Abstract: Various examples are provided related to monitoring of nervous system activity. In one example, a method includes obtaining at least one image of a portion of skin of a subject wherein the subject is not in contact with an imaging system and processing the at least one image to determine at least one characteristic of activated sweat pores in the at least one image. The image(s) can include at least one thermal image. The image(s) can be processed to generate at least one enhanced image for the SPA determination. In another example, a system includes an infrared camera that can capture at least one thermal image of a portion of skin of a subject with the system not in contact with the subject and image processing circuitry that can process the at least one thermal image to determine at least one characteristic of activated sweat pores in the thermal image(s).