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Ad-hoc forensic instruments have been developed for the contemporaneous or retrospective evaluation of testamentary capacity, among which the Testament Definition Scale (TDS), a short rating scale designed to evaluate and quantify the individual’s capacity to give an exhaustive definition of what a testament is. The aim of the study was to derive Italian normative values for the TDS in an adult sample and to provide preliminary evidence for its usability in neurological patients with cognitive decline. The TDS was administered to 341 healthy subjects of different ages (range= 30–92 years) and educational levels (range= 1–20 years), along with the Montreal Cognitive Assessment (MoCA) and the Frontal Assessment Battery (FAB), and to 6 adults with neurodegenerative diseases. In healthy subjects, TDS scores were associated with MoCA and FAB scores;; education was the only significant predictor of TDS scores. In patients with neurodegenerative diseases, TDS scores can dissociate from MoCA and FAB scores. Normative data (cutoff and equivalent scores) for favoring the adoption of the TDS in the assessment of testamentary capacity are here provided.

The becoming of the human being is a multisensory process that starts in the womb. By integrating spontaneous neuronal activity with inputs from the external world, the developing brain learns to make sense of itself through multiple sensory experiences. Over the past ten years, advances in neuroimaging and electrophysiological techniques have allowed the exploration of the neural correlates of multisensory processing in the newborn and infant brain, thus adding an important piece of information to behavioral evidence of early sensitivity to multisensory events. Here, we review recent behavioral and neuroimaging findings to document the origins and early development of multisensory processing, particularly showing that the human brain appears naturally tuned to multisensory events at birth, which requires multisensory experience to fully mature. We conclude the review by highlighting the potential uses and benefits of multisensory interventions in promoting healthy development by discussing emerging studies in preterm infants.

Since birth, we learn about the perceptual and social world through our senses. Learning to appropriately bind multisensory information is key to effectively interact with our surroundings. In this chapter, we will review the behavioral, computational, and neurophysiological methods used to assess multisensory processing in healthy adult individuals. In the first part, we will provide an overview of fundamental principles governing the activity of multisensory neurons in the animal brain since these principles still provide an influential framework for the investigation of multisensory processing in humans too. In the second part, we will present a series of behavioral paradigms that have been adopted in the past 20 years to assess multisensory processing, particularly focusing on the difference between paradigms assessing multisensory integration and paradigms assessing crossmodal interactions, in which stimulation of one sensory system affects the experience in a different sense, typically leading to illusory percepts. The last part will provide a critical overview of electrophysiological and neuroimaging approaches to measure multisensory interactions in the human brain.

The sense of agency is the ability to recognize that we are the actors of our actions and their consequences. We explored whether and how spatial cues may modulate the agency experience by manipulating the ecological validity of the experimental setup (real-space or computer-based setup) and the distance of the action-outcome (near or far). We tested 58 healthy adults collecting explicit agency judgments and the perceived time interval between movements and outcomes (to quantify the intentional binding phenomenon, an implicit index of agency). Participants show greater implicit agency for voluntary actions when there is a temporal and spatial action-outcome contingency. Conversely, participants reported similar explicit agency for outcomes appearing in the near and far space. Notably, these effects were independent of the ecological validity of the setting. These results suggest that spatial proximity, realistic or illusory, is essential for feeling implicitly responsible for the consequences of our actions.

