Cognitive deficits are prevalent in bipolar disorder even during the euthymic phase, having a negative impact on global functioning and quality of life. As such, more and more mental health professionals agree that neuropsychological assessment should be considered an essential component of the clinical management of bipolar patients. However, no gold standard tool has been established so far. According to bipolar disorder experts targeting cognition, appropriate cognitive tools should be brief, easy to administer, cost-effective and validated in the target population. In this commentary, we critically appraised the strengths and limitations of the tools most commonly used to assess cognitive functioning in bipolar patients, both for screening and diagnostic purposes.

Early-life adverse events or childhood adversities (CAs) are stressors and harmful experiences severely impacting on a child's wellbeing and development. Examples of CAs include parental neglect, emotional and physical abuse and bullying. Even though the prevalence of CAs and their psychological effects in both healthy and psychiatric populations is established, only a paucity of studies have investigated the neurobiological firms associated with CAs in bipolar disorder (BD). In particular, the exact neural mechanisms and trajectories of biopsychosocial models integrating both environmental and genetic effects are still debated. Considering the potential impact of CAs on BD, including its clinical manifestations, we reviewed existing literature discussing the association between CAs and brain alterations in BD patients. Results showed that CAs are associated with volume alterations of several grey matter regions including the hippocampus, thalamus, amygdala and frontal cortex. A handful of studies suggest the presence of alterations in the corpus callosum and the pre-fronto-limbic connectivity at rest. Alterations in these regions of the brain of patients with BD are possibly due to the effect of stress produced by CAs, being hippocampus part of the hypothalamus–pituitary–adrenal axis and thalamus together with amygdala filtering sensory information and regulating emotional responses. However, results are mixed possibly due to the heterogeneity of methods and study design. Future neuroimaging studies disentangling between different types of CAs or differentiating between BD sub-types are needed in order to understand the link between CAs and BD.

According to the social brain hypothesis, the human brain includes a network designed for the processing of social information. This network includes several brain regions that elaborate social cues, interactions and contexts, i.e. prefrontal paracingulate and parietal cortices, amygdala, temporal lobes and the posterior superior temporal sulcus. While current literature suggests the importance of this network from both a psychological and evolutionary perspective, little is known about its neurobiological bases. Specifically, only a paucity of studies explored the neural underpinnings of constructs that are ascribed to the social brain network functioning, i.e. objective social isolation and perceived loneliness. As such, this review aimed to overview neuroimaging studies that investigated social isolation in healthy subjects. Social isolation correlated with both structural and functional alterations within the social brain network and in other regions that seem to support mentalising and social processes (i.e. hippocampus, insula, ventral striatum and cerebellum). However, results are mixed possibly due to the heterogeneity of methods and study design. Future neuroimaging studies with longitudinal designs are needed to measure the effect of social isolation in experimental v. control groups and to explore its relationship with perceived loneliness, ultimately helping to clarify the neural correlates of the social brain.

Since its discovery in 1997, the default mode network (DMN) and its components have been extensively studied in both healthy individuals and psychiatric patients. Several studies have investigated possible DMN alterations in specific mental conditions such as bipolar disorder (BD). In this review, we describe current evidence from resting-state functional magnetic resonance imaging studies with the aim to understand possible changes in the functioning of the DMN in BD. Overall, several types of analyses including seed-based and independent component have been conducted on heterogeneous groups of patients highlighting different results. Despite the differences, findings seem to indicate that BD is associated with alterations in both frontal and posterior DMN structures, mainly in the prefrontal, posterior cingulate and inferior parietal cortices. We conclude this review by suggesting possible future research directions.

Impairments in neuro and social cognition are considered core features of schizophrenia (SCZ) since they affect patients' functioning and contribute to poor socio-occupational outcomes. Therefore, the improvement of cognitive performances has become a primary goal in the care of patients with SCZ, especially in the first phases of the disease, as early interventions may favour better long-term outcomes. Cognitive remediation (CR) is a behavioural training aimed at improving cognitive functions with the goal of durability and generalisation in everyday life. Neuroimaging studies suggest that CR leads to neuroplasticity in chronic SCZ, whereas only a few studies tested the neural effects of CR in the early phase of the disease. Thus, in this review, we aimed at summarising CR-induced structural and functional brain changes in early SCZ. Existing evidence showed a protective effect of CR on grey matter volume in selected medial-temporal (i.e. hippocampus, parahippocampus and amygdala) and thalamic regions whereas functional changes affected mostly dorsolateral prefrontal and insular cortices both associated with improvements in cognitive performance and emotion regulation. Overall, CR in early SCZ appears to be associated with neural adaptations mostly allocated in prefrontal and limbic regions, however future longitudinal studies are needed to clarify whether the positive effects of cognitive training persist over time. It may also be interesting to investigate whether the application of CR in the early v. the late stage of the disease may lead to incremental benefits.

