1,140 research outputs found
Le basi neurali dell’empatia sociale nei processi decisionali economici
No full textDi recente, studi nel campo delle neuroscienze sociali hanno esplorato i processi neurali che sottostanno al fenomeno dell’empatia. Ci riferiamo, con il termine empatia, alla capacità di comprendere e condividere lo stato mentale, in particolare affettivo ed emotivo, di un’altra persona.
E’ ormai riconosciuto che gli stati emotivi giocano un ruolo importante sui processi decisionali di tipo economico. Invece, pochi studi hanno investigato il ruolo e l’influenza dell’empatia sui processi decisionali.
Nell’ambito delle neuroscienze sociali, il paradigma sperimentale dell’Ultimatum Game (UG), viene usato per studiare le relazioni tra le componenti emotive umane e l’ economia.
Nell’UG, un giocatore (proponente) sceglie come dividere una somma di denaro tra sè e un altro giocatore. Il secondo giocatore (ricevente) può accettare o rifiutare l’offerta. In caso accetti, entrambi ricevono la somma pattuita, in caso contrario nessuno dei due riceve denaro.
Lo scopo del nostro studio è quello di investigare i substrati neurali dell’empatia sociale nell’ambito di processi decisionali di tipo economico; a questo fine, abbiamo utilizzato la tecnica della risonanza magnetica funzionale ed un protocollo sperimentale in cui i nostri volontari giocavano nel ruolo del ricevente, mentre il proponente (fittizio) era rappresentato o da A) un’anziana con pensione minima, o da B) una manager/direttrice d’azienda. Nella nostra versione dell’UG, tutti i giocatori erano donne; la nostra condizione di controllo era rappresentata dal proponente ‘computer’, . Abbiamo diviso le offerte in tre categorie: eque,inique e intermedie.
Abbiamo testato l’ipotesi che l’identità (in particolare età e status sociale) del proponente, influenzi la percentuale di accettazione delle offerte e moduli l’attività neurale del ricevente. Inoltre abbiamo raccolto dati sul grado di empatia del ricevente, sia generica, sia riferita specificatamente alle singole categorie di proponenti.
I dati comportamentali mostrano che la percentuale di accettazione è significativamente maggiore per il proponente A rispetto agli altri proponenti, sia per le offerte intermedie che inique (p<0.001), mentre le offerte eque hanno una percentuale di accettazione simile (alta) per i differenti proponenti.
I dati funzionali mostrano, invece, un quadro molto complesso in cui alcune regioni sembrano essere correlate all'identità del proponente in quanto tale, o correlate al grado di empatia e alla percentuale di accettazione. Queste regioni sono: la corteccia prefrontale dorso laterale (DLPFC), il precuneo/corteccia cingolata posteriore (PC/PCC) e l’insula.
Abbiamo inoltre condotto un analisi di connettività funzionale, usando un modello di interazioni psico-fisiologiche (PPI), per esplorare i vari modelli di interazione tra queste stesse regioni nelle differenti condizioni proposte dal nostro paradigma sperimentale.
I nostri dati supportano fortemente l’ipotesi che le scelte di tipo economiche siano influenzata da processi di empatia sociale, ed estendono le attuali conoscenze sui substrati neurali degli effetti delle interazioni sociali sui processi decisionali.In recent years, social neuroscience has begun to shed light on the neural underpinnings of the phenomenon of empathy. We refer to empathy as the capacity to share the mental, and especially affective states of another person.
It is now well established that emotional states play an important role in the economic decision-making process. However, very little is known about how decision-making processes are modulated by empathy.
In the Ultimatum Game (UG) protocol, a player (proposer) proposes to split a certain amount of money, and the other player (responder) can accept or reject the offer. In case the responder accepts, they both get the money, otherwise no one gets nothing. We performed functional magnetic resonance imaging of UG responders, when (fictitious) proposers were presented as either A) old-age retirees living on a small pension, or B) well-to do businesswomen/professionals, to investigate the neural substrates of social empathic processes involved in economic decision-making.