Motor interactions require observing and monitoring a partner’s performance as the interaction unfolds. Studies i n monkeys suggest that thi s form of soci al moni tori ng might be mediated by the activity of the ventral premotor cortex (vPMc), a critical brain region in action observation and motor planning. Our previous fMRI studies in humans showed that the left vPMc is indeed recruited during social monitoring, but its causal role is unexplored. In three experiments, we applied online anodal or cathodal transcra-nial direct current stimulation over the left lateral frontal cortex during a music-like interactive task to test the hypothesis that neuromodulation of the left vPMc affects participants’ performance when a partner violates the agent’s expectations. Participants pl ayed short musi cal sequences together with a virtual partner by playing one note each in turn-taking. In 50% of the trials, the partner violated the participant’s expectations by generating the correct note through an unexpected movement. During sham stimulation, the partner’s unexpected behavior led to a slowdown in the participant’s performance (observation-induced posterror slowing). A significant interaction with the stimulation type showed that cathodal and anodal transcranial direct current stimulation induced modulation of the observation-induced posterror slowing in opposite directions by reducing or enhancing it, respectively. Cath-odal stimulation significantly reduced the effect compared to sham stimulation. No effect of neuromodul ati on was found when the partner behaved as expected or when the observed violation occurred within a context that was perceptual l y matched but noni nt eracti ve i n nature. These results provide evidence for the critical causal role that the left vPMc might play in social monitoring during motor interactions, possibly through the interplay with other brain regions in the posterior medial frontal cortex.

Amnesia is a frequent claim in major crimes, and it is estimated that the complete or partial absence of memory following a crime ranges from 25% to 50% of total cases. Although some cases may constitute a genuine form of amnesia, due to organic-neurological defects or psychological causes, and possibly combined with a dissociative or repressive coping style after an extreme experience, malingering is still fairly common in offenders. Therefore, one of the main goals in medico-legal proceedings is to find methods to determine the credibility of crime-related amnesia. At present, a number of lie and memory detection techniques can assist the forensic assessment of the reliability of declarative proof, and have been devised and improved over the past century: for example, modern polygraphs, event-related potentials, thermal imaging, functional magnetic resonance imaging, kinematic, and facial analysis. Other ad hoc psychological tests, such as the so-called Symptom Validity Test (SVT) and Performance Validity Test (PVT), as well as the autobiographical Implicit Association Test (aIAT), can also be used. To date, however, there is little evidence or case reports that document their real usefulness in forensic practice. Here, we report two cases of crime-related amnesia, whereby both defendants, who were found guilty of homicide, appeared to exhibit dissociative amnesia but where the application of SVTs, PVTs, and aIAT detected a malingered amnesia.

In the present work, we applied anodal transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and frontal eye field (FEF) of the right hemisphere in healthy subjects to modulate attentional orienting and disengagement in a gap-overlap task. Both stimulations led to bilateral improvements in saccadic reaction times (SRTs), with larger effects for gap trials. However, analyses showed that the gap effect was not affected by tDCS. Importantly, we observed significant effects of baseline performance that may mediate side- and task-specific effects of brain stimulation.

Recent literature suggests that the primary somatosensory cortex (S1), once thought to be a low-level area only modality-specific, is also involved in higher-level, cross-modal, cognitive functions. In particular, electrophysiological studies have highlighted that the cross-modal activation of this area may also extend to visual Working Memory (WM), being part of a mnemonic network specific for the temporary storage and manipulation of visual information concerning bodies and body-related actions. However, the causal recruitment of S1 in the WM network remains speculation. In the present study, by taking advantage of repetitive Transcranial Magnetic Stimulation (rTMS), we look for causal evidence that S1 is implicated in the retention of visual stimuli that are salient for this cortical area. To this purpose, in a first experiment, high-frequency (10 Hz) rTMS was delivered over S1 of the right hemisphere, and over two control sites, the right lateral occipital cortex (LOC) and the right dorsolateral prefrontal cortex (dlPFC), during the maintenance phase of a high-load delayed match-to-sample task in which body-related visual stimuli (non-symbolic hand gestures) have to be retained. In a second experiment, the specificity of S1 recruitment was deepened by using a version of the delayed match-to-sample task in which visual stimuli depict geometrical shapes (non-body related stimuli). Results show that rTMS perturbation of S1 activity leads to an enhancement of participants’ performance that is selective for body-related visual stimuli; instead, the stimulation of the right LOC and dlPFC does not affect the temporary storage of body-related visual stimuli. These findings suggest that S1 may be recruited in visual WM when information to store (and recall) is salient for this area, corroborating models which suggest the existence of a dedicated mnemonic system for body-related information in which also somatosensory cortices play a key role, likely thanks to their cross

