Brain responses associated with consciousness of breathlessness (air hunger)

Abstract

Little is known about the physiological mechanisms subserving the experience of air hunger and the affective control of breathing in humans. Acute hunger for air after inhalation of CO2 was studied in nine healthy volunteers with positron emission tomography. Subjective breathlessness was manipulated while end-tidal CO2-was held constant. Subjects experienced a significantly greater sense of air hunger breathing through a face mask than through a mouthpiece. The statistical contrast between the two conditions delineated a distributed network of primarily limbic͞paralimbic brain regions, including multiple foci in dorsal anterior and middle cingulate gyrus, insula͞claustrum, amygdala͞periamygdala, lingual and middle temporal gyrus, hypothalamus, pulvinar, and midbrain. This pattern of activations was confirmed by a correlational analysis with breathlessness ratings. The commonality of regions of mesencephalon, diencephalon and limbic͞paralimbic areas involved in primal emotions engendered by the basic vegetative systems including hunger for air, thirst, hunger, pain, micturition, and sleep, is discussed with particular reference to the cingulate gyrus. A theory that the phylogenetic origin of consciousness came from primal emotions engendered by immediate threat to the existence of the organism is discussed along with an alternative hypothesis by Edelman that primary awareness emerged with processes of ongoing perceptual categorization giving rise to a scene [Edelman, G. M. (1992) Bright Air, Brilliant Fire (Penguin, London)].

Effects of mandibular advancement on brain activation during inspiratory loading in healthy subjects: a functional magnetic resonance imaging study

“…Limbic areas, including the parahippocampal gyrus, insula, and cingulate gyrus, participate in emotive and visceral sensorimotor functions. Indeed, activation of these structures in response to respiratory challenges has been previously reported (5,8,11,31,35,47). The prefrontal cortex, including the middle and inferior frontal gyri, was also activated during respiratory challenge, as in previous studies (5,11,31,46).…”

“…Indeed, activation of these structures in response to respiratory challenges has been previously reported (5,8,11,31,35,47). The prefrontal cortex, including the middle and inferior frontal gyri, was also activated during respiratory challenge, as in previous studies (5,11,31,46). The cerebellum, which receives vagal inputs (24), plays an essential role in coordinating sensory aspects of loads with respiratory motor output.…”

“…Parietal lobules are somatosensory association areas and are particularly concerned with vigilance. It is reasonable that these regions are activated, because respiratory loading (27,31) induced activation of the inferior parietal lobule.…”

“…It has been shown that respiratory loading is associated with the activation of basal ganglia (5,8,11,20,27,31,35,47). Limbic areas, including the parahippocampal gyrus, insula, and cingulate gyrus, participate in emotive and visceral sensorimotor functions.…”

Mental processes and strategic equilibration: An fMRI study of selling strategies in second price auctions

“…More broadly speaking, the anterior cingulate cortex is involved in maintaining physiological homeostasis through the regulation of a wide variety of mechanisms necessary for life including hunger and thirst. (Liotti, et al 2001). This broader view of a homeostatic role for anterior cingulate is consistent with the lack of activation in these structures during economic decision making during equilibrium conditions.…”