#visual illusions

[schizopositivity]

I read your post on auditory hallucinations and illusions but I wanted to know if you could possibly do one on the visual versions of them. I have a hard time telling the difference between them and identifying which is which.

So the same rule still applies: hallucinations are your senses creating something that isn't there, and illusions are your senses altering something that is already there.

If you are at your house and home alone with no pets, and you see a panda bear crawling around, that's a hallucination. Nothing is moving like that in your house but your brain created the visual of a panda.

If you are at your house and home alone but you have a large dog, and you see your dog walking around but with the head of a panda, that's an illusion. Your dog is moving around, but your brain changes the visual of the dog's head into the head of a panda.

I'll do another example. But I will be describing bugs and food, read under the cut if you want to, or don't press "read more" if you don't want to read about bugs and food.

Imagine you are about to eat a stir fry with rice, you made it, and you know your kitchen is clean. But when you go to eat it suddenly you see a tarantula on top of the food. It doesn't make sense because you don't even have tarantulas in your area, and there aren't bugs in your house. After a minute the spider just disappears, not crawling away but just vanishing. That was a hallucination, there were no bugs or moving things on top of you food, but your brain created the image of a tarantula. The hallucination was sitting on top of a real item (your food) but was an entirely new thing that your brain created.

Now imagine you are about to eat a stir fry with rice, you made it, you know you used rice, and that your kitchen is clean. But when you go to eat the food, suddenly each grain of rice on your plate looks like a little worm. After a minute the worms stop moving and go back to looking like regular grains of rice. That was an illusion. The grains of rice were there, but your brain changed what they look like and made them look like little worms.

I'm sorry for the gross descriptions but the illusion example is actually one of my most frequent visual illusions that I get (I hate it). Both hallucinations and illusions can be very disturbing and impact your life. It isn't always easy to tell them apart, but it also isn't super important to identify them correctly unless you want to track your personal progress or worsening symptoms.

[neurosciencenews]

Visual Illusion That May Help Explain Consciousness A new visual illusion sheds light on redundancy masking and how we perceive our visual environment. The findings provide new insight into human consciousness.

[compneuropapers]

Interesting Papers for Week 9, 2021

The Rotating Snakes Illusion Is a Straightforward Consequence of Nonlinearity in Arrays of Standard Motion Detectors. Bach, M., & Atala-Gérard, L. (2020). I-Perception, 11(5), 204166952095802.

Improving emotional-action control by targeting long-range phase-amplitude neuronal coupling. Bramson, B., den Ouden, H. E., Toni, I., & Roelofs, K. (2020). eLife, 9, e59600.

Divergent projections of the prelimbic cortex bidirectionally regulate active avoidance. Diehl, M. M., Iravedra-Garcia, J. M., Morán-Sierra, J., Rojas-Bowe, G., Gonzalez-Diaz, F. N., Valentín-Valentín, V. P., & Quirk, G. J. (2020). eLife, 9, e59281.

Data‐driven integration of hippocampal CA1 synaptic physiology in silico. Ecker, A., Romani, A., Sáray, S., Káli, S., Migliore, M., Falck, J., … Ramaswamy, S. (2020). Hippocampus, 30(11), 1129–1145.

Synthesis of Conserved Odor Object Representations in a Random, Divergent-Convergent Network. Endo, K., Tsuchimoto, Y., & Kazama, H. (2020). Neuron, 108(2), 367-381.e5.

Precise Holographic Manipulation of Olfactory Circuits Reveals Coding Features Determining Perceptual Detection. Gill, J. V., Lerman, G. M., Zhao, H., Stetler, B. J., Rinberg, D., & Shoham, S. (2020). Neuron, 108(2), 382-393.e5.

Spatial encoding in dorsomedial prefrontal cortex and hippocampus is related during deliberation. Hasz, B. M., & Redish, A. D. (2020). Hippocampus, 30(11), 1194–1208.

A Minimal Biophysical Model of Neocortical Pyramidal Cells: Implications for Frontal Cortex Microcircuitry and Field Potential Generation. Herrera, B., Sajad, A., Woodman, G. F., Schall, J. D., & Riera, J. J. (2020). Journal of Neuroscience, 40(44), 8513–8529.

