Evidence for an additive inhibitory component of contrast adaptation

The latency of visual responses generally decreases as contrast increases. Recording in the lateral geniculate nucleus (LGN), we find that response latency increases with increasing contrast in ON cells for some visual stimuli. We propose that this surprising latency trend can be explained if ON cells rest further from threshold at higher contrasts. Indeed, while contrast changes caused a combination of multiplicative gain change and additive shift in LGN cells, the additive shift predominated in ON cells. Modeling results supported this theory: the ON cell latency trend was found when the distance-to-threshold shifted with contrast, but not when distance-to-threshold was fixed across contrasts. In the model, latency also increases as surround-to-center ratios increase, which has been shown to occur at higher contrasts. We propose that higher-contrast full-field stimuli can evoke more surround inhibition, shifting the potential further from spiking threshold and thereby increasing response latency

Subversive Stitch

WhiteBox Harlem is thrilled to present Subversive Stitch, a group exhibition featuring female contemporary artists that work in textiles, curated by Kimberly Reinagel. Presented at this show will be works by Eozen Agopian, Alexandria Deters, Zhen Guo, Lisa Kellner, Mariana Garibay Raeke, Kimberly Reinagel, Leila Seyedzadeh, Victoria Udondian and Christina Whitney Wong. This exhibition will look at the societal reassignment of the textile in the art market. Textiles throughout history have been primarily considered a feminine medium. Fabrics, fashion, embroidery and tapestry all connote a feminine background, and have thus notoriously not been received with much gravity. This exhibition is here to prove that the textile medium carries just as much clout and strength in the art world at large as any other male-dominated medium does. The title of the show is an homage to feminist and writer Rozsika Parker and her book “The Subversive Stitch: Embroidery and the Making of the Feminine”1 . In this book Parker investigates the art of embroidery and how this craft was elevated from private female domesticity into the fine arts, a movement which fostered the increasing growth of the craft movement in the art world. Embroidery to this day is still primarily considered a feminine medium, but one that is no less subversive, innovative, and political than any other art medium. This exhibition will bring together female artists from a range of cultural backgrounds, who work in textile mediums in a display of artistic strength. These artists tackle the themes of culture, identity, displacement, feminism, economics and a responsibility to the truth of material through their work. This group of artists represent diversity and what the textile means as it is carried through the atmosphere of their respective backgrounds. In this exhibition, China, Iran, Nigeria, Greece, United States, Thailand, and Mexico will all share a unique and yet collaborate voice through textiles. Victoria Udondian examines the role of second hand clothes in the economics of Nigerian life. Zhen Guo uses female biology to narrate a meaning that changes with age which every woman undergoes. Leila Seyedzadeh reconstructs the Iranian mountainsides from her home country from memory, Christina Whitney Wong looks at medical apartheid in America, and creates the patterns which she hand weaves from algorithms based on those medical studies, and Alexandria Deters focuses on female empowerment through the embracing of our vibrantly different yet truly beautiful bodies. Every single thread in this space holds within it a deeper story. During this exhibition, funds will be collected on a donation basis, and a portion of all artwork sales will go to support the programming of the Lower Eastside Girls Club, a New York based organization that provides a safe haven, as well as programs in the arts, sciences, leadership, entrepreneurship, and wellness for girls in middle and high school. The Lower Eastside Girls Club aims to break the cycle of poverty by training the next generation of ethical, entrepreneurial and environmental female leaders. This exhibition is on view at WhiteBox Harlem from October 19th - 31st, 2019

The Inner Life of Bursts

In the thalamus, bursts and single spikes are elicited by distinct visual stimuli, suggesting distinct visual functions. In this issue of Neuron, Wang et al. make use of intracellular recordings of thalamic neurons in vivo to provide a clear, detailed explanation of how natural stimuli are converted into a neural code that uses both bursts and single spikes

A Lower Bound for the First Passage Time Density of the Suprathreshold Ornstein-Uhlenbeck Process

