We report on the design and modeling of vertical-cavity surface-emitting laser (VCSEL) integrated in the lateral direction with a cascade of multiple passive cavities. The scheme is proposed to ...increase the bandwidth of the VCSEL in the mm-waveband to generate ultra-high-frequency oscillations with low-frequency chirp. The model treats the transverse feedback induced by the cascaded transverse coupled cavities (TTCs) as time delay of the transverse slow light due to round trips in these cavities. The simulation is based on numerical integration of the modified time-delay rate equations of the intensity and phase of the electric field. The simulation results are used to optimize the TCCs parameters, including the coupling ratio and TCC length, for generating ultra-high-frequency signals with high intensity, low chirping and low distortion. The obtained results show that the proposed structure could achieve 300% enhancement of the modulation bandwidth of the C-VCSEL due to either extended carrier-photon resonance (CPR) frequencies of photon–photon resonance (PPR). Signals with frequencies as high as (40–49 GHz) with second-harmonic distortion lower than − 30 dB are presented.
In this article, we argue that motor and cognitive processes are functionally related and most likely share a similar evolutionary history. This is supported by clinical and neural data showing that ...some brain regions integrate both motor and cognitive functions. In addition, we also argue that cognitive processes coincide with complex motor output. Further, we also review data that support the converse notion that motor processes can contribute to cognitive function, as found by many rehabilitation and aerobic exercise training programs. Support is provided for motor and cognitive processes possessing dynamic bidirectional influences on each other.
A neurocomputational model of creative processes Khalil, Radwa; Moustafa, Ahmed A.
Neuroscience & biobehavioral reviews/Neuroscience and biobehavioral reviews,
06/2022, Letnik:
137
Journal Article
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Creativity is associated with finding novel, surprising, and useful solutions. We argue that creative cognitive processes, divergent thinking, abstraction, and improvisation are constructed on ...different novelty-based processes. The prefrontal cortex plays a role in creative ideation by providing a control mechanism. Moreover, thinking about novel solutions activates the distant or loosely connected neurons of a semantic network that involves the hippocampus. Novelty can also be interpreted as different combinations of earlier learned processes, such as the motor sequencing mechanism of the basal ganglia. In addition, the cerebellum is responsible for the precise control of movements, which is particularly important in improvisation. Our neurocomputational perspective is based on three creative processes centered on novelty seeking, subserved by the prefrontal cortex, hippocampus, cerebellum, basal ganglia, and dopamine. The algorithmic implementation of our model would enable us to describe commonalities and differences between these creative processes based on the proposed neural circuitry. Given that most previous studies have mainly provided theoretical and conceptual models of creativity, this article presents the first brain-inspired neural network model of creative cognition.
•Creative cognitive processes, such as divergent thinking (DT), abstraction, and improvisation, are based on different novelty-based processes.•These creative cognitive processes are based on novelty seeking, which is subserved by the prefrontal cortex, hippocampus, basal ganglia, cerebellum and dopamine.•This perspective paper provides a neurocomputational account for DT, abstraction, and improvisation.•An algorithmic implementation of our model is provided, which helps describe commonalities and differences between these types of creativity based on their relevant neural circuitry.•This model is the first brain-inspired neural network model of creative cognition, as most prior works mainly provide theoretical and conceptual models of creativity.
The COVID-19 pandemic has contributed to an increase in psychological distress. However, protective factors such as social support, psychological flexibility, and coping mechanisms can help ...individuals cope with the effects of psychological distress. This study aimed to test a recent hypothesis suggesting that psychological flexibility is not necessarily a coping strategy but a mechanism that can influence the coping strategies an individual employs during stressful events. We tested a mediation model that COVID-19 concerns would contribute to higher levels of perceived social support, which would directly increase psychological flexibility, and finally test if the effect of psychological flexibility on distress was mediated by approach and avoidant coping strategies. The results show that social support facilitates higher levels of psychological flexibility. Further, that psychological flexibility indirectly reduces psychological distress by reducing avoidant coping and increasing approach coping strategies. Within the context of COVID-19, we have shown the importance of social support and psychological flexibility for reducing distress. We have provided further evidence that psychological flexibility might not be a coping mechanism but a strategy that leads individuals to engage in more approach coping strategies and fewer avoidant coping strategies.
