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question about prosopagnosia and/or capgras delusion.

<p> prosopagnosia can be caused by lesions in various parts of the inferior occipital areas (occipital face area), fusiform gyrus (fusiform face area), and the anterior temporal cortex. positron emission tomography (pet) and fmri scans have shown that, in individuals without prosopagnosia, these areas are activated specifically in response to face stimuli. the inferior occipital areas are mainly involved in the early stages of face perception and the anterior temporal structures integrate specific information about the face, voice, and name of a familiar person. <p> capgras syndrome has also been linked to reduplicative paramnesia, another delusional misidentification syndrome. since these two syndromes are highly associated, it has been proposed that they affect similar areas of the brain and therefore have similar neurological implications. reduplicative paramnesia is understood to affect the frontal lobe and thus it is believed that capgras syndrome is also associated with the frontal lobe. even if the damage is not directly to the frontal lobe, an interruption of signals between other lobes and the frontal lobe could result in capgras syndrome. <p> the capgras delusion is classified as a delusional misidentification syndrome, a class of delusional beliefs that involves the misidentification of people, places, or objects. it can occur in acute, transient, or chronic forms. cases in which patients hold the belief that time has been "warped" or "substituted" have also been reported. <p> a case of a prosopagnosia is "dr p." in oliver sacks' 1985 book "the man who mistook his wife for a hat," though this is more properly considered to be one of a more general visual agnosia. although dr p. could not recognize his wife from her face, he was able to recognize her by her voice. his recognition of pictures of his family and friends appeared to be based on highly specific features, such as his brother's square jaw and big teeth. oliver sacks himself suffered from prosopagnosia, but did not know it for much of his life. <p> the first clues to the possible causes of the capgras delusion were suggested by the study of brain-injured patients who had developed prosopagnosia. in this condition, patients are unable to recognize faces consciously, despite being able to recognize other types of visual objects. however, a 1984 study by bauer showed that even though conscious face recognition was impaired, patients with the condition showed autonomic arousal (measured by a galvanic skin response measure) to familiar faces, suggesting that there are two pathways to face recognition—one conscious and one unconscious. <p> acquired prosopagnosia can develop as the result of several neurologically damaging causes. vascular causes of prosopagnosia include posterior cerebral artery infarcts (pcais) and hemorrhages in the infero-medial part of the temporo-occipital area. these can be either bilateral or unilateral, but if they are unilateral, they are almost always in the right hemisphere. recent studies have confirmed that right hemisphere damage to the specific temporo-occipital areas mentioned above is sufficient to induce prosopagnosia. mri scans of patients with prosopagnosia showed lesions isolated to the right hemisphere, while fmri scans showed that the left hemisphere was functioning normally. unilateral left temporo-occipital lesions result in object agnosia, but spare face recognition processes, although a few cases have been documented where left unilateral damage resulted in prosopagnosia. it has been suggested that these face recognition impairments caused by left hemisphere damage are due to a semantic defect blocking retrieval processes that are involved in obtaining person-specific semantic information from the visual modality. <p> capgras delusion is a psychiatric disorder in which a person holds a delusion that a friend, spouse, parent, or other close family member (or pet) has been replaced by an identical impostor. it is named after joseph capgras (1873–1950), a french psychiatrist.

Have you had an MRI recently?

if an earth-sized planet hit jupiter, what would happen, what would we see?