We prove that the first passage time density $\rho(t)$ for an Ornstein-Uhlenbeck process $X(t)$ obeying $dX=-\beta X dt + \sigma dW$ to reach a fixed threshold $\theta$ from a suprathreshold initial condition $x_0>\theta>0$ has a lower bound of the form $\rho(t)>k \exp\left[-p e^{6\beta t}\right]$ for positive constants $k$ and $p$ for times $t$ exceeding some positive value $u$. We obtain explicit expressions for $k, p$ and $u$ in terms of $\beta$, $\sigma$, $x_0$ and $\theta$, and discuss application of the results to the synchronization of periodically forced stochastic leaky integrate-and-fire model neurons.Comment: 15 pages, 1 figur

Developing online extensive reading and listening materials

This paper aims to explain the process of creating extensive reading (ER) and extensive listening materials (EL) for learners of English. Four graded readers and four episodes of a podcast were produced in collaboration with other graduate students and faculty at the University of Hawaiʻi at Mānoa. Although a direct learner population is not specified, these materials were designed for second/foreign English language learners preparing for or entering their first years at an English medium university. The main goals of this paper are to: 1. Explain my materials development process 2. Explain the pitfalls and solutions that occur during the materials development process 3. Show what materials exist online that can be used for extensive reading and listenin

Dorsal lateral geniculate substructure in the Long-Evans rat: A cholera toxin B-subunit study

This study describes the substructure of the dorsal lateral geniculate nucleus of the thalamus of the pigmented rat (Rattus norvegicus) based on the eye-of-origin of its retinal ganglion cell inputs. We made monocular intra-ocular injections of the B-subunit of cholera toxin (CTB), a sensitive anterograde tracer, in three adult male Long-Evans rats. In four additional subjects, we injected fluorophor-conjugated CTB in both eyes, using a different fluorophor in each eye. Brains of these subjects were fixed and sectioned, and the labeled retinal ganglion cell termini were imaged with wide-field sub-micron resolution slide scanners. Retinal termination zones were traced to reconstruct a three dimensional model of the ipsilateral and contralateral retinal termination zones in the dLGN on both sides of the brain. The dLGN volume was 1.58 \pm0.094 mm^{3}, comprising 70 \pm 3% the volume of the entire retinorecipient LGN. We find the retinal terminals to be well-segregated by eye of origin. We consistently found three or four spatially separated ipsilateral-recipient zones within each dLGN, rather than the single compact zone expected. It remains to be determined whether these subdomains represent distinct functional sublaminae

The information transmitted by spike patterns in single neurons

Spike patterns have been reported to encode sensory information in several brain areas. Here we assess the role of specific patterns in the neural code, by comparing the amount of information transmitted with different choices of the readout neural alphabet. This allows us to rank several alternative alphabets depending on the amount of information that can be extracted from them. One can thereby identify the specific patterns that constitute the most prominent ingredients of the code. We finally discuss the interplay of categorical and temporal information in the amount of synergy or redundancy in the neural code.Comment: To be published in Journal of Physiology Paris 200

Multiscale Discriminant Saliency for Visual Attention

The bottom-up saliency, an early stage of humans' visual attention, can be considered as a binary classification problem between center and surround classes. Discriminant power of features for the classification is measured as mutual information between features and two classes distribution. The estimated discrepancy of two feature classes very much depends on considered scale levels; then, multi-scale structure and discriminant power are integrated by employing discrete wavelet features and Hidden markov tree (HMT). With wavelet coefficients and Hidden Markov Tree parameters, quad-tree like label structures are constructed and utilized in maximum a posterior probability (MAP) of hidden class variables at corresponding dyadic sub-squares. Then, saliency value for each dyadic square at each scale level is computed with discriminant power principle and the MAP. Finally, across multiple scales is integrated the final saliency map by an information maximization rule. Both standard quantitative tools such as NSS, LCC, AUC and qualitative assessments are used for evaluating the proposed multiscale discriminant saliency method (MDIS) against the well-know information-based saliency method AIM on its Bruce Database wity eye-tracking data. Simulation results are presented and analyzed to verify the validity of MDIS as well as point out its disadvantages for further research direction.Comment: 16 pages, ICCSA 2013 - BIOCA sessio