis to measure local field potentials (LFPs) just prior to spikes, or reverse spike-triggered LFP "wavelets," for neurons recorded in primary visual cortex (V1) of monkeys performing a contrast change detection task requiring covert shifts in visual spatial attention. We used dimensionality reduction to define LFP wavelet shapes with single numerical values, and we found that LFP wavelet shape changes correlated with changes in neuronal firing rate. We then tested whether a simple classifier could predict monkeys' focus of attention from LFP wavelet shape. LFP wavelet shapes sampled in discrete windows were predictive of the locus of attention for some neuronal types. These findings suggest that LFP wavelets are a useful proxy for local network activity influencing spike generation, and changes in LFP wavelet shape are predictive of the focus of attention.

Thinking differently: Re-framing family violence responsiveness in the mental health and addictions health care context.

Aotearoa New Zealand's high rates of intimate partner violence (IPV) and child abuse and neglect point to a clear need to develop and resource equitable mental health and addiction practices that are responsive both to people experiencing and using violence, and to their families. Current responses to IPV in mental health and addiction settings in Aotearoa New Zealand require a critical re-framing, from an individualistic autonomy and empowerment framework that constrains practitioners' practice, to an understanding IPV as a form of social entrapment. Using a composite story constructed from 28 in-depth New Zealand family violence death reviews, we highlight current problematic practice and discuss alternative responses that could create safer lives for people and families. Re-framing IPV as a form of social entrapment acknowledges it as a complex social problem that requires collective steps to secure people's safety and well-being. Importantly, a social entrapment framework encompasses interpersonal and structural forms of violence, such as the historical and intergenerational trauma of colonization and links to ongoing structural inequities for Maori (the indigenous people of Aotearoa) in Aotearoa New Zealand.

Phase shifts in high-beta- and low-gamma-band local field potentials predict the focus of visual spatial attention.

The local field potential (LFP) contains rich information about activity in local neuronal populations. However, it has been challenging to establish direct links between LFP modulations and task-relevant behavior or cognitive processes, such as attention. We sought to determine whether LFP amplitude or phase modulations are predictive of the allocation of visual spatial attention. LFPs were recorded simultaneously in multiple early visual brain structures of alert macaque monkeys performing attention-demanding detection and discrimination tasks. Attention directed toward the receptive field of recorded neurons generated systematically larger phase shifts in high-beta- and low-gamma-frequency LFPs compared with LFP phase shifts on trials in which attention was directed away from the receptive field. This attention-mediated temporal advance corresponded to ~10 ms. LFP phase shifts also correlated with reaction times when monkeys were engaged in the tasks. Importantly, attentional modulation of LFP phase was consistent across monkeys, tasks, visual brain structures, and cortical layers. In contrast, attentional modulation of LFP amplitude varied across frequency bands, visual structures/layers, and tasks. Because LFP phase shifts were robust, consistent, and predictive of spatial attention, they could serve as a reliable marker for attention signals in the brain. NEW & NOTEWORTHY Local field potentials (LFPs) reflect the activity of spatially localized populations of neurons. Whether alterations in LFP activity are indicative of cognitive processes, such as attention, is unclear. We found that shifts in the phase of LFPs measured in multiple visual brain areas reliably predicted the focus of spatial attention. LFP phase shifts could therefore serve as a marker for behaviorally relevant attention signals in the brain.

Attention Enhances the Efficacy of Communication in V1 Local Circuits.

