Abstract: Cognitive functions such as attention and working memory are an integral part of our daily life. A core region in the control of cognitive functions is the prefrontal cortex, which is well positioned to do this control. It sends to and receives projections from virtually all cortical sensory and motor areas, and many subcortical structures and it is believed that prefrontal cortex exerts its role in top-down control of cognitive functions by controlling sensory and motor signals via these reciprocal connections. This seminar will be about the neurons and neuromodulators involved in prefrontal control of visual signals and the contribution of this control to cognitive functions such as attention and working memory.