Let's take a look. For us humans, then, what's the sensory system we have? [FOREIGN] Of course, this is your visual system. And then, if enjoy the flavor of this wine, or it has a good sense of smell, this olfaction. And of course, then the flavor of this delicious fruit, then it's using your sense of taste. [FOREIGN] And of course, if you listen to the music, then it's through the sense of audition. It's a hearing, timbre, and also the touch is one of the five basic senses, right? For this five basic senses, the principles underlying this thing, let's take a look. You're kind of appreciative of the pictures, kind of enjoy the flavor, or when you enjoy the music. All begins with the physical stimuli, actually you need to transduce into electric signal that our brain can understand. Okay, this is the first step, this step is called sensory transduction. This is [FOREIGN]. Now it's a from the physical or chemical stimuli. Then transduced into electric signal [FOREIGN]. Now let's take a look, in the visual system, of course, this is achieved by the eye. [FOREIGN]. So for the smell, then you have the chemical coming [FOREIGN]. For the taste, of course, it's the use of the tongue. [FOREIGN] taste bud. [FOREIGN] detect bitter. [FOREIGN]. In most cases, actually, bitter is associated with the toxin. [FOREIGN]. Now, of course then sweet. [FOREIGN]. Okay, so this is actually the taste, the system, also transduced, those chemicals actually into the electrical system by the tongue, the taste bud. And the difference between these two, what's the difference? Smell and the taste. Make it more specific. Both are chemical receptors, those detect chemicals. [FOREIGN] What's the difference between these two types of chemicals? Smell and taste. >> [INAUDIBLE] >> Okay, that's a good question, good answer. So smell, then is to detect those chemicals, can [FOREIGN]. [FOREIGN]. This distinction, [FOREIGN] taste system [FOREIGN] detect easier is a chemical. [FOREIGN]. All right, so the other one that's basically most actually the physical stimulation, like the touch. [FOREIGN]. So it doesn't matter, okay? So the sensor system, you need the first step. [FOREIGN] sensory organ. [FOREIGN]. Okay, so first actually we talk about the sum of these principles under the sensory system. [FOREIGN]. Now one important concept is the receptive field. Now [FOREIGN] specifically the neuron, [FOREIGN]. The neuron can be excited. [FOREIGN] or inhibited, [FOREIGN]. Spacial domain, [FOREIGN] you can change the firing of the neuron. [FOREIGN] excitation. You decrease the [FOREIGN] okay?