Timeline

10 May 2013 12:30

La plasticità del cervello tra mito e realtà

Room: Sala Direzione

Il concetto di plasticità cerebrale è quasi entrato a far parte del linguaggio comune, comparendo ormai frequentemente tanto nelle comunicazioni scientifiche quanto nei mezzi di comunicazione di massa. Viene usato genericamente per indicare il fatto che il cervello cambia durante l'arco della vita e che può essere plasmato dall'apprendimento; e viene usato per promuovere tecniche di apprendimento o prodotti per contrastare l'invecchiamento cognitivo (es., il brain-training). In questa relazione cercherò di delineare il concetto di plasticità cerebrale, secondo le indicazioni che derivano dalle neuroscienze cogntive, con particolare riferimento a quanto accade nei contesti di deprivazione sensoriale (cecità e sordità). Lo scopo è quello di contribuire a definire le potenzialità ed i vincoli dell'idea di plasticità cerebrale, delineando per quanto possibile i confini del mito mediatico e mettendo a fuoco alcune evidenze sistematiche che sono emerse dalla ricerca.

21 May 2013 08:30

Una rappresentazione sopramodale e topografica delle azioni nel cervello umano

Room: Sala Paci

Il recente sviluppo di sofisticate metodologie di esplorazione funzionale del cervello, quali la risonanza magnetica funzionale (fMRI), ha permesso di esaminare i correlati neurali delle attività cerebrali in maniera non invasiva direttamente nelluomo, in condizioni fisiologiche o in presenza di patologie mentali. Mediante paradigmi sperimentali sempre più raffinati si è cominciato a studiare i meccanismi neurobiologici che sottendono non solo le funzioni sensoriali e motorie ma anche i processi cognitivi, le emozioni, il comportamento, fino ad arrivare allo studio di quelle funzioni che sono ritenute essere alla base della vita di relazione e delle interazioni sociali, quali lempatia e la comprensione delle intenzioni altrui. Facendo seguito ai risultati ottenuti nei primati non umani nei quali sono stati individuati neuroni che si attivano non solo quando lanimale compie unazione ma anche quando la vede fare da un altro (i cosiddetti neuroni specchio), studi recenti hanno dimostrato lesistenza di un analogo sistema specchio anche nelluomo. Il sistema specchio è ritenuto svolgere un ruolo di primo piano nei meccanismi di apprendimento dagli altri e di interazione sociale. Ricerche del nostro gruppo hanno rivelato che il sistema specchio è presente anche in individui privi della vista fin dalla nascita, indicando che lesperienza visiva non è un prerequisito fondamentale perché il sistema specchio si sviluppi e funzioni e mostrando al contempo che il sistema è capace di processare anche stimoli non visivi. Questo suggerisce che il sistema specchio elabora e sottende il concetto astratto di unazione e di un comportamento piuttosto che la mera rappresentazione dello schema motorio dello stesso. Infine, la recente introduzione di algoritmi di machine learning applicati alle misure di attività cerebrale ci ha permesso, non solo di confermare la natura sopramodale della rappresentazione delle azioni, ma soprattutto di dimostrare che questa rappresentazione è distribuita spazialmente nell'ambito del sistema specchio e in modo specifico a seconda della finalità dell'atto motorio

04 July 2013 12:30

An Epistemic Model of Scientific Integration

Room: Sala Direzione

Philosophers have traditionally addressed the issue of theory unification in terms of theoretical reduction. Reductive models, however, cannot explain the occurrence of unification in areas of science where successful reductions are hard to find. The goal of this talk is to present a concrete example of unication in biology - the Developmental Synthesis - as a general model of scientic unication, according to which two fields are in the process of being integrated when they become explanatorily relevant for each other. I conclude by suggesting that this methodological conception of unity, which is independent of the debate on the metaphysical foundations of science, is closely connected to the notion of interdisciplinarity.

06 June 2014 12:30

Philosophy and the Brain – Do we need a Non-Reductive Neurophilosophy?

