Archerfish number discrimination

Debates have arisen as to whether non-human animals actually can learn abstract non-symbolic numerousness or whether they always rely on some continuous physical aspect of the stimuli, covarying with number. Here we investigated archerfish (Toxotes jaculatrix) non-symbolic numerical discrimination with accurate control for co-varying continuous physical stimulus attributes. Archerfish were trained to select one of two groups of black dots (Exp. 1: 3 vs. 6 elements; Exp. 2: 2 vs. 3 elements); these were controlled for several combinations of physical variables (elements’ size, overall area, overall perimeter, density and sparsity), ensuring that only numerical information was available. Generalization tests with novel numerical comparisons (2 vs. 3, 5 vs. 8 and 6 vs. 9 in Exp. 1; 3 vs. 4, 3 vs. 6 in Exp. 2) revealed choice for the largest or smallest numerical group according to the relative number that was rewarded at training. None of the continuous physical variables, including spatial frequency, were affecting archerfish performance. Results provide evidence that archerfish spontaneously use abstract relative numerical information for both small and large numbers when only numerical cues are available.

Ebbinghaus Illusion

For 25 years, the web has been used for psychological research ( Krantz et al., 1997 ; Reips, 1997 ). While many areas of psychology have benefitted from the increased access to participants and other benefits of web-based research, one area of psychology has rarely taken advantage of the online format, that is, sensation and perception. Largely, sensation and perception research has not used the web because of the need for carefully calibrated equipment to successfully run their experiments. However, there may be classes of phenomena in our sensory processes that might be studied online where the equipment and stimuli vary. Suppose the critical feature of the stimulus is an abstraction of the physical stimulus that does not vary with different displays. In that case, these features can be successfully studied online, meaning that results from online studies will match those from controlled laboratories. This study will examine the Ebbinghaus illusion to illustrate the successful use of the web for perceptual research. The implications and some discussion of types of perceptual studies conducted on the web will be discussed.

Archerfish number discrimination

Debates have arisen as to whether non-human animals actually can learn astract non-symbolic numerousness or whether they always rely on some continuous physical aspect of the stimuli covarying with number. Here we investigated archerfish (Toxotes jaculatrix) non-symbolic numerical discrimination with accurate control for co-varying continuous physical stimulus attributes. Archerfish were trained to select one of two groups of black dots (Exp. 1: 3 vs. 6 elements; Exp. 2: 2 vs. 3 elements); these were controlled for several combinations of physical variables (elements' size, overall area, overall perimeter, density and sparsity), ensuring that only numerical information was available. Generalization tests with novel numerical comparisons (2 vs. 3, 5 vs. 8 and 6 vs. 9 in Exp. 1; 3 vs. 4, 3 vs. 6 in Exp. 2) revealed choice for the largest or smallest numerical group according to the relative number that was rewarded at training. None of the continuous physical variables, including spatial frequency, were affecting archerfish performance. Results provide evidence of the spontaneous use of abstract relative numerical information in archerfish for both small and large numbers.

A covered eye fails to follow an object moving in depth

To clearly view approaching objects, the eyes rotate inward (vergence), and the intraocular lenses focus (accommodation). Current ocular control models assume both eyes are driven by unitary vergence and unitary accommodation commands that causally interact. The models typically describe discrete gaze shifts to non-accommodative targets performed under laboratory conditions. We probe these unitary signals using a physical stimulus moving in depth on the midline while recording vergence and accommodation simultaneously from both eyes in normal observers. Using monocular viewing, retinal disparity is removed, leaving only monocular cues for interpreting the object’s motion in depth. The viewing eye always followed the target’s motion. However, the occluded eye did not follow the target, and surprisingly, rotated out of phase with it. In contrast, accommodation in both eyes was synchronized with the target under monocular viewing. The results challenge existing unitary vergence command theories, and causal accommodation-vergence linkage.

Biochemical Analysis of the Differential Tissue Expression of Heat Shock Protein70 Following Exposure to Electromagnetic

Low field electromagnetic radiation that is emitted from cell phones may induce morphological aberrations and change in gene expression of heat shock protein 70 (Hsp 70). Using Real Time PCR (RTPCR) and protein concentration methods, we studied changes in levels of Hsp70 mRNA and protein synthesis after exposure to the physical stimulus. We also evaluated the suitability of using chick embryo as a model to study alteration in heat shock proteins expression and translation using specific egg incubator set up. Zero-day fertilized chicken eggs were used and a popular mobile phone and service provider was selected with 1800 MHz frequency, power of 0.47 W/kg body and SAR 1.10 w/KG (head). The total daily exposure duration was 50 minutes in each 24 hours with variable maximum exposure time. Experimental samples were divided into controls with no exposure and experimental samples. The developing embryos were removed and different organs were isolated for estimation of Hsp70mRNA and protein. This physical stimulus caused a sequential increase of mRNA corresponding to the period of exposure. Liver tissue demonstrated higher levels of mRNA than heart tissue. Nonetheless, this increase in mRNA was not matched with an increase in the amount of protein of the corresponding mRNA in both tissues at different exposure times. Total protein in all tissues remained unchanged due to slow down of the clearance process and as an indication that the cell is struggling to preserve housekeeping proteins signaling attempt of survival.

A digitization theory of the Weber–Fechner law

Since the publication of Shannon’s article about information theory, there have been many attempts to apply information theory to the field of neuroscience. Meanwhile, the Weber–Fechner law of psychophysics states that the magnitude of a subjective sensation of a person increases in proportion to the logarithm of the intensity of the external physical-stimulus. It is not surprising that we assign the amount of information to the response in the Weber–Fechner law. But no one has succeeded in applying information theory directly to that law: the direct links between information theory and that response in the Weber–Fechner law have not yet been found. The proposed theory unveils a link between information theory and that response, and differs subtly from the field such as neural coding that involves complicated calculations and models. Because our theory targets the Weber–Fechner law which is a macroscopic phenomenon, this theory does not involve complicated calculations. Our theory is expected to mark a new era in the fields of sensory perception research. Our theory must be studied in parallel with the fields of microscopic scale such as neural coding. This article ultimately aim to provide the fundamental concepts and their applications so that a new field of research on stimuli and responses can be created.

The conscious crow

SummaryNieder, Wagener, & Rinnert (Science, 369(6511), 1626–1629, 2020) demonstrated that some neurons in a prefrontal-like brain area of carrion crows signal neither the physical stimulus nor the intended action but the upcoming choice. This pattern of results implies that neural computations for consciousness can be generated by nonmammalian brains in similar ways as in primates.

Magnetically stimulated cryogels to enhance osteogenic and chondrogenic differentiation of stem cells

Cells can respond to the physical stimulus that comes from their micro-environments. There are several strategies to alter cell behavior. Several tissues like bone and cartilage, which are the point of interest of regenerative medicine, are under significant degrees of mechanical stress in real life. Within this stress, the arising mechanotransduction effect may trigger several behavioral responses on cells. As a novel and efficient way, magnetic nanoparticles can be used to make such a mechanotransductive effect on cells.In this study, pre-functionalized Fe3O4 superparamagnetic magnetite nanoparticles were synthesized and used to fabricate gelatin-based magnetic cryogels. Cell growth, tissue-specific metabolic activities, differentiation potential to the bone, and cartilage under static magnetic field at different magnetic field strength (1000-4000G) were investigated. Results indicated that there was a better induction in considerable higher magnetic field among all others and magnetic cryogels helps to mediate mesenchymal stem cell behaviour, promote their growth and induce osteogenic and chondrogenic differentiation.