Attention is a critical component of visual perception; however, the mechanisms of attention at the granular level are poorly understood. One possible mechanism by which attention modulates neuronal activity is to control the efficacy of communication between connected neurons; however, it is unclear whether attention alters communication efficacy across a variety of neuronal circuits. In parallel, attentional modulation of neuronal firing rate is not uniform but depends upon the match between neuronal feature selectivity and the feature required for successful task completion. Here we tested whether modulation of communication efficacy is a viable mechanism of attention by assessing whether it is consistent across a variety of neuronal circuits and dependent upon the type of information conveyed in each circuit. We identified monosynaptically connected pairs of V1 neurons through cross-correlation of neuronal spike trains recorded in adult female macaque monkeys performing attention-demanding contrast-change detection tasks. Attention toward the stimulus in the receptive field of recorded neurons significantly facilitated the efficacy of communication among connected pairs of V1 neurons. The amount of attentional enhancement depended upon neuronal physiology, with larger facilitation for circuits conveying information about task-relevant features. Furthermore, presynaptic activity was more determinant of attentional enhancement of communication efficacy than postsynaptic activity, and feedforward local circuits often displayed the largest facilitation with attention. Together, these findings highlight attentional modulation of communication efficacy as a generalized mechanism of attention and demonstrate that attentional modulation at the granular level depends on the relevance of feature-specific information conveyed by neuronal circuits.SIGNIFICANCE STATEMENT How we pay attention to objects and locations in the visual environment has a profound impact on visual perception. Individual neurons in the visual cortex are similarly regulated by shifts in visual attention; however, the rules that govern whether and how attention alters neuronal activity are not known. In this study, we explored whether attention regulates communication between connected pairs of neurons in the primary visual cortex. We observed robust attentional facilitation of communication among these circuits. Furthermore, the extent to which the circuits were facilitated by attention depended on whether the information they conveyed was relevant for the particular attention task.

Dynamic communication of attention signals between the LGN and V1.

Correlations and inferred causal interactions among local field potentials (LFPs) simultaneously recorded in distinct visual brain areas can provide insight into how visual and cognitive signals are communicated between neuronal populations. Based on the known anatomical connectivity of hierarchically organized visual cortical areas and electrophysiological measurements of LFP interactions, a framework for interareal frequency-specific communication has emerged. Our goals were to test the predictions of this framework in the context of the early visual pathways and to understand how attention modulates communication between the visual thalamus and primary visual cortex. We recorded LFPs simultaneously in retinotopically aligned regions of the visual thalamus and primary visual cortex in alert and behaving macaque monkeys trained on a contrast-change detection task requiring covert shifts in visual spatial attention. Coherence and Granger-causal interactions among early visual circuits varied dynamically over different trial periods. Attention significantly enhanced alpha-, beta-, and gamma-frequency interactions, often in a manner consistent with the known anatomy of early visual circuits. However, attentional modulation of communication among early visual circuits was not consistent with a simple static framework in which distinct frequency bands convey directed inputs. Instead, neuronal network interactions in early visual circuits were flexible and dynamic, perhaps reflecting task-related shifts in attention. NEW & NOTEWORTHY Attention alters the way we perceive the visual world. For example, attention can modulate how visual information is communicated between the thalamus and cortex. We recorded local field potentials simultaneously in the visual thalamus and cortex to quantify the impact of attention on visual information communication. We found that attentional modulation of visual information communication was not static, but dynamic over the time course of trials.

Attentional Modulation of Neuronal Activity Depends on Neuronal Feature Selectivity.

Attention exerts a powerful influence on visual perception. The impact of attention on neuronal activity manifests at early visual information processing stages and progressively increases throughout the visual cortical hierarchy. However, the neuronal mechanisms of attention are unresolved. In particular, the rules governing attentional modulation of individual neurons, whether they are facilitated by or suppressed by attention, are not known. To obtain a more granular or neuron- and circuit-level understanding of the mechanisms of attention and to directly test the feature similarity gain model in V1, we compared attentional modulation with neuronal feature selectivity across a large population of V1 neurons in alert and behaving macaque monkeys trained on an attention-demanding contrast-change detection task. We utilized emerging multi-electrode array technology to record simultaneously from V1 neurons spanning all six cortical layers so that we could characterize the laminar position and physiological response properties of diverse V1 neuronal populations. We found significant relationships between attentional modulation and neuronal position within the cortical hierarchy, neuronal physiology, and neuronal feature selectivity. Our results support the feature similarity gain model and further suggest that attentional modulation depends critically upon the match between neuronal feature selectivity and the features required for the task.

