Andrea Nani

Mindfulness meditation and consciousness: An integrative neuroscientific perspective

Although mindfulness meditation has been practiced in the East for more than two millennia, Western scientific research and healthcare programs have only recently drawn their attention to it. Basically, the concept of mindfulness hinges on focusing on ones own awareness at the present moment. In this review we analyze different hypotheses about the functioning and the cerebral correlates of mindfulness meditation. Since mindfulness is strictly associated with a particular state of consciousness, we also examine some of the most relevant theories that have been proposed as accounts of consciousness. Finally, we suggest that consciousness and mindfulness meditation can be integrated within a neuroscientific perspective, by identifying the brain areas which seem to play an essential role in both, namely the anterior cingulate cortex, posterior cingulate cortex, insula and thalamus.

Tourette Syndrome and Consciousness of Action

Background Tourette syndrome (TS) is a neuropsychiatric disorder characterized by the chronic presence of multiple motor tics and at least one vocal/phonic tic since childhood. Tics typically change and vary in both intensity and severity over time, with remission and exacerbation common. In the vast majority of patients, tic expression is characteristically accompanied by discomforting bodily sensations, known as sensory phenomena or premonitory urges. Methods We reviewed the existing literature on premonitory urges associated with the sense of voluntariness of action in TS. Results Although the wish to move is perceived by the patient as involuntary, the decision to release the tic is often perceived by the patient as a voluntary capitulation to the subjective urge. Most patients with TS can exert a degree of control over the urge and constantly try to inhibit the movement. Based on these features, it has been suggested that tics performed in response to an urge to move should be classified as ‘unvoluntary’, as opposed to voluntary or involuntary acts. However, recent experimental data suggest that the brain areas involved in the generation of the wish to act show considerable overlap between healthy subjects and patients with TS. Discussion The simultaneous presence of both voluntary and involuntary aspects in the expression of tic symptoms by patients with TS is consistent with the hypothesis that tics can have the same neurophysiologic substrate as voluntary acts, even though they are misperceived as being involuntary. This reinforces the view of TS as a hyperkinetic movement disorder primarily affecting the conscious experience of action.

Antiepileptic drugs and Tourette syndrome.

Tourette syndrome is a neurodevelopmental disorder characterized by the chronic presence of multiple motor tics and at least one vocal/phonic tic for the duration of 1 year. The clinical picture of patients with Tourette syndrome is often complicated by tic-related behavioral problems and associated psychopathology. The pathophysiology of Tourette syndrome is not thoroughly understood, however converging evidence from neuroimaging studies suggests abnormalities within the frontostriatal pathways which are mediated by several neurotransmitters. The pharmacological management of the tic symptoms focuses on the dopaminergic and noradrenergic pathways and aims to improve the health-related quality of life of patients. The most common medications are neuroleptics and atypical antipsychotics, which have a strong D2 blocking action. Also, preliminary studies have documented the efficacy of antiepileptic drugs in controlling tics. Thus far, two anticonvulsants (topiramate and levetiracetam) have been tested with a randomized, double-blind, placebo-controlled procedure in the treatment of tics. A study has reported an improvement in the control of tics with topiramate. This pharmacological agent was also reported to be well tolerated by the patients. However, the most frequent observed topiramate side effects (such as somnolence, cognitive problems, and weight loss) could not have manifested because of the short trial duration. Levetiracetam has shown conflicting results. A study found significant improvements in the control of tics, also associated with improvement in school performance. These results, however, were not replicated in other studies. Further investigations are therefore needed to assess the real efficacy of antiepileptic drugs in the treatment of tics.