Recent literature suggests that the primary somatosensory cortex (S1), once thought to be a low-level area only modality-specific, is also involved in higher-level, cross-modal, cognitive functions. In particular, electrophysiological studies have highlighted that the cross-modal activation of this area may also extend to visual Working Memory (WM), being part of a mnemonic network specific for the temporary storage and manipulation of visual information concerning bodies and body-related actions. However, the causal recruitment of S1 in the WM network remains speculation. In the present study, by taking advantage of repetitive Transcranial Magnetic Stimulation (rTMS), we look for causal evidence that S1 is implicated in the retention of visual stimuli that are salient for this cortical area. To this purpose, in a first experiment, high-frequency (10 Hz) rTMS was delivered over S1 of the right hemisphere, and over two control sites, the right lateral occipital cortex (LOC) and the right dorsolateral prefrontal cortex (dlPFC), during the maintenance phase of a high-load delayed match-to-sample task in which body-related visual stimuli (non-symbolic hand gestures) have to be retained. In a second experiment, the specificity of S1 recruitment was deepened by using a version of the delayed match-to-sample task in which visual stimuli depict geometrical shapes (non-body related stimuli). Results show that rTMS perturbation of S1 activity leads to an enhancement of participants’ performance that is selective for body-related visual stimuli; instead, the stimulation of the right LOC and dlPFC does not affect the temporary storage of body-related visual stimuli. These findings suggest that S1 may be recruited in visual WM when information to store (and recall) is salient for this area, corroborating models which suggest the existence of a dedicated mnemonic system for body-related information in which also somatosensory cortices play a key role, likely thanks to their cross

The brain preserves its capacity to integrate information from different senses in many pathological conditions, including stroke. Multisensory integration mechanisms, which may be spared by brain damage, provide a tool for setting up rehabilitation programs of poststroke sensory and cognitive disorders. Indeed, proper multisensory stimulation can ameliorate some unisensory perceptual and spatial impairments of brain-damaged patients. In the case of postchiasmatic visual field defects, intensive audiovisual stimulation of the blind hemifield allows the development of compensatory eye movements, in turn reducing vision-related functional disability in daily living. This approach is effective in both adult stroke patients and in children with cerebral palsy. In the rehabilitation of unilateral spatial neglect, many available treatments are intrinsically multisensory, because they primarily act through a crossmodal reinforcement of spatial representations. This is the case of adaptation to optical prisms displacing the visual scene, a widely used method that affects sensorimotor neuroplasticity. In patients with spatial neglect, prism adaptation induces a remapping of spatial coordinates, enabling the reconstruction of a stable representation of space across different sensory modalities. Other promising therapeutic strategies are offered by multisensory illusions, which can be used for restoring disarranged spatial and body representations, thereby improving the resulting deficits.

The forensic assessment of testamentary capacity is a topical issue given the prevalence of dementia illnesses and the increase in the complexity of modern financial and family structures. Although a contemporaneous assessment would be desirable, the majority of situations require a retrospective assessment of the mental state a deceased individual. Neuropsychologists, independently or as part of a board of consultants, are, therefore, frequently requested to give an expert opinion of the competence of cognitively impaired elderly testators. This paper offers a guide for carrying out a neuropsychological autopsy, namely the process of posthumous evaluation, for determining testamentary capacity. Taking into account the recent literature on the assessment of testamentary capacity, we propose a three-phase procedure for carrying out the neuropsychological autopsy in the forensic context. The neuropsychological autopsy of testamentary capacity is based on the meticulous, chronologically structured evaluation of any medical documents, available psychometric data, along with the critical examination of any source of information about the cognitive level of functioning of the deceased person at the time of the will.

