3 ms·

fMRI is a step above dowsing rods. It's plugging a multimeter into an outlet and guessing what type and brand of appliances you are running in your house.

fgfarben 5mo ago
Have you heard of time-domain reflectometry? A $20,000 multimeter could have the "impossible" feature you describe all but built in.
yummybrainz 5mo ago
I'd say you're right about any given individual channel: the activation of a single voxel doesn't tell us much about all the fancy computation happening in that ~1 mm^3 of tissue. But the pattern of activity of thousands of voxels across cortex does contain reliable information! And a decent amount of it too, at least in sensory cortices.
BigTTYGothGF 5mo ago
I was at a talk maybe 15 years ago in which the speaker gave pretty convincing evidence that given a time series of voltages you could learn a lot of things about what kind of appliances you've got running.
- zdragnar 5mo ago
  There are a lot of devices that have reasonably distinct patterns to their power consumption. Motors- especially well pumps, but also large central air fans and some others- are going to look very different from a microwave or vacuum cleaner or refrigerator, especially if you have time of day on your readings. Constant lower draw devices- chargers, lights, speakers and such- are going to be harder to distinguish, though.
  - aix1 5mo ago
    Turns out it's a (somewhat) active area of research. https://ubicomplab.cs.washington.edu/pdfs/electrisense.pdf https://ubicomplab.cs.washington.edu/pdfs/electrisense.pdf https://www.researchgate.net/publication/266461208_Multimedia_Content_Identification_Through_Smart_Meter_Power_Usage_Profiles https://www.researchgate.net/publication/266461208_Multimedi... https://www.mdpi.com/1996-1073/14/9/2485 https://www.mdpi.com/1996-1073/14/9/2485
lostlogin 5mo ago
Try it with a crude task - eg finger tapping. It’s pretty convincing.

fgfarben 5mo ago

Have you heard of time-domain reflectometry? A $20,000 multimeter could have the "impossible" feature you describe all but built in.

yummybrainz 5mo ago

I'd say you're right about any given individual channel: the activation of a single voxel doesn't tell us much about all the fancy computation happening in that ~1 mm^3 of tissue. But the pattern of activity of thousands of voxels across cortex does contain reliable information! And a decent amount of it too, at least in sensory cortices.

BigTTYGothGF 5mo ago

I was at a talk maybe 15 years ago in which the speaker gave pretty convincing evidence that given a time series of voltages you could learn a lot of things about what kind of appliances you've got running.

zdragnar 5mo ago
There are a lot of devices that have reasonably distinct patterns to their power consumption. Motors- especially well pumps, but also large central air fans and some others- are going to look very different from a microwave or vacuum cleaner or refrigerator, especially if you have time of day on your readings. Constant lower draw devices- chargers, lights, speakers and such- are going to be harder to distinguish, though.
- aix1 5mo ago
  Turns out it's a (somewhat) active area of research. https://ubicomplab.cs.washington.edu/pdfs/electrisense.pdf https://ubicomplab.cs.washington.edu/pdfs/electrisense.pdf https://www.researchgate.net/publication/266461208_Multimedia_Content_Identification_Through_Smart_Meter_Power_Usage_Profiles https://www.researchgate.net/publication/266461208_Multimedi... https://www.mdpi.com/1996-1073/14/9/2485 https://www.mdpi.com/1996-1073/14/9/2485

lostlogin 5mo ago

Try it with a crude task - eg finger tapping. It’s pretty convincing.