What olfactory cues do mice use to landmark their HD system? Previous work indicates that rodents can use a variety of odors, including self-generated odors, conspecific odors, and other non-animal odors, to guide spatial navigation 36, 37, 61. In our experiments, for each mouse, its first open-field exposure began on a new floor, which had never been explored by another mouse, meaning the mice had to use cues intrinsic to the floor or that were self-generated. Chaos at Congressional Halloween party: House Republicans all show up wearing identical clown costumes Goddess particle': Earth slammed by ultra-powerful cosmic ray, and we have no idea where it came from

Hubel and Wiesel discovered a critical period during development for ocular dominance plasticity in the visual cortex 66, and similar critical periods have been shown to exist for many other sensory systems and behaviors 67. Here, we provide evidence of a critical period in the refinement and maturation of the HD system in ADn that depends on visual inputs in the period shortly after eye-opening—the evidence being that rd1 mice, who have attenuated vision upon eye-opening before going blind around P30 40, 47, have more refined HD cell tuning as adults than congenitally blind Gnat1/2 mut mice. Both rd1 and Gnat1/2 mut mice go blind due to problems with retinal photoreceptors. rd1 mice go blind as a result of photoreceptor degeneration caused by a mutation in phosphodiesterase in rod photoreceptors (due to a mutation of the Pde6B gene), which initially leads to rod death followed by cone death, and this is a commonly used mouse model of retinitis pigmentosa 39. Gnat1/2 mut mice are blind as a result of mutations in both rod and cone forms of the alpha subunit of the G-protein transducin (due to mutations in both Gnat1 and Gnat2 genes), resulting in nonfunctioning rod and cone photoreceptors (see Methods). As the mutated genes in both mouse lines are predominantly expressed in photoreceptors, it is likely that the difference in HD cell tuning in blind adult Gnat1/2 mut vs. rd1 mice is a direct result of the timing of the onset of vision loss (congenital vs. ~P30). We thus propose that vision around the time of eye-opening allows the HD cell system to stabilize (i.e., upon eye-opening, vision enables HD cells to exhibit heightened stability in their preferred direction tuning 29, 30), and this stability results in refinement and maturation of the HD network, such that though both rd1 and Gnat1/2 mut are equally blind as adults, rd1 mice have more refined HD cell tuning. These findings are consistent with multisensory studies in the superior colliculus, which showed the importance of vision during development for enabling the generation of normal auditory space maps 43, 44, 68. Attractor dynamics in the presence and absence of anchoring external sensory inputs

Daniel Shiffman

Our results indicate that vision and olfaction can be used, either independently or in tandem, to stabilize HD cell tuning. Visual signals are believed to enter the HD system via inputs from the visual cortex to the post-subiculum and retrosplenial cortex 12. With respect to olfactory inputs, the pathway into the HD system remains unclear, though direct projections from the olfactory bulb and piriform cortex to the entorhinal cortex 54, 55 could, in turn, reach ADn via post-subiculum, which is reciprocally connected to the entorhinal cortex and ADn 56. Alternatively, olfactory signals could reach the HD system indirectly via the projection of the post-subiculum to the lateral mammillary bodies, which constitute the main subcortical input to the ADn 12. Future studies examining these pathways in more detail in both sighted and blind mice will be required to develop a better understanding of the circuitry involved. Air Force officer breaks silence on 'red, glowing UFO the size of a football field' hovering at low altitude over California space launch base Retired US Army Colonel says secret UFO projects should be made public by October 2030 - to beat America's rivals and get ahead of a 'catastrophic' leak Working on a branch of physics called supersymmetry, Dr. James Gates Jr., discovered what he describes as the presence of what appear to resemble a form of computer code, called error correcting codes, embedded within, or resulting from, the equations of supersymmetry that describe fundamental particles. Best of the Web: I've studied more than 5,000 near death experiences. My research has convinced me without a doubt that there's life after death