We developed and assessed the effects of a novel cross-modal protocol aimed at inducing associative (Hebbian-like) plasticity in the somatosensory cortical system through vision. Associative long-term potentiation can be induced in the primary somatosensory cortex (S1) by means of paired associative stimulation (PAS), in which a peripheral electrical stimulation of the median nerve is repeatedly paired with a transcranial magnetic stimulation (TMS) pulse over S1. Considering the mirror proprieties of S1, the cross-modal PAS (cm-PAS) consists of repetitive observation of bodily tactile stimulations, paired with TMS pulses over the contralateral S1. Through three experiments in healthy participants, we demonstrate that the cm-PAS is able to induce excitatory plastic effects with functional significance in S1, improving somatosensory processing at both behavioral (tactile acuity) and neurophysiological (somatosensory-evoked potentials) levels. The plastic effects induced by cm-PAS depend on the interval (20 ms) between the visual stimulus and the magnetic pulse, the targeted cortical site (S1), and the tactile content of the visual stimulus, which must represent a touch event. Such specificity implies the involvement of cross-modal, mirror-like, mechanisms in S1, which are able to visually promote associative synaptic plasticity in S1 likely through the recruitment of predictive coding processes.

The development of the ability to recognize the whole human body shape has long been investigated in infants, while less is known about their ability to recognize the shape of single body parts, and in particular their biomechanical constraints. This study aimed to explore whether 9- and 12-month-old infants have knowledge of a hand-grasping movement (i.e., pincer grip), being able to recognize violations of the hand's anatomical constraints during the observation of that movement. Using a preferential looking paradigm, we showed that 12-month-olds discriminate between biomechanically possible and impossible pincer grips, preferring the former over the latter (Experiment 1). This capacity begins to emerge by 9 months of age, modulated by infants' own sensorimotor experience with pincer grip (Experiment 2). Our findings indicate that the ability to visually discriminate between pincer grasps differing in their biomechanical properties develops between 9 and 12 months of age, and that experience with self-produced hand movements might help infants in building a representation of the hand that encompasses knowledge of the physical constraints of this body part.

Optimal motor performance requires the monitoring of sensorimotor input to ensure that the motor output matches current intentions. The brain is thought to be equipped with a “comparator” system, which monitors and detects the congruence between intended and actual movement; results of such a comparison can reach awareness. This study explored in healthy participants whether the cathodal transcranial direct current stimulation (tDCS) of the right premotor cortex (PM) and right posterior parietal cortex (PPC) can disrupt performance monitoring in a skilled motor task. Before and after tDCS, participants underwent a two-digit sequence motor task; in post-tDCS session, single-pulse TMS (sTMS) was applied to the right motor cortex, contralateral to the performing hand, with the aim of interfering with motor execution. Then, participants rated on a five-item questionnaire their performance at the motor task. Cathodal tDCS of PM (but not sham or PPC tDCS) impaired the participants’ ability to evaluate their motor performance reliably, making them unconfident about their judgments. Congruently with the worsened motor performance induced by sTMS, participants reported to have committed more errors after sham and PPC tDCS; such a correlation was not significant after PM tDCS. In line with current computational and neuropsychological models of motor control and awareness, the present results show that a mechanism in the PM monitors and compares intended versus actual movements, evaluating their congruence. Cathodal tDCS of the PM impairs the activity of such a “comparator,” disrupting self-confidence about own motor performance.

Sound-induced flash illusions depend on visual cortical excitability. In this study, we explored whether sound-induced flash illusions are perceived differently in migraine, a condition associated with pathologic cortical hyperexcitability. Methods: Sound-induced flash illusions were examined in 59 migraine patients (mean age 32 ± 16 years; 36 females), 32 without aura and 27 with aura, and in 24 healthy controls (mean age 42 ± 17 years; 16 females). Patients were studied during attacks and interictally. Visual stimuli (flashes) accompanied by sounds (beeps) were presented in different combinations: a single flash with multiple beeps was given to induce the perception of multiple flashes ("fission" illusion), and multiple flashes with a single beep were used to reduce the number of perceived flashes ("fusion" illusion). Results: For migraineurs, the fission illusion was reduced, especially during the attack, and almost abolished when a single flash was combined with 2 beeps (except for those without aura tested interictally); the fusion illusion was less consistently reported in both migraine groups, but not completely disrupted. Conclusions: Results from this study add novel clues to our understanding of visual cortex hyperexcitability in migraine, especially migraine with aura. Furthermore, these analyses underscore how pathologic changes in cortical excitability affect multisensory interactions. Cross-modal illusions represent a valid tool for exploration of functional connectivity between sensory areas, which likely has an important role in the pathophysiology of migraine.

