Sleep profoundly influences human behaviour across cognition, affect, and daily experience. This study evaluated how subjective reports and objective measures of sleep capture the interaction between sleep quality and quantity on cognition and affect. We collected subjective sleep reports using the Pittsburgh Sleep Quality Index and objective seven-day actigraphy recordings from 83 participants. A test battery, including the Stop Signal, Digit Span, and Emotional Bias Tasks, measured response inhibition, working memory, and affect. Mood was evaluated using the Positive and Negative Affect Schedule, State-Trait Anxiety Inventory, and Beck’s Anxiety Inventory. We reveal that subjective sleep reports do not predict objectively measured sleep duration or quality. We demonstrate that objective measures predict cognitive performance on executive function and memory tasks for the upper and lower sleep quartiles, while subjective reports do not. Moreover, we demonstrate that subjective reports, but not objective measures, are strongly predicted by emotional state. These findings suggest that while subjective measures do not accurately index actual sleep, they are a reliable proxy for emotional well-being. We propose that combined subjective and objective measures are required to characterise the multifaceted interaction between sleep, cognition and emotion. We discuss the implications of these findings for understanding the cause-effect relationship of sleep-disturbance in neurological and psychiatric disorders.

This study was to investigate the relationship between the ventral caudate connectivity and anhedonia. Nineteen depressed patients and 16 healthy controls participated in two identical functional magnetic resonance imaging scans during a 1-year period to determine the resting-state functional connectivity changes using a seed-based approach. Patients showed increased left ventral caudate functional connectivity with superior frontal gyrus over time and the increased connectivity was associated with anhedonia improvement. None of these associations were observed in healthy controls. The findings suggest that left ventral caudate may serve as a potential target to improve the severity of anhedonia.

ABSTRACTBackgroundEnhanced temporal summation (TS), measured through self-reported pain ratings, has been interpreted as indicative of central sensitisation in fibromyalgia. Greater TS in patients, however, has not been universally observed. It is also unclear whether increased pain report maintains beyond the TS period.MethodsIn this study, we measured TS through continuously reported pain ratings. Fibromyalgia-diagnosed patients (n = 17) and matched pain-free controls (n = 13) rated painful transcutaneous electrical stimulation of various intensity levels in 18 one-minute-long blocks. Pain was rated on a 101-point visual analogue scale. The resulting continuous response was divided into TS (< 15s) and adaptation (15 – 60s) periods. Average pain values were extracted for each period alongside the timing of key events such as maximal pain ratings. The difference in temporal summation and adaptation measures between fibromyalgia and control participants was analysed using mixed-effects modelling.ResultsThe average pain ratings for TS and adaptation periods were not significantly associated with fibromyalgia diagnosis but were with stimulation intensity. The same was true for the magnitude of the maximal rating during TS and the slope leading to that peak rating. The presence of fibromyalgia, however, did predict the time of the maximal TS rating, as well as the value and the time of the maximal adaptation rating.ConclusionsOur study did not find homogeneously increased TS pain ratings. Instead, by utilising continuous pain data we demonstrate for the first time that the time of TS peak rating, as well as the magnitude and time of adaptation peak rating are linked to fibromyalgia diagnosis.

Background: : Motivational anhedonia has been observed in patients with a wide range of mental disorders. However, the similarity and uniqueness of this deficit across diagnostic groups has not been thoroughly investigated. Method: : The study compared motivational deficits in 37 patients with major depressive disorder (MDD), 32 with bipolar depression, 33 with manic bipolar disorder (BD), 30 with acute phase and 33 with stable phase schizophrenia, as well as 47 healthy controls. Participants were administered the Effort-Expenditure for Reward Task which measures allocation of effort between a high-effort and a low-effort task for monetary rewards at varying magnitudes and probabilities. Results: : Compared with healthy controls, BD manic, acute and stable phase schizophrenia patients were significantly less likely to choose the high-effort task in the high reward magnitude condition. BD manic and acute phase schizophrenia patients were significantly less likely to choose the high-effort task in the high probability condition. Acute and stable phase schizophrenia patients made less effort in the high estimated value condition. Bipolar manic patients made excessive effort in low estimated value but less effort in high estimated value. Contrary to expectations, both the unipolar and bipolar depression patients did not differ significantly from healthy controls in reward magnitude, probability, and estimated value conditions. Anhedonia and negative symptoms were associated with fewer high-effort task choices in schizophrenia patients. Conclusion: : Motivation anhedonia showed distinct patterns across psychiatric patients: acute phase schizophrenia was the most severely affected, bipolar mania was similar to schizophrenia, but bipolar depression was similar to unipolar depression.