Node Detection Using High-Dimensional Fuzzy Parcellation Applied to the Insular Cortex

Several functional connectivity approaches require the definition of a set of regions of interest (ROIs) that act as network nodes. Different methods have been developed to define these nodes and to derive their functional and effective connections, most of which are rather complex. Here we aim to propose a relatively simple “one-step” border detection and ROI estimation procedure employing the fuzzy c-mean clustering algorithm. To test this procedure and to explore insular connectivity beyond the two/three-region model currently proposed in the literature, we parcellated the insular cortex of 20 healthy right-handed volunteers scanned in a resting state. By employing a high-dimensional functional connectivity-based clustering process, we confirmed the two patterns of connectivity previously described. This method revealed a complex pattern of functional connectivity where the two previously detected insular clusters are subdivided into several other networks, some of which are not commonly associated with the insular cortex, such as the default mode network and parts of the dorsal attentional network. Furthermore, the detection of nodes was reliable, as demonstrated by the confirmative analysis performed on a replication group of subjects.

Neuroimaging of consciousness

Neuroimaging of consciousness / , Neuroimaging of consciousness / , کتابخانه دیجیتال جندی شاپور اهواز

Are schizophrenia, autistic, and obsessive spectrum disorders dissociable on the basis of neuroimaging morphological findings?: A voxel‐based meta‐analysis

Schizophrenia spectrum disorder (SCZD), autism spectrum disorder (ASD), and obsessive‐compulsive spectrum disorder (OCSD) are considered as three separate psychiatric conditions with, supposedly, different brain alterations patterns. From a neuroimaging perspective, this meta‐analytic study aimed to address whether this nosographical differentiation is actually supported by different brain patterns of gray matter (GM) or white matter (WM) morphological alterations. We explored two possibilities: (a) to find out whether GM alterations are specific for SCZD, ASD, and OCSD; and (b) to associate the identified brain alteration patterns with cognitive dysfunctions by means of an analysis of lesion decoding. Our analysis reveals that these psychiatric spectra do not present clear distinctive patterns of alterations; rather, they all tend to be distributed in two alteration clusters. Cluster 1, which is more specific for SCZD, includes the anterior insular, anterior cingulate cortex, ventromedial prefrontal cortex, and frontopolar areas, which are parts of the cognitive control system. Cluster 2, which is more specific for OCSD, presents occipital, temporal, and parietal alteration patterns with the involvement of sensorimotor, premotor, visual, and lingual areas, thus forming a network that is more associated with the auditory‐visual, auditory, premotor visual somatic functions. In turn, ASD appears to be uniformly distributed in the two clusters. The three spectra share a significant set of alterations. Our new approach promises to provide insight into the understanding of psychiatric conditions under the aspect of a common neurobiological substrate, possibly related to neuroinflammation during brain development. Autism Res 2017.

The quantitative measurement of consciousness during epileptic seizures.

The assessment of consciousness is a fundamental element in the classification of epileptic seizures. It is, therefore, of great importance for clinical practice to develop instruments that enable an accurate and reliable measurement of the alteration of consciousness during seizures. Over the last few years, three psychometric scales have been specifically proposed to measure ictal consciousness: the Ictal Consciousness Inventory (ICI), the Consciousness Seizure Scale (CSS), and the Responsiveness in Epilepsy Scale--versions I and II (RES-I and RES-II). The ICI is a self-report psychometric instrument which retrospectively assesses ictal consciousness along the dimensions of the level/arousal and contents/awareness. The CSS has been used by clinicians to quantify the impairment of consciousness in order to establish correlations with the brain mechanisms underlying alterations of consciousness during temporal lobe seizures. The most recently developed observer-rated instrument is the RES-I, which has been used to assess responsiveness during epileptic seizures in patients undergoing video-EEG. The implementation of standardized psychometric tools for the assessment of ictal consciousness can complement clinical observations and contribute to improve accuracy in seizure classification.