<p> on march 17, 2016, a jupiter impact event occurred involving an unknown object, possibly a small comet or asteroid initially estimated at 30–90 meters (or a few hundred feet) across. the size estimate was later corrected to 7 and 19 meters. the event was first reported by austrian amateur astronomer gerrit kernbauer, and later confirmed in footage from the telescope of amateur astronomer john mckeon. <p> the object that hit jupiter was not identified before wesley discovered the impact. a 2003 paper estimated comets with a diameter larger than 1.5 kilometers impact jupiter about every 90 to 500 years, while a 1997 survey suggested that the astronomer cassini may have recorded an impact in 1690. <p> the 2009 jupiter impact event happened on july 19 when a new black spot about the size of earth was discovered in jupiter's southern hemisphere by amateur astronomer anthony wesley. thermal infrared analysis showed it was warm and spectroscopic methods detected ammonia. jpl scientists confirmed that there was another impact event on jupiter, probably involving a small undiscovered comet or other icy body. the impactor is estimated to have been about 200–500 meters in diameter. <p> after more observations, astronomers determined that the object would impact the earth on 13 november 2015 at 06:18 utc (11:48 local time), south of sri lanka. due to its small size, it was expected that most or all of the object would burn up in the atmosphere before impacting, but would be visible as a bright daytime fireball if the sky was not badly overcast. <p> the 2010 jupiter impact event was a bolide impact event on jupiter by an object estimated to be about 8–13 meters in diameter. the impactor may have been an asteroid, comet, centaur, extinct comet, or temporary satellite capture. <p> paul kalas and collaborators confirmed the sighting. they had time on the keck ii telescope in hawaii, and had been planning to observe fomalhaut b, but they spent some of their time looking at the jupiter impact. infrared observation by keck and the nasa infrared telescope facility (irtf) at mauna kea showed a bright spot where the impact took place, indicating the impact warmed a 190 million square km area of the lower atmosphere at 305° west, 57° south near jupiter's south pole. <p> if it were ever to impact earth, it would likely create a large fireball in the sky and possibly an impact crater 100–575 meters (328–1,886 ft) across, assuming an impact angle of less than 45 degrees.

care to put up your maths?

how is instinctual behaviors like flight in birds produced by their brains?

<p> some instinctive behaviors depend on maturational processes to appear. for instance, we commonly refer to birds "learning" to fly. however, young birds have been experimentally reared in devices that prevent them from moving their wings until they reached the age at which their cohorts were flying. these birds flew immediately and normally when released, showing that their improvement resulted from neuromuscular maturation and not true learning. <p> bird flight is one of the most complex forms of locomotion in the animal kingdom. each facet of this type of motion, including hovering, taking off, and landing, involves many complex movements. as different bird species adapted over millions of years through evolution for specific environments, prey, predators, and other needs, they developed specializations in their wings, and acquired different forms of flight. <p> optocollic reflex is a gaze stabilization reflex that occurs in birds in response to visual (optokinetic) inputs, and leads to head movements that compensate for passive displacements and rotations of the animal. the reflex seems to be more prominent when the bird is flying (or at least held in a "flying position"). the brain systems involved in the reflex are the nucleus of the basal optic roots, the pretectal nucleus lentiformis mesencephali, the vestibular nuclei, and the cerebellum <p> flight is a unique feat among birds and provides them with many advantages in terms of food, predation, and movement. it is suggested that cardiovascular variables play a large part in avian flight and were naturally selected over time. specifically, the avian heart evolved to pump more blood throughout a bird’s body while it is engaged in flight. during rigorous activity, especially when flying, the demand for oxygen is high. <p> recent studies indicate that some birds may have an ability to memorize "syntactic" patterns of sounds, and that they can be taught to reject the ones determined to be incorrect by the human trainers. these experiments were carried out by combining whistles, rattles, warbles, and high-frequency motifs. <p> various theories exist about how bird flight evolved, including flight from falling or gliding (the "trees down" hypothesis), from running or leaping (the "ground up" hypothesis), from "wing-assisted incline running" or from " proavis" (pouncing) behavior. <p> the common raven migrates long distances for food and mating. since ravens, and birds in general, travel to such extents, they have a unique adaptation for flying in high altitude environments. specifically, neural mediating reflexes increase breathing. the locomotors system stimulates breathing directly from feed forward stimulation from brainstem centers and feedback stimulation from exercising muscles. in the carotid body, the bird’s chemoreceptors detect low oxygen and stimulate breathing during hypoxia. also, if breathing is hypoxic, the bird can use co2/ph-sensitive chemoreceptors to restrain breathing. due to ventilatory responses, this process leads to secondary hypocapnia. because birds are exposed to a wide variety of toxic gases and air borne particles in the environment, studies have used birds to measure air quality.

That is one of the open questions of science. We've only made small headway in understanding how brains are wired - and separating the Nature from Nurture components of the wiring is still beyond what our tools can do.

why is it easier to interpret small pixelated images over large pixelated images?