ABSTRACT Background Anxiety, evoked by continuous inspiration of a 5 – 8% CO 2 mixture, has been found to have an analgesic eLect on self-reported pain. The precise mechanism whereby this effect obtains remains unknown. Methods The present study tested whether temporal summation, the psychological counterpart of wind-up, is involved in hypercapnic analgesia. 21 healthy participants received painful transcutaneous electrical stimuli of varied intensity, during continuous inhalation of 7.5% CO 2 mixture and medical air, presented in a single-blinded counterbalanced order. Continuous pain ratings were acquired to measure the temporal development of the pain response. Several points and events of interest that characterise the pain response profile were extracted from the continuous data. Results Mixed-eLects modelling demonstrated a reduction of all pain measures during inspiration of the anxiogenic mixture, but not air. This was accompanied by an increase in the psychological and physiological measures of anxiety. Analyses of the characteristic measures of temporal summation suggested that the hypercapnic mixture has an analgesic property evident from the start of the pain response. The same was true for the remainder of the response, the adaptation period, where pain ratings were also inhibited. The reduced pain ratings persisted during the remainder of the response. Anxiety was found to be a mediating factor for summative pain ratings but not the temporally sensitive TS measures, suggesting an overall, cumulative effect. Conclusions The findings provide an explanation for the previously observed low self-reported pain during the inhalation of an anxiogenic hypercapnic mixture.

Background: Early research on the impact of the COVID-19 pandemic found persistent related anxiety in the general population. We hypothesised that this anxiety will be associated with increased pain in chronic pain patients diagnosed with fibromyalgia (FM). Methods: To study this, we carried out a 10-day online survey with 58 female participants, diagnosed with FM and no other pain condition. We identified which aspects of the COVID-19 pandemic evoked anxiety. We then asked participants to provide daily ratings of both anxiety and pain on 101-point visual analogue scales (VAS). Key participant characteristics were included as mediators in a mixed-effects analysis, where the primary outcome was pain VAS. Results: We found that participants were most often anxious about "impact on relationships", "a family member contracting COVID-19", and "financial hardship", but on average rated "financial hardships", "access to medication", and "home loss/eviction" as evoking the strongest anxiety. Mixed-effects modelling showed that an increase in pain was significantly associated with an increase in anxiety, when taking into account individual variance and daily caffeine intake. Age and intake of some mild analgesics were also linked to stronger pain. Conclusion: Our results extend the initial findings from the literature about the effects of COVID-19 pandemic on chronic pain sufferers. We found that not only is pandemic anxiety in FM patients present, but it is associated with amplified self-assessed chronic pain.

Prior research conceptualised action understanding primarily as a kinematic matching of observed actions to own motor representations but has ignored the role of object information. The current study utilized fMRI to identify (a) regions uniquely involved in encoding the goal of others' actions, and (b) to test whether these goal understanding processes draw more strongly on regions involved in encoding object semantics or movement kinematics. Participants watched sequences of instrumental actions while attending to either the actions' goal (goal task), the movements performed (movement task) or the objects used (object task). The results confirmed, first, a unique role of the inferior frontal gyrus, middle temporal gyrus and medial frontal gyrus in action goal understanding. Second, they show for the first time that activation in the goal task overlaps directly with object- but not movement-related activation. Moreover, subsequent parametric analyses revealed that movement-related regions become activated only when goals are unclear, or observers have little action experience. In contrast to motor theories of action understanding, these data suggest that objects-rather than movement kinematics-carry the key information about others' actions. Kinematic information is additionally recruited when goals are ambiguous or unfamiliar.

