Role of inhibitory neurons in temporal correlations of critical and supercritical spontaneous activity

Experimental and numerical results suggest that the brain can be viewed as a system acting close to a critical point, as confirmed by scale-free distributions of relevant quantities in a variety of different systems and models. Less attention has received the investigation of the temporal correlation functions in brain activity in different, healthy and pathological, conditions. Here we perform this analysis by means of a model with short and long-term plasticity which implements the novel feature of different recovery rates for excitatory and inhibitory neurons, found experimentally. We evidence the important role played by inhibitory neurons in the supercritical state: We detect an unexpected oscillatory behaviour of the correlation decay, whose frequency depends on the fraction of inhibitory neurons and their connectivity degree. This behaviour can be rationalized by the observation that bursts in activity become more frequent and with a smaller amplitude as inhibition becomes more relevant.Comment: 15 pages, 6 figure

Neural correlates of apathy in patients with neurodegenerative disorders: an activation likelihood estimation (ALE) meta-analysis

Apathy is commonly reported in Alzheimer’s Disease (AD), Fronto-Temporal Dementia (FTD) and Parkinson’s Disease (PD). In our meta-analysis we analysed a total of 41 studies to identify brain patterns associated with apathy. For these purposes we used activation likelihood estimation meta-analyses. Our main overall analysis showed that apathy is associated to hypometabolism and a decreased gray matter volume in the left inferior frontal gyrus (BA 45, 46). Disorder-specific analyses, not performed by means of meta-analysis, because of the small number of studies, but by means a label-based review, revealed an altered brain perfusion and decreased gray matter volume in anterior cingulate cortex (BA 24, 32) in AD patients and a decreased gray matter volume in inferior frontal gyrus (BA 44, 45) and parietal cortex (BA 40) in FTD patients. These findings suggest that apathy is mainly associated with a cortical dysfunction of areas involved in executive-cognitive processing (i.e. action planning) and emotional regulation (auto-activation and reward processing). Knowledge about the neural underpinnings of apathy is crucial for understanding its clinical characteristics in neurodegenerative diseases and for developing novel strategies of treatment in clinical practice

The Addenbrooke’s Cognitive Examination Revised (ACE-R) and its sub-scores: normative values in an Italian population sample

BACKGROUND A complex relationship exists between postural control and cognition in the elderly. Namely, neural mechanisms that are required for the regulation of posture have been variably associated with cognitive dysfunctions. Parkinson's disease (PD) is the second most common neurodegenerative disease among the elderly, and it has been associated with both cognitive and postural abnormalities such as Pisa syndrome (PS). Although its onset has been considered to be multifactorial, the pathophysiological mechanisms underpinning PS are still not fully explained. Until now, no study investigated the possible contribution of cognitive dysfunction to occurrence of PS in PD. PATIENTS AND METHODS: Twenty PD patients with PS and 20 PD patients without PS were enrolled. All patients with PD underwent neuropsychological battery to assess behavioural disturbances, memory, attention, frontal/executive and visuospatial functions. RESULTS: The two groups did not differ on demographic features, age at PD onset and disease duration, whereas they significantly differed on UPDRS-Part III, and levodopa-equivalent daily dose (LEDD). MANCOVA with above-mentioned clinical variable as covariates revealed significant differences on tasks tapping verbal long-term memory, and attentional and visuoperceptual abilities between groups. The binary logistic regression revealed that higher LEDD and lower performance on visuospatial task (Benton Judgment of Lines Orientation test) significantly predicted occurrence of PS. CONCLUSION: Our results revealed a significant association of PS with altered attention and visuoperceptual functions in PD, suggesting that the occurrence of PS may be associated with alteration of both frontal-striatal systems and posterior cortical areas

Neuropsychological Correlates of Theory of Mind Deficits in Patients With Multiple Sclerosis

Background: Theory of mind (ToM) is the ability to understand and interpret another person's beliefs, intentions (cognitive ToM) and emotions (affective ToM). Objective: To explore affective and cognitive ToM and their neuropsychological correlates in patients affected by multiple sclerosis (MS). Material and Method: Forty MS patients and 40 matched control individuals underwent tasks assessing cognitive (the ToM Pictures Sequencing Task and the Advanced Test of ToM) and affective ToM (the Reading the Mind in the Eyes Task and the Emotion Attribution Task), in both verbal and nonverbal modality, a comprehensive neuropsychological battery, and questionnaires for behavioral disorders. Results: MS patients performed significantly worse than controls on tasks assessing cognitive and affective ToM, in verbal and nonverbal modality. Moreover, MS patients achieved significantly lower scores on tests assessing visuospatial learning and speed of spatial information processing, and significantly higher scores on scales for alexithymia and depression with respect to controls. After covarying for cognitive and behavioral variables different in the 2 groups, the differences between patients and controls on ToM tasks remained significant. ToM abilities were significantly related to executive functions, but not to depressive, anxious and apathetic symptoms. Higher alexithymia scores were associated with poor recognition of others' mental states. Conclusion: The findings demonstrated that both affective and cognitive aspects of ToM are impaired in nondemented and mildly to moderately disabled MS and suggest that impaired social cognition can occur independently from behavioral disorders. (PsycINFO Database Recor

Neural substrates of interoceptive sensibility: An integrated study in normal and pathological functioning

