code: def _slowIsSegmentActive(self, seg, timeStep):
      
  
      numSyn = seg.size()
      numActiveSyns = 0
      for synIdx in xrange(numSyn):
        if seg.getPermanence(synIdx) < self.connectedPerm:
          continue
        sc, si = self.getColCellIdx(seg.getSrcCellIdx(synIdx))
        if self.infActiveState[timeStep][sc, si]:
          numActiveSyns += 1
          if numActiveSyns >= self.activationThreshold:
            return True
  
      return numActiveSyns >= self.activationThreshold
docs: A segment is active if it has >= activationThreshold connected
      synapses that are active due to infActiveState.