An exploratory fNIRS study with immersive virtual reality: a new method for technical implementation

For over two decades Virtual Reality (VR) has been used as a useful tool in several fields, from medical and psychological treatments, to industrial and military applications. Only in recent years researchers have begun to study the neural correlates that subtend VR experiences. Even if the functional Magnetic Resonance Imaging (fMRI) is the most common and used technique, it suffers several limitations and problems. Here we present a methodology that involves the use of a new and growing brain imaging technique, functional Near-infrared Spectroscopy (fNIRS), while participants experience immersive VR. In order to allow a proper fNIRS probe application, a custom-made VR helmet was created. To test the adapted helmet, a virtual version of the line bisection task was used. Participants could bisect the lines in a virtual peripersonal or extrapersonal space, through the manipulation of a Nintendo Wiimote ® controller in order for the participants to move a virtual laser pointer. Although no neural correlates of the dissociation between peripersonal and extrapersonal space were found, a significant hemodynamic activity with respect to the baseline was present in the right parietal and occipital areas. Both advantages and disadvantages of the presented methodology are discussed

Peripersonal and Extrapersonal Space: Line Bisection Experiments in Real and Virtual Environments

The human interest on understanding how the surrounding space is perceived and processed has stimulated the scientific and experimental research in this field for several decades. Moreover, from the earliest human interaction with computer-generated virtual environments, interest in this subject has received increasing attention, in order to verify whether the observed behavior in virtual environments is similar to that seen in real environments. Virtual reality technologies are currently used in different fields, from the implementation in medicine to the rehabilitation of neuropsychological and psychological disorders, from the use in the military to the exploitation in industry. The positive results obtained through the use of virtual reality continue to support this new technology and its evolution. Research on the human brain mechanisms involved during interactions with these synthetic environments plays an important role from a neuropsychological point of view, and in terms of reliability and credibility of the instrument. Of particular importance in the study of spatial perception is the question of its representation that distinguishes the surrounding environment in peripersonal space, or near space, the space within arm reach, and extrapersonal space, or far space, defined the space beyond the arm reach. Neuropsychological evidences confirm the existence of different neural mechanisms involved in peripersonal and extrapersonal space representation. Moreover, it is known that the use of standard tools results in a modulation of the perceptual space, expanding the representation of peripersonal space to include the part of extrapersonal space occupied by the end of the tools manipulated. The aim of the present study is to analyze and understand some unclear aspects of this area of research, and to add information to the basic theory. To this end, several experiments were conducted to investigate the following aspects: • peripersonal and extrapersonal space limits during tool-use; • neural circuits involved in representation of peripersonal and extrapersonal space; • body and arm position influence in the perception of peripersonal and extrapersonal space; • the mechanism involved in extrapersonal space perception. The first chapter is an overview of peripersonal and extrapersonal space theories, and of the brain areas involved in their representation, through the analysis of researches and experiments with animal subjects; next, further studies are examined with human participants, in different situations and methods, in order to define the characteristics of this perceptual phenomenon. The second chapter presents the literature concerning the applications in the virtual reality field in the study of artificial environments spatial perception. The first part of the chapter introduces the basic concepts of the technology. Then, empirical evidences that support the utility and potential of this new technology are exposed Finally, an analysis of the researches concerning the phenomenon of peripersonal space perception in virtual environments is provided. The third chapter presents the research, and particularly explains the, methodology, experimental procedures and materials used for the experiments. The experimental paradigm used in the present work was the line bisection task. It is a widely used experimental