Primary sensory cortexes provide massive descending axons to the thalamus to modulate sensory responsiveness of thalamic relay neurons. These top-down controls are pivotal for shifting neuronal firing between burst and tonic modes. The impact of the corticothalamic pathways on the firing mode and sensory gain of thalamic neurons has only been extensively examined in anesthetized animals, but has yet to be established in the awake state. We investigated what change were caused by lesions of the barrel cortex in responses of thalamocortical and thalamic reticular neurons to a single vibrissal deflection during wakefulness. Our results showed that the cortical lesions shifted the response of thalamic neurons towards bursting, elevated the response probability and the gain of thalamocortical neurons, predominantly of recurring responses. In addition, after the lesions, the spontaneous activities of the vibrissa-responsive thalamic neurons were typified by rhythmic spiking with frequent bursting. In single neuron recording/labeling experiments, layer 6 corticothalamic neurons responded to a single vibrissal deflection with short latencies in awake rats, strongly suggesting the existence of an immediate corticothalamic feedback. Because these results showed the importance of corticothalamic neurons in shaping thalamic activities during wakefulness, we next explored what neural circuits in the cortex affected the activities of the corticothalamic circuits. We will further present morphological analyses of corticocortical networks which input to the barrel cortex.