Análise metabolômica do cérebro de abelhas (Apis mellifera) submetidas a ensaio de Reflexo de Extensão de Probóscide (REP)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Elderly Individuals with Diabetes: Adding Cognitive Training to Psychoeducational Intervention

The present research examined the effects of a cognitive training program combined with psychoeducational intervention for diabetic elderly patients. Specifically, it aimed at assessing the effects of an eight-session cognitive training and educational program in diabetic elderly individuals and investigating changes in their awareness about specific aspects of diabetes. The final sample consisted of 34 individuals-19 in the experimental group (EG) and 15 in the control group (CG), all residing in the eastern region of the city of Sao Paulo. The protocol included clinical and sociodemographic questions; the Diabetes Attitudes Questionnaire (ATT-19); Diabetes Knowledge Scale (DKN-A); Mini Mental State Examination (MMSE); Verbal Fluency-animal category (VF); Geriatric Depression Scale (GDS); Short Cognitive Performance Test (SKT); and the Rivermead Behavioral Memory Test (RBMT). Results pointed to a significant difference between the two groups for the ATT-19, DKN, and SKT-memory and SKT-total, and a marginally significant difference for the RBMT history in the posttest. As for the remaining cognitive variables, no changes were observed. Retest effects were not observed in the CG. We concluded that cognitive training combined with psychoeducational intervention in diabetic elderly individuals may be effective in producing cognitive gains as well as attitude and knowledge improvement concerning diabetes mellitus (DM).

Normative Data for Healthy Middle-Aged and Elderly Performance on the Addenbrooke Cognitive Examination-Revised

Objective: To provide normative data for healthy middle-aged and elderly Brazilians' performance on the Addenbrooke Cognitive Examination-Revised (ACE-R) and to investigate the effects of age, sex, and schooling on test performance. Background: The ACE-R is a brief cognitive battery that assesses various aspects of cognition. Its 5 subdomains (Attention and Orientation, Memory, Verbal Fluency, Language, and Visuospatial Abilities) are commonly impaired in Alzheimer disease or frontotemporal dementia. Methods: We evaluated 144 cognitively healthy volunteers (50% men, 50% women) aged 50 to 93 years, with 4 to 24 years of schooling. We divided the participants into 4 age groups, each of which was then stratified into 3 groups according to years of education. We assessed all participants with the ACE-R, the Mattis Dementia Rating Scale, and the Cornell Scale for Depression in Dementia. Results: Years of education affected all ACE-R subscores. Age influenced the Verbal Fluency subscore (P < 0.001) and the ACE-R total score (P < 0.05). Sex affected the Attention and Orientation (P = 0.037) and Mini-Mental State Examination subscores (P = 0.048), but not the ACE-R total score (P > 0.05). Conclusions: The performance of healthy middle-aged and elderly individuals on the ACE-R battery is strongly influenced by education and, to a lesser extent, by age. These findings are of special relevance in countries with populations that have marked heterogeneity in educational levels.

First record of chemical signals from the queen during the oviposition process in stingless bees

In stingless bees, the cell provisioning and oviposition process consists of several integrated behavioral sequences and several stereotyped queen-worker interactions. This study aims to demonstrate that chemical signals originating from the queen may contribute as cues for the sequence of the oviposition process in Melipona marginata. For this, we analyzed the cell before and after queen laying, and compared them with the cuticular hydrocarbons of the queen's abdomen, using a gas-chromatography and mass spectrometry system.

Reduced platelet amyloid precursor protein ratio (APP ratio) predicts conversion from mild cognitive impairment to Alzheimer's disease

Studies have shown that platelet APP ratio (representing the percentage of 120-130 kDa to 110 kDa isoforms of the amyloid precursor protein) is reduced in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). In the present study, we sought to determine if baseline APP ratio predicts the conversion from MCI to AD dementia after 4 years of longitudinal assessment. Fifty-five older adults with varying degrees of cognitive impairment (34 with MCI and 21 with AD) were assessed at baseline and after 4 years. MCI patients were re-classified according to the conversion status upon follow-up: 25 individuals retained the diagnostic status of MCI and were considered as stable cases (MCI-MCI); conversely, in nine cases the diagnosis of dementia due to AD was ascertained. The APP ratio (APPr) was determined by the Western blot method in samples of platelets collected at baseline. We found a significant reduction of APPr in MCI patients who converted to dementia upon follow-up. These individuals had baseline APPr values similar to those of demented AD patients. The overall accuracy of APPr to identify subjects with MCI who will progress to AD was 0.74 +/- A 0.10, p = 0.05. The cut-off of 1.12 yielded a sensitivity of 75 % and a specificity of 75 %. Platelet APPr may be a surrogate marker of the disease process in AD, with potential implications for the assessment of abnormalities in the APP metabolism in patients with and at risk for dementia. However, diagnostic accuracy was relatively low. Therefore, studies in larger samples are needed to determine whether APPr may warrant its use as a biomarker to support the early diagnosis of AD.