Room: Sala Direzione

14 December 2015 10:30

Motor Responses to Action Observation: a Dual-Route Account

Room: M205

Motor Simulation is thought to be a mechanism allowing automatic mapping of the observed actions from visual to motor domain, i.e., the visual information activates correspondent motor representations of the action observed, as the observer was to perform the action himself. However In light of these considerations how is it possible that we can perform actions that are different from those observed when reacting to an observed action? In this talk I will describe the results I obtained so far studying the interplay between the automatic activation of the motor representations correspondent to the actions observed and the motor representations voluntarily selected to fulfill task requirements.

25 January 2016 10:30

TMS-EEG: A Novel Technique to Study Cortico-Cortical Connectivity

Room: Sala Paci

In the past, the major focus of research defining the brain-behavior relationship was to identify the segregated brain regions recruited by a given task. More recent developments have emphasized the importance of distributed networks at all levels, from individual neurons to neural populations and brain regions. Defining the human brain connectome has become one of the major goals of neuroscience, as confirmed by the large-scale economical investments on this topic (e.g., NIH-funded Human Connectome Project and the Brain Initiative; The European CONNECT project and the Human Brain Project; the Asian Brainnetome project). Our current understanding is that the brain architecture has a modular organization in which segregated networks supporting specialized processing are linked through a few long-range connections, ensuring processing integration. Although such architecture is structurally stable, it appears to be flexible in its functioning, enabling long-range connections to regulate the information flow and facilitate communication among the relevant modules, depending on the contingent cognitive demands. In my talk, I will highlight an emerging distinctive approach to study cortical connectivity based on the direct activation of an area by non-invasive brain stimulation (TMS) and the simultaneous evaluation of the distribution of this activity in cortical networks by electrophysiological recordings (EEG). The TMS-EEG coregistration allows to study cortico-cortical connectivity by measuring the spatio-temporal distribution of cortical currents evoked by the stimulation. By reviewing TMS-EEG studies on network dynamics at rest and during cognition, and comparing them with fMRI-based functional connectomics, I will show how TMS-EEG data support the general principles of brain architecture inferred from graph theory models and provide further insights into the properties of effective connectivity. Moreover, I will highlight the types of data that can be obtained through TMS-EEG, such as the timing of signal propagation, the excitatory/inhibitory nature of connections and causality. Last, I will discuss recent emerging applications of TMS-EEG in the study of brain disorders.

15 February 2016 10:30

Space without Sight

Room: Sala Paci

Vision typically provides the most reliable information about our surrounding space. What happens when you cannot rely on this sensory input due to blindness? I will explore the behavioral and brain reorganizations that occur in blind people for the processing of space. Aside from quantitative differences, I will demonstrate that congenitally blind individuals have a qualitatively different way of representing space, that impacts also on the way they represent more abstract concepts like numbers.

29 February 2016 12:30

From Symmetry Perception to Neuroaesthetics.

Room: Sala Paci

ilateral symmetry is a prominent feature of the visual world. Not only are human faces and bodies symmetric, but most other living organisms have at least one axis of symmetry, as do manufactured items, such as tools and buildings. I’ll present the results of a series of experiments that shed light on the neural correlates of visual (and haptic) symmetry detection, also considering the case of blind individuals (is the perceptual salience of symmetry rooted in normal visual development?). Symmetry is not just a principle of perceptual organization, it is also an important cue in driving visual aesthetic preference. Moving from more basic perceptual mechanisms to neuroaesthetics, I’ll discuss some recent brain stimulation data that contribute to shed light on the complex neural network mediating human aesthetic experience.

