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Transcranial direct current stimulation as a new method for changing the accommodative response of the eye

Wendel M., Burdziński G., Michalak K. P., Przekoracka-Krawczyk A.

Optica Applicata

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2017

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Vol. 47, nr 4

499--510

EN

The aim of the present study was to test if the exposure to transcranial direct current stimulation (tDCS) would change the excitability of the visual cortex and influence an accommodative response of the ocular lens. Twenty four subjects were divided into two groups: real-stimulation of the occipital cortex in which participants were exposed to real stimulation (1 mA for 12 min), and sham in which subjects were tested with placebo stimulation. The results showed that tDCS might indeed influence accommodative response. The strongest and most evident effect was observed when a 3.0 D accommodative stimulus was used: anodal tDCS increased but cathodal tDCS – decreased the accommodative response. The second finding was that the effect of stimulation was dependent on the examined eye. The right eye with slightly lower visual acuity and weaker accommodative response in pre-test, responded more strongly than the left eye. The short-time tDCS might modulate excitability of the neurons in visual cortex and eye sensitivity, reflected in the change of accommodative response. The tDCS method may be considered a technique that could reinforce conventional active visual training to improve accommodative functions.

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An integrative approach to analyze EEG signals and human brain dynamics in different cognitive states

Davis J. J., Lin C. -T., Gillett G., Kozma R.

Journal of Artificial Intelligence and Soft Computing Research

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2017

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Vol. 7, No. 4

287--299

EN

Electroencephalograph (EEG) data provide insight into the interconnections and relationships between various cognitive states and their corresponding brain dynamics, by demonstrating dynamic connections between brain regions at different frequency bands. While sensory input tends to stimulate neural activity in different frequency bands, peaceful states of being and self-induced meditation tend to produce activity in the mid-range (Alpha). These studies were conducted with the aim of: (a) testing different equipment in order to assess two (2) different EEG technologies together with their benefits and limitations and (b) having an initial impression of different brain states associated with different experimental modalities and tasks, by analyzing the spatial and temporal power spectrum and applying our movie making methodology to engage in qualitative exploration via the art of encephalography. This study complements our previous study of measuring multichannel EEG brain dynamics using MINDO48 equipment associated with three experimental modalities measured both in the laboratory and the natural environment. Together with Hilbert analysis, we conjecture, the results will provide us with the tools to engage in more complex brain dynamics and mental states, such as Meditation, Mathematical Audio Lectures, Music Induced Meditation, and Mental Arithmetic Exercises. This paper focuses on open eye and closed eye conditions, as well as meditation states in laboratory conditions. We assess similarities and differences between experimental modalities and their associated brain states as well as differences between the different tools for analysis and equipment.

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Pulsed near infrared laser stimulates the rat visual cortex in vivo

Mou Z. X., Hou W. S., Zheng X. L., Yao J. P., Shang G. B., Yin Z. Q.

Biocybernetics and Biomedical Engineering

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2015

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Vol. 35, no. 4

247--254

EN

Pulsed infrared irradiation is an alternative neural stimulation with the advantages of being non-contact, spatially precise and artifact-free. Although infrared neural stimulation (INS) is well characterized in the peripheral nervous system, research has been limited in the central nervous system (CNS), especially the near infrared with wavelength around 800 nm. To establish feasibility of INS in the CNS, pulsed near infrared laser (λ = 808 nm, pulse duration = 300–1000 μs, radiant exposure = 0.73–2.45 J/cm2, fiber size = 105 μm, repetition rate = 2 Hz) was used to stimulate the primary visual cortex (V1) of anesthetized Long Evans (LE) rats and the near-infrared-evoked neural activities in V1 was recorded. The impact of the duration of infrared pulse on the intensity and the latency of evoked potentials was assessed. We found that V1 was activated by 808 nm laser and the optical evoked potential (OEP) included a descending wave (D1) and an ascending wave (A1) after optical stimuli. Furthermore, with the increase of the stimulation pulse duration, both the amplitude of D1 and the latency of A1 were increased. The results from this paper will facilitate the applications of near infrared neural stimulation on central nervous system.

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A proposal of biologically inspired hierarchical approach to object recognition

Kozik R.

Journal of Medical Informatics & Technologies

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2013

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Vol. 22

169--176

EN

In this article a biologically-inspired algorithm for object recognition is presented. The approach is based on a hierarchical HMAX cortex model that was initially proposed by Riesenhuber and Poggio [12] and later extended by Serre et al [13]. The results show that despite the modification that were undertaken to simplify the HMAX model (in order to make it feasible for a real-time solutions) it is possible to achieve high effectiveness for a one-class detection problems. Moreover, it is also demonstrated how the proposed algorithm can be successfully deployed on a low-cost Android smartphone.