Discovering stigma through recovery teaching.

OBJECTIVE: From the perspective of the tutor, course coordinators and a clinical supervisor, we describe and reflect on our observations of innovative service-user led tutorials on recovery that were delivered to final year medical students as part of their psychiatric module. CONCLUSIONS: Much to our surprise, and in contrast to observations elsewhere during the module, students openly expressed blatant stigmatising attitudes in the tutorials on recovery, particularly after spending time with inpatient services. More specifically, they were pessimistic about the possibility of recovery and they struggled to accept the service user status of the recovery tutor. This prompted us to reflect on what and how we teach psychiatry.

Accuracy of formulas used to predict post-transfusion packed cell volume rise in anemic dogs.

OBJECTIVE: To assess the accuracy of published formulas used to guide packed red blood cell (pRBC) transfusions in anemic dogs and to compare the predicted rise in packed cell volume (PCV) to the actual post-transfusion rise in PCV. DESIGN: Prospective observational study from April 2009 through July 2009. SETTING: A small animal emergency and specialty hospital. ANIMALS: Thirty-one anemic client-owned dogs that received pRBC transfusions for treatment of anemia. INTERVENTIONS: None MEASUREMENTS: Four formulas were evaluated to determine their predictive ability with respect to rise in PCV following transfusion with pRBC. Post-transfusion rise in PCV were compared to calculated rise in PCV using 4 different formulas. Bias and limits of agreement were investigated using Bland-Altman analyses. RESULTS: Accuracy of existing formulas to predict rise in PCV following transfusion varied significantly. Formula 1 (volume to be transfused [VT] [mL] = 1 mL × % PCV rise × kg body weight [BW]) overestimated the expected rise in PCV (mean difference, 6.30), while formula 2 (VT [mL] = 2 mL ×% PCV rise × kg BW) underestimated the rise in PCV (mean difference, -3.01). Formula 3 (VT [mL] = 90 mL × kg BW × [(desired PCV - Patient PCV)/PCV of donor blood]) and formula 4 (VT [mL] = 1.5 mL ×% PCV rise × kg BW) performed well (mean difference 0.23 and 0.09, respectively) in predicting rise in PCV following pRBC transfusion. CONCLUSIONS: Agreement between 2 formulas, "VT (mL) = kg BW × blood volume (90 mL) × [(desired PCV - recipient PCV)/Donor PCV]" and "VT (mL) = 1.5 ×desired rise in PCV × kg BW," was found when they were compared to the actual rise in PCV following pRBC transfusion in anemic dogs. Further research is warranted to determine whether these formulas perform similarly well for other species.

Pathways to practice: overseas trained psychiatrists' experiences of the processes involved in commencing professional practice in Australasia.

OBJECTIVE: There are significant shortages in the psychiatric workforce in Australasia, particularly in the rural and remote regions of Australia and New Zealand. In response to these shortages, mental health services have recruited large numbers of overseas trained psychiatrists (OTP). These are specialist psychiatrists, trained and recognised as such in other countries. Our objective was to ascertain how OTPs experience the processes of commencing professional practice in Australasia. METHOD: OTPs were surveyed to identify the pathways to obtaining specialist registration and College Fellowship in Australasia and to explore their experiences as they engaged in this process. RESULTS: Although limited by a low response rate, the data does highlight a level of discontentment among those OTPs surveyed. The key issues identified related to the examination process, poor communication between different agencies (including the RANZCP), visa and residency related issues, medical board registration difficulties and notable differences between Australia and New Zealand. CONCLUSION: There is a negative perception among OTPs regarding the existing pathways to registration as specialist psychiatrists and the attainment of Fellowship. We submit that the RANZCP has a central and important role in resolving some of the underlying issues and supporting OTPs as vital and valued members of the workforce in Australia and New Zealand.