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The complexity of a human is emphasized when we are compared to animals in experiments that strive to explain what makes us so special and different. However, it has been known in neuroscience that animals may be some of the most useful models in studying the wiring of our brain. Specifically, Macaque monkeys, who have structural and functional similarities with the wiring of the human brain.
This similarity between Macaque monkeys and humans allowed two biologists, Le Chang and Doris Y. Tsao, from Caltech to "decipher the code of how faces are recognized" by studying "face cells" in macaque monkeys and their relative triggering to manipulation of 2,000 faces of humans. The "face cells" that were being targetted are neurons that fire electrical signals when the retina is presented with an image of a face. They used an electrical recording that was probed into face cells of macaque monkeys, first identified by an MRI, to perform the experiment and ultimately were able to construct the dimensions that wre used by the primate brain to decode faces. The monkeys were shown manipulated photos of human faces that were distinguished by size and appearance.
The article described the facial recognition system in both humans and macaque monkeys as being grouped into "patches" of at least 10,000 face cells each. These patches are six-fold on each side of the brain. Before the researchers of Caltech discovered the ways in which the brain encodes faces, it was speculated that the brain dedicated a cell to each face. However, Caltech has debunked this idea and found that the "brain's face cells respond to the dimensions and features of a face in an elegantly simple, though abstract, way" that helps explain why the brain identifies and perceives a familiar face we have never seen before. The Caltech team also claims that there are "50 such dimensions [that] are required to identify a face" which allows the brain to create a mental "face space" in which any number of faces may be recognized, parallel to forming a long term store of information.
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| https://ocw.mit.edu/courses/brain-and-cognitive-sciences/9-01-introduction-to-neuroscience-fall-2007/ |
The article along with the findings of the Caltech research team further enhance the evolutionary field of neuroscience and pose an interesting question towards object recognition. Whether or not there are more dimensions to what it takes to recognize a face is an issue that must be researched further. However, it is interesting to note the remarkable ability of humans and monkeys, as social animals, to have the ability of recognizing faces of familiarity and distinguishing them from those that may pose a threat to their survival.
Recent studies show that the fusiform gyrus is the most responsible for facial recognition and expertise recognition. What significance does dimensionality and the fusiform gyrus have on this study? Overall this was a great article! Great Job!
ReplyDeletePrior to reading this, I did not know that there were cell's dedicated to facial recognition. I found it even more interesting that these cells are specifically grouped in patches, and that 50 or more dimensions are required to recognize a face.
ReplyDeleteThis is a very interesting article. Even in infants, you can see them imitate facial expressions of adults around them. Once they can reliably see the face, the begin to recognize and simulate the faces presented to them. Some have hypothesized it was because of mirror neurons, which are neurons that are active when you are doing a task and while you observe someone else doing the same task. These have only been found in monkeys, specifically macaque monkeys, and could be the reason for their learning of different facial expressions. Using this knowledge, we may be able to find areas in the human brain where we would be more likely to find mirror neurons.
ReplyDeleteAfter reading this, I think it would be interesting to study these Macaque monkeys and use the knowledge that we have learned about prosopagnosia to see if there are any signs that these monkeys can experience a deficit in facial recognitions comparable to humans who suffer from prosopagnosia. It would be interesting to see if the monkeys give off any kind of behavioral cue that they are experiencing a difficulty in recognizing faces, and connect this behavior to the cognitive functions of the brain in order to pinpoint the cause.
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ReplyDeleteThis article relates to chapter six material from the class. I read this blog before reading chapter six, then, I read it again after reading chapter six and my perception changed 180 degrees. In order to recognize a face, I think we can use view-invariant theory beause we must visually scan and recognize specific characteristics in a face that remain constant. In contrast, if these properties change, then we won’t be able to recognize a particular face. A holistic form of processing, which requires the “what” pathway (ventral or occipitotemporal pathway). It is interesting that the article mentioned that 50 or so dimensions must be categorized perhaps by the fusiform face area in the fusiform gyrus. This makes sense because the neurons in the temporal lobe have large receptive fields and are selective where information always represent the foveal. And what I find even more amazing is the way in which we capture signals through our eyes and reflect that signal, in this case, in the right hemisphere with such precision and accuracy. People with prosopagnosia cannot recognize faces, yet they remain able to see and capture signals from the environment through their visual sensory biological machinery but perhaps the signals produced by face stimuli incompletely project in the brain. In other words, this signal somehow doesn’t transmit correctly. Is like ordering your secretary (signal) to get a file (information) from the library (brain) and she comes back with the file but with missing pages perhaps, thus rendering you unable to interpret the whole.
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