This study investigates whether the rubber hand illusion (RHI) can induce a remission of somatoparaphrenia, a somatic delusion usually following righthemisphere damage, which typically manifests as a defective sense of ownership of one's contralesional body parts. First, we show that patients with somatoparaphrenia can experience a reliable RHI, exhibiting illusory effects similar to those reported by healthy participants. Moreover, synchronous touches applied to the patients' visible disowned left hand (rather than to the rubber hand), and to their right invisible unimpaired hand, induce an immediate self-attribution of the disowned hand, without affecting other sensorimotor or attentional disorders. The higher-level representation of the body concerned with ownership, deranged as a somatic delusion in patients with somatoparaphrenia, is penetrable, and can be restored by multisensory stimulations. © 2014 American Academy of Neurology.

Crossmodal illusions clearly show how perception, rather than being a modular and self-contained function, can be dramatically altered by interactions between senses. Here, we provide evidence for a novel crossmodal "physiological" illusion, showing that sounds can boost visual cortical responses in such a way to give rise to a striking illusory visual percept. In healthy participants, a single-pulse transcranial magnetic stimulation (sTMS) delivered to the occipital cortex evoked a visual percept, i.e., a phosphene. When sTMS is accompanied by two auditory beeps, the second beep induces in neurologically unimpaired participants the perception of an illusory second phosphene, namely the sound-induced phosphene illusion. This perceptual "fission" of a single phosphene, due to multiple beeps, is not matched by a "fusion" of double phosphenes due to a single beep, and it is characterized by an early auditory modulation of the TMS-induced visual responses (~80 ms). Multiple beeps also induce an illusory feeling of multiple TMS pulses on the participants' scalp, consistent with an audio-tactile fission illusion. In conclusion, an auditory stimulation may bring about a phenomenological change in the conscious visual experience produced by the transcranial stimulation of the occipital cortex, which reveals crossmodal binding mechanisms within early stages of visual processing. © 2013 Springer-Verlag Berlin Heidelberg.

Multisensory interactions can produce analgesic effects. In particular, viewing one's own body reduces pain levels, perhaps because of changes in connectivity between visual areas specialized for body representation, and sensory areas underlying pain perception. We tested the causal role of the extrastriate visual cortex in triggering visually induced analgesia by modulating the excitability of this region with transcranial direct current stimulation (tDCS). Anodal, cathodal, or sham tDCS (2 mA, 10 min) was administered to 24 healthy participants over the right occipital or over the centro-parietal areas thought to be involved in the sensory processing of pain. Participants were required to rate the intensity of painful electrical stimuli while viewing either their left hand or an object occluding the left hand, both before and immediately after tDCS. We found that the analgesic effect of viewing the body was enhanced selectively by anodal stimulation of the occipital cortex. The effect was specific for the polarity and the site of stimulation. The present results indicate that visually induced analgesia may depend on neural signals from the extrastriate visual cortex

We used Transcranial Magnetic Stimulation (TMS) to assess whether reading literal, non-literal (i.e., metaphorical, idiomatic) and fictive motion sentences modulates the activity of the motor system. Sentences were divided into three segments visually presented one at a time: the noun phrase, the verb and the final part of the sentence. Single pulse-TMS was delivered at the end of the sentence over the leg motor area in the left hemisphere and motor evoked potentials (MEPs) were recorded from the right gastrocnemius and tibialis anterior muscles. MEPs were larger when participants were presented with literal, fictive and metaphorical motion sentences than with idiomatic motion or mental sentences. These results suggest that the excitability of the motor system is modulated by the motor component of the verb, which is preserved in fictive and metaphorical motion sentences. © 2011 Elsevier Inc. All rights reserved.

