Neuroanatomical and functional evidence indicates that pain and temperature are represented with numerous other interoceptive sensory inputs in a phylogenetically novel spinothalamocortical pathway in primates (for review, see Craig, TINS 2003 26:303-307). Prior tract-tracing studies in the monkey demonstrated that nociceptive and thermoreceptive spinothalamic tract neurons in spinal lamina I primarily project to the posterior part of the ventromedial nucleus of the thalamus (VMpo; a nucleus specific to primates) and that nociceptive and thermoreceptive thalamocortical tract neurons in VMpo project to the dorsal posterior insular cortex. Electrophysiological recordings in spinal lamina I and VMpo in the anesthetized monkey revealed precise encoding of the grading of thermal and pain stimuli. Functional imaging in humans and EEG in monkeys indicated that the dorsal posterior insula is strongly activated by graded cooling of the skin. In the present study, we examined the activation of the insular cortex using high-resolution functional magnetic resonance imaging (4.7T) with thermal stimulation of the skin in two anesthetized cynomolgus monkeys. A graded cooling of the palmar surface of the foot from a baseline temperature of 35癈 to a target temperature of 15癈 (0.5癈/sec) followed by a re-warming to baseline (0.5癈/sec) produced highly significant (p < 0.001) BOLD signal exclusively in the dorsal mid-posterior portion of the contralateral insular cortex. No or poorly significant (p < 0.05) BOLD signal occurred in primary and secondary somatosensory cortices. These results support prior evidence that the insula in primates encodes ongoing interoceptive activity necessary to maintain homeostatic balance (e.g. thermoregulation). Neuroanatomical tract-tracers were injected in the insular regions displaying significant BOLD signal; mapping of anterograde and retrograde labeling from these injections will be presented. Understanding the neural underpinnings of conscious perception has long intrigued the students of the brain from philosophers to modern neuroscientists. In the visual domain, the primary visual cortex (V1) is by far the most extensively studied cortical area. It entails the main gateway of visual information to higher cortical areas and we understand a lot about its function in sensory processing. Nevertheless, the role of V1 in perceptual awareness remains intensely debated. Under certain stimulus conditions perception alternates between two or multiple stimulus interpretations. Notably such perceptual alternations happen while the sensory input is kept constant, offering thus a clear dissociation of sensory stimulation and subjective awareness. A celebrated example of such a perceptual phenomenon is binocular rivalry (BR). It involves the dichoptic presentation of two different stimuli at corresponding retinal locations and results in the perceptual suppression of one of the two stimuli at different times. A slight variant of BR, binocular flash suppression (BFS), ensures excellent control over the subjects’ perceptual state by intermittent presentation of monocular and binocular stimuli. We have trained rhesus macaques to report their perception during BFS and BR to study the effects of perceptual suppression in V1. We have recorded the spiking activity of a large number of well isolated single units (SUA) and acquired simultaneous local field potentials (LFPs) during the dichoptic presentation of orthogonal orientation gratings. We found that during BFS, 20% of the single units modulated their activities in consonance with the perceptual