Mind-Craft: Exploring the Effect of Digital Visual Experience on Changes to Orientation Sensitivity in Visual Contour Perception. Hipp, D., Olsen, S., & Gerhardstein, P. (2020). Perception, 49(10), 1005–1025.

Protonic conductor: better understanding neural resting and action potential. Lee, J. W. (2020). Journal of Neurophysiology, 124(4), 1029–1044.

Stress Alters the Neural Context for Building New Memories. Meier, J. K., Weymar, M., & Schwabe, L. (2020). Journal of Cognitive Neuroscience, 32(12), 2226–2240.

Reward history impacts attentional orienting and inhibitory control on untrained tasks. Meyer, K. N., Sheridan, M. A., & Hopfinger, J. B. (2020). Attention, Perception, & Psychophysics, 82(8), 3842–3862.

Reaching movements are attracted by stimuli that signal reward. Nissens, T., & Fiehler, K. (2020). Attention, Perception, & Psychophysics, 82(8), 3804–3810.

Processing of Hippocampal Network Activity in the Receiver Network of the Medial Entorhinal Cortex Layer V. Rozov, A., Rannap, M., Lorenz, F., Nasretdinov, A., Draguhn, A., & Egorov, A. V. (2020). Journal of Neuroscience, 40(44), 8413–8425.

Septal GABAergic inputs to CA1 govern contextual memory retrieval. Sans-Dublanc, A., Razzauti, A., Desikan, S., Pascual, M., Monyer, H., & Sindreu, C. (2020). Science Advances, 6(44), eaba5003.

Network-level mechanisms underlying effects of transcranial direct current stimulation (tDCS) on visuomotor learning. Sehatpour, P., Dondé, C., Hoptman, M. J., Kreither, J., Adair, D., Dias, E., … Javitt, D. C. (2020). NeuroImage, 223, 117311.

Spatial organization of functional clusters representing reward and movement information in the striatal direct and indirect pathways. Shin, J. H., Song, M., Paik, S.-B., & Jung, M. W. (2020). Proceedings of the National Academy of Sciences of the United States of America, 117(43), 27004–27015.

Wireless Programmable Recording and Stimulation of Deep Brain Activity in Freely Moving Humans. Topalovic, U., Aghajan, Z. M., Villaroman, D., Hiller, S., Christov-Moore, L., Wishard, T. J., … Suthana, N. (2020). Neuron, 108(2), 322-334.e9.

Nasal airflow engages central olfactory processing and shapes olfactory percepts. Yao, F., Ye, Y., & Zhou, W. (2020). Proceedings of the Royal Society B: Biological Sciences, 287(1937), 20201772.

A twisted visual field map in the primate dorsomedial cortex predicted by topographic continuity. Yu, H.-H., Rowley, D. P., Price, N. S. C., Rosa, M. G. P., & Zavitz, E. (2020). Science Advances, 6(44), eaaz8673.

[eopederson]

Alpha à oméga, autels, église Saint-Roch, Paris, 2017.

One of the more amazing architectural tricks is this visual illusion seen by parishoners standing in front of the main altar. A chapel behind has the Christ figure on a  cross, and thus one sees the beginning and the end of the life of Christ. On the rue de Rivoli not far from the Louvre, the church of St. Roch has played an important part in the history of Paris and should be, but is not, a major stop for visitors to the city.

[magictransistor]

Matthew Luckiesh. Spiral, Mirror Magic, Rotating Mason, Twisted-Cord Illusion (Straight Cords), Twisted-Cord Illusion (Concentric Circles), Brightness-Contrast, Concave and Convex Hemispheres Lighted by Large Angle Light-Source, Directional Illusion, Reversible Cubes. Visual Illusions. 1922.

[neurosciencenews]

Time-Traveling Illusion Tricks the Brain

Researchers have developed two new illusions that reveal how the senses can influence each other—in particular, how sound can give rise to visual illusions.

The research is in PLOS ONE. (full open access)

[neurosciencenews]

From Blue and Black Dresses to Turbine Blades: The Science of 'Fake Fake' Photos

Whether it's a blue and black dress - or white and gold depending on your take - or a pair of legs streaked with white paint, eagle-eyed viewers are always keen to debate a visual illusion when these puzzling images appear online.

The research is in i-Perception. (full open access)

[ainnez]

How Many Faces Can You See? This Illusion Tricks Your Brain