Cognitive Training and Educational Intervention for Individuals with Hypertension: Effects on Cognition

Objectives: To evaluate the possibility of combining cognitive training to an educational intervention composed by eight sessions about hypertension for a better management of the disease among the elderly. Methods: 64 older adults who reported having hypertension, divided into experimental group (EG, n=35) and control group (CG, n=29) participated in the study. Control participants received training after the post-test. The protocol contained socio-demographic and clinical data, Mini-Mental State Examination (MMSE), Geriatric Depression Scale (GDS), Rivermead Behavioral Memory Test (RBMT), Verbal Fluency Animal Category (VF) and Short Cognitive Test (SKT). Results: The EG showed better cognitive performance when compared with the CG, at post-test. Conclusion: Cognitive gains may occur after psychoeducational interventions for older adults with hypertension.

Cannabidiol reduces host immune response and prevents cognitive impairments in Wistar rats submitted to pneumococcal meningitis

Pneumococcal meningitis is a life-threatening disease characterized by an acute infection affecting the pia matter, arachnoid and subarachnoid space. The intense inflammatory response is associated with a significant mortality rate and neurologic sequelae, such as, seizures, sensory-motor deficits and impairment of learning and memory. The aim of this study was to evaluate the effects of acute and extended administration of cannabidiol on pro-inflammatory cytokines and behavioral parameters in adult Wistar rats submitted to pneumococcal meningitis. Male Wistar rats underwent a cisterna magna tap and received either 10 mu l of sterile saline as a placebo or an equivalent volume of S. pneumoniae suspension. Rats subjected to meningitis were treated by intraperitoneal injection with cannabidiol (2.5, 5, or 10 mg/kg once or daily for 9 days after meningitis induction) or a placebo. Six hours after meningitis induction, the rats that received one dose were killed and the hippocampus and frontal cortex were obtained to assess cytokines/chemokine and brain-derived neurotrophic factor levels. On the 10th day, the rats were submitted to the inhibitory avoidance task. After the task, the animals were killed and samples from the hippocampus and frontal cortex were obtained. The extended administration of cannabidiol at different doses reduced the TNF-alpha level in frontal cortex. Prolonged treatment with canabidiol, 10 mg/kg, prevented memory impairment in rats with pneumococcal meningitis. Although descriptive, our results demonstrate that cannabidiol has anti-inflammatory effects in pneumococcal meningitis and prevents cognitive sequel. (C) 2012 Elsevier B.V. All rights reserved.

The effect of overweight/obesity on cognitive function in euthymic individuals with bipolar disorder

Background. - Persistent impairment in cognitive function has been described in euthymic individuals with bipolar disorder. Collective work indicates that obesity is associated with reduced cognitive function in otherwise healthy individuals. This sub-group post-hoc analysis preliminarily explores and examines the association between overweight/obesity and cognitive function in euthymic individuals with bipolar disorder. Methods. - Euthymic adults with DSM-IV-TR-defined bipolar I or II disorder were enrolled. Subjects included in this post-hoc analysis (n = 67) were divided into two groups (normal weight, body mass index [BMI] of 18.5-24.9 kg/m(2); overweight/obese, BMI >= 25.0 kg/m(2)). Demographic and clinical information were obtained at screening. At baseline, study participants completed a comprehensive cognitive battery to assess premorbid IQ, verbal learning and memory, attention and psychomotor processing speed, executive function, general intellectual abilities, recollection and habit memory, as well as self-perceptions of cognitive failures. Results. - BMI was negatively correlated with attention and psychomotor processing speed as measured by the Digit Symbol Substitution Test (P < 0.01). Overweight and obese bipolar individuals had a significantly lower score on the Verbal Fluency Test when compared to normal weight subjects (P < 0.05). For all other measures of cognitive function, non-significant trends suggesting a negative association with BMI were observed, with the exception of measures of executive function (i.e. Trail Making Test B) and recollection memory (i.e. process-dissociation task). Conclusion. - Notwithstanding the post-hoc methodology and relatively small sample size, the results of this study suggest a possible negative effect of overweight/obesity on cognitive function in euthymic individuals with bipolar disorder. Taken together, these data provide the impetus for more rigorous evaluation of the mediational role of overweight/obesity (and other medical co-morbidity) on cognitive function in psychiatric populations. (C) 2011 Elsevier Masson SAS. All rights reserved.

