Effects of Synaptic and Myelin Plasticity on Learning in a Network of Kuramoto Phase Oscillators

Models of learning typically focus on synaptic plasticity. However, learning is the result of both synaptic and myelin plasticity. Specifically, synaptic changes often co-occur and interact with myelin changes, leading to complex dynamic interactions between these processes. Here, we investigate the implications of these interactions for the coupling behavior of a system of Kuramoto oscillators. To that end, we construct a fully connected, one-dimensional ring network of phase oscillators whose coupling strength (reflecting synaptic strength) as well as conduction velocity (reflecting myelination) are each regulated by a Hebbian learning rule. We evaluate the behavior of the system in terms of structural (pairwise connection strength and conduction velocity) and functional connectivity (local and global synchronization behavior). We find that for conditions in which a system limited to synaptic plasticity develops two distinct clusters both structurally and functionally, additional adaptive myelination allows for functional communication across these structural clusters. Hence, dynamic conduction velocity permits the functional integration of structurally segregated clusters. Our results confirm that network states following learning may be different when myelin plasticity is considered in addition to synaptic plasticity, pointing towards the relevance of integrating both factors in computational models of learning.Comment: 39 pages, 15 figures This work is submitted in Chaos: An Interdisciplinary Journal of Nonlinear Scienc

Decay and interference effects in visuospatial short-term memory

No description supplie

Hazard Perception and Demand for Insurance Among Selected Motorcyclists in Lagos, Nigeria

This study examines hazard perception effects on the demand for insurance withspecial focus on motorcycle riders in Lagos state. For this purpose, the researchershave been able to examine selected hazard perception determinants and theireffects on the insuring attitude and desire of motorcycle riders. An explanatoryresearch design was employed and a convenience sampling type of the nonprobabilitysampling technique was adopted.  Data was gathered by interviewsconducted at motorcycle parks along the Lagos-Badagry expressway.  The sampleconsisted of 126 respondents made up of commercial motorcycle riders within thesample areas. Data collected was analysed using multiple regression technique.The study was able to establish some level of contributory linkage between hazardperception and demand for motorcycle insurance. The findings show that whiledread and trust both appeared to have significant effect, publicity and controllabilityboth have positive contributory effect; furthermore, choice expressed an inverserelationship with demand for insurance among the motorcycle riders. The studytherefore recommends pre-loss and post-loss measures among the motorcycleriders so that unforeseen motorcycle risks can be managed. Also, insurancecompanies should endeavour to invest more on enlightening the motorcycle riders in order to lessen their dread of loss outcome, and thus, design policy that can instil trust in motorcycle riders in insurance as a loss control measure

Short-and medium-term plasticity for speaker adaptation seem to be independent

The author wishes to thank James McQueen and Elizabeth Johnson for comments made on an earlier drafts of this paper.In a classic paper, Ladefoged and Broadbent [1] showed that listeners adapt to speakers based on short-term exposure of a single phrase. Recently, Norris, McQueen, and Cutler [2] presented evidence for a lexically conditioned medium-term adaptation to a particular speaker based on an exposure of 40 critical words among 200 items. In two experiments, I investigated whether there is a connection between the two findings. To this end, a vowel-normalization paradigm (similar to [1]) was used with a carrier phrase that consisted of either words or nonwords. The range of the second formant was manipulated and this affected the perception of a target vowel in a compensatory fashion: A low F2-range made it more likely that a target vowel was perceived as a front vowel, that is, with an inherently high F2. Manipulation of the lexical status of the carrier phrase, however, did not affect vowel normalization. In contrast, the range of vowels in the carrier phrase did influence vowel normalization. If the carrier phrase consisted of high-front vowels only, vowel categories shifted only for high-front vowels. This may indicate that the short-term and medium-term adaptations are brought about by different mechanisms.peer-reviewe

Herbal Medicine Perception and Practice Among Childbearing Mother with Medical Education Background in Bandung: a Preliminary Study

Herbal medicine has been widely used among Indonesians as an alternative medicine to chemical based drugs. However, there is still a doubt about its effectiveness and efficiency. Many studies report that natural side of herbal medicine has healthier effect than additive or chemistry ingredient of chemical based drugs. Nowadays, there is a shifting in nurturing children among childbearing mother, including mother with medical education background, living in more nature. The aim of this study is to explore their perception and practice towards herbal medicine. Open-ended questionnaires were online distributed among 30 childbearing mothers with medical education background and analyzed using descriptive method. The result shows that 73% of respondents use herbal medicine such as honey (33.3%), onion (13.3%), lime (13.3%), etc. The less side-effect is a strongest point of their USAges (45%), followed by mild illness treatment (36%), and natural ingredient (18%). Those respondents admitted the symptoms were reduced after using herbal medicine, but 81.6% of them would use chemical drugs when the symptoms persisted. Twenty seven percent of the respondents never used herbal medicine because of complicated preparation and unclear effect. However, the entire respondents said chemical drugs have a clear effect, and its effectiveness and efficiency even better than herbal medicine. Hence, it can be concluded that most respondents even though have medical knowledge would use herbal medicine on first medication for their children rather than chemical based drug

Priscian on Perception

An aporia posed by Theophrastus prompts Priscian to describe the process by which perception formally assimilates to its object as a progressive perfection. I present an interpretation of Priscian’s account of perception’s progressive perfection. And I consider a dilemma for the general class of accounts to which Priscian’s belongs based on related problems raised by Plotinus and Aquinas

I know you are beautiful even without looking at you: discrimination of facial beauty in peripheral vision

Prior research suggests that facial attractiveness may capture attention at parafovea. However, little is known about how well facial beauty can be detected at parafoveal and peripheral vision. Participants in this study judged relative attractiveness of a face pair presented simultaneously at several eccentricities from the central fixation. The results show that beauty is not only detectable at parafovea but also at periphery. The discrimination performance at parafovea was indistinguishable from the performance around the fovea. Moreover, performance was well above chance even at the periphery. The results show that the visual system is able to use the low spatial frequency information to appraise attractiveness. These findings not only provide an explanation for why a beautiful face could capture attention when central vision is already engaged elsewhere, but also reveal the potential means by which a crowd of faces is quickly scanned for attractiveness