1,721,031 research outputs found
Still controversial issues on assessing anhedonia in experimental modeling of depression
Full text linkElevated levels of serotonin 5-HT2A receptors in the orbitofrontal cortex of antisocial individuals
No full textAntisocial behavior (ASB) is characterized by frequent violations of the rights and properties of others, as well as aggressive conduct. While ample evidence points to a critical role of serotonin in the emotional modulation of social responses, the implication of this neurotransmitter in ASB is unclear. Here, we performed the first-ever postmortem analysis of serotonergic markers in the orbitofrontal cortex (OFC) of male subjects with ASB (n = 9). We focused on this brain region, given its well-recognized role in social response and ASB pathophysiology. Given that all individuals also had a substance use disorder (SUD) diagnosis, two age-matched control groups were used: SUD only and unaffected controls. Tissues were processed for immunoblotting analyses on eight key serotonergic targets: tryptophan hydroxylase 2 (TPH2), the rate-limiting enzyme of brain serotonin synthesis; serotonin transporter (SERT), the primary carrier for serotonin uptake; monoamine oxidase A (MAOA), the primary enzyme for serotonin catabolism; and five serotonin receptors previously shown to influence social behavior: 5-HT1A, 5-HT1B, 5-HT2A, 5-HT2C, and 5-HT4. Our analyses documented a significant increase in 5-HT2A receptor levels in the ASB + SUD group compared to SUD-only controls. Furthermore, TPH2 levels were significantly reduced in the SUD group (including SUD only and ASB + SUD) compared to unaffected controls. No difference was detected in the expression of any other serotonergic target. These results are in keeping with previous evidence showing high 5-HT2A receptor binding in the OFC of pathologically aggressive individuals and point to this molecule as a potential target for ASB treatment
A vibrotactile bracelet to improve the navigation of older adults in large and crowded environments
No full textThe decline of the cognitive abilities related to age usually determines a gradual withdrawal of older adults within the domestic walls. Part of the problem is the difficulty in navigating in large and crowded environments thatmay be perceived as intimidating. To alleviate this problem, we propose a vibrotactile device which can be used along with a walking assistant endowed with autonomous sensing and active brakes able to guide the user. In this paper, we address the problem of guiding the user with a minimal impact on his/her freedom of motion. We propose a solution based on the use of vibrotactile feedback to display directional cues. Psychophysical tests performed on a group of older adults show the effectiveness of the proposed vibrotactile strategy for the navigation of elderly people
KCT: a MATLAB toolbox for motion control of KUKA robot manipulators
No full textThe Kuka Control Toolbox (KCT) is a collection of MATLAB functions for motion control of KUKA robot manipulators, developed to offer an intuitive and high-level programming interface to the user. The toolbox, which is compatible with all 6 DOF small and low payload KUKA robots that use the Eth.RSIXML, runs on a remote computer connected with the KUKA controller via TCP/IP. KCT includes more than 30 functions, spanning operations such as forward and inverse kinematics computation, point-to-point joint and Cartesian control, trajectory generation, graphical display and diagnostics. The flexibility, ease of use and reliability of the toolbox is demonstrated through two applicative examples
The steroidogenic inhibitor finasteride reverses pramipexole-induced alterations in probability discounting
Full text linkPramipexole is a potent agonist of D3 and D2 dopamine receptors, currently approved for clinical use in Parkinson's disease (PD) and restless leg syndrome. Several studies have shown that pramipexole significantly increases the risk of pathological gambling and impulse-control disorders. While these iatrogenic complications can impose a severe social and financial burden, their treatment poses serious clinical challenges. Our group previously reported that the steroidogenic inhibitor finasteride reduced pathological gambling severity in PD patients who developed this complication following pramipexole treatment. To study the mechanisms underlying these effects, here we tested the impact of finasteride in a rat model of pramipexole-induced alterations of probability discounting. We previously showed that, in rats exposed to low doses of the monoamine-depleting agent reserpine (1 mg/kg/day, SC), pramipexole (0.3 mg/kg/day, SC) increased the propensity to engage in disadvantageous choices. This effect was paralleled by a marked D3 receptor upregulation in the nucleus accumbens. First, we tested how finasteride (25–50 mg/kg, IP) intrinsically affects probability discounting. While the highest dose of finasteride produced a marked lack of interest in lever pressing (manifested as a significant increase in omissions), the 25 mg/kg (IP) dose did not intrinsically modify probability discounting. However, this finasteride regimen significantly reduced the adverse effects of reserpine and pramipexole in probability discounting by diminishing rats' propensity to engage in highly disadvantageous probabilistic choices. The same regimen also reversed the upregulation of D3 receptors in the nucleus accumbens induced by reserpine and pramipexole. These findings confirm that finasteride opposes the impulsivity caused by pramipexole and suggest that this effect may be underpinned by a normalizing effect on D3 receptor expression in the nucleus accumbens