Early and late neurodegeneration and memory disruption after intracerebroventricular streptozotocin

Glucose metabolism and insulin signaling disruptions in the brain have been proposed as a likely etiology of Alzheimer's disease. The aim of the present study was to investigate the time course of cognitive impairments induced by intracerebroventricular injection of streptozotocin (STZ) in rats and correlate them with the ensuing neurodegenerative process. Early and late effects of STZ were evaluated by using the reference and working memory versions of the Morris' water maze task and the evaluation of neurodegenerative markers by immunoblotting and the Fluoro-jade C histochemistry. The results revealed different types of behavioral and neurodegenerative responses, with distinct time courses. We observed an early disruption on the working memory as early as 3 h after STZ injections, which was followed by degenerative processes in the hippocampus at 1 and 15 days after STZ injections. Memory disruption increases over time and culminates with significant changes in amyloid-beta peptide and hyperphosphorylated Tau protein levels in distinct brain structures. These findings add information on the Alzheimer's disease-like STZ animal model and on the mechanisms underlying neurodegenerative processes. (C) 2012 Elsevier Inc. All rights reserved.

Curcumin requires tumor necrosis Factor α signaling to alleviate cognitive impairment elicited by Lipopolysaccharide

A decline in cognitive ability is a typical feature of the normal aging process, and of neurodegenerative disorders such as Alzheimer’s, Parkinson’s and Huntington’s diseases. Although their etiologies differ, all of these disorders involve local activation of innate immune pathways and associated inflammatory cytokines. However, clinical trials of anti-inflammatory agents in neurodegenerative disorders have been disappointing, and it is therefore necessary to better understand the complex roles of the inflammatory process in neurological dysfunction. The dietary phytochemical curcumin can exert anti-inflammatory, antioxidant and neuroprotective actions. Here we provide evidence that curcumin ameliorates cognitive deficits associated with activation of the innate immune response by mechanisms requiring functional tumor necrosis factor α receptor 2 (TNFR2) signaling. In vivo, the ability of curcumin to counteract hippocampusdependent spatial memory deficits, to stimulate neuroprotective mechanisms such as upregulation of BDNF, to decrease glutaminase levels, and to modulate N-methyl- D –aspartate receptor levels was absent in mice lacking functional TNFRs. Curcumin treatment protected cultured neurons against glutamate-induced excitotoxicity by a mechanism requiring TNFR2 activation. Our results suggest the possibility that therapeutic approaches against cognitive decline designed to selectively enhance TNFR2 signaling are likely to be more beneficial than the use of anti-inflammatory drugs per se.

The role of Nox2-derived ROS in the development of cognitive impairment after sepsis

BACKGROUND: Sepsis- associated encephalopathy (SAE) is an early and common feature of severe infections. Oxidative stress is one of the mechanisms associated with the pathophysiology of SAE. The goal of this study was to investigate the involvement of NADPH oxidase in neuroinflammation and in the long-term cognitive impairment of sepsis survivors. METHODS: Sepsis was induced in WT and gp91phox knockout mice (gp91phox-/-) by cecal ligation and puncture (CLP) to induce fecal peritonitis. We measured oxidative stress, Nox2 and Nox4 gene expression and neuroinflammation in the hippocampus at six hours, twenty-four hours and five days post-sepsis. Mice were also treated with apocynin, a NADPH oxidase inhibitor. Behavioral outcomes were evaluated 15 days after sepsis with the inhibitory avoidance test and the Morris water maze in control and apocynin-treated WT mice. RESULTS: Acute oxidative damage to the hippocampus was identified by increased 4-HNE expression in parallel with an increase in Nox2 gene expression after sepsis. Pharmacological inhibition of Nox2 with apocynin completely inhibited hippocampal oxidative stress in septic animals. Pharmacologic inhibition or the absence of Nox2 in gp91phox-/- mice prevented glial cell activation, one of the central mechanisms associated with SAE. Finally, treatment with apocynin and inhibition of hippocampal oxidative stress in the acute phase of sepsis prevented the development of long-term cognitive impairment. CONCLUSIONS: Our results demonstrate that Nox2 is the main source of reactive oxygen species (ROS) involved in the oxidative damage to the hippocampus in SAE and that Nox2-derived ROS are determining factors for cognitive impairments after sepsis. These findings highlight the importance of Nox2-derived ROS as a central mechanism in the development of neuroinflammation associated with SAE.