Behavioral evidence has shown that humans automatically develop internal representations adapted to the temporal and spatial statistics of the environment. Building on prior fMRI studies that have focused on statistical learning of temporal sequences, we investigated the neural substrates and mechanisms underlying statistical learning from scenes with a structured spatial layout. Our goals were twofold: (1) to determine discrete brain regions in which degree of learning (i.e., behavioral performance) was a significant predictor of neural activity during acquisition of spatial regularities and (2) to examine how connectivity between this set of areas and the rest of the brain changed over the course of learning. Univariate activity analyses indicated a diffuse set of dorsal striatal and occipitoparietal activations correlated with individual differences in participants' ability to acquire the underlying spatial structure of the scenes. In addition, bilateral medial-temporal activation was linked to participants' behavioral performance, suggesting that spatial statistical learning recruits additional resources from the limbic system. Connectivity analyses examined, across the time course of learning, psychophysiological interactions with peak regions defined by the initial univariate analysis. Generally, we find that task-based connectivity with these regions was significantly greater in early relative to later periods of learning. Moreover, in certain cases, decreased task-based connectivity between time points was predicted by overall posttest performance. Results suggest a narrowing mechanism whereby the brain, confronted with a novel structured environment, initially boosts overall functional integration and then reduces interregional coupling over time.