paradigm since relatively easy for participants to perform, but provides valid results in terms of perception and visuospatial attention. The first study aimed to understand how far up tool-use can expand peripersonal space. The results showed an expansion of perceived peripersonal space when handling a tool up to a distance of 240 cm. The second study explored which brain areas are involved in a visuospatial attention task performed in a virtual environment, by using the neuroimaging technique functional Near Infrared Spectroscopy (i.e., fNIRS). The experiment represents one of the first attempts to investigate the neural correlates by using the fNIRS during an immersive virtual reality experience. Body position can influence the perception of the surrounding space and the space beyond arm reaching distance. Based on previous results, the third experiment investigated if the feeling of having the body blocked or free to move during a visuospatial attention task has implications in the attentional shift that modulates peripersonal and extrapersonal space perception. The results showed that both for the first and the second case, an abrupt attentional shift, not gradual, during the transition from peripersonal to extrapersonal space was observed. Arm position can influence the perception of the surrounding space and the space beyond arm reaching distance. Based on previous results, the fourth experiment investigated whether having the arm stretched or bent during a visuospatial attention task, has implications in the modulation of peripersonal and extrapersonal space perception. The results confirmed that the position of the arm affects visuospatial attention. The last experiment has specifically investigated the underlying causes of peripersonal space expansion when using a tool. It is believed that is the ability to actively manipulate the space the essential feature to induce the peripersonal space expansion. But, as noted in previous studies, it is possible that the visual continuity from the hand toward the manipulated region of space represents the key feature in modulating peripersonal space expansion. The results confirm the hypothesis that the essential feature in order to induce peripersonal space expansion is represented by the active manipulation of the observed region of space. The studies reported in the present study explored several issues relating to the understanding of the perception of the surrounding space and its implications on the attentional processes related. In the fourth chapter the results are discussed and evaluated.L’interesse da parte dell’uomo di comprendere come lo spazio che lo circonda sia percepito ed elaborato stimola la ricerca scientifica e sperimentale ormai da diversi decenni. Inoltre, fin dalle prime interazioni umane con ambienti virtuali generati al computer, l'interesse per questo argomento ha ottenuto sempre maggiore attenzione, anche allo scopo di verificare se il comportamento osservato negli ambienti virtuali è simile a quello osservato negli ambienti reali. Le tecnologie di realtà virtuale sono attualmente impiegate in diversi settori, dall’implementazione in campo medico alla riabilitazione di disturbi psicologici e neuropsicologici, dall’utilizzo in campo militare allo sfruttamento in ambito industriale. I risultati positivi ottenuti attraverso l’utilizzo della realtà virtuale continuano a supportare questa nuova tecnologia e la sua evoluzione. La ricerca sulle reazioni del cervello umano durante le interazioni con tali ambienti sintetici svolge un ruolo importante da un punto di vista neuropsicologico, nonché in termini di affidabilità e credibilità dello strumento. Di particolare importanza nell’ambito dello studio della percezione spaziale è la questione riguardante la sua diversa rappresentazione che distingue l’ambiente circostante in spazio peripersonale, o spazio vicino, definito lo spazio di raggiungimento dei nostri arti, e spazio extrapersonale, o spazio lontano, definito lo spazio oltre il raggiungimento dei nostri arti. Evidenze neuropsicologiche confermano l'esistenza di differenti meccanismi neurali coinvolti nella rappresentazione dello spazio peripersonale ed extrapersonale. Inoltre, è noto che l’utilizzo di normali strumenti provochi una rielaborazione percettiva dello spazio, espandendo la rappresentazione dello spazio peripersonale ad includere la parte di spazio extrapersonale occupata dalle estremità degli strumenti manipolati. Lo scopo del presente elaborato è di analizzare e comprendere alcuni degli aspetti ancora inesplorati in questo ambito di ricerca, nonché di aggiungere informazioni alla teoria di base. A tal fine, sono stati condotti diversi esperimenti al fine di indagare i seguanti aspetti: • il limite di espansione dello spazio peripersonale attraverso l’utilizzo di uno strumento; • le aree