<p> a drawback of pixelization is that any differences between the large pixels can be exploited in moving images to reconstruct the original, unpixelized image; squinting at a pixelized, moving image can sometimes achieve a similar result. in both cases, integration of the large pixels over time allows smaller, more accurate pixels to be constructed in a still image result. completely obscuring the censored area with pixels of a constant color or pixels of random colors escapes this drawback but can be more aesthetically jarring. <p> first, the spatial resolution of an image can obviously not be better than the grain size (in the case of film) or the pixel size (in the case of digital detectors) with which it was recorded. this is the reason why topography requires high-resolution x-ray films or ccd cameras with the smallest pixel sizes available today. secondly, resolution can be additionally blurred by a geometric projection effect. if one point of the sample is a "hole" in an otherwise opaque mask, then the x-ray source, of finite lateral size s, is imaged through the hole onto a finite image domain given by the formula <p> rendering "buddhabrot" images is typically more computationally intensive than standard mandelbrot rendering techniques. this is partly due to requiring more random points to be iterated than pixels in the image in order to build up a sharp image. rendering highly zoomed areas requires even more computation than for standard mandelbrot images in which a given pixel can be computed directly regardless of zoom level. conversely, a pixel in a zoomed region of a buddhabrot image can be affected by initial points from regions far outside the one being rendered. without resorting to more complex probabilistic techniques, rendering zoomed portions of "buddhabrot" consists of merely cropping a large full sized rendering. <p> whether features in a digital image are sharp enough to achieve sub-pixel resolution can be quantified by measuring the point spread function (psf) of an isolated point in the image. if the image does not contain isolated points, similar methods can be applied to edges in the image. it is also important when attempting sub-pixel resolution to keep image noise to a minimum. this, in the case of a stationary scene, can be measured from a time series of images. appropriate pixel averaging, through both time (for stationary images) and space (for uniform regions of the image) is often used to prepare the image for sub-pixel resolution measurements. <p> in computer vision and image processing a common assumption is that sufficiently small image regions can be characterized as locally one-dimensional, e.g., in terms of lines or edges. for natural images this assumption is usually correct except at specific points, e.g., corners or line junctions or crossings, or in regions of high frequency textures. however, what size the regions have to be in order to appear as one-dimensional varies both between images and within an image. also, in practice a local region is never exactly one-dimensional but can be so to a sufficient degree of approximation. <p> one problem that any rendering system must deal with, no matter which approach it takes, is the sampling problem. essentially, the rendering process tries to depict a continuous function from image space to colors by using a finite number of pixels. as a consequence of the nyquist–shannon sampling theorem (or kotelnikov theorem), any spatial waveform that can be displayed must consist of at least two pixels, which is proportional to image resolution. in simpler terms, this expresses the idea that an image cannot display details, peaks or troughs in color or intensity, that are smaller than one pixel. <p> an example of pixel shape affecting "resolution" or perceived sharpness: displaying more information in a smaller area using a higher resolution makes the image much clearer or "sharper". however, most recent screen technologies are fixed at a certain resolution; making the resolution lower on these kinds of screens will greatly decrease sharpness, as an interpolation process is used to "fix" the non-native resolution input into the display's native resolution output.

There are a few reasons. The basic reason, though, is that for a given pixelated image, the spatial frequency of the image changes with viewing distance, and that when viewed close up. In the examples you linked to, the smaller images at right have a relatively high spatial frequency, not far off from the images you'd normally see. Certainly not very far from the spatial frequency of early video games. when such images are blown up (viewed across a wider portion of the visual field), however, the spatial frequency falls, to the point that it's not within the range of spatial frequencies that the brain is used to finding information in. It's the equivalent of excessively lowering the taste of change (though not the actual auditory frequency)g of speech, and taaaaaaalkiiiiiiiiiiing liiiiiiiiiike thiiiiiiiiiiiis... Drawing each word out so much that it takes several seconds. It's harder to interpret, because the brain expects speech to involve changes in sound from one millisecond to the next, not one second to the next. The same is true of images. The brain expects to find useful information in visual patterns that change from one tiny part of the visual field to the next, not from one big chunk to the next. This is especially true of detail information. Since additional factors: At low spatial frequencies, the brain is much more strongly able to pick up differences in overall brightness. The images you showed have relatively small overall changes in brightness. Lastly, when viewed at a larger size, very high frequency information (the texture of the paint) becomes visible, which probably biases the brain's interpretation of the image.