La sorpresa come fattore critico indicatore di sintonizzazione emotiva in bambini normali e con disturbi pervasivi dello sviluppo

The topic of this study is surprise, re gard as an evolutionary complex process, with manifold implication in different fields, from neurological, since aspecific correlate of surprise exist more or less at every level of neuronal processes (e.g. Rao e Ballard, 1999.), to behavioral , inasmuch a s our ability to quickly valuate(assess), recognize and learn from surprising events, are be regarded as pivotal for survival (e.g. Ranganath e Rainer, 2003). In particular this work, going from belief that surprise is really a psychoevolutive mechanism of primary relevance, has the objective to investigate if there may be a substantial connection between development of surprise' emotion and specific developmental problems, or, if in subjects with pervasive developmental disorders surprise may embody (represent) a essential mechanism of emotional tuning, and consequently if abnormalities in such process may be at the base of at least a part of cognitive and behavioural problems that determine (describe) this pathology. Theoretical reasons lead us to conside r this particular pathologic condition, recall to a broad area of research concern the comprehension of belief as marker of ability to reasons about mental states of others (i.e. Theory of Mind), and in addition, at the detection of specific subjects' diff iculty in this field. On the experimental side, as well as limited of this work, we have to compare comprehension and expression of surprise in a sample of 21 children with pervasive developmental disorders (PDD), with a sample of 35 children without deve lopmental problems, in a range of age 3-12. Method After the customary approach to become friendly with the child, an experimenter and an accomplice showed three boxes of nuts, easily to distinguish one from the other because of their different colours an d , working together with the child, the contents of one of the boxes were replaced and a different material (macaroni, pebbles) was put in the box. for the purpose of preparing a surprise for someone. At this stage, the accomplice excused himself/herself and left and the experimenter suggested to the child that he prepare another surprise, replacing the contents in the second box. When the accomplice came back, the child was asked to prepare a surprise for him by picking out the box that he thought was the right one for the purpose. After, and the child doesn't know it, the accomplice change the content of one of the boxes with candies and asked out to the children to open the box, in order to see if he show surprise. Result Date have obtain a significant difference between autistic and normal group, in all four tests. The expression of surprise too, is present in significantly lower degree in autistic group than in control group. Moreover, autistic children do not provide appropriate metarappresentative explanations. Conclusion Our outcome, with knowledge of the limit of our investigation at an experimental level (low number of the champions, no possibility of video registration to firm the expressions ) orient to consider eventuality that surprise, may be seen as relevant component, or indicative, in autistic spectrum disorders.