Consciousness and Neuroscience

Neuroscience has received a strong impulse from brain imaging techniques. For the first time, neuroimaging made it possible to study the brain in vivo and thereby associate mental processes with distinctive patterns of cerebral activity. Moreover, functional images of the living brain have provided a powerful instrument for the scientific study of consciousness. Advances in imaging techniques have proved invaluable for obtaining high-resolution maps of the functional and anatomical brain connectivity. Over the last few years, the notion that cerebral regions work together to form a functional network at rest was substantiated by functional imaging studies. These resting-state networks show a high level of spontaneous coupling of ongoing neuronal activity. Among the functional networks identified thus far, the so-called default mode network exhibits particularly interesting features, which might play an important role in the promotion and maintenance of conscious states, especially with regard to the level of consciousness (arousal). The objective level of arousal and the subjective contents of awareness appear to be the two planes within which the neural correlates of consciousness can be interpreted. With regard to the content dimension, which has traditionally been the most elusive to scientific exploration, a theory of conscious access should incorporate five essential concepts: a supervisory system, a serial processing, a coherent structure of recurrent neural loops, a global neuronal workspace capable to differentiate and integrate the various contents of experience, and a complex system of topological properties which identifies crucial hub nodes.

The morphometric co-atrophy networking of schizophrenia, autistic and obsessive spectrum disorders

By means of a novel methodology that can statistically derive patterns of co‐alterations distribution from voxel‐based morphological data, this study analyzes the patterns of brain alterations of three important psychiatric spectra—that is, schizophrenia spectrum disorder (SCZD), autistic spectrum disorder (ASD), and obsessive‐compulsive spectrum disorder (OCSD). Our analysis provides five important results. First, in SCZD, ASD, and OCSD brain alterations do not distribute randomly but, rather, follow network‐like patterns of co‐alteration. Second, the clusters of co‐altered areas form a net of alterations that can be defined as morphometric co‐alteration network or co‐atrophy network (in the case of gray matter decreases). Third, within this network certain cerebral areas can be identified as pathoconnectivity hubs, the alteration of which is supposed to enhance the development of neuronal abnormalities. Fourth, within the morphometric co‐atrophy network of SCZD, ASD, and OCSD, a subnetwork composed of eleven highly connected nodes can be distinguished. This subnetwork encompasses the anterior insulae, inferior frontal areas, left superior temporal areas, left parahippocampal regions, left thalamus and right precentral gyri. Fifth, the co‐altered areas also exhibit a normal structural covariance pattern which overlaps, for some of these areas (like the insulae), the co‐alteration pattern. These findings reveal that, similarly to neurodegenerative diseases, psychiatric disorders are characterized by anatomical alterations that distribute according to connectivity constraints so as to form identifiable morphometric co‐atrophy patterns.

The alteration landscape of the cerebral cortex

&NA; Growing evidence is challenging the assumption that brain disorders are diagnostically clear‐cut categories. Transdiagnostic studies show that a set of cerebral areas is frequently altered in a variety of psychiatric as well as neurological syndromes. In order to provide a map of the altered areas in the pathological brain we devised a metric, called alteration entropy (A‐entropy), capable of denoting the “structural alteration variety” of an altered region. Using the whole voxel‐based morphometry database of BrainMap, we were able to differentiate the brain areas exhibiting a high degree of overlap between different neuropathologies (or high value of A‐entropy) from those exhibiting a low degree of overlap (or low value of A‐entropy). The former, which are parts of large‐scale brain networks with attentional, emotional, salience, and premotor functions, are thought to be more vulnerable to a great range of brain diseases; while the latter, which include the sensorimotor, visual, inferior temporal, and supramarginal regions, are thought to be more informative about the specific impact of brain diseases. Since low A‐entropy areas appear to be altered by a smaller number of brain disorders, they are more informative than the areas characterized by high values of A‐entropy. It is also noteworthy that even the areas showing low values of A‐entropy are substantially altered by a variety of brain disorders. In fact, no cerebral area appears to be only altered by a specific disorder. Our study shows that the overlap of areas with high A‐entropy provides support for a transdiagnostic approach to brain disorders but, at the same time, suggests that fruitful differences can be traced among brain diseases, as some areas can exhibit an alteration profile more specific to certain disorders than to others. HighlightsBrain disorders preferentially cause alterations to few specific brain areas.A‐entropy can denote the “structural alteration variety” of an altered region.Multimodal/polymodal brain areas are characterized by high values of A‐entropy.Some “core areas” are altered by a large number of brain disorders.The “core areas” are mainly the regions of high overlap of task‐based activations.