In our version of the UG, all human players were female. The control condition were offers by computer. Offers were categorized as fair, mid-value or unfair. We tested the hypothesis that the identity (age, social status) of the proposer affects the acceptance rates and modulates brain activity of the responder. We also collected data on the degree of empathy shown by the responder, either in general, and specifically towards the proponents.
On the behavioural point of view, we found that acceptance rates were significantly higher when the proposers were old age retirees than for the other proposers, both for unfair and mid-value offers (p<0.001), whereas fair offers had similar (high) acceptance rates for all proposers.
Functional magnetic data gave us a complex picture, in which some brain regions appear especially related to the identity of the proposer, either per se or depending on empathy scores and acceptance rates; there regions were dorsolateral prefrontal cortex (DLPFC), precuneus/posterior cingulated cortex (PC/PCC), and insula.
Furthermore, we used functional connectivity analyses, using a psycho-physiological interactions model (PPI), to explore the different patterns of interactions between these same regions in the different conditions proposed by our task.
Our data strongly support the hypothesis that economic decisions are affected by social empathic processes, and extend the current understanding of the neural substrates of social interaction effects in decision-making
Interview with Armando Hugo Ortiz Guerrero
No full textCathy Ragland interviews music historian and author, Armando Hugo Ortiz Guerrero.https://scholarworks.utrgv.edu/cathyraglandrec/1003/thumbnail.jp
Leggere il tempo. Conversazione sull’architettura sensibile di Armando Ruinelli
No full textArmando Ruinelli’s forty-year architectural experience, as documented in the recent publication Leggere il tempo, is characterised by its sensitivity and attention to context. Devoid of excess and extravagance, his work establishes a polite dialogue with its surroundings, reflecting the discreet personality of the author. At the core of Ruinelli’s practice lies a profound ethical consideration, extending beyond the design phase to encompass the entire spectrum of operational intricacies. His perspective on time translates into an acceptance of material aging, emphasising the importance of allowing buildings to follow their natural course. Rooted in context, his architecture seeks not only continuity but harmonious integration within the Alpine landscapes they inhabit. In dialogue with the interviewer, Ruinelli emphasises his preference for artisanal work, highlighting the significance of precision in execution and the centrality of humans over materials. His poetic exploration is manifested in creating atmospheres and carefully balancing the dynamic components of a project. Reflecting on the role of the architect, he envisions them as craftsmen endowed with both technical acumen and creative vision. Finally, Ruinelli shares a meaningful project – the fountains in the Soglio cemetery – a creation laden with delicacy and symbolism that underscores the spiritual depth of his work
Cajambre de Armando Romero
No full textThe last novel of the Colombian author Armando Romero takes place in the forest traversed by the river Cajambre, which flows into the Pacific Ocean. In this work, Romero recollect the culture of the Pacific coast, where he had the opportunity to live as a young man, and pays a tribute to African-American women of that area, which have always been the support of local communities. The tragic story of Ruperta allows the author to explore the social dynamics between different sectors of that community, and to investigate the relationships with the white strangers, called «paisas» . It is a strange noire and a tribute to the river, to its people and a personal story describing the wonderful and difficult impressionist landscape of the damp tropical jungle
The spatial resolution of the nociceptive system.
No full textBackground and aims: A systematic study of the spatial resolution of the nociceptive system across different body districts is surprisingly lacking, especially considering the recent description of a fovea for pain at the fingertips (Mancini et al Curr Biol 2013). In this psychophysical study we assessed the spatial acuity of ten body regions, using the two-point discrimination (2PD) of Nd:YAP laser pulses that selectively activate Aδ cutaneous afferents.
Methods: Using two Nd:YAP lasers we delivered either one or two simultaneous pulses (diameter: 1.3 mm) of identical energy on each of the following body sites: forehead, volar forearm, hand dorsum, hand palm, fingertip, shoulder, lower back, upper thigh, calf, and foot dorsum. The 2PD task consisted in judging whether one or two stimuli were delivered, using ascending and descending staircases of varying spatial distance between the two pulses. Single stimuli were included as catch trials. All stimuli elicited a clear pinprick sensation related to the activation of Aδ afferents.
