1 Introduction -- 2 Anatomical projections from sensory cortical areas to the thalamus -- 2.1 General characteristics of corticothalamic projections -- 2.2 Types of corticothalamic projections -- 2.3 Cells of origin for the corticothalamic projections -- 2.4 Neurotransmitter actions -- 2.5 Specific characteristics of corticothalamic projections to the sensory thalamus -- 3. Corticofugal projection to subthalamic relay stations -- 3.1 Auditory system -- 3.2 Visual system -- 3.3 Somatosensory system -- 4 Corticofugal modulations of sensory responses -- 4.1 Corticofugal modulation of auditory responses -- 4.2 Corticofugal modulation of visual responses -- 4.3 Somatosensory system -- 5 Functional considerations -- 5.1 Corticofugal modulation of sensory transmission. Egocentric selection -- 5.2 Corticofugal modulation of neuronal rhythmic activities and neuronal synchronization -- 5.3 Contribution of corticofugal projections in attentional filtering -- References -- Subject index. (will follow)