18 April 2016 10:30

Bodily Sense and Sensibility: Anosognosia, Asomatognosia and Anorexia

Room: Sala Paci

According to the ‘embodied cognition’ approach several facets of selfhood are causally related to the physical body and its properties. In cognitive neuroscience, primary sensorimotor signals are thought as integrated and re-represented in various levels of the neurocognitive hierarchy to form a number of neurocognitively distinct bodily models, including unconscious and conscious facets of the bodily self. However, the precise mechanisms by which bodily signals are integrated and re-mapped in the brain, as well as the relation between bottom-up and top-down factors in each of these hierarchical levels remain unknown. In this talk, I will discuss empirical studies on neuropsychiatric disorders of body awareness, including anosognosia for hemiplegia and somatoparaphrenia following right hemisphere stroke, as well as anorexia nervosa (if time permits). The results highlight that these disorders can be described as different aberrations of a core antagonism between bottom-up sensory signals, and top-down motor and higher-order signals at different hierarchical levels, reflecting psychological differences in perceiving the body from 1st versus 2nd and 3rd person perspectives. I will particularly focus on the constitution of the embodied self in 1st person perspective, the constitution of social reality in the 3rd person and the unique role of 2nd-person, embodied cognition for mediating the transition from the ‘subjectivity’ to the ‘objectivity’ of the bodily self (and back).

09 May 2016 10:30

Cortical Networks for Hand Dexterity

Room: Sala Paci

The dexterity of the hand in grasping and manipulating objects is one of the distinctive properties of human and non human primates. Grasping movements involve transforming the visual properties of the object into the coordinated activation of arm and hand muscles to move the upper limb in a coherent way. The cerebral cortex, with its descending outputs to the brainstem and the spinal cord is the major structure for the control of grasping movements. We will present our recent studies describing the spatio-temporal structure of motor cortex activity during complex reach-to-grasp tasks. In particular, we will focus on recent technical advances that allow investigating the dynamic of neuronal activity at the mesoscopic scale for upper limb control and discuss novel ideas about the functional organization of the motor cortex.

10 October 2016 10:30

Top-Down Modulations of Motor Resonance to Social Stimuli

Room: M205

Several previous studies have shown a muscle-specific facilitation of cortico-spinal excitability during observation of others’ actions (motor resonance). While motor resonance has been shown to be automatically triggered independently from the observer’s effort to simulate the actions, high-level aspects of actions, including the actor’s intention and context, can modulate its extent and spatio-temporal selectivity. In a series of studies, we used single-pulse and repetitive TMS and behavioral action prediction tasks to investigate how the observer’s motor system maps the kinematics and intention of actions embedded in congruent or incongruent contexts. Participants watched videos showing everyday actions and were asked to predict their final outcome ahead of realization. We manipulated both the context in which the actions were embedded, being congruent, incongruent or ambiguous, as well as the intention of the actor, who could provide either genuine or fooling information to the observers. At different delays from action onset, we recorded motor evoked potentials (MEPs) from arm and forearm muscles to measure motor resonance. We found that both context and intention modulate participants’ performance, leading to improved discrimination of actions embedded in congruent context and driven by genuine intention and impaired discrimination of actions embedded in incongruent contexts and driven by deceptive intentions. Crucially, these two high-level aspects modulated motor resonance in a different way. In particular, we found an early facilitation of motor resonance for actions embedded in congruent context and a later inhibition for those embedded in incongruent contexts. Conversely, the reduction of performance in predicting deceptive actions was associated to a muscle-specific facilitation of motor resonance as compared to observing genuine actions. These results suggest that high-level aspects of actions can boost or suppress motor resonance through top-down modulations from high-level systems, including prefrontal and temporo-parietal areas involved in semantic representations and social cognition. To investigate the mechanisms underlying top-down modulations of motor resonance, we used a perturb-and-measure TMS approach, which combines off-line continuous theta burst stimulation of areas within and beyond the action observation network with online spTMS of the primary motor cortex to measures the consequent functional modulation of motor resonance. The results showed that prefrontal and temporo-parietal areas play an important role in modulating the facilitation of cortico-spinal excitability during action observation, suggesting that motor resonance does not emerge from an encapsulated system, but reflects the processing of multiple aspects of actions (e.g., kinematics, intention, context) in different and interconnected networks.