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D A Denton - One of the best experts on this subject based on the ideXlab platform.
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influence of anterior midcingulate cortex on drinking behavior during Thirst and following satiation
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Pascal Saker, Michael Farrell, Gary F Egan, M J Mckinley, D A DentonAbstract:In humans, activity in the anterior midcingulate cortex (aMCC) is associated with both subjective Thirst and swallowing. This region is therefore likely to play a prominent role in the regulation of drinking in response to dehydration. Using functional MRI, we investigated this possibility during a period of "drinking behavior" represented by a conjunction of preswallow and swallowing events. These events were examined in the context of a Thirsty condition and an "oversated" condition, the latter induced by compliant ingestion of excess fluid. Brain regions associated with swallowing showed increased activity for drinking behavior in the Thirsty condition relative to the oversated condition. These regions included the cingulate cortex, premotor areas, primary sensorimotor cortices, the parietal operculum, and the supplementary motor area. Psychophysical interaction analyses revealed increased functional connectivity between the same regions and the aMCC during drinking behavior in the Thirsty condition. Functional connectivity during drinking behavior was also greater for the Thirsty condition relative to the oversated condition between the aMCC and two subcortical regions, the cerebellum and the rostroventral medulla, the latter containing nuclei responsible for the swallowing reflex. Finally, during drinking behavior in the oversated condition, ratings of swallowing effort showed a negative association with functional connectivity between the aMCC and two cortical regions, the sensorimotor cortex and the supramarginal gyrus. The results of this study provide evidence that the aMCC helps facilitate swallowing during a state of Thirst and is therefore likely to contribute to the regulation of drinking after dehydration.
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regional brain responses associated with drinking water during Thirst and after its satiation
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Pascal Saker, Michael Farrell, Faiz R M Adib, Gary F Egan, M J Mckinley, D A DentonAbstract:The instinct of Thirst was a cardinal element in the successful colonization by vertebrates of the dry land of the planet, which began in the Ordovician period about 400 million y ago. It is a commonplace experience in humans that drinking water in response to Thirst following fluid loss is a pleasant experience. However, continuing to drink water once Thirst has been satiated becomes unpleasant and, eventually, quite aversive. Functional MRI experiments reported here show pleasantness of drinking is associated with activation in the anterior cingulate cortex (Brodmann area 32) and the orbitofrontal cortex. The unpleasantness and aversion of overdrinking is associated with activation in the midcingulate cortex, insula, amygdala, and periaqueductal gray. Drinking activations in the putamen and cerebellum also correlated with the unpleasantness of water, and the motor cortex showed increased activation during overdrinking compared with drinking during Thirst. These activations in motor regions may possibly reflect volitional effort to conduct compliant drinking in the face of regulatory mechanisms inhibiting intake. The results suggestive of a specific inhibitory system in the control of drinking are unique.
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cortical activation and lamina terminalis functional connectivity during Thirst and drinking in humans
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2011Co-Authors: Michael Farrell, Robin M. Mcallen, M J Mckinley, D A Denton, Tharushini K Bowala, Maria Gavrilescu, Paddy A Phillips, Gary F EganAbstract:The pattern of regional brain activation in humans during Thirst associated with dehydration, increased blood osmolality, and decreased blood volume is not known. Furthermore, there is little information available about associations between activation in osmoreceptive brain regions such as the organum vasculosum of the lamina terminalis and the brain regions implicated in Thirst and its satiation in humans. With the objective of investigating the neuroanatomical correlates of dehydration and activation in the ventral lamina terminalis, this study involved exercise-induced sweating in 15 people and measures of regional cerebral blood flow (rCBF) using a functional magnetic resonance imaging technique called pulsed arterial spin labeling. Regional brain activations during dehydration, Thirst, and postdrinking were consistent with the network previously identified during systemic hypertonic infusions, thus providing further evidence that the network is involved in monitoring body fluid and the experience of Thirst. rCBF measurements in the ventral lamina terminalis were correlated with whole brain rCBF measures to identify regions that correlated with the osmoreceptive region. Regions implicated in the experience of Thirst were identified including cingulate cortex, prefrontal cortex, striatum, parahippocampus, and cerebellum. Furthermore, the correlation of rCBF between the ventral lamina terminalis and the cingulate cortex and insula was different for the states of Thirst and recent drinking, suggesting that functional connectivity of the ventral lamina terminalis is a dynamic process influenced by hydration status and ingestive behavior.
