WHAT ARE THE CHARACTERISTICS OF NEGATIVE FEEDBACK?
The mitral and tufted cells in the bulb (type M) are excitatory, whereas the granule cells (type G) are inhibitory. Excitation of type M cells by single-shock stimulation normally leads to excitation of type G cells and to feedback inhibition of type M cells (46). The inhibited type M cells disexcite type G cells which disinhibit or re-excite type M cells, and so on, such that the impulse response in the closed-loop state is predictably oscillatory. The same prediction holds for the interaction of types A and B neutrons in the cortex (34, 36, 57). In a narrowly limited range of function (to be described in a later section), the transfer function for these negative feedback loops for orthodromic input to the excitatory neural mass and output (Figure 3, upper right) from the same neural mass (the forward limb) is For input to the forward limb and output (Figure 3, lower right) from the feedback limb (the inhibitory bulbar or cortical granule cells), the transference is For antidromic inp