Mathematical models of cognitive processes

The research activity carried out during the PhD course was focused on the development of mathematical models of some cognitive processes and their validation by means of data present in literature, with a double aim: i) to achieve a better interpretation and explanation of the great amount of data obtained on these processes from different methodologies (electrophysiological recordings on animals, neuropsychological, psychophysical and neuroimaging studies in humans), ii) to exploit model predictions and results to guide future research and experiments. In particular, the research activity has been focused on two different projects: 1) the first one concerns the development of neural oscillators networks, in order to investigate the mechanisms of synchronization of the neural oscillatory activity during cognitive processes, such as object recognition, memory, language, attention; 2) the second one concerns the mathematical modelling of multisensory integration processes (e.g. visual-acoustic), which occur in several cortical and subcortical regions (in particular in a subcortical structure named Superior Colliculus (SC)), and which are fundamental for orienting motor and attentive responses to external world stimuli. This activity has been realized in collaboration with the Center for Studies and Researches in Cognitive Neuroscience of the University of Bologna (in Cesena) and the Department of Neurobiology and Anatomy of the Wake Forest University School of Medicine (NC, USA). PART 1. Objects representation in a number of cognitive functions, like perception and recognition, foresees distribute processes in different cortical areas. One of the main neurophysiological question concerns how the correlation between these disparate areas is realized, in order to succeed in grouping together the characteristics of the same object (binding problem) and in maintaining segregated the properties belonging to different objects simultaneously present (segmentation problem). Different theories have been proposed to address these questions (Barlow, 1972). One of the most influential theory is the so called “assembly coding”, postulated by Singer (2003), according to which 1) an object is well described by a few fundamental properties, processing in different and distributed cortical areas; 2) the recognition of the object would be realized by means of the simultaneously activation of the cortical areas representing its different features; 3) groups of properties belonging to different objects would be kept separated in the time domain. In Chapter 1.1 and in Chapter 1.2 we present two neural network models for object recognition, based on the “assembly coding” hypothesis. These models are networks of Wilson-Cowan oscillators which exploit: i) two high-level “Gestalt Rules” (the similarity and previous knowledge rules), to realize the functional link between elements of different cortical areas representing properties of the same object (binding problem); 2) the synchronization of the neural oscillatory activity in the γ-band (30-100Hz), to segregate in time the representations of different objects simultaneously present (segmentation problem). These models are able to recognize and reconstruct multiple simultaneous external objects, even in difficult case (some wrong or lacking features, shared features, superimposed noise). In Chapter 1.3 the previous models are extended to realize a semantic memory, in which sensory-motor representations of objects are linked with words. To this aim, the network, previously developed, devoted to the representation of objects as a collection of sensory-motor features, is reciprocally linked with a second network devoted to the representation of words (lexical network) Synapses linking the two networks are trained via a time-dependent Hebbian rule, during a training period in which individual objects are presented together with the corresponding words. Simulation results demonstrate that, during the retrieval phase, the network can deal with the simultaneous presence of objects (from sensory-motor inputs) and words (from linguistic inputs), can correctly associate objects with words and segment objects even in the presence of incomplete information. Moreover, the network can realize some semantic links among words representing objects with some shared features. These results support the idea that semantic memory can be described as an integrated process, whose content is retrieved by the co-activation of different multimodal regions. In perspective, extended versions of this model may be used to test conceptual theories, and to provide a quantitative assessment of existing data (for instance concerning patients with neural deficits). PART 2. The ability of the brain to integrate information from different sensory channels is fundamental to perception of the external world (Stein et al, 1993). It is well documented that a number of extraprimary areas have neurons capable of such a task; one of the best known of these is the superior colliculus (SC). This midbrain structure receives auditory, visual and somatosensory inputs from different subcortical and cortical areas, and is involved in the control of orientation to external events (Wallace et al, 1993). SC neurons respond to each of these sensory inputs separately, but is also capable of integrating them (Stein et al, 1993) so that the response to the combined multisensory stimuli is greater than that to the individual component stimuli (enhancement). This enhancement is proportionately greater if the modality-specific paired stimuli are weaker (the principle of inverse effectiveness). Several studies have shown that the capability of SC neurons to engage in multisensory integration requires inputs from cortex; primarily the anterior ectosylvian sulcus (AES), but also the rostral lateral suprasylvian sulcus (rLS). If these cortical inputs are deactivated the response of SC neurons to cross-modal stimulation is no different from that evoked by the most effective of its individual component stimuli (Jiang et al 2001). This phenomenon can be better understood through mathematical models. The use of mathematical models and neural networks can place the mass of data that has been accumulated about this phenomenon and its underlying circuitry into a coherent theoretical structure. In Chapter 2.1 a simple neural network model of this structure is presented; this model is able to reproduce a large number of SC behaviours like multisensory enhancement, multisensory and unisensory depression, inverse effectiveness. In Chapter 2.2 this model was improved by incorporating more neurophysiological knowledge about the neural circuitry underlying SC multisensory integration, in order to suggest possible physiological mechanisms through which it is effected. This endeavour was realized in collaboration with Professor B.E. Stein and Doctor B. Rowland during the 6 months-period spent at the Department of Neurobiology and Anatomy of the Wake Forest University School of Medicine (NC, USA), within the Marco Polo Project. The model includes four distinct unisensory areas that are devoted to a topological representation of external stimuli. Two of them represent subregions of the AES (i.e., FAES, an auditory area, and AEV, a visual area) and send descending inputs to the ipsilateral SC; the other two represent subcortical areas (one auditory and one visual) projecting ascending inputs to the same SC. Different competitive mechanisms, realized by means of population of interneurons, are used in the model to reproduce the different behaviour of SC neurons in conditions of cortical activation and deactivation. The model, with a single set of parameters, is able to mimic the behaviour of SC multisensory neurons in response to very different stimulus conditions (multisensory enhancement, inverse effectiveness, within- and cross-modal suppression of spatially disparate stimuli), with cortex functional and cortex deactivated, and with a particular type of membrane receptors (NMDA receptors) active or inhibited. All these results agree with the data reported in Jiang et al. (2001) and in Binns and Salt (1996). The model suggests that non-linearities in neural responses and synaptic (excitatory and inhibitory) connections can explain the fundamental aspects of multisensory integration, and provides a biologically plausible hypothesis about the underlying circuitry.