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effect of aging on regional cerebral blood flow responses associated with osmotic Thirst and its satiation by water drinking a pet study
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Michael Farrell, M J Mckinley, D A Denton, Paddy A Phillips, Robert E Shade, Peter T Fox, Frank Zamarripa, J R Blairwest, Gary F EganAbstract:Levels of Thirst and ad libitum drinking decrease with advancing age, making older people vulnerable to dehydration. This study investigated age-related changes in brain responses to Thirst and drinking in healthy men. Thirst was induced with hypertonic infusions (3.1 ml/kg 0.51M NaCl) in young (Y) and older (O) subjects. Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET). Thirst activations were identified by correlating rCBF with Thirst ratings. Average rCBF was measured from regions of interest (ROI) corresponding to activation clusters in each group. The effects of drinking were examined by correlating volume of water drunk with changes in ROI rCBF from maximum Thirst to postdrinking. There were increases in blood osmolality (Y, 2.8 ± 1.8%; O, 2.2 ± 1.4%) and Thirst ratings (Y, 3.1 ± 2.1; O, 3.7 ± 2.8) from baseline to the end of the hypertonic infusion. Older subjects drank less water (1.9 ± 1.6 ml/kg) than younger subjects (3.9 ± 1.9 ml/kg). Thirst-related activation was evident in S1/M1, prefrontal cortex, anterior midcingulate cortex (aMCC), premotor cortex, and superior temporal gyrus in both groups. Postdrinking changes of rCBF in the aMCC correlated with drinking volumes in both groups. There was a greater reduction in aMCC rCBF relative to water drunk in the older group. Aging is associated with changes in satiation that militate against adequate hydration in response to hyperosmolarity, although it is unclear whether these alterations are due to changes in primary afferent inflow or higher cortical functioning.
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neuroimaging evidence implicating cerebellum in support of sensory cognitive processes associated with Thirst
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Lawrence M Parsons, Gary F Egan, M J Mckinley, D A Denton, Robert E Shade, Jack L Lancaster, Peter T FoxAbstract:Recent studies implicate the cerebellum, long considered strictly a motor control structure, in cognitive, sensory, and affective phe- nomenon. The cerebellum, a phylogenetically ancient structure, has reciprocal ancient connections to the hypothalamus, a struc- ture important in vegetative functions. The present study investi- gated whether the cerebellum was involved in vegetative func- tions and the primal emotions engendered by them. Using positron emission tomography, we examined the effects on the cerebellum of the rise of plasma sodium concentration and the emergence of Thirst in 10 healthy adults. The correlation of regional cerebral blood flow with subjects' ratings of Thirst showed major activation in the vermal central lobule. During the development of Thirst, the anterior and posterior quadrangular lobule, lingula, and the vermis were activated. At maximum Thirst and then during irrigation of the mouth with water to alleviate dryness, the cerebellum was less activated. However, 3 min after drinking to satiation, the anterior quadrangular lobule and posterior cerebellum were highly acti- vated. The increased cerebellar activity was not related to motor behavior as this did not occur. Instead, responses in ancient cerebellar regions (vermis, fastigal nucleus, archicerebellum) may be more directly related to vegetative and affective aspects of Thirst experiences, whereas activity in neocerebellar (posterior) regions may be related to sensory and cognitive aspects. More- over, the cerebellum is apparently not involved in the computation of Thirst per se but rather is activated during changes in Thirsty satiation state when the brain is ''vigilant'' and is monitoring its sensory systems. Some neocerebellar activity may also reflect an intentionality for gratification by drinking inherent in the con- sciousness of Thirst.