In deductive reasoning, people are asked to infer the truth of an argument's conclusion given a set of premises. Research into the processes underlying deduction has focused on examining how well people discriminate between logically valid and invalid arguments, and how irrelevant factors such as one's prior beliefs interfere with the ability to reason logically (Evans et al., 1983). This normative approach to validity has traditionally informed both practice and theory in the literature. However, its critics argue that “normativism” often leads investigators to biased or misleading interpretations of phenomena (Elqayam and Evans, 2011). Formal modeling of deductive reasoning has often been successful by taking the traditional, normative approach. A case in point is the application of signal detection theory (SDT; Macmillan and Creelman, 2005) to the investigation of belief bias in syllogistic reasoning (Dube et al., 2010). In the SDT model, deductive judgments are based on strength of evidence; an argument is judged to be valid if its strength exceeds a criterion value. Because the choice of criterion is independent of the ability to discriminate between classes of arguments, the SDT model makes it possible to isolate response bias from accuracy. Dube et al. examined these two factors using ROC curves, which plot hits against false alarms at several levels of confidence. Hits and false alarms were defined in normative fashion as responding “valid” to logically valid and logically invalid conclusions, respectively. Their analysis of ROCs led them to argue two significant points. First, contrary to prevailing theories of belief bias, conclusion believability can affect response bias without affecting the quality of reasoning. Second, the curvilinear shape of the ROCs is consistent with the distributional assumptions of SDT. The latter is a key test because finding linear rather than curvilinear ROCs would be problematic for the model. The curvilinear ROCs obtained in syllogistic (see also Dube et al., 2011; Trippas et al., 2013; but see Klauer and Kellen, 2010) and other forms of reasoning (Heit and Rotello, 2010, 2014) are similar to those widely observed in memory and perception (Pazzaglia et al., 2013). This consistency across domains strengthens the case for the usefulness of the SDT approach. It also leads to an expectation of similar findings in other areas of reasoning. Below, we describe findings from conditional reasoning that violate this expectation in a surprising yet enlightening way. Causal conditionals are a form of deduction prevalent in everyday life. Consider the proposition: “If healthy foods are cheaper, then more people will eat healthy foods.” Four types of conditional inferences are possible: modus ponens (MP; “Healthy foods are cheaper, therefore more people will eat healthy foods”), modus tollens (MT; “Fewer people eat healthy foods, therefore healthy foods are not cheaper”), affirmation of the consequent (AC; “More people eat healthy foods, therefore healthy foods are cheaper”), and denial of the antecedent (DA; “Healthy foods are not cheaper, therefore less people eat healthy foods”). From a normative point of view, MP and MT are valid and AC and DA are invalid inferences. Theories differ as to how people determine validity in these problems. According to mental model theory (Johnson-Laird and Byrne, 2002), people construct an initial mental model of the conditional (e.g., p q) which may then be fleshed out by considering additional models (not-p q; not-p not-q). According to the suppositional account of the conditional (Evans et al., 2003, 2002; Evans and Over, 2004, 2012), people evaluate the subjective probability of a conditional by hypothetically supposing p and then assessing the conditional probability of q given p, P(q|p). This relation between the natural language conditional and the conditional probability, P(if p then q) = P(q|p), can be used in a Bayesian/probabilistic model of conditional inference (Oaksford et al., 2000; Oaksford and Chater, 2009, 2013). What these theories have in common is that there is no fundamental difference in how people process affirmation (MP + AC) and denial (MT + DA) inferences. This makes an SDT analysis straightforward and no different to that taken with the study of belief bias in syllogistic reasoning. For our case study, we analyzed aspects of a data set collected as part of a larger project under the direction of the fourth author of this paper1. This study examined the influence of belief in causal conditional problems (e.g., believable: “If oil prices continue to rise, then UK petrol prices will rise”; unbelievable: “If global temperatures rise, then less arctic ice will melt”). Hits were defined as “valid” responses to MP and MT and false alarms were defined as “valid” responses to AC and DA. This produced the ROCs seen in the top panel of Figure ​Figure1.1. The results are similar in some respects to those reported by Dube et al. (2010) for syllogisms: believability had no effect on accuracy (ROCs for believable and unbelievable items fall on the same curve) but seemed to affect response bias (confidence criteria for believable items are shifted to the right)2. However, there is a surprising difference: in contrast to the curvilinear ROCs observed with syllogisms, conditionals produced linear ROCs. A linear regression of the ROC (collapsing over believability) provided a good fit, R2 = 99.9%. Adding a quadratic component did not improve the fit, p = 0.78. Taken at face value, this result suggests that conditional reasoning requires a profoundly different model than the one that has seemed so successful when applied to other forms of reasoning, not to mention other cognitive tasks. Figure 1 ROC curves of causal conditionals. Top panel: Valid (MP + MT) vs. invalid (AC + DA). Bottom left: affirmation conditionals (MP vs. AC). Bottom right: denial conditionals (MT vs. DA). Points on the ROC imply a more liberal response criterion (lower confidence ... A different picture emerges when we depart from the strictly normative approach and consider separately how people respond to affirmation and denial conditionals. In the bottom left panel of Figure ​Figure1,1, plotting MP (hits) against AC (false alarms) yields typically curvilinear ROCs. Linear regression (collapsing over believability) provided a fit, R2 = 96%, that was significantly improved by the addition of a quadratic component, R2 = 99.99%, p < 0.004. Accuracy is defined by the distance of the ROCs from the chance diagonal. Contrary to the poor accuracy on display in the aggregate results in the top panel, people are quite sensitive to argument structure when affirmation is involved. In the bottom right panel of Figure ​Figure1,1, plotting MT (hits) against DA (false alarms) again yields typically curvilinear ROCs. Linear regression (collapsing over believability) provided a fit, R2 = 98%, that was significantly improved by the additional of a quadratic component, R2 = 99.99%, p < 0.002. People were sensitive to argument structure, but the position of the ROCs below the diagonal indicates that their treatment of denial arguments departed from the normative; MT are treated as less valid than AC. Applying the SDT model in a normative fashion, as would seem reasonable given extant theories of conditional reasoning, produced results that contrast sharply with previous findings. The clearly linear ROC in the top panel of Figure ​Figure11 is not only unlike the curvilinear ROCs observed with syllogisms but if taken at face value is problematic for the SDT model. It could be that there is something fundamentally different in the way that people reason about causal conditionals as compared to other types of problems. It seems to us more likely that the difference lies with affirmation and denial inferences; the latter do not seem to be treated in the normatively prescribed fashion. Once this is assumed, the ROC results become more sensible and fall in line with previous results (in a reanalysis of published and unpublished data sets, Heit and Rotello, 2014, have also reported curvilinear ROCs from MP plotted in the manner of Figure ​Figure1,1, lower left). This interpretation converges with Singmann and Klauer's (2011) finding, based on state-trace analysis, that affirmation and denial problems may depend on different processes. Why use ROC analysis rather than simply examine the raw validity judgments? Interpreting the latter often relies on assumptions that may not be justified (Klauer et al., 2000; Dube et al., 2010). The main advantage of a formal model like SDT lies in its specification of assumptions. However, models can also produce insights that are not obvious at first glance. A qualitative difference between affirmation and denial inferences is not necessarily predicted by extant theories. Moreover, various manipulations seem to exert a similar effect on both types of inferences (e.g., Cummins, 1995). Finally, it is interesting to note that the production of linear ROCs when performance is driven by multiple underlying processes has been predicted in theory (DeCarlo, 2002). These results may offer a case study of how this can occur in practice.