Shape and weight rendering for haptic augmented reality
Full text linkHaptic interfaces in Augmented Reality scenarios are an efficient way to enhance the interaction with a virtual world. We introduce a new system that involves both hands in virtual object experience. We render contemporary shape and weight of a virtual object, merged in a real world environment, using a commercial haptic interface and a new kind of finger-worn device. We test the system with an experimental setup where a virtual cube is placed over a real marker. The system developed can be used in several applications of augmented reality where rendering only the object shape is not enough to perceive the virtual world. It can also lead towards the introduction of more wearable devices in the haptics augmented reality context
Repeated acetyl-L-carnitine administration increases phospho-Thr34 DARPP-32 levels and antagonizes cocaine-induced increase in Cdk5 and phospho-Thr75 DARPP-32 levels in rat striatum
No full textAcute cocaine administration increases phosphorylation of dopamine and cAMP-regulated phosphoprotein (Mr 32 kDa) (DARPP-32) at threonine (Thr)-34, whereas repeated cocaine administration increases DARPP-32 phosphorylation at Thr-75 in rat striatum. Repeated acetyl-L-carnitine (ALCAR) administration persistently increases dopamine outflow in the nucleus accumbens. The present study examined the effect of repeated ALCAR administration on DARPP-32 phosphorylation pattern in the nucleus accumbens and caudate-putamen. ALCAR increased phosphoThr-34 DARPP-32 levels and decreased phosphoThr-75 DARPP-32 levels, after 1 and 10 days of washout. We compared the effects of repeated cocaine and repeated ALCAR administrations on the behavioral response to cocaine challenge and on DARPP-32 phosphorylation pattern and cyclin-dependent kinase 5 (Cdk5) levels in the striatum. We also studied whether ALCAR administered daily during or after cocaine sensitization procedure would interfere with the effects of cocaine. When the response to cocaine challenge was assessed, cocaine- and ALCAR-treated rats showed a similar sensitized behavioral response, and rats receiving combined cocaine and ALCAR treatments, irrespectively of treatment order, also showed a sensitized response. A week after cocaine challenge, the 2 drugs had induced opposite modifications in DARPP-32 phosphorylation, as cocaine increased phosphorylation at Thr-75, while ALCAR increased phosphorylation at Thr-34. In cocaine plus ALCAR treated rats, irrespectively of treatment order, ALCAR administration antagonized cocaine effects on DARPP-32 phosphorylation. Moreover, cocaine, but not ALCAR, increased ΔFosB and Cdk5 expression, and the increase in Cdk5 was antagonized by ALCAR administration in rats receiving combined treatments. These effects were relatively persistent, as they were still present 7 days after the last treatment
Evaluation of a predictive approach in steering the human locomotion via haptic feedback
Full text linkIn this paper, we present a haptic guidance policy
to steer the user along predefined paths, and we evaluate
a predictive approach to compensate actuation delays that
humans have when they are guided along a given trajectory
via sensory stimuli. The proposed navigation policy exploits
the nonholonomic nature of human locomotion in goal directed
paths, which leads to a very simple guidance mechanism.
The proposed method has been evaluated in a real scenario
where seven human subjects were asked to walk along a set of
predefined paths, and were guided via vibrotactile cues. Their
poses as well as the related distances from the path have been
recorded using an accurate optical tracking system. Results
revealed that an average error of 0.24 m is achieved by using
the proposed haptic policy, and that the predictive approach
does not bring significant improvements to the path following
problem for what concerns the distance error. On the contrary,
the predictive approach achieved a definitely lower activation
time of the haptic interfaces
A remote guidance system for blind and visually impaired people via vibrotactile haptic feedback
No full textTrained guide dogs and canes provide the visually impaired with the highest degree of independence; however, they are very limited in guiding the user towards a specific desired location, especially in an unknown environment. The assistance of other people represents a feasible solution, but it does not improve the idea of autonomous guidance and privacy. In this paper we present a remote guidance system which provides the visually impaired with haptic directional cues, useful for navigating in unknown environments. The blind user is equipped with a pair of camera glasses, two vibrotactile bracelets and a cane which is used to avoid potential obstacles. The video captured by the camera glasses is streamed to a remote operator who can properly navigate the impaired person by activating the vibrotactile stimulations. The proposed approach has been validated on a group of blind subjects in an indoor scenario. Results revealed the effectiveness of the proposed strategy for the guidance of visually impaired in unknown environments
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