The classical mirror neuron theory of action understanding asserts that when we observe an action, the representations that are engaged for performing it, are automatically activated. In order to do gain information about the role of the simulation in action understanding a state dependent TMS experiment has been carried out. The fundamental idea is to adapt a neural population in the motor system and then testing the effects of this adaptation when participants categorize visually presented actions. The second aim of the present work is to find a paradigm, or a particular cognitive set, that does not allow the simulation process to take place when the participants are observing actions. This step will be important in testing whether the simulation process is necessary in order to understand a visually presented action.

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory. At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing. This work aims to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order, and whether this impairment also affects processing beyond the verbal domain. In three studies, dyslexic children in Italy, good and poor reading school children in Germany and a sample of adults in Belgium participated in 2 x 2 experiments in which short-term recognition performance for order and item information was assessed, using both verbal and nonverbal material. The findings indicate that, irrespective of the type of material, children and adult participants with dyslexia recalled the individual items with the same accuracy as the matched control group, whereas the ability to recognize the serial order in which those items were presented appeared to be affected in the dyslexic groups. This work concludes with the assumption that dyslexia is characterized by a selective impairment of serial order short-term memory and discusses the implications of these findings for current theoretical views on dyslexia and its associated dysfunctions.

Teaching and learning in a foreign language: the CLIL approach in Europe, in Italy, in Trentino. Monitoring a CLIL pilot programme at Primary school in Italy: Context Analysis and Curriculum Study. Arithmetic facts and language of acquisition effects in Primary school children: Experiment 1,2,3 and 4. Arithmetic facts in Primary school children:Does the language of acquisition really matter? Experiment 5 and 6.

The visual analysis of the world around us is an incredibly complex neural process that allows humans to function appropriately within the environment. When one considers the intricacy of both the visual input and the (currently known) neural mechanisms necessary for its analysis, it is difficult not to remain enchanted by the fact that, even though the signal that hits the retina has a tremendous amount of simple visual features and that is ever changing, ambiguous and incomplete, we experience the world around us in a very easy, stable and straightforward manner. So much effort has been put into the study of vision, and despite the enormous scientific advances and important findings, many questions still need answers. During my years spent as Ph.D. student, I investigated some questions related to top-down attentional mechanisms in real-world visual search. Specifically, Chapter 2 and 3 address the processing stage of preparation, by investigating the characteristics of attentional templates when preparing to search for objects in scenes; Chapter 4 addresses the stage of guidance and selection, by investigating the temporal course of spatial attention guidance; and finally, Chapter 5 addresses the identification phase, by investigating the temporal dynamics of size-constancy mechanisms in real-world scenes. To anticipate some results, we proposed that attentional templates in real-world visual search tasks are based on category-diagnostic features and code the expected target size/distance. In the context of the attentional guidance and selection stage, we demonstrate that attention spatially focuses on targets around 240ms, following category-based attentional modulations appearing at 180ms after scene onset. Finally, we propose that size constancy mechanisms appear before 200ms post-scene. This is in line with the expectation that a coarse identification of an object, including its size, should be computed before spatially focusing attention onto the target. Together these studies improve our understanding of top-down attentional processes engaged in real-world visual search, and raise some questions which future research could address.

Object individuation is the process by which organisms establish the number of distinct objects present in an event. The ability of individuating objects was investigated in two/three-day-old chicks (Gallus gallus). A first series of experiments (Exp. 1 - Exp. 6) assessed the role of the property information provided by colour, shape, size or individually distinctive features, as well as spatiotemporal information in object individuation. A second series (Exp. 7 - Exp. 10) aimed at investigating the ability to use property/kind information using imprinting objects and food items (i.e. mealworms) as stimuli of different category. Newborn chicks were exposed (i.e., imprinted) to sets of objects which were different or identical for property and property/kind information, and the chicks’ spontaneous tendency to approach the larger group of imprinting objects and food items was exploited. Each chick underwent a free choice test in which two groups of events were shown: a group comprised two different stimuli (i.e. for property or for kind); the second group was composed by a single stimulus presented twice. Every stimulus in each group of events was sequentially presented and concealed in the same spatial location and the number of events taking place at each location was equalized (Sequential Presentation test). Chicks spontaneously approached the two different objects rather than the single object seen twice. A possible preference for the more varied set of stimuli was excluded by testing chicks in a simultaneous presentation of two different objects Vs. two identical objects (Simultaneous Presentation test). Moreover, use of spatiotemporal information was assessed through simultaneous presentation of three identical objects Vs. two different objects. When increasing the number of presentations of the single stimulus (up to 3 times) and comparing it with two different stimuli presented once each, chicks correctly individuated the larger group of imprinting objects only if objects were all different from one another (i.e. distinctive features had been put on each object). Any role of experience was excluded by presenting chicks with stimuli of a completely novel colour with respect to the original colour of the imprinting stimuli. Results show that chicks are able to use the property information provided by colour, shape, size or individually distinctive features, spatiotemporal information and property/kind information provided by social and food categories for object individuation. The fact that object individuation is precociously available in the young of a vertebrate species suggests it may depend on inborn biological predispositions rather than on experiential or language-related processes.

