code: def G(self, v, t):
          
          ret = np.zeros((8, 1))
          ret[4,0] = self.ke1 * self.He1 * self.u_sdev
          ret[5,0] = self.ke2 * self.He2 * self.p_sdev
          return ret
docs: Aburn2012 equations right hand side, noise term
          Args: 
            v: (8,) array 
               state vector
            t: number
               scalar time
          Returns:
            (8,1) array
            Only one matrix column, meaning that in this example we are modelling
            the noise input to pyramidal and spiny populations as fully 
            correlated.  To simulate uncorrelated inputs instead, use an array of
            shape (8, 2) with the second noise element [5,1] instead of [5,0].