Next, we compared several metrics for HD cell responses between blind and sighted mice. For vector length, tuning width, and mutual information, each group of mice was statistically different from one another, demonstrating the following hierarchy in HD tuning refinement: WT L> rd1 > WT D (Fig. 2c; Supplementary Fig. 2a, b). Furthermore, if we limited our analysis in WT animals to HD cells that were recorded in both light and dark environments, and performed paired statistical tests, we found a similar relationship with HD tuning being significantly impaired for WT animals in the dark compared to the light (Supplementary Fig. 2c). Thus, sighted mice exhibit significant impairment in HD cell tuning when placed in the dark, with a level of impairment much more severe than is seen in blind animals, for whom HD cell tuning—although slightly less refined than in sighted animals in the light—is robust and stable. Prior visual experience leads to refined HD cell tuning in blind adult mice Best of the Web: Ancient Sumerians invented water flumes thousands of years earlier than previously thought If we look at the computer from the outside, our artwork looks solid. If we take apart the outside layers of the computer and watch in slow motion how its hardware works beyond the microscopic level, we will see that it is made of vast streams of electrical currents. Electrical currents are another form of energy. Putin: Russophobia, racism and other forms of neo-Nazism have become the official ideology of Western elitesBest of the Web: 60 years after JFK's death it is more and more apparent that Kennedy was a victim of a palace coup - spearheaded by Vice-President Johnson In my book titled Staradigm (published in 2011), I mentioned about this idea and roughly explained how it worked. It is great to finally hear that physicists of today are finding evidence that the Universe is a giant hologram. To directly test whether olfactory inputs were required for stabilizing HD cell tuning in blind mice, we ablated olfactory sensory neurons (OSNs) and examined the effect on HD cell tuning. To ablate OSNs, we used a previously established chemical lesioning method 48 (see Methods). To ensure that this method was effective at ablating OSNs and severely impairing olfaction, we developed an olfactory place avoidance task in which a mouse was placed in a two-chamber arena, with one of the chambers housing an aversive olfactory substance (3-methyl-1-butanethiol 49) and the other chamber housing a neutral olfactory substance (distilled H 2O; Fig. 5b; see Methods). Mice with intact OSNs completely avoided the chamber containing the aversive olfactory substance (Fig. 5b, c). In contrast, following OSN ablation, mice showed no preference between the two chambers (Fig. 5b, c). Having established a method to reliably ablate olfaction, we tested the effect of olfactory ablation on HD cell tuning in blind animals. Olfactory ablation resulted in complete loss of HD cell tuning in ADn of blind mice (Fig. 5d, e; we pooled together rd1 and Gnat1/2 mut mice as OSN ablation affected both similarly (Supplementary Fig. 5c, d)). The percent of ADn cells that passed the criteria for being designated as HD cells drastically decreased for blind mice following olfactory ablation (Fig. 5e, Supplementary Fig. 5e, f). For some experiments, whiskers were intact during olfactory ablation, while in other animals, whiskers were ablated prior to olfactory ablation, but in both cases, olfactory ablation resulted in complete loss of HD cell tuning (Supplementary Fig. 5), again indicating that, at least in this experimental paradigm, the vibrissal system was not being used to tune HD cells. These results show that blind mice use olfactory cues to anchor their HD system. listo] Expertos plantean temores de salud pública sobre el síndrome de microondas de las antenas 5G

A similar drift in HD cell preferred firing direction appears to have been described in a previous study recording from HD cells in the lateral dorsal nucleus in rats placed in the dark, though those animals were placed in a radial maze, making it difficult to draw exact parallels to our results 33. In a more recent study in mice placed in the dark, it was reported that ~40% of HD cells became unstable in the dark, with one example HD cell recording being shown where the instability resulted in the preferred firing direction exhibiting a drift similar to what we describe 34. However, a follow-up paper from the same lab showed no effect of dark exposure on HD cell stability and instead found that optogenetic silencing of the nucleus prepositus hypoglossi (NHP)—which relays vestibular signals to the HD system—was required in tandem with dark exposure to cause the preferred direction of a subset of HD cells recorded in ADn to drift over time 14. This latter study also found that preferred firing direction drift was sometimes correlated with the animal’s head turns 14. Finally, at least some portion of the drift in HD preferred firing directions that we find appears to be related to the effect described for HD cells prior to eye-opening, where the broadness of tuning curves resulted in part from an under-signaling of angular head velocity 22. Nonetheless, future work is required to better understand the circuit and synaptic basis whereby different sensory inputs enable tuning within the HD attractor network to stabilize, and how perturbations to different sensory modalities can alter the input to the HD network and result in drift. Relating head direction cell recordings in blind rodents to spatial cognition in visually impaired humans SOTT Focus: MindMatters: Psychedelics, Sobriety, and Altered States: Processing Reality with John Buchanan The idea that we live in a holographic universe is very real. With the invention of quantum computers, physicists should soon be able to prove this beyond a reasonable doubt. So, what does it mean that we live in a holographic universe generated by some kind of quantum computer? It means that the Universe was created by an intelligent creator, and therefore it was not created by accident. In other words, the Prime Creator exists! World's biggest iceberg starts moving for first time in decades — and it could cause some serious problems

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Archaeologists unearthed a pot of copper coins in first major discovery at Mohenjo Daro in Pakistan, in 93 years The HD network is often modeled as a continuous ring attractor 11, 18, 19, 20. Evidence in favor of an attractor network is plentiful, from the finding that the relative difference in preferred directions between a given pair of HD cells is maintained across different environments and during visual cue rotation experiments 21, to the finding that HD cells that fire coherently during spatial navigation continue to do so during sleep 11, to the finding that before eye-opening—when HD cell tuning curves are broad—pairs of cells exhibit similar coherence during spatial navigation as is seen in the adult HD system 22, 29, 30. Furthermore, a recent manifold analysis has validated a one-dimensional ring as a robust description of the rodent HD network 19. Our results in blind mice are consistent with those of a continuous ring attractor. Performing a manifold analysis revealed a one-dimensional ring attractor similar to that found in normally sighted animals. Additionally, upon ablating OSNs in blind animals, while this completely removed stability of HD cell preferred direction, attractor dynamics and the ring architecture remained intact. Earliest evidence for mass production of weapons in southern Levant discovered, sling stones dated to 7,200 years ago