Human occipitotemporal cortex (OTC) is organized into distinct areas that are selectively activated by the visual presentation of different categories, like faces (Kanwisher et al., 1997), bodies (Downing et al., 2001), tools (Chao et al., 1999), hands (Bracci et al., 2010), and places (Epstein et al., 1999). However, the precise role of these areas in processing their preferred stimulus category is still unclear. Moreover, the debate on how such brain organization originates is still unresolved. In order to investigate these issues, we focused on one of these selective areas: a region in left lateral-occipitotemporal cortex (lLOTC) that has been shown to be selective to both hands and tools and that is functionally connected to left intraparietal sulcus (IPS) and premotor cortex (PM), regions involved in action processing (Bracci et al., 2012). Although tools and hands are visually very different, they are both involved in object-directed actions. Thus, lLOTC might process both categories in order to efficiently communicate with IPS and PM. Alternatively, however, tool selectivity in lLOTC may simply reflect epiphenomenal association of tools with hands, for example related to mental imagery. Furthermore, the role of feedback projections between IPS and lLOTC in shaping tool selectivity in lLOTC has not yet been investigated. Using fMRI, we found that lLOTC was more strongly activated when participants processed action-related properties of tools (deciding on the typical hand action associated with a tool), as compared to when they processed contextual properties of tools (deciding on the typical location associated with a tool). Importantly, TMS over lLOTC led to a specific decrease in accuracy for action judgments but not for contextual judgments, supporting a causal role for lLOTC in processing tool actions. We investigated lLOTC-IPS connections by interleaving repetitive TMS with short fMRI scans. In a first experiment, we applied TMS over left IPS and found a decrease in BOLD signal in left IPS, confirming that TMS suppressed neural processing in the target area. Moreover, BOLD responses also decreased in left dorsal PM and right IPS, suggesting that these two areas receive projections from left IPS. However, no significant change was found in lLOTC, indicating that tool selectivity in lLOTC does not require feedback from IPS. In a second study, we stimulated lLOTC. In this study, however, no significant TMS-induced BOLD changes were found in the target region, possible reflecting insufficient statistical power. In conclusion, our results show that lLOTC is critical in processing action-related properties of tools, indicating that tool selectivity in this area reflects processes that are necessary for understanding tool actions. As a consequence, the finding that lLOTC is causally selective for both tools and hands, even if these two categories are visually very different, supports the hypothesis that the functional organization of OTC partly reflects non-visual organizational principles. Finally, the fact that we did not find significant back projections from IPS to lLOTC suggests that the role of lLOTC in processing tools does not arise as a consequence of activity in higher areas, but that lLOTC is relatively autonomous in processing action-related properties of tools.

What we consciously see in our everyday life is not an exact copy of the information that our eyes receive from the external world. Our brain actively elaborates and transforms the light that impinges onto the two dimensional surface of our retinas to create complex three dimensional scenes full of colorful objects of different shapes and sizes, motion and depth. Our visual perception is not a passive reception of information: our brain actively decodes and separates the retinal information into relevant and significant objects and compares this information with previous memories. One remarkable example is the ability of the visual system to decode the information that arrives from the eyes into recognizable visual objects and scenes. We are able to recognize objects even under conditions of low illumination or low contrast, when these objects are partially occluded, presented among other objects or when they are defined by textures, for example. In addition to this process of recognition, the visual system generates the conscious sensations of those objects and scenes. Even though we need our eyes to see the world these are not enough by themselves to generate visual perception. The light impinging on our retinas needs further elaboration in higher areas of the brain to generate perception. Several situations in which vision is separated from perception can demonstrate this. For example, we can imagine some object with our eyes closed in our “mind’s eye†or we can generate images in our dreams that are completely independent of external stimulation. Experimentally, it is possible to manipulate visual perception while keeping visual stimulation to the eyes constant. Examples of this are the changes in perception that occur with multi-stable phenomena (i.e, as with the Necker cube) or when subjects are presented with dissimilar images to each eye, a condition called binocular rivalry. Without a functioning visual brain we are not able to properly see. Lesions to the visual cortex produce a wide variety of visual deficits ranging from blindness to achromatopsia (the impossibility of perceiving color), akinetopsia (the impossibility of perceiving motion) and/or visual agnosias (the difficulty in recognizing objects through vision). Also, extensive neuroimaging experiments have shown that visual information causes the activation of wide areas of the brain and the role of many of these areas has been studied in the last two decades. However, currently the neuroscientific study of perception can only be addressed with limited resources. We cannot measure the activity of the 10 billion neurons that constitute our brain. Neither can scientists manipulate the human brain by disrupting, modifying or altering the activity of neuronal circuits. The current imaging methods for studying the brain can only provide incomplete information at different spatial levels of analysis and with different temporal resolutions. Thus, the conclusions that neuroscientists we can extract from these data are only partial attempts to reach to a better understanding of the functioning of the brain. Despite these limitations, few neuroscientists would disagree today with the fact that visual perception has a basis on distributed neuronal circuits in the brain. In the same line of thought, it is agreed that there must be circuits of neurons that code for the conscious perception of those objects. Consciousness has always been considered as one of the major mysteries of life. The study of the origins of sensations and “feelings†from the operations of our brain is for many scientists one of the final challenges for the biological sciences (Koch, 2003). The mystery of consciousness is considered to be at the same level of the mystery of the creation of the universe and the mystery of the origin of life out of inanimate matter. The topic of this thesis is the study of visual consciousness. Considering its complexity, we do not intend to provide a final answer to the explanation of consciousness. Instead, this thesis will focus on the study of vision and it will describe some properties of conscious vision as opposed to unconscious vision. We will explore the fate of unseen vision: the information that reaches the retina but that does not generate any conscious sensation. We will analyze the processing and limits of unseen visual stimuli and we will compare them with conscious processing of the same objects. In doing this we expect to shed light into some of the properties of conscious and unconscious visual perception and on the role that visual awareness might have had in evolution.