Science anxiety refers to students' negative emotions about learning science. Across two studies, we investigated the psychometric properties of the newly developed Abbreviated Science Anxiety Scale ...(ASAS), which was adapted from the modified Abbreviated Math Anxiety Scale (m-AMAS) (Carey E., 2017). Using a sample of students in grades 7 to 10 (N = 710), Study 1 reported a two-factor structure of the ASAS (learning science anxiety and science evaluation anxiety) and negative associations between the ASAS factors and science achievement. Study 2 replicated this two-factor model in students in grades 11 and 12 (N = 362) and found that students in the "Arts" track were more anxious about science than those in "Sciences" track. Both studies consistently reported positive inter-correlations between the ASAS factors, with good internal reliabilities and modest meaningful associations with test anxiety and general anxiety, suggesting that science anxiety might be a distinct construct. Further, female students had higher science anxiety (especially science evaluation anxiety) than male students, even when test anxiety and general anxiety were considered in models. In summary, the ASAS is a brief, valid, and reliable instrument that can be used to guide and improve science education.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Introduction: There is a burgeoning interest in the effects of odor exposure on autobiographical memory in Alzheimer's disease (AD). We pursued this line of research by assessing the effect of odor ...exposure on the retrieval of recent and remote memories in AD.
Method: Twenty-six patients with mild AD and 28 controls were tested in two conditions: with and without odor exposure. In each condition, participants were invited to retrieve two childhood memories, two adulthood memories, and two recent memories.
Results: Analysis showed that AD patients produced a higher number of and more specific childhood memories, adulthood memories, and recent memories after odor exposure than without odor.
Discussion: These findings demonstrate how odor exposure may alleviate anterograde and retrograde amnesia, at least when considering the ability of patients with mild AD to retrieve few recent or remote memories.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Alzheimer's disease (AD) is currently diagnosed using a mixture of psychological tests and clinical observations. However, these diagnoses are not perfect, and additional diagnostic tools (e.g., MRI) ...can help improve our understanding of AD as well as our ability to detect the disease. Accordingly, a large amount of research has been invested into innovative diagnostic methods for AD. Functional MRI (fMRI) is a form of neuroimaging technology that has been used to diagnose AD; however, fMRI is incredibly noisy, complex, and thus lacks clinical use. Nonetheless, recent innovations in deep learning technology could enable the simplified and streamlined analysis of fMRI. Deep learning is a form of artificial intelligence that uses computer algorithms based on human neural networks to solve complex problems. For example, in fMRI research, deep learning models can automatically denoise images and classify AD by detecting patterns in participants’ brain scans. In this systematic review, we investigate how fMRI (specifically resting‐state fMRI) and deep learning methods are used to diagnose AD. In turn, we outline the common deep neural network, preprocessing, and classification methods used in the literature. We also discuss the accuracy, strengths, limitations, and future direction of fMRI deep learning methods. In turn, we aim to summarize the current field for new researchers, suggest specific areas for future research, and highlight the potential of fMRI to aid AD diagnoses.
Recent studies have shown that alpha oscillations (8–13 Hz) enable the decoding of auditory spatial attention. Inspired by sparse coding in cortical neurons, we propose a spiking neural network model ...for auditory spatial attention detection. The proposed model can extract the patterns of recorded EEG of leftward and rightward attention, independently, and uses them to train the network to detect auditory spatial attention. Specifically, our model is composed of three layers, two of which are Integrate and Fire spiking neurons. We formulate a new learning rule that is based on the firing rate of pre- and post-synaptic neurons in the first and second layers of spiking neurons. The third layer has 10 spiking neurons and the pattern of their firing rate is used in the test phase to decode the auditory spatial attention of a given test sample. Moreover, the effects of using low connectivity rates of the layers and specific range of learning parameters of the learning rule are investigated. The proposed model achieves an average accuracy of 90% with only 10% of EEG signals as training data. This study also provides new insights into the role of sparse coding in both cortical networks subserving cognitive tasks and brain-inspired machine learning.
•Childhood traumatic events increase a risk of psychosis.•Childhood trauma might be associated with a specific psychosis manifestation.•Childhood adversities trigger specific biological alterations ...in psychosis.•Childhood trauma might predict poor prognosis in psychotic disorders.•Psychosis with positive history of childhood trauma might be a distinct phenotype.
There is a growing body of research focused on the relationship between childhood trauma and the risk of developing psychosis. Numerous studies, including many large-scale population-based studies, controlling for possible mediating variables, provide persuasive evidence of a dose-response association and are indicative of a causal relationship. Existing evidence supports the specificity model, showing differential associations between particular adversities and clinical symptoms, with cumulative adversity causing less favorable clinical and functional outcomes in psychotic patients. To date, several psychological and biological models have been proposed to search for underlying developmental trajectories leading to the onset of psychosis, influencing psychopathological manifestation and negative functional outcomes due to a history of childhood trauma. In this article, we provide a unified review on the relationship between childhood trauma and psychosis by integrating results of epidemiological, clinical, neuropsychological and biological studies. The question whether psychosis with a positive history of childhood trauma should be considered as a new psychotic phenotype, requiring specific therapeutic interventions, warrants further investigation.
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