Neuropsychological and behavioral studies on object grasping in humans with and without vision

Sensorimotor transformations are used to translate sensory information on intrinsic properties of objects (i.e., size, shape, orientation) onto motor commands for appropriate hand-object interaction. Hence, the direct result of sensorimotor transformation for reach-to-grasp action is hand kinematics (hand shaping) fitting with the object size. We assembled and evaluated a sensor-based glove to measure finger flexion during reaching of differently sized cylinders. Once ensured of the good functioning of the tool, we adopt the glove in two studies dealing with grasping with and without vision. The first study aimed to causally draw a functional map of PMC for visually-based grasping. Specifically, online TMS was applied over a grid covering the whole precentral gyrus while subjects grasped three differently sized cylinders. Output from our sensor glove was analyzed with a hypothesis-independent approach using classification algorithms. Results from classifiers convincingly suggested a multifocal representation of visually-based grasping in human PMC involving the ventral PMC and, for the first time in human, the supplementary motor area. The second study aimed to establish whether the gaze direction modulated hand shaping during haptically-based reaching as it does during visually-based reaching. Participants haptically explored and then grasped an object of three possible sizes aligned with body midline while looking in the direction of the object or laterally to it. Results showed that gaze direction asymmetrically affected finger flexion during haptically-based reaching. Despite this asymmetrical effect, the investigation provided evidence for retinotopic coding of haptically-explored objects

Attentional networks and mindfulness: investigations through multiple indexes

A reciprocal relation between attention and awareness is crucial for adaptive behavior. However, for investigating these relationships could be important to take into consideration the different components that constitute the attentional system. According to Posner and Petersen’ model (Posner, 1994; Posner and Petersen, 1990), three different cognitive functions could be distinguished in human attention which are sub-served by three independent (although coordinated) neural systems: alerting responses, orienting to sensory stimulation and executive control of performance. The Alerting network is aimed at achieving and maintaining a state of high sensitivity to incoming stimuli and is related to the performance in tasks that involve both phasic and tonic alertness; the Orienting network is involved in the selection of information from the sensory input; the Executive control network is defined as involving the mechanisms for resolving cognitive conflict. As mindfulness meditation has been described as “the intentional cultivation of a non-judgmentally awareness that arise through paying attention, on purpose, in the present moment” (Kabat-Zinn, 1990; Kabat-Zinn, 2003), a putative candidate mechanism for its effects is a modification in attentional processing. This doctoral dissertation analyses the influence of mindfulness meditation on attentional performance. More specifically, in Chapter 1, theories and models of attention are introduced subdivided in four macro areas: Selective attention, Divided attention, Search and Signal detection and vigilance. In addition, Posner’s model of attention is presented as the main core of this final work. This model, one of the most influent in attention literature, postulates that distinct areas of the brain underlie distinct attentional processes. In 2002, Fan and collaborators developed the Attention Network Test (ANT) in order to measure these attentional functions separately. Finally, a series of evolutions of this task, that have been proposed and developed in the last decades, are described in detail. In Chapter 2, mindfulness definition is introduced together with its historical background. Buddhist roots and Western Psychology overlap in theory and practice. Operational definition and the three-component model of mindfulness are important constructs that permit us to specify each component in terms of specific behaviors, experiential manifestations, and implicated psychological processes (Bishop et al., 2004). Furthermore, in Western world, mindfulness-based interventions are becoming widely accepted methods of addressing the symptoms associated with many commonly experienced mental health problems and/or emotional disorders. Although these approaches involve mindfulness techniques, there are small differences between each modality that are here described in detail. Moreover, self-report assessments of mindfulness are convenient and efficient and can provide reliable and valid information if they are well constructed for the populations in which they will be used. The most important mindfulness questionnaires are described, highlighting the assessment used in this dissertation: the Five Facet Mindfulness Questionnaire (FFMQ; Baer et al., 2006). Finally, neuroscience of mindfulness is introduced as a new way to explore whether and how our brain is affected by this kind of practice. In Chapter 3, two experiments are presented. The main goal of Experiment 1 is to investigate attention improvements of Mindfulness-Based Stress Reduction training (MBSR; Kabat-Zinn, 1990) compared to a Control group, using the Attention Network Test for Interactions-Vigilance (ANTI-V; Roca et al., 2011), that includes a direct measure of executive vigilance together with the classical attentional networks, introduced above, with the intent to better understand awareness strategies used by our attentional system. The aim of Experiment 2 is to assess the relationship between mindfulness facets of FFMQ and the Attention Network Test for Interactions-Vigilance. In Chapter 4, two more experiments are presented. The main goal of Experiment 3 is to replicate results from Luna et al., (In preparation). The authors designed a task (Attention Network Test for Interactions and Vigilance - executive and arousal components (ANTI-Vea) that could measure simultaneously the functioning of the typical attentional networks (phasic alertness, orienting and executive control), together with two different components of vigilance (executive –detection of infrequent signals-, and arousal –immediate reaction without response control-). The aim of Experiment 4 is to investigate whether and how FFMQ mindfulness facets interacts with attentional performance using ANTI-Vea task. Finally, a general discussion is presented. The general discussion focuses on overall results from the four experiments introduced above together with limitations and future directions

Gaze direction influences grasping actions towards unseen, haptically explored, objects