Alan Kim Johnson - One of the best experts on this subject based on the ideXlab platform.
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Integration of thermal and osmotic regulation of water homeostasis: the role of TRPV channels.
American journal of physiology. Regulatory integrative and comparative physiology, 2013Co-Authors: Celia D. Sladek, Alan Kim JohnsonAbstract:Maintenance of body water homeostasis is critical for preventing hyperthermia, because evaporative cooling is the most efficient means of dissipating excess body heat. Water homeostasis is achieved by regulation of water intake and water loss by the kidneys. The former is achieved by sensations of Thirst that motivate water acquisition, whereas the latter is regulated by the antidiuretic action of vasopressin. Vasopressin secretion and Thirst are stimulated by increases in the osmolality of the extracellular fluid as well as decreases in blood pressure and/or blood volume, signals that are precipitated by water depletion associated with the excess evaporative water loss required to prevent hyperthermia. In addition, they are stimulated by increases in body temperature. The sites and molecular mechanisms involved in integrating thermal and osmotic regulation of Thirst and vasopressin secretion are reviewed here with a focus on the role of the thermal and mechanosensitive transient receptor potential-vanilloid (TRPV) family of ion channels.
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the physiological regulation of Thirst and fluid intake
Physiology, 2004Co-Authors: M J Mckinley, Alan Kim JohnsonAbstract:Thirst is important for maintaining body fluid homeostasis and may arise from deficits in either intracellular or extracellular fluid volume. Neural signals arising from osmotic and hormonal influences on the lamina terminalis may be integrated within the brain, with afferent information relayed from intrathoracic baroreceptors via the hindbrain to generate Thirst.
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the neuroendocrinology of Thirst and salt appetite visceral sensory signals and mechanisms of central integration
Frontiers in Neuroendocrinology, 1997Co-Authors: Alan Kim Johnson, Robert L ThunhorstAbstract:Abstract This review examines recent advances in the study of the behavioral responses to deficits of body water and body sodium that in humans are accompanied by the sensations of Thirst and salt appetite. Thirst and salt appetite are satisfied by ingesting water and salty substances. These behavioral responses to losses of body fluids, together with reflex endocrine and neural responses, are critical for reestablishing homeostasis. Like their endocrine and neural counterparts, these behaviors are under the control of both excitatory and inhibitory influences arising from changes in osmolality, endocrine factors such as angiotensin and aldosterone, and neural signals from low and high pressure baroreceptors. The excitatory and inhibitory influences reaching the brain require the integrative capacity of a neural network which includes the structures of the lamina terminalis, the amygdala, the perifornical area, and the paraventricular nucleus in the forebrain, and the lateral parabrachial nucleus (LPBN), the nucleus tractus solitarius (NTS), and the area postrema in the hindbrain. These regions are discussed in terms of their roles in receiving afferent sensory input and in processing information related to hydromineral balance. Osmoreceptors controlling Thirst are located in systemic viscera and in central structures that lack the blood–brain barrier. Angiotensin and aldosterone act on and through structures of the lamina terminalis and the amygdala to stimulate Thirst and sodium appetite under conditions of hypovolemia. The NTS and LPBN receive neural signals from baroreceptors and are responsible for inhibiting the ingestion of fluids under conditions of increased volume and pressure and for stimulating Thirst under conditions of hypovolemia and hypotension. The interplay of multiple facilitory influences within the brain may take the form of interactions between descending angiotensinergic systems originating in the forebrain and ascending adrenergic systems emanating from the hindbrain. Oxytocin and serotonin are additional candidate neurochemicals with postulated inhibitory central actions and with essential roles in the overall integration of sensory input within the neural network devoted to maintaining hydromineral balance.
M J Mckinley - One of the best experts on this subject based on the ideXlab platform.