OBJECTIVEIndividuals with autism spectrum disorder (ASD) are often characterized as having social engagement and language deficiencies, but a sparing of visuospatial processing and short-term memory (STM), with some evidence of supranormal levels of performance in these domains. The present study expanded on this evidence by investigating the observational learning of visuospatial concepts from patterns of covariation across multiple exemplars.METHODChild and adult participants with ASD, and age-matched control participants, viewed multishape arrays composed from a random combination of pairs of shapes that were each positioned in a fixed spatial arrangement.RESULTSAfter this passive exposure phase, a posttest revealed that all participant groups could discriminate pairs of shapes with high covariation from randomly paired shapes with low covariation. Moreover, learning these shape-pairs with high covariation was superior in adults with ASD than in age-matched controls, whereas performance in children with ASD was no different than controls.CONCLUSIONSThese results extend previous observations of visuospatial enhancement in ASD into the domain of learning, and suggest that enhanced visual statistical learning may have arisen from a sustained bias to attend to local details in complex arrays of visual features.

Humans handle uncertainty poorly. Prospect theory accounts for this with a value function in which possible losses are overweighted compared to possible gains, and the marginal utility of rewards decreases with size. fMRI studies have explored the neural basis of this value function. A separate body of research claims that prediction errors are calculated by midbrain dopamine neurons. We investigated whether the prospect theoretic effects shown in behavioral and fMRI studies were present in midbrain prediction error coding by using the feedback-related negativity, an ERP component believed to reflect midbrain prediction errors. Participants stated satisfaction with outcomes followed prospect theory but their feedback-related negativity did not, instead showing no effect of marginal utility and greater sensitivity to potential gains than losses.

Several studies report a right hemisphere advantage for visuospatial integration and a left hemisphere advantage for inferring conceptual knowledge from patterns of covariation. The present study examined hemispheric asymmetry in the implicit learning of new visual feature combinations. A split-brain patient and normal control participants viewed multishape scenes presented in either the right or the left visual fields. Unbeknownst to the participants, the scenes were composed from a random combination of fixed pairs of shapes. Subsequent testing found that control participants could discriminate fixed-pair shapes from randomly combined shapes when presented in either visual field. The split-brain patient performed at chance except when both the practice and the test displays were presented in the left visual field (right hemisphere). These results suggest that the statistical learning of new visual features is dominated by visuospatial processing in the right hemisphere and provide a prediction about how fMRI activation patterns might change during unsupervised statistical learning.

We investigated whether abnormalities in the structural organization of the corpus callosum in the presence of curvilinear lipoma are associated with increased facilitation of response time to bilateral stimuli, an effect known as the redundancy gain (RG). A patient (A.J.) with a curvilinear lipoma of the corpus callosum, his genetically-identical twin, and age-matched control participants made speeded responses to luminant stimuli. Structural organization of callosal regions was assessed with diffusion-tensor imaging. A.J. was found to have reduced structural integrity in the splenium of the corpus callosum and produced a large RG suggestive of neural summation.