Haptic exploration produces mental object representations that can be memorized for subsequent object-directed behaviour. Storage of haptically-acquired object images (HOIs), engages, besides canonical somatosensory areas, the early visual cortex (EVC). Clear evidence for a causal contribution of EVC to HOI representation is still lacking. The use of visual information by the grasping system undergoes necessarily a frame of reference shift by integrating eye-position. We hypothesize that if the motor system uses HOIs stored in a retinotopic coding in the visual cortex, then its use is likely to depend at least in part on eye position. We measured the kinematics of 4 fingers in the right hand of 15 healthy participants during the task of grasping different unseen objects behind an opaque panel, that had been previously explored haptically. The participants never saw the object and operated exclusively based on haptic information. The position of the object was fixed, in front of the participant, but the subject's gaze varied from trial to trial between 3 possible positions, towards the unseen object or away from it, on either side. Results showed that the middle and little fingers' kinematics during reaching for the unseen object changed significantly according to gaze position. In a control experiment we showed that intransitive hand movements were not modulated by gaze direction. Manipulating eye-position produces small but significant configuration errors, (behavioural errors due to shifts in frame of reference) possibly related to an eye-centered frame of reference, despite the absence of visual information, indicating sharing of resources between the haptic and the visual/oculomotor system to delayed haptic grasping

Coherent absorption and enhanced photoluminescence in thin layers of nanorods

We demonstrate a large light absorptance (80%) in a nanometric layer of quantum dots in rods (QRs) with a thickness of 23 nm. This behavior is explained in terms of the coherent absorption by interference of the light incident at a certain angle onto the very thin QR layer. We exploit this coherent light absorption to enhance the photoluminescent emission from the QRs. Up to a seven- and fivefold enhancement of the photoluminescence is observed for p- and s-polarized incident light, respectively.Comment: Physical Review B 201

Thinkacting through liberatory frames: (re)imagining the academy beyond

After being burnt down by the liberal politics of the university, I call for a (re)imagining of its structure that can offer hope for those seeking a home in academia. This thesis asks the question, “how can we thinkact differently?” by engaging with a plurality of frames that offer grass-roots possibilities for the students, researchers, staff, and faulty members whose identities and politic are often targeted by the reproduction of status quo. I suggest a reaching out unto anarchist, abolitionist, and Indigenous liberatory frames as means of moving beyond the traditions of the neo liberal university, towards emotional, just, and actionable futurities

La astrología y su relación con la mente humana

El objetivo del presente estudio es describir los rasgos de aquellos individuos que creen en la astrología, aclarar si los signos zodiacales ejercen alguna influencia sobre las características psicológicas y determinar también si el fenómeno conocido como profecía autocumplida ejerce un efecto sobre el autoconcepto de los individuos que creen en astrología y conocen su respectivo signo zodiacal. Para ello se ha contado con una muestra de 240 individuos (109 hombres y 131 mujeres). Los instrumentos empleados fueron el test BF-12 y NE-13GT para medir la extraversión, el test NSP-13 para medir el afecto positivo y negativo y el test de creatividad para medir el nivel de creatividad que se atribuían los participantes. Los resultados obtenidos muestran que las mujeres tienden a creer más en la astrología que los hombres; los individuos que creen en la astrología tienden a conocer mejor los rasgos de su respectivo signo zodiacal y, además, tienden a ser más extrovertidos, creativos y proclives a manifestar emociones positivas. Los sujetos con signo Leo resultaron ser más extrovertidos que el resto de los signos zodiacales, mientras que los individuos con signo Capricornio no mostraron diferencias en cuanto a la extraversión en comparación con el resto de los signos. En cuanto a la creatividad no se hallaron diferencias significativas entre los signos. Por último, la creencia en astrología y el conocimiento de las características del propio signo zodiacal no afectaron al autoconcepto. Así se concluye en esta investigación que existen claras diferencias entre los individuos que creen y aquellos que no creen en la astrología, que la relación entre los signos zodiacales y las características psicológicas no es del todo clara y, finalmente, la creencia en astrología y el conocimiento del signo zodiacal no ejerce ninguna influencia sobre las características psicológicas.The aim of the current study is to describe the traits of those individuals that believe in astrology, to clarify if the zodiac signs have any influence on psychological characteristics and determine as well if the phenomenon known as self-fulfilling prophecy exerts an effect over the self-concept of those individuals that believe in astrology and know their respective zodiac sign. For this, a sample of 240 individuals (109 men and 131 females) was used. The instruments utilized for the investigation are the following: the BF-12 and NE-13GT tests to measure extraversion, the NSP-13 test was used to measure Positive and Negative affect, and the creativity test to measure the amount of creativity that the participants attributed to themselves. The results show that women tend to believe more in astrology than men; those individuals that believe in astrology tend to know better the traits that belong to their zodiac sign and, also, tend to be more extroverted, more creative, and prone to exhibit more positive emotions. Subjects with a Leo sign were more extraverted than the rest of signs, while those with a Capricorn sign were as extroverted as the rest of signs. Regarding creativity, there were no statistical differences between the signs. Lastly, belief in astrology and knowledge of those traits associated with the respective zodiac sign, did not affect self-concept. Thus, we conclude in this investigation that there are plain differences between those that believe and those that don’t believe in astrology, that the relationship between psychological traits and zodiac signs isn’t clear and, finally, belief in astrology and knowledge of the zodiac sign doesn’t exert any influence over psychological traits