Attentional focusing can be implemented with a neural field [1], which uses a discharge rate code. As an alternative, we propose in the present work an implementation based on spiking neurons. Such implementation will allow to investigate the possible contribution of a spike time based code with a network of leaky integrate-and-fire neurons. The network is able to detect and to focus on a stimulus even in the presence of distractors. Experimental data show that this behavior is very robust to noise. This process implements an early visual attention mechanism.