When we paint a picture or model a three dimensional object using computer software, all the instructions are processed by the CPU and its counterparts before they are projected onto the screen. This process happens almost instantaneously, and it shows that instructions are processed by the CPU before they are used to create the computer generated object. In a sense, our picture or three dimensional model is nothing more than a perception of the CPU. Best of the Web: Gunung Padang: Giant pyramid buried in Indonesia could be oldest in the world, initial construction began 27,000 years ago Goddess particle': Earth slammed by ultra-powerful cosmic ray, and we have no idea where it came from 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! 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.

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where HD actual and HD iso refers to the actual and Isomap decoded HD, respectively. Next, the angular difference over time was unwrapped and smoothed with a Gaussian kernel (s.d. = 2), from which drift was computed as the absolute average rate of change (Fig. 7e). The shuffles shown in Fig. 7j were computed by correlating the AHV of each animal to the ADV of all other animals to generate a null distribution of AHV vs ADV correlations. Quantification of ADn units We next examined the effect that olfactory ablation had on HD cells in blind animals. To test this, used an alternative method to reliably identify HD cells in ADn regardless of whether or not they exhibited strong tuning preferences for head direction. Previous work 50 noted that HD cells in ADn exhibit highly distinctive autocorrelograms. Similarly, we found that HD cells in ADn maintain their distinctive autocorrelograms in blind animals and following OSN ablation (Fig. 5f, Supplementary Fig. 5). Following Veijo and Peyrache 50, we implemented a machine learning approach, using Extreme Gradient Boosting 51 (XGB) to classify neurons as either HD or non-HD cells based on the shape of their autocorrelogram. First, we used our standard method to define cells as either HD cells (which rely on cells having highly selective preferred firing directions for a given head direction; see Methods) or non-HD cells, and trained the classifier using an equal number of HD and non-HD cells from WT L mice. To assess model generalizability, here, the classifier was validated on data from blind controls (pooled rd1 and Gnat1/2 mut mice; Fig. 5g). Furthermore, the classifier characterized a similar percentage of cells in ADn in blind animals with intact OSNs and following OSN ablation (Fig. 5h; see Methods). We, therefore, used the classifier to define HD cells in ADn of blind mice following OSN ablation, allowing us to compare their response properties with HD cells in blind animals with intact OSNs. By using the same model to identify HD cells in blind controls and OSN ablated animals, we found that OSN ablation led to a significant decrease in vector length (Fig. 5i). These results indicate that removing olfaction from blind animals results in untuned HD cells in ADn. Olfaction can modulate HD cell tuning in sighted animals Coronavirus fragments can persist in the body of a person for up to a year: an estimated 65 million people worldwide suffer from the consequences

where, \(\triangle\)PFD is defined as the change in the preferred firing direction (in degrees) for each HD cell following reintroduction into the arena, and \(\triangle {{{{{{\mathrm{cue}}}}}}\; {{{{{\mathrm{is}}}}}}}\) defined as the extent (either 90° or 180°) that the visual cue was rotated. Floor rotation listo] Expertos plantean temores de salud pública sobre el síndrome de microondas de las antenas 5G Full size image The olfactory system is required for stabilizing head direction cell tuning in blind animalsAside from visual and olfactory inputs, our results rule out a contribution of vibrissal signals in stabilizing HD cell tuning within our specific experimental environment, consistent with recent findings from the somatosensory cortex 38. Nonetheless, one can imagine that in a different environmental context (e.g., where the walls or object contours provide useful spatial information) that the vibrissal system could possibly affect HD cell tuning. Next, since our experiments were done in the presence of white noise, we did not directly test possible auditory control of HD cell tuning. As such, future studies will be required to test for the possible use of auditory cues in stabilizing HD cell tuning in blind mice, though previous work in blindfolded rats suggests that auditory cues do not exert a strong effect on HD cell tuning 31. However, it should be noted that a recent study found that some mice can echolocate 53. Olfaction, HD cell tuning, and cognitive maps 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 UK suffering highest gonorrhea cases since records began 100 years ago, NHS dept pushes for vaccine program

Best of the Web: Ancient Sumerians invented water flumes thousands of years earlier than previously thoughtTo eliminate (or at least greatly reduce) the sense of smell, OSNs were chemically ablated based on established methods 48, 92. In brief, mice were anesthetized with isoflurane after which a blunted 33-gauge needle was used to administer 20 μl of ZnSO4 (10 % in sterile H 2O) in both nostrils. Previous work has shown that this leads to the rapid death of OSNs 48, 92. After intranasally administering the chemical, mice were inverted to drain the excess fluid from the nasal cavity. Behavioral and electrophysiological recordings were carried out at least 24 h following OSN ablation. 2-Chamber olfactory test 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.

The Jews and Boris Johnson: Zelensky's top political ally looking for scapegoats as Ukrainian elites begin to accept the war is lostFull size image The vibrissal system is not required for head direction cell tuning in blind animals in the open-field environment 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.