Results: We found a proximal-distal gradient of spatial acuity for nociceptive stimuli, with higher acuity for proximal stimuli, an observation in agreement with innervation density of skin nociceptors and perceptual threshold of Aδ stimuli. Two distal regions (fingertips and palm) represented an exception, and showed maximal spatial acuity (see also Mancini et al., 2013).
Conclusions: This study provides the first systematic description of spatial acuity of the nociceptive system across the entire body in healthy participants
Short echo-time 3D-TSE with and without VASO preparation: functional MRI
No full textPurpose: Short echo time (shTE) turbo-spin echo (TSE) pulse sequences are considered very weakly sensitive to blood oxygenation level dependent (BOLD) signal changes, and have been proposed to avoid cancellation of functional responses in blood nulled vascular space occupancy (VASO) fMRI studies where task-related increases in blood volume lead to decreases in signal (1,2). A positive functional contrast in shTE TSE studies has, however, been reported by some authors and attributed to changes in extravascular water distribution termed SEEP (3). Our purpose was to determine whether functional contrast in shTE TSE-based VASO experiments might be contaminated by BOLD or SEEP effects.
Methods: A 3D-TSE sequence without (shTE TSE; TE/TR/TDyn 8.5ms/2400ms/9.6s, FOV: 210x52x12mm, Matrix 160x40x8, Refocussing Angle 180deg, Turbo factor 80, echo spacing 8.5ms, 70 dynamics, centre-out sampling) and with blood-nulling (VASO; TI 600ms) was used to acquire image series from the hand sensorimotor area of the cerebral cortex during a block-design finger tapping task (block duration 48s, 9 blocks). The inversion time assumed suppression of longitudinal relaxation during the TSEecho train. For comparison purposes, a BOLD-sensitive gradient-echo EPI series was also obtained (TE/TR/TDyn 35ms/3000ms/3s, FOV: 230x230x120, Matrix 64x64x30, Excitation Flip Angle 90deg, 70 dynamics) with the same task. The finger tapping task was self-paced left-hand finger tapping, and controlled via auditory commands.
fMRI time-series were motion-corrected, and an independent component analysis (MELODIC, fsl) used to identify 7 components for denoising prior to a glm (FEAT, fsl) with a single regressor convolved with the default hemodynamic response function. Spatial smoothing was limited to a 1.5mm FWHM. Voxels were considered to show a significant functional response using a p-value < 0.005 with cluster-wise correction for multiple comparisons. We present results from the first 2 subjects who participated in the study.
Results: Functional responses were found using both variants of the shTE TSE sequence within the area of BOLD response seen with conventional EPI-based fMRI. The spatial correspondence of responses was striking (Figures 1a and 1b), but having an inverted response when blood-nulling is applied (Figure 1c; bars indicate task blocks). The sequences yielded similar maximum functional contrast to noise ratios of 4.0 and 4.6 (on % signal changes of 0.98% and 3.6%) without and with blood-nulling respectively.
Discussion: The inverted functional response when blood-nulling is applied indicates the expected VASO changes. The robust functional contrast in shTE TSE without blood nulling may also be consistent with this effect, but our results are not sufficient to exclude contributions from SEEP, or BOLD that would run counter to the VASO contrast in blood-nulled measurements. The functional contrast to noise ratio in both cases are similar. Nonetheless, the small fractional signal change in the non-nulled case suggests that BOLD and SEEP and inflow effects make only minor contributions. The 3D TSE strategy used here is hampered by limited spatial coverage and low temporal efficiency relative to conventional EPI. Improvements are likely possible however, as we have not made use of parallel imaging techniques, nor pursued extremely long echo trains that may reduce scan time.
References: 1. Stroman P, et al. Magnetic Resonance in Medicine 49:433–439 (2003). 2. Cretti F, et al. ESMRMB 2009 187. 3. Poser B, Norris D. Magn Reson Mater Phy (2007) 20:63–67
Comparison of tissue occupancy functional contrasts for 3D turbo-spin-echo acquisition
No full textIntroduction:
Functional vascular occupancy imaging has demonstrated task correlated MR signal changes using
inversion recovery (IR) prepared images, where the inversion time (TI) has been chosen to selectively
null blood (vascular space occupancy – VASO, (Lu et al., 2003)), grey matter (VASO by tissue
suppression – VAST (Wu et al., 2008)), or CSF (VASO-FLAIR (Donahue et al., 2006)). Weakness of these
approaches are that functional responses may not be due to volume changes in a single tissue
compartment, and that the underlying imaging sequence may be sensitive to other mechanisms (e.g.