cerebrali coinvolte nella percezione dello spazio peripersonale ed extrapersonale; • l’influenza della posizione del corpo e delle braccia nella percezione dello spazio peripersonale ed extrapersonale; • infine, il meccanismo coinvolto nella modulazione della percezione dello spazio extrapersonale. Nel primo capitolo è esposta una rassegna teorica sullo spazio peripersonale ed extrapersonale, sulle aree cerebrali coinvolte nella loro rappresentazione, attraverso l’analisi di ricerche ed esperimenti condotti con soggetti animali; in seguito, sono esaminati ulteriori studi realizzati con partecipanti umani, in diverse situazioni e modalità, al fine di delineare il funzionamento di questo particolare fenomeno percettivo. Nel secondo capitolo è presentata la letteratura riguardante le applicazioni in ambito virtuale inerenti allo studio della percezione spaziale all’interno di ambienti artificiali. Nella prima parte del capitolo sono introdotti i concetti di base sul funzionamento di questa particolare tecnologia; in seguito sono esposte evidenze empiriche a sostegno dell’utilità e delle potenzialità che questa nuova tecnologia fornisce. Infine viene analizzata una serie di ricerche inerenti al fenomeno di percezione dello spazio peripersonale all’interno di ambienti virtuali. Nel terzo capitolo è presentata la ricerca, ed in particolare sono illustrati gli scopi, la metodologia, le procedure sperimentali e gli strumenti utilizzati per gli esperimenti condotti. Il paradigma sperimentale utilizzato all’interno del presente lavoro è stato il compito di bisezione di linea. Si tratta di un paradigma sperimentale ampiamente utilizzato poiché relativamente semplice per i partecipanti da svolgere, tuttavia valido in termini di risultati riguardo attenzione visuospaziale e percezione. Il primo studio ha avuto come obiettivo principale quello di capire fino a che distanza l’utilizzo di uno strumento possa espandere lo spazio peripersonale. I risultati hanno mostrato un ampliamento dello spazio percepito peripersonale, durante la manipolazione dello strumento fino alla distanza di 240 cm. L'obiettivo del secondo studio è stato di identificare le aree cerebrali coinvolte durante un compito di attenzione visuospaziale in ambiente virtuale, tramite l’utilizzo della tecnica di neuroimmagine Spettroscopia Funzionale del Vicino Infrarosso (i.e., functional Near Infrared Spectroscopy; fNIRS). L’esperimento rappresenta uno dei primi tentativi di indagare i correlati neurali tramite l’utilizzo della fNIRS durante un’esperienza di realtà virtuale immersiva. La posizione del corpo può modificare il modo di percepire lo spazio circostante e lo spazio oltre la distanza di raggiungimento delle braccia. Sulla base di risultati ottenuti in studi precedenti, il terzo esperimento è volto a verificare se la sensazione di avere il corpo bloccato o libero di muoversi durante un compito di attenzione visuospaziale, abbia implicazioni sulla modulazione percettiva nello spostamento attentivo dallo spazio peripersonale a quello extrapersonale. I risultati hanno mostrato che sia nel primo sia nel secondo caso, si assiste ad uno spostamento attentivo netto, è non graduale, durante la transizione dallo spazio peripersonale a quello extrapersonale. La posizione del braccio può influenzare il modo di percepire lo spazio circostante e lo spazio oltre la distanza di raggiungimento del braccio. Sulla base di risultati ottenuti in studi precedenti, il quarto esperimento è volto a verificare se la distensione del braccio davanti al corpo o il suo posizionamento lungo un fianco durante un compito di attenzione visuospaziale, abbia implicazioni sulla modulazione percettiva dello spazio peripersonale ed extrapersonale. I risultati hanno confermato che la posizione del braccio influenza l’attenzione visuospaziale. Infine, l’ultimo esperimento ha indagato nello specifico le cause alla base dell’espansione dello spazio peripersonale durante l’utilizzo di uno strumento. Si ritiene che sia la capacità di manipolare attivamente lo spazio l'elemento essenziale per indurre l'espansione dello spazio peripersonale. Tuttavia, come osservato in studi precedenti, è possibile che anche la continuità visiva dalla mano verso la regione di spazio manipolato sia una caratteristica fondamentale per modulare l'espansione dello spazio peripersonale. I risultati confermano l’ipotesi che la caratteristica essenziale per indurre l'espansione dello spazio peripersonale è rappresentata dalla manipolazione attiva della regione di spazio osservata. Gli studi riportati nel presente elaborato hanno esplorato diverse questioni riguardanti la comprensione della percezione dello spazio circostante e le sue implicazioni sui processi di attenzione ad essa collegati. Nel quarto capitolo sono discussi e valutati i risultati alla luce della letteratura di riferimento