BACKGROUND: Recovery of motor function after stroke may depend on a balance of activity in the neural network involving the affected and the unaffected motor cortices. OBJECTIVE: To assess whether transcranial direct current stimulation (tDCS) can increase the training-induced recovery of motor functions. METHODS: In an exploratory study, 14 patients with chronic stroke and mean Fugl-Meyer Upper Extremity Motor Assessment of 29 (range = 8-50) entered a double-blind sham-controlled study, aimed to investigate neurophysiological and behavioral effects of bihemispheric tDCS (cathodal stimulation of the unaffected motor cortex and anodal stimulation of the affected motor cortex), combined with constraint-induced movement therapy (CIMT). RESULTS: Patients in both groups demonstrated gains on primary outcome measures, that is, Jebsen Taylor Hand Function Test, Handgrip Strength, Motor Activity Log Scale, and Fugl-Meyer Motor Score. Gains were larger in the active tDCS group. Neurophysiological measurements showed a reduction in transcallosal inhibition from the intact to the affected hemisphere and increased corticospinal excitability in the affected hemisphere only in the active tDCS/CIMT group. Such neurophysiological changes correlated with the magnitude of the behavioral gains. Both groups showed a reduction in corticospinal excitability of the unaffected hemisphere. CONCLUSIONS: CIMT alone appears effective in modulating local excitability but not in removing the imbalance in transcallosal inhibition. Bihemispheric tDCS may achieve this goal and foster greater functional recovery.

Autoscopic phenomena refer to complex experiences involving the illusory reduplication of one's own body. Here we report the third long-lasting case of autoscopy in a patient with right occipital lesion. Instead of the commonly reported frontal mirror view (fantôme spéculaire), the patient saw her head and upper trunk laterally in side view (fantôme de profil). We found that the visual appearance and completeness of the autoscopic image could be selectively modulated by active and passive movements, without being influenced by imagining the samemovements or by tactile and auditory stimulation. Eyes closure did not disrupt either the perception of the autoscopic body or the effects of the motor stimulation. Moreover, the visual body reduplication was coded neither in purely eye-centered nor in head-centered frames of reference, suggesting the involvement of egocentric coordinate systems (eyes and head centered). A follow-up examination highlighted the stability of the visual characteristics of the body reduplication and its shift induced by displacement of both head and eyes. These findings support the viewthat autoscopic phenomena have a multisensory motor origin and proprioceptive signals may play an important role in modulating the illusory visual reduplication of the patient's own body,most likely via cross-modalmodulation of extrastriate areas involved in body and face perception. © 2011 Massachusetts Institute of Technology.

Perception of the outside world results from integration of information simultaneously derived via multiple senses. Increasing evidence suggests that the neural underpinnings of multisensory integration extend into the early stages of sensory processing. In the present study, we investigated whether the superior temporal gyrus (STG), an auditorymodality-specific area, is critical for processing tactile events. Transcranialmagnetic stimulation (TMS) was applied over the left STG and the left primary somatosensory cortex (SI) at different time intervals (60, 120, and 180 msec) during a tactile temporal discrimination task (Experiment 1) and a tactile spatial discrimination task (Experiment 2). Tactile temporal processing was disrupted when TMS was applied to SI at 60 msec after tactile presentation, confirming themodality specificity of this region. Crucially, TMS over STG also affected tactile temporal processing but at 180 msec delay. In both cases, the impairment was limited to the contralateral touches and was due to reduced perceptual sensitivity. In contrary, tactile spatial processing was impaired only by TMS over SI at 60-120 msec. These findings demonstrate the causal involvement of auditory areas in processing the duration of somatosensory events, suggesting that STG might play a supramodal role in temporal perception. Furthermore, the involvement of auditory cortex in somatosensory processing supports the view that multisensory integration occurs at an early stage of cortical processing. © 2009 Massachusetts Institute of Technology.