BOLD) (Donahue et al., 2006). Our purpose was to compare the functional responses from different
vascular space occupancy preparations of a short TE turbo-spin echo (TSE) sequence.
Methods:
Eight healthy subjects were scanned at 3T after providing informed consent. The task consisted of
self-paced, left-hand finger tapping.
Four variants of vascular occupancy fMRI were tested: VASO (TI = 646ms), VAST (TI = 578ms),
VASO-FLAIR (TI = 781ms) and nonInVASO (no inversion pulse VASO), all based on a 3D TSE acquisition
(TE/TR 8.4ms/2.4s, 4 shots, time per volume 9.6s, 1.5x1.5x1.5mm, 8 slices, FOV 222x60x12mm, 180°
refocusing pulses, ant/post sat bands). Task blocks were 48s long, and each run consisted of 45
volumes, with the sequence order varied between subjects. These scans were centered on the focus of
BOLD response in/adjacent to the right hand knob detected with an EPI acquisition (TE/TR 30ms/3s,
3x3x3mm, 42 slices) performed during execution of the same task (30 second blocks, 70 volumes).
Whole-brain T2, 3D T1, and nonInVASO images were also obtained.
GLM analysis (1.5mm FWHM smoothing, high pass filter cut-off 100s, default gamma-variate hrf,
GRF-based voxel-wise corrected p<0.05) was per formed following motion correction and ICA denoising
(4 components) using fsl (v 5.0.1). Due to slight rotations during acquisition, only 6 slices were
retained for analysis.
Results:
Despite operator confirmation of task performance, one subject showed minimal BOLD and no significant
vascular occupancy responses, and was therefore excluded from analysis. In the other subjects, VASO,
VAST and VASO-FLAIR showed nearly identical patterns and locations of activity (Figure 1) and no
significant differences in the grey matter (GM), white matter, CSF distribution of activated voxels. The
nonInVASO scans showed smaller volumes of activity. GM was the predominant site of response for all
scans.
VAST yielded the highest % signal changes; VASO yielded the highest z-score followed closely by
VASO-FLAIR; and these all had signal changes negatively correlated with the task. The nonInVASO
responses correlated positively with the task and were the smallest % signal change and maximum
z-scores roughly one-third lower than VASO. Significant oppositely-signed responses (i.e. positive of
VASO, VAST and VASO-FLAIR, negative for nonInVASO) were not observed.Conclusions:
Our results suggest that VASO, VAST and VASO-FLAIR are sensitive to volume changes in the same
tissue compartment. VAST yielded the highest % signal changes due mainly to the smallest baseline
signal but this did not result in greater sensitivity to activation as indicated by maximum z-scores. The
negative VAST response however, suggests that the inversion was not fully optimized to grey matter but
could reflect T2 blurring of white matter signal. VASO was the most sensitive to activation followed
closely by VASO-FLAIR. Similarly located activations were seen with nonInVASO, but with smaller spatial
extents and lower sensitivity.
The implications and operative mechanism for the nonInVASO functional contrast remain to be
established. Possible mechanisms include BOLD contrast (through T2 sensitivity or blurring by the long
TSE echo train), vascular space occupancy changes coupled with inherent blood-tissue contrast,
diffusion, or changes within the tissue compartment as proposed for SEEP - signal enhancement by
extravascular protons (Stroman et al, 2003)
Functional connectivity of frontal components of the human mirror system: a PPI study.
