“The Multiple Functions of T Stellate/Multipolar/Chopper Cells in the Ventral Cochlear Nucleus”
- [tone and envelope / speech too] T Stellate cells encode the spectrum and envelope of sounds.
- [phase to tone] These cells convert phasic excitation from the auditory nerve to tonic firing.
Stellate cells have a SLIGHT delay (1 ms)
By contrast, octopus cells are the most accurate but respond only to tone (successions of identically timed clicks ) “Onset Response”. up to 1000x a second. Extremely accurate, source of timing.
By contrast, Bushy cells can improve the precision of the timing information by in essence averaging out jitter in timing of the inputs. Bushy cells can also be inhibited by sounds adjacent to the frequency to which they are tuned, leading to even sharper tuning than seen in auditory nerve fibers.
By contrast, Fusiform cells (also known as pyramidal cells) help in sound location for those who have loss of hearing in one ear.
0.1ms incremental shocks to activation. Super precise. Loving these octopus cells (auditory system)
The convergent input from a relatively large number of auditory nerve fibers is reflected in the responses of octopus cells to the activation of the auditory nerve with shocks in slices. Synaptic responses grow incrementally as more and more auditory nerve fibers are simultaneously brought to threshold with brief (0.1 msec) shocks of increasing strength (Fig. 3). Several features of synaptic responses in octopus cells are noteworthy. First, the amplitude of excitatory postsynaptic potentials varied over a wide range, from just detectable responses to weak shocks to about 30-mV responses to strong shocks; maximum amplitudes ranged between about 15 and 50 mV in different cells (19). The responses are so finely graded with shock strength that incremental responses from individual auditory nerve fiber inputs could not be resolved. Second, one small jump in amplitude, which was accompanied by a small action potential, was consistently detected at intermediate stimulus strengths (19) (Fig. 3, arrowhead). Responses to shocks recorded at the cell body comprised small action potentials superimposed on large synaptic potentials. Such an arrangement allows the timing of the synaptic inputs to be reflected in the timing of the action potential with precision because the relatively small action potential distorts the timing of the peak of the synaptic response only minimally. Third, over the entire range of suprathreshold responses the timing of the peaks of responses varied by only about 300 µsec. The timing of peaks was not only consistent but also precise.
It looks like Octopus Cells. Fires up to 1000 second with extreme accuracy and so smoothly that there’s aspects our instruments cannot detect.
It’s the most precise timing mechanism we have in the human body. 1 ms accurate.
“Thus, the morphology, connectivity, and membrane biophysics of octopus cells allow them to compensate for the cochlear traveling wave delay and respond to clicks with exquisite temporal precision.
In the context of the time–frequency (Gabor) uncertainty principle, octopus cells can be seen to solve a general problem of encoding frequency-dispersed but temporally restricted patterns using somatopetal sweep sensitivity.”
PERFECT! Illustration of 5ms, 10ms, 20ms, 50ms, etc.
Uses latency and sound.
The bottom limit for human ability to notice is 2ms. That’s fusion, 5 ms is a practical lower limit. If you pay attention you should be able to hear the difference between 0 ms and 5 ms although I’m sure not all people can. You’ll definitely hear it at 20 ms and beyond and 300 ms lag absolutely.,
Second order processing. I’ve been finding quite a few things. One processes onset time with 1ms precision (Octopus cells). One sends it through mostly unchanged with just a few tweaks (bushy cells). One encodes the tones and envelope (chopper cells).
I think there’s another one or two but I’m getting closer to ‘getting it’.