Cell B2 from the midbrain central gray is shown responding during but not immediately before and after a display of affective defense (A). Cell A3 from the midbrain just lateral to the border of the central gray is shown firing only two spikes during a display of affective defense (A) and at no other time immediately before and after the display. The cell with smaller amplitude spikes which may be seen firing in the baseline and reaching a maximum rate during the affective defense is cell A2. Cell FI from the midbrain central gray is shown firing throughout a display of affective defense (A). Note the multineuronal activity in response to opening of the cage. None of these cells was facilitated by other manipulations of the cat.