No full textIntroduction
Great attention has been paid to the human mirror system (MNS) in recent years (Caspers et al., 2010; Rizzolatti & Sinigaglia 2010); among the peculiarities of the human MNS, the fact that it responds to action observation even in the absence of a target object (Lui et al., 2008). However, so far few studies have dealt with the functional connectivity of the components of this system (Skippers et al., 2007; Hattori et al., 2009; Xu et al., 2009; Emmorey et al., 2010). With the present work, we aimed at revealing patterns of connectivity of ventral premotor cortex/dorsal BA44 (PMv) and Broca area (BA44/45) during the observation of different types of gestures: Symbolic (SY) and Grasping (GR).
Methods
Twenty healthy right-handed volunteers (8 males, 12 females; mean age 26.6) took part in this study. An event-related paradigm was adopted. A continuous video was presented, showing some common objects (glasses, cup, scissors, etc.) on a table. At intervals, an actor, of whom only the trunk and arms were visible, performed different kinds of hand movements: a) SY: non-object related symbolic actions (OK, hello, etc.); b) GR: grasping of an object. Three runs were carried out for each subject. Six movements for each class were shown in each run, alternated in pseudorandom order; each single movement was presented only once to each volunteer. Functional imaging was performed on a 3T Philips Intera scanner. Twenty-four axial slices were acquired (in-plane matrix: 64x64; TR: 2515 ms; voxel size: 3.75x3.75x4 mm, with a 0.6 mm gap between contiguous slices). Data analysis was carried out using SPM5.
After a conventional GLM analysis, we assessed changes in functional connectivity related to the SY and GR observation tasks, by means of two separate PsychoPhysiologic Interaction (PPI) analyses (Friston et al., 1997). Foci in the right PMv and left BA44/45, identified by the conventional GLM analyses, were the seed regions. Group analyses were performed by random-effect models.
Results
Activity in right PMv during the observation of SY was positively related to activity in bilateral regions in posterior (occipito-temporo-parietal) cortex and cerebellum; during the observation of GR, the pattern was similar, but an additional correlated focus was present in the right inferior and middle frontal gyri, BA44/45/46 (Fig. 1).
Activity in left BA44/45 during the observation of SY was positively related to activity in two foci: a larger focus in the left inferior and middle frontal gyri, mainly in BA45/46/47, and a second focus in the medial and superior frontal gyri, BA6/8, also mostly in the left hemisphere (Fig. 2). During the observation of GR, a very different pattern was present, with extensive bilateral clusters in sensorimotor and premotor cortex (mainly BA3/4/6/7 and BA6/8).
Conclusions
The present data suggest that right PMv and left Broca area are parts of different functional networks, differentially active during the observation of different meaningful arm-hand actions. The PMv connections to a mainly visual network during the observation of symbolic, intransitive movements are probably related to extracting visuo/spatial features of the observed scene; only during observation of grasping, PMv relates to the inferior frontal gyrus. On the other hand, the left Broca area has a specific pattern of connectivity with premotor regions involved in higher-order motor programming during the observation of symbolic gestures.
References
Caspers, S. et al. (2010), 'ALE meta-analysis of action observation and imitation in the human brain', NeuroImage, vol. 50, pp. 1148-1167.
Emmorey, K. et al. (2010), ‘CNS activation and regional connectivity during pantomime observation: no engagement of the mirror neuron system for deaf signers’, Neuroimage vol. 49, pp. 994-1005.
Hattori, N. et al. (2009), ‘Discrete parieto-frontal functional connectivity related to grasping’, Journal of Neurophysiology, vol. 101, pp. 1267-1282.
Lui, F. et al. (2008), ‘Neural substrates for observing and imagining non-object-directed actions’, Social Neuroscience, vol. 3, pp.261-275.
Rizzolatti, G. & Sinigaglia, C. (2010), ‘The functional role of the parieto-frontal mirror circuit: interpretations and misinterpretations’, Nature Reviews Neuroscience, vol. 11, pp. 264-274.
Skipper, J.I. et al. (2007), ‘Speech-associated gestures, Broca's area, and the human mirror system’, Brain and Language, vol. 101, pp. 260-277.
Xu, J. et al. (2009), ‘Symbolic gestures and spoken language are processed by a common neural system’, Proceedings of the National Academy of Sciences U S A, vol. 106, pp. 20664-20669
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