Characterising the inconsistency between perceived and actual sleep and its impact upon cognition and mood.

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.

Anhedonia reduction correlates with increased ventral caudate connectivity with superior frontal gyrus in depression.

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.

Motivational differences in unipolar and bipolar depression, manic bipolar, acute and stable phase schizophrenia.

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.

Neural Signatures of Spatial Statistical Learning: Characterizing the Extraction of Structure from Complex Visual Scenes.

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.

Prospect theory does not describe the feedback-related negativity value function.

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.

Age-related differences in interhemispheric visuomotor integration measured by the redundant target effect.

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.

Bilateral redundancy gain and callosal integrity in a man with callosal lipoma: a diffusion-tensor imaging study.

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.

Right hemisphere dominance in visual statistical learning.

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.

Representations of physical plausibility revealed by event-related potentials.

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.

Dissociating processes supporting causal perception and causal inference in the brain.

An understanding of relations between causes and effects is essential for making sense of the dynamic physical world. It has been argued that this understanding of causality depends on both perceptual and inferential components. To investigate whether causal perception and causal inference rely on common or on distinct processes, the authors tested 2 callosotomy (split-brain) patients and a group of neurologically intact participants.

Brain mechanisms underlying perceptual causality.

Functional magnetic resonance imaging (fMRI) was used to examine the neural correlates of perceptual causality. Participants were imaged while viewing alternating blocks of causal events in which a ball collides with, and causes movement of another ball, versus non-causal events in which a spatial or a temporal gap precedes the movement of a second ball. There were significantly higher levels of relative activation in the right middle frontal gyrus and the right inferior parietal lobule for causal relative to non-causal events.

Interhemispheric neural summation in the split brain: effects of stimulus colour and task.

Four split-brained subjects, two subjects with agenesis of the corpus callosum, and 14 normal subjects performed two tasks requiring responses to red or green disks, briefly presented either singly in the left visual field, singly in the right visual field, or simultaneously in both visual fields. In Experiment 1, simple reaction times to these stimuli, regardless of colour, were recorded (the Go-Both Task), and found to be faster to bilateral-redundant stimulus pairs, than to single stimuli. This so-called "redundancy gain" was much larger for acallosal or split-brained subjects than for normal subjects and exceeded the predictions of a race model, implying neural summation.

Interhemispheric neural summation in the split brain with symmetrical and asymmetrical displays.

The present study, investigates interhemispheric integration in the split brain. Four split-brained, two acallosal and 14 normal subjects carried out a simple reaction time task in which they responded to stimuli presented either singly in the left visual field, singly in the right visual field, or simultaneously in both visual fields. Stimuli were white against a black background and bilateral stimuli were either symmetrical or asymmetrical around the central vertical meridian.