Since its development and theorisation in the 60s, attachment theory has greatly influenced both clinical and developmental psychology suggesting the existence of complex dynamics based on the relationship between an infant and its caregiver, that affects personality traits and interpersonal relationships in adulthood. Many studies have been conducted to explore the association between attachment styles and psychosocial functioning and mental health. By contrast, only a few studies have investigated the neurobiological underpinnings of attachment style, showing mixed results. Therefore, in this review, we described current evidence from structural and functional imaging studies with the final aim to disentangle the neural correlates of attachment style in healthy individuals. Overall, different attachment styles have been correlated with volumetric alterations mainly in the cingulate cortex, amygdala, hippocampus and anterior temporal pole. Consistently, functional imaging studies suggested patterns of activations in fronto-striatal-limbic circuits during the processing of social and attachment-related stimuli. Further studies are needed to clarify the neurobiological signature of attachment style, possibly taking into consideration a wide range of demographic, psychosocial and clinical factors that may mediate the associations between the style of attachment and brain systems (e.g., gender, personality traits, psychosocial functioning, early-life experience).

The decision making can be defined as the mental process in which a “choice is made after reflecting on the consequences of that choice” (Bechara & Van Der Linden, 2005; Bechara et al., 1997). It is a complex process that involves cognitive as well as emotion-based functions. In fact human beings make fast adaptive decisions in daily life, and that is based on the skill to relate emotion to contextual stimuli in order to anticipate outcomes through activation of emotional states (Bechara et al., 2005). In this regard, the ventromedial prefrontal cortex (VMPFC) has been widely recognized to play a key role in the emotional decision making process. The VMPFC includes the medial part of the orbitofrontal cortex (OFC), the more ventral sectors of the medial prefrontal cortex and the anterior cingulate cortex (Bechara et al., 1997). In particular the OFC, within the VMPFC, is part of a neural system underpinning decision-making and reward-related behaviours which are thought to be linked to social conduct (Rolls, 2000).

The continuous performance test (CPT) is a behavioural assessment of attentional modulation of the motor system (Rosvold et al., 1956). It has firstly been used in patients with brain injuries and then applied to assess sustained attention and vigilance in epilepsy, brain tumor, dementia, schizophrenia and other psychiatric diseases, such as attention-deficit hyperactivity disorder (ADHD) and anxiety disorders (Rosvold et al., 1956; Honey et al., 2005; Kanaka et al., 2008). There are several versions of the test. For instance, the X-CPT version presents randomly different stimuli and subjects are asked to push a button only on presentation of the target stimuli (X). In the AX-CPT version, the subjects are required to push the button only when a cue stimulus is presented before the target one (A before X). The following items are measured for the X and AX tasks: omission errors (number of times subjects fail to respond to target stimulation), commission errors (number of times subjects respond to non target stimulation), average reaction time and coefficient of variance for both correct reactions and commission errors (Suwa et al., 2004). There are other versions, such as the CPT-not X version where the subjects are asked not to push a button when the target stimulus (X) is presented; the Degraded Stimuli (DS)-CPT (Nuechterlein, 1983); the CPT playing card version (Rutschmann et al., 1977); and the CPT Identical Pairs version (Cornblatt et al., 1988), which is a more difficult task prepared to assess high risk population. Interestingly, the Identical Pairs version has been included in the Matrics neurocognitive assessment, a consensus cognitive battery for clinical trials of cognition in schizophrenia (Nuechterlein et al., 2008).

The magnetic resonance imaging studies investigating the volumes of the orbitofrontal cortex in patients suffering from schizophrenia are here presented, trying to elucidate its role for the pathophysiology and for the cognition of the disease.

Although the anatomy of the parietal lobe has been under-investigated in schizophrenia, some magnetic resonance imaging studies have shown decreased volumes, suggesting its possible implication for the pathophysiology of the disease.