Humans are capable of recognizing a myriad of objects in everyday life. To do that, they have evolved the ability to detect their commonalities and differences, moving from perceptual details to construct more abstract representations that we call concepts, which span entire categories (such as the one of people) or refer to very specific and individual entities (such as our parents). Organizing our knowledge of the world around concepts, rather than around individual experiences, allows us for more rapid access to behavioural relevant information (for instance, how to behave when we encounter a dangerous animal), and to quickly generalize this information to what we never encountered before. In few words, this is what permeates the world with meaning. The present work is about the neural bases of learning novel object concepts, a process that in our species is vastly supported by symbols and language: for this reason, I talk about semantic representations. The word “semantics” generally refers to the study of meaning (and to what a “meaning” ultimately is) as it is conveyed by a symbol; in the specific case of cognitive neuroscience, it deals with the neural mechanisms that allow symbols to re-present the meanings or concepts they refer to in the brain. For instance, we can easily describe what is the meaning of the word “DOG”, pretty much as we can explain what “DEMOCRACY” means. However, although cognitive neuroscience has focused on the neuro-cognitive bases of semantic representations for decades, the neural mechanisms underlying their acquisition remain elusive. How does the human brain change when learning novel concepts using symbols? How does a symbol acquire its meaning in the brain? Does this learning generate novel neural representations and/or does it modify pre-existing ones? What internal representational format (neural code) supports the representation of newly learnt concepts in the human brain? The contribution of this work is three-fold. First, I show how new semantic representations learned by categorizing novel objects (defined through a combination of multisensory perceptual features) memory systems. Second, I show results converging on the idea that brain regions that evolved in lower-level mammals to represent spatial relationships between objects and locations, such as the hippocampal formation and medial prefrontal cortex, in humans are recruited to encode relationships between words and concepts by means of the same neural codes used to represent and navigate the physical environment. Finally, I present preliminary data on the cognitive effects of using symbols during learning novel object concepts, showing how language supports the construction of generalizable semantic representations.

In this thesis, I am going to address the issue of how both reward and punishment affect visual representation, by the use of a visual search paradigm performed in naturalistic scenes. More specifically, I am going to approach these two motivational forces by referring to their constituting dimensions, namely valence and salience. In fact, while being positioned in oppositely valenced space, these two outcomes share the burden of signaling stimuli with strong behavioral importance, coding therefore for motivational salience. After reviewing the main existing literature in this field (Chapter 1), I will describe a series of studies which examine how reward and punishment impact visual attention through the analysis of behavioral measures (Chapter 2) and fMRI activation (Chapter 3 and 4). The main idea resulting from these studies is that, in spite of what a rational approach to the problem would suggest, automatic visual attention does not process these two outcomes according to a salience, but rather through a valence pattern.

This thesis describes three behavioral and one fMRI study in which the underlying psychological and neural mechanisms of stay/leave decision making in both a nonsocial and social context were investigated and compared. In Study 1A and 1B participants played a social or nonsocial version of a novel economic game in which participants were dependent on a social partner or nonsocial resource to increase their monetary outcomes. Both actual and expected reward probability of social partners and nonsocial resources positively affected the time participants decided to stay with a specific social partner or nonsocial resource. The effect of expected reward probability on staying times was much more pronounced in the nonsocial context. In Study 2, Reinforcement Learning models were fitted to participant's choices in a social and nonsocial version of the 4-armed bandit task in which prior beliefs about partners or resources were manipulated. The effects of Study 1B were replicated. Furthermore, it was found that participants weight expectancy-consistent and inconsistent new observations differentially when learning about both social partners and nonsocial resources. Participants had generally higher learning rates in the social than nonsocial context but this was not the case when prior beliefs were not induced. In Study 3, participants played a social and nonsocial version of the 4-armed bandit task while undergoing fMRI. Increased activation in caudate nucleus was associated with stay decisions in a social rather than nonsocial context; and the dorsal anterior cingulate cortex showed differential activation as a function of stay and leave decisions and this pattern was reversed in the nonsocial and social context. Interpretation of these results are discussed in light of a fundamental need to belong that motivates people to stay with social partners specifically and resist against breaking social connections.