Processing of peripersonal and extrapersonal space using tools: Evidence from visual line bisection in real and virtual environments

The dissociation between peripersonal space (within reaching) and extrapersonal space (beyond reaching) has been reported in studies using the line bisection task in left neglect patients and in healthy participants. Furthermore, this dissociation can be modulated by tool use. We conducted two experiments to compare line bisection in peripersonal (i.e., 30, 60cm) and extrapersonal space (i.e., 90, 120cm). Healthy participants bisected visual lines using sticks and a laser pointer, according to the experimental paradigm of Longo and Lourenco [On the nature of near space: Effects of tool use and the transition to far space. Neuropsychologia, 44, 977-981, 2006]. In Experiment 1 participants performed line bisection in a real environment, whereas in Experiment 2 participants performed line bisection in a virtual environment. Results from both experiments revealed an abrupt midpoint shift from the peripersonal to the extrapersonal space but only when a laser pointer was used. In addition, we confirmed that peripersonal space can be extended to extrapersonal space when participants used a stick. Notably, virtual reality can be a useful technique for studying the dissociation between peripersonal and extrapersonal space and their interaction by means of tool use

Cognitive training with Nintendo Wii\uae for the elderly: An evaluation

Two groups of elderly people were monitored during a period of three months: one group followed an experimental training program with games developed for the Nintendo Wii console, while the other group performed a regular training program offered by the elderly care center. Classic neuropsychological tests were administered before and after this period to both groups. The results show better cognitive performances of the experimental group in several tests

Neuropsychological testing through a nintendo wii

In recent years, videogames have demonstrated their positive effects in the psychological treatments and cognitive training of the old population. In this paper we present a pilot study in which a group of elderly people in an old people's home was requested to play a set of cognitive tasks administered through a popular videogames console, the Nintendo Wii®. The results obtained by comparing the Wii® cognitive games with traditional paper and pencil tests are described and discussed to orient further improvements

Neuropsychological testing through a Nintendo Wii console

Abstract In recent years, videogames have demonstrated their positive effects in the psychological treatments and cognitive training of the old population. In this paper we present a pilot study in which a group of elderly people in an old people's home was requested to play a set of cognitive tasks administered through a popular videogames console, the Nintendo Wii. The results obtained by comparing the Wii cognitive games with traditional paper and pencil tests are described and discussed to orient further improvements

A behavioural experiment in virtual reality to verify the role of action function in space coding

Neurophysiological data indicate that the reachable peripersonal space and the unreachable extrapersonal space are represented in segregated parietofrontal circuits and that when the unreachable space becomes reachable because of tool use, it is automatically coded by the network selective for peripersonal space. Here we directly tested the role of action's consequences in space coding. Thirty-eight participants bisected lines at either a reachable distance (60 cm) or unreachable distance (120 cm) using either a laser pointer or laser cutter. The laser cutter but not the laser pointer had an action consequence; the line broke into two pieces. The results showed that distance moderated the effect of action. At an unreachable distance, the mean bisection point was closer to the centre when participants used the laser cutter compared to when they used the laser pointer. There were no differences at a reachable distance (60 cm). This result suggests that the space in which the individual may determine a physical consequence is categorized as peripersonal space, independently from its actual distance from the individual's body

Cognitive training with Nintendo Wii® for the elderly: An evaluation

Two groups of elderly people were monitored during a period of three months: one group followed an experimental training program with games developed for the Nintendo Wii console, while the other group performed a regular training program offered by the elderly care center. Classic neuropsychological tests were administered before and after this period to both groups. The results show better cognitive performances of the experimental group in several tests

A behavioural experiment in virtual reality to verify the role of action function in space coding

Neurophysiological data indicate that the reachable peripersonal space and the unreachable extrapersonal space are represented in segregated parieto-frontal circuits and that when the unreachable space becomes reachable because of tool use, it is automatically coded by the network selective for peripersonal space. Here we directly tested the role of action’s consequences in space coding. Thirty-eight participants bisected lines at either a reachable distance (60 cms) or unreachable distance (120 cms) using either a laser pointer or laser cutter. The laser cutter but not the laser pointer had an action consequence; the line broke into two pieces. The results showed that distance moderated the effect of action. At an unreachable distance, the mean bisection point was closer to the center when participants used the laser cutter compared to when they used the laser pointer. There were no differences at a reachable distance (60 cms). This result suggests that the space in which the individual may determine a physical consequence is categorized as peripersonal space, independently from its actual distance from the individual’s bod

Fucoxanthin from Undaria pinnatifida: Photostability and Coextractive Effects

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