The roles of dorsal and ventral processing streams in visual orienting and conscious perception were examined in two experiments. The first employed high density EEG with source localization. The second comprised a neuropsychological case study. Visual orienting was assessed with an attention procedure, where peripheral letters cued participants towards a target location. In the perception procedure participants responded to the same letters by performing an explicit conscious discrimination. In Experiment 1, the peripheral letters elicited rapid dorsal stream activation in the attention procedure, and this activation preceded top-down enhancement of target processing in occipital cortex. In the perception procedure early ventral stream activation was seen. In addition, peripheral letters elicited an “early directing attention negativity” (EDAN) over parietal recording sites in the attention procedure, but not in the perception procedure. In Experiment 2, a patient with a bilateral ventral stream lesion but preserved dorsal stream function showed clear disruption to performance in the perception procedure, whilst exhibiting a normal visual orienting effect in the attention procedure. Taken together these findings (1) highlight the distinct roles of the dorsal and ventral streams in attention and perception, and (2) suggest how these streams might interact, via reentrant effects of attention on perceptual processing.

Presentation of bilateral redundant visual stimuli produces faster reaction times (RT) than presentation of a single unilateral stimulus; an effect known as the redundant target effect (RTE; Miller, 1982), and is a means of testing interhemispheric visuomotor integration (Ouimet, 2009). RTEs that exceed expectations, based on Miller's race model of inequality (RMI), are referred to as "enhanced RTEs" and imply neural coactivation. Paradoxically, enhanced RTEs are observed in cases of corpus callosum disruption. The Hemispheric Coactivation Hypothesis accounts for this paradox by positing that bihemispheric processing occurs to both unilateral and bilateral stimuli in the normal brain, but occurs only with bilateral stimuli in the disconnected brain. Neuroimaging has revealed decreases in the microstructural integrity of the corpus callosum with age (Ota et al., 2006), but research investigating the bilateral RTE in healthy older individuals is lacking. The present study investigated the bilateral RTE in healthy younger and healthy older adults using simple RT and choice RT tasks. Our prediction that older individuals would show significantly larger RTEs than younger individuals was found to be true for both tasks. Tests of the RMI produced little evidence for coactivation. The crossed-uncrossed difference, generally used as a means of testing visuomotor interhemispheric transfer, was also investigated, but no age effects were found. The observation of greater RTE in age is congruent with the Hemispheric Coactivation hypothesis (Miller, 2004) in which callosal disconnection is associated with increased RTE.

Much research has supported the hypothesis that the perceptual system generates impressions of causality based on simple cues available in the environment. We review evidence that this extraction of causal relations from perceptual cues is likely an automatic property of the visual system akin to other basic perceptual processes, such as perceptual grouping and illusory contour completion. We posit that it is this automatic characteristic of perceptual causality that underlies the proliferation of context effects associated with perceived causal events. Here, the presence of a perceived causal relationship may impact the perception of other features of the causal stimulus and other stimuli surrounding the causal event. We discuss current research, and present future research directions that promise to uncover some of the mechanisms underlying how causality is attributed from, and changes how we perceive and respond to, simple low-level stimuli in the environment. Such research will enrich our understanding of how the perception of causally-relevant stimulus features interacts with their context to enable us to effectively perceive, understand, and act upon our environment.

Maintaining an accurate mental representation of the current environment is crucial to detecting change in that environment and ensuring behavioral coherence. Past experience with interactions between objects, such as collisions, has been shown to influence the perception of object interactions. To assess whether mental representations of object interactions derived from experience influence the maintenance of a mental model of the current stimulus environment, we presented physically plausible and implausible collision events while recording brain electrical activity. The parietal P300 response to ‘oddball’ events was found to be modulated by the physical plausibility of the stimuli, suggesting that past experience of object interactions can influence working memory processes involved in monitoring ongoing changes to the environment.

Split-brain patients, in whom the cortical commissures, principally the corpus callosum, have been cut, provide a unique window into functional specialization of each cerebral hemisphere. Early testing of these patients, using various methods for lateralizing stimulus input and responses, confirmed hemispheric specializations suspected from previous studies of patients with lateralized brain damage. The following decades produced many examples of functional differences between the two hemispheres in the attentional, perceptual, and cognitive domains. Comparisons of partial- and complete-callosotomy patients have yielded information about functionally specific pathways through the corpus callosum. Division of the brain has also provided insight into the nature of consciousness in each hemisphere.