In early studies interoception strictly referred to the awareness of visceral sensations, but recent theories have expanded this concept to denote the ongoing status of the body, including somatosensory feelings. Here, we integrated data from normal and pathological functioning to disclose neural underpinnings of interoceptive sensibility, taking into account the crucial distinction between visceral and somatosensory feelings. Twenty-seven healthy young individuals underwent structural MRI (including T1w images and DTI). Voxel-wise ana-lyses of the gyrification index (GI) and fractional anisotropy (FA) data were performed to assess the relation between interoceptive sensibility and surface morphometry and anatomical connectivity. Thirty-three unilateral brain-damaged patients took part in this study for Voxel-Based Lesion-Symptom Mapping (VLSM) and track-wise hodological lesion-deficit analysis (TWH). All participants completed the Self-Awareness Questionnaire (SAQ), a self-report tool assessing interoceptive sensibility of visceral (F1) and somatosensory feelings (F2). Tract-Based Spatial Statistics showed that F2 was positively associated with FA in the bilateral anterior thalamic radiation, corticospinal tract, cingulum, forceps, inferior longitudinal, fronto-occipital, superior longitudinal, and uncinate fasciculi; no significant association was detected for F1. However, F1 was positively associated with GI in the left anterior cingulate cortex. VLSM showed that F1 mainly relies on the right posterior insula, whereas F2 is related mostly to subcortical nuclei and surrounding white matter in the right hemisphere. Accordingly, patients with disconnection of the anterior thalamic projection, corticospinal tract, inferior fronto-occipital, inferior longitu-dinal, uncinate and superior longitudinal fasciculus III showed lower scores on F2. Overall, results support the dissociation between interoceptive sensibility of visceral and somatosensory feelings

The Body across the Lifespan: On the Relation between Interoceptive Sensibility and High-Order Body Representations

Background: Interoceptive information plays a pivotal role in building higher-order cognitive body representations (BR) that neuropsychological and neuroimaging evidence classifies as action-oriented (i.e., body schema) or non-action-oriented (i.e., visuo-spatial body map). This study aimed to explore the development of BR, considering the association with the interoceptive sensibility throughout the lifespan. Methods: Two hundred thirty-nine healthy participants divided into five age groups (7 to 8 years; 9 to 10 years; 18 to 40 years; 41 to 60 years; over 60 years) completed a self-report measure of interoceptive sensibility (the Self-Awareness Questionnaire; SAQ) and were given tasks assessing the two BR (action-oriented: hand laterality task; non-action-oriented: frontal body evocation task). Results: Both children (7–8 and 9–10 years) and older adults (over 60 years) performed worse than young (18–40 years) and middle-aged adults (41–60 years) in action- and non-action-oriented BR tasks. Moderation analyses showed that the SAQ score significantly moderated the relationship between age and action-oriented BR. Conclusions: The current results are consistent with inverted U-shaped developmental curves for action- and non-action-oriented BR. As an innovative aspect, the ability to mentally represent one’s own body parts in diverse states could be negatively affected by higher interoceptive sensibility levels in childhood and late adulthood

Assessment of apathy independent of physical disability: validation of the Dimensional Apathy Scale in Italian healthy sample

Apathy is well described in neurodegenerative diseases characterized by motor disability; therefore, assessment of apathy avoiding possible confounding effects of motor impairments is necessary in neurological diseases. Recently, the Dimensional Apathy Scale (DAS) was developed to assess apathy as multifaceted construct, independent of physical disability. We developed the Italian version of the Dimensional Apathy Scale (I-DAS) and explored its psychometric properties in a sample of 309 healthy individuals. Participants also completed Apathy Evaluation Scale, Beck Depression Inventory-II and Addenbrooke’s Cognitive Examination-Revised. The I-DAS showed high internal consistency, good convergent and divergent validity. The I-DAS had a three-factor structure, such as the original scale. The I-DAS scored was significantly correlated with individuals’ education, but not with age or gender. We, therefore, computed correction factor for education and provided percentile distribution of the adjusted scores to identify individuals with high levels of apathy. The I-DAS showed good psychometric properties and can be a valid and reliable tool to assess multidimensional apathy

Sicilia Architettura e Territorio: Sfide Aperte

Convegno sull'architettura nel territorio siciliano sulla base delle esperienze di personalità che hanno operato con continuità sul territorio siciliano e sulla base dei lavori dei workshop del SicilyLab. Tra i relatori Giacomo Leone e Giovanni Leone, Vincenzo Latina, Claudio Lucchesi di Urban Future Organization, Marcello Panzarella, Antonio Presti, Rosetta Angelini, Gaetano De Francesco e Antonino Di Raimo. È seguita una breve mostra dei lavori del SicilyLab

Body Representation Alterations in Patients with Unilateral Brain Damage

OBJECTIVE: Systematic studies about the impact of unilateral brain damage on the different body representations (body schema, body structural representation, and body semantics) are still rare. Aim of this study was to evaluate body representation deficits in a relatively large sample of patients with unilateral brain damage and to investigate the impact of right or left brain damage on body representations (BRs), independently from deficits in other cognitive processes.METHOD: Sixty-four patients with unilateral stroke (22 with left brain damage, LBD; 31 with right brain damage without neglect, RBD-N; 11 with right brain damage with neglect, RBD+N) and 41 healthy individuals underwent a specific battery including BR as well as control tasks.RESULTS: In more than a third of the sample, selective (37.5%) and pure (31%) deficits of BR were presented and equally distributed among the different BRs (~10% for each representation), with selective (27.2%) and pure (22.7%) body schema deficit mainly presented after left brain damage. As a group, patients with unilateral brain damage, independently of the side of lesion (LBD, RBD-N, RBD+N), had significantly worse performance on body structural representation with respect to healthy individuals, whereas LBD had numerically worse performance on body schema with respect to healthy individuals and RBD-N. No significant differences among groups were found on body semantics.CONCLUSION: BR deficits are not a rare consequence of unilateral brain damage and are independent of a more general cognitive dysfunction. Accordingly, the need for an accurate assessment and specific neuropsychological training in clinical settings is discussed