Testo e memoria tra semiotica e scienze cognitive: una situazione sperimentale intorno al ricordo di un film

The research project presented in this dissertation is about text and memory. The title of the work is "Text and memory between Semiotics and Cognitive Science: an experimental setting about remembering a movie". The object of the research is the relationship between texts or "textuality" - using a more general semiotic term - and memory. The goal is to analyze the link between those semiotic artifacts that a culture defines as autonomous meaningful objects - namely texts - and the cognitive performance of memory that allows to remember them. An active dialogue between Semiotics and Cognitive Science is the theoretical paradigm in which this research is set, the major intend is to establish a productive alignment between the "theory of text" developed in Semiotics and the "theory of memory" outlined in Cognitive Science. In particular the research is an attempt to study how human subjects remember and/or misremember a film, as a specific case study; in semiotics, films are “cinematographic texts”. The research is based on the production of a corpus of data gained through the qualitative method of interviewing. After an initial screening of a fulllength feature film each participant of the experiment has been interviewed twice, according to a pre-established set of questions. The first interview immediately after the screening: the subsequent, follow-up interview three months from screening. The purpose of this design is to elicit two types of recall from the participants. In order to conduce a comparative inquiry, three films have been used in the experimental setting. Each film has been watched by thirteen subjects, that have been interviewed twice. The corpus of data is then made by seventy-eight interviews. The present dissertation displays the results of the investigation of these interviews. It is divided into six main parts. Chapter one presents a theoretical framework about the two main issues: memory and text. The issue of the memory is introduced through many recherches drown up in the field of Cognitive Science and Neuroscience. It is developed, at the same time, a possible relationship with a semiotic approach. The theoretical debate about textuality, characterizing the field of Semiotics, is examined in the same chapter. Chapter two deals with methodology, showing the process of definition of the whole method used for production of the corpus of data. The interview is explored in detail: how it is born, what are the expected results, what are the main underlying hypothesis. In Chapter three the investigation of the answers given by the spectators starts. It is examined the phenomenon of the outstanding details of the process of remembering, trying to define them in a semiotic way. Moreover there is an investigation of the most remembered scenes in the movie. Chapter four considers how the spectators deal with the whole narrative. At the same time it is examined what they think about the global meaning of the film. Chapter five is about affects. It tries to define the role of emotions in the process of comprehension and remembering. Chapter six presents a study of how the spectators account for a single scene of the movie. The complete work offers a broad perspective about the semiotic issue of textuality, using both a semiotic competence and a cognitive one. At the same time it presents a new outlook on the issue of memory, opening several direction of research.

The Simon effect and its time courses: an investigation

The objective of the current thesis is to investigate the temporal dynamics (i.e., time courses) of the Simon effect, both from a theoretical and experimental point of view, for a better understanding of whether a) one or more process are responsible for the Simon effect and b) how this/these mechanism/s differently influence performance. In the first theoretical (i.e., “Theoretical Overview”) part, I examined in detail the process and justification for analyzing the temporal dynamics of the Simon effect and the assumptions that underlie interpretation of the results which have been obtained in the existing literature so far. In the second part (“Experimental Investigations”), though, I experimentally investigated several issues which the existing literature left unsolved, in order to get further evidence in favor or in contrast with the mainstream models which are currently used to account for the different Simon effect time courses. Some points about the experiments are worth mentioning: First, all the experiments were conducted in the laboratory, facing participants with stimuli presented on a PC screen and then recording their responses. Both stimuli presentation and response collection was controlled by the E-Prime software. The dependent variables of interest were always behavioral measures of performance, such as velocity and accuracy. Second, the most part of my experiments had been conducted at the Communication Sciences Department (University of Bologna), under Prof. Nicoletti’s supervision. The remaining part, though, had been conducted at the Psychological Sciences Department of Purdue University (West Lafayette, Indiana, USA), where I collaborated for one year as a visiting student with Prof. Proctor and his team. Third, my experimental pool was entirely composed by healthy and young students, since the cognitive functioning of elderly people was not the target of my research.