Brain, images and imagination: how the brain represents the world

The present work aims to describe the main results obtained from the neuroimaging studies on the study of those cognitive processes related to imaging and imagination. A brief excursus on the development of modern neuroimaging techniques presents the methodological background of the many studies. The relationship between sight, blindness and conceptual representation is explored. Research has shown that the ventro-temporal cortex is responsible for recognizing the surrounding environment, to distinguish an object from a face and, in general, objects’ categorization. This area is responsible of imagery in both sighted and blind people, being its morpho-functional organization independent of the visual experience. It follows that a very precise classification of all categories of objects could be obtained in the human brain, and it is supported by a distributed cortical representation independent from the sensorial modality. The last part of the paper presents a series of studies, in which the study of imagery was related to aggressivity. The prefrontal cortex is deactivated when an individual imagines himself becoming aggressive, being this effect more relevant in females than in males. As a conclusion, the neuroscientific approach produced important results in the definition of what imagery is, and showed its relevance to the study of how mind and brain work

(a cura di) Manuale di tecniche diagnostiche ed esami di laboratorio / Wilson Denise

Il Manuale di Tecniche Diagnostiche ed Esami di Laboratorio di McGraw-Hill illustra in maniera specifica tutto ciò che è necessario conoscere sulla corretta indicazione all'utilizzo e all'interpretazione degli esami diagnostici. Affronta inoltre il tema della preparazione del paziente nelle fasi di esecuzione e che precedono e seguono l'esame, allo scopo di fornirgli un'assistenza scrupolosa e attenta alle diverse normative relative alla sicurezza. Il Manuale, di agile formato e facile consultazione, rappresenta l'unico testo interamente pensato e costruito a partire dalle linee guida della pratica professionale basate sulle evidenze scientifiche, un valido motivo in più per utilizzarlo con successo nella pratica clinica quotidiana

Interactions between auditory statistics processing and visual experience emerge only in late development

The auditory system relies on local and global representations to discriminate sounds. This study investigated whether vision influences the development and functioning of these fundamental sound computations. We employed a computational approach to control statistical properties embedded in sounds and tested samples of sighted controls (SC) and congenitally (CB) and late-onset (LB) blind individuals in two experiments. In experiment 1, performance relied on local features analysis; in experiment 2, performance benefited from computing global representations. In both experiments, SC and CB performance remarkably overlapped. Conversely, LB performed systematically worse than the other groups when relying on local features, with no alterations on global representations. Results suggest that auditory computations tested here develop independently from vision. The efficiency of local auditory processing can be hampered in case sight becomes unavailable later in life, supporting the existence of an audiovisual interplay for the processing of auditory details, which emerges only in late development

Covert brand recognition engages emotion-specific brain networks

Consumer goods' brands have become a major driver of consumers' choice: they have got symbolic, relational and even social properties that add substantial cultural and affective value to goods and services. Therefore, measuring the role of brands in consumers' cognitive and affective processes would be very helpful to better understand economic decision making. This work aimed at finding the neural correlates of automatic, spontaneous emotional response to brands, showing how deeply integrated are consumption symbols within the cognitive and affective processes of individuals. Functional magnetic resonance imaging (fMRI) was measured during a visual oddball paradigm consisting in the presentation of scrambled pictures as frequent stimuli, colored squares as targets, and brands and emotional pictures (selected from the International Affective Picture System [IAPS]) as emotionally-salient distractors. Affective rating of brands was assessed individually after scanning by a validated questionnaire. Results showed that, similarly to IAPS pictures, brands activated a well-defined emotional network, including amygdala and dorsolateral prefrontal cortex, highly specific of affective valence. In conclusion, this work identified the neural correlates of brands within cognitive and affective processes of consumers

Selective Effects of Cholinergic Modulation on Task Performance during Selective Attention

The cholinergic neurotransmitter system is critically linked to cognitive functions including attention. The current studies were designed to evaluate the effect of a cholinergic agonist and an antagonist on performance during a selective visual attention task where the inherent salience of attended/unattended stimuli was modulated. Two randomized, placebo-controlled, crossover studies were performed, one (n=9) with the anticholinesterase physostigmine (1.0 mg/h), and the other (n=30) with the anticholinergic scopolamine (0.4 mc/kg). During the task, two double-exposure pictures of faces and houses were presented side by side. Subjects were cued to attend to either the face or the house component of the stimuli, and were instructed to perform a matching task with the two exemplars from the attended category. The cue changed every 4–7 trials to instruct subjects to shift attention from one stimulus component to the other. During placebo in both studies, reaction time (RT) associated with the first trial following a cued shift in attention was longer than RT associated with later trials (p<0.05); RT also was significantly longer when attending to houses than to faces (p<0.05). Physostigmine decreased RT relative to placebo preferentially during trials greater than one (p<0.05), with no change during trial one; and decreased RT preferentially during the attention to houses condition (p<0.05) vs attention to faces. Scopolamine increased RT relative to placebo selectively during trials greater than one (p<0.05), and preferentially increased RT during the attention to faces condition (p<0.05). The results suggest that enhancement or impairment of cholinergic activity preferentially influences the maintenance of selective attention (ie trials greater than 1). Moreover, effects of cholinergic manipulation depend on the selective attention condition (ie faces vs houses), which may suggest that cholinergic activity interacts with stimulus salience. The findings are discussed within the context of the role of acetylcholine both in stimulus processing and stimulus salience, and in establishing attention biases through top-down and bottom-up mechanisms of attention

Conditional granger causality analysis of fMRI data shows a direct connection from LGN to hMT+ bypassing V1

The human middle temporal complex (hMT+) is devoted to motion perception. To determine whether motion-related neural information may reach hMT+ directly from the thalamus, by-passing the primary visual cortex (V1), we measured effective connectivity in an optic flow fMRI experiment in humans. Conditional Granger Causality analysis was employed to measure direct influences between the lateral geniculate nucleus (LGN) and hMT+, discarding indirect effects mediated by V1. Results indicated the existence of a bilateral alternative pathway for visual motion processing that allows for a direct flow of information from LGN to hMT+. This direct link may play a role in blindsight