Week 5: chemical senses and vision
The fifth week of our course focused on the chemical senses, eye and central visual system. I did not consider smell and taste that interesting when it comes to the operation of brain, but of course some details got my attention, such as the fact that smell and taste are also oriented in the brain like a ‘map’ like vision and hearing. This week had a lot to read.
The anatomy and operation of the eye was a bit surprising. I had always thought that the dark pupil in the eye would be some ink or other dimming matter, but I was wrong — it is actually a hole into the eye, and the eye is just really dark from the inside due to the pigmented retina! The dark pigment prevents that the light would reflect in the eye, disturbing the seen image. Another surprising fact was that the neurons and their connections in the eye are actually on the photoreceptor cells and not below. And as the neurons in the eyes are really closely connected to the brain, one could say that you could see to someones brain when you look them in the eyes. Wow.
The operation of the vision was also a bit unexpected. The eyes seem to focus more on the edges and differences in the image than in the actual brightness of different colors. The image stays also quite normal to the deeper region of the brain as the striate cortex mostly contains a mapping of the original binocular image with added information about line orientation and movement. Other brain regions seem to recognize the objects. These structures are interesting for me, as I work with convolutional neural networks (CNNs) that are used in pattern recognition with deep learning. They are inspired from the operation on the human vision, and they also are the state-of-the-art in pattern recognition tasks, which I find a rather amazing connection.
The final discussion about how specific people (like own grandmother) are recognized is intriguing. I agree with the intuitive approach, that a combination of a large amount of neurons represents a single person. It would be also quite robust and would also explain the feeling that some people look similar.