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influence of anterior midcingulate cortex on drinking behavior during Thirst and following satiation
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Pascal Saker, Michael Farrell, Gary F Egan, M J Mckinley, D A DentonAbstract:In humans, activity in the anterior midcingulate cortex (aMCC) is associated with both subjective Thirst and swallowing. This region is therefore likely to play a prominent role in the regulation of drinking in response to dehydration. Using functional MRI, we investigated this possibility during a period of "drinking behavior" represented by a conjunction of preswallow and swallowing events. These events were examined in the context of a Thirsty condition and an "oversated" condition, the latter induced by compliant ingestion of excess fluid. Brain regions associated with swallowing showed increased activity for drinking behavior in the Thirsty condition relative to the oversated condition. These regions included the cingulate cortex, premotor areas, primary sensorimotor cortices, the parietal operculum, and the supplementary motor area. Psychophysical interaction analyses revealed increased functional connectivity between the same regions and the aMCC during drinking behavior in the Thirsty condition. Functional connectivity during drinking behavior was also greater for the Thirsty condition relative to the oversated condition between the aMCC and two subcortical regions, the cerebellum and the rostroventral medulla, the latter containing nuclei responsible for the swallowing reflex. Finally, during drinking behavior in the oversated condition, ratings of swallowing effort showed a negative association with functional connectivity between the aMCC and two cortical regions, the sensorimotor cortex and the supramarginal gyrus. The results of this study provide evidence that the aMCC helps facilitate swallowing during a state of Thirst and is therefore likely to contribute to the regulation of drinking after dehydration.
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regional brain responses associated with drinking water during Thirst and after its satiation
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Pascal Saker, Michael Farrell, Faiz R M Adib, Gary F Egan, M J Mckinley, D A DentonAbstract:The instinct of Thirst was a cardinal element in the successful colonization by vertebrates of the dry land of the planet, which began in the Ordovician period about 400 million y ago. It is a commonplace experience in humans that drinking water in response to Thirst following fluid loss is a pleasant experience. However, continuing to drink water once Thirst has been satiated becomes unpleasant and, eventually, quite aversive. Functional MRI experiments reported here show pleasantness of drinking is associated with activation in the anterior cingulate cortex (Brodmann area 32) and the orbitofrontal cortex. The unpleasantness and aversion of overdrinking is associated with activation in the midcingulate cortex, insula, amygdala, and periaqueductal gray. Drinking activations in the putamen and cerebellum also correlated with the unpleasantness of water, and the motor cortex showed increased activation during overdrinking compared with drinking during Thirst. These activations in motor regions may possibly reflect volitional effort to conduct compliant drinking in the face of regulatory mechanisms inhibiting intake. The results suggestive of a specific inhibitory system in the control of drinking are unique.
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cortical activation and lamina terminalis functional connectivity during Thirst and drinking in humans
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2011Co-Authors: Michael Farrell, Robin M. Mcallen, M J Mckinley, D A Denton, Tharushini K Bowala, Maria Gavrilescu, Paddy A Phillips, Gary F EganAbstract:The pattern of regional brain activation in humans during Thirst associated with dehydration, increased blood osmolality, and decreased blood volume is not known. Furthermore, there is little information available about associations between activation in osmoreceptive brain regions such as the organum vasculosum of the lamina terminalis and the brain regions implicated in Thirst and its satiation in humans. With the objective of investigating the neuroanatomical correlates of dehydration and activation in the ventral lamina terminalis, this study involved exercise-induced sweating in 15 people and measures of regional cerebral blood flow (rCBF) using a functional magnetic resonance imaging technique called pulsed arterial spin labeling. Regional brain activations during dehydration, Thirst, and postdrinking were consistent with the network previously identified during systemic hypertonic infusions, thus providing further evidence that the network is involved in monitoring body fluid and the experience of Thirst. rCBF measurements in the ventral lamina terminalis were correlated with whole brain rCBF measures to identify regions that correlated with the osmoreceptive region. Regions implicated in the experience of Thirst were identified including cingulate cortex, prefrontal cortex, striatum, parahippocampus, and cerebellum. Furthermore, the correlation of rCBF between the ventral lamina terminalis and the cingulate cortex and insula was different for the states of Thirst and recent drinking, suggesting that functional connectivity of the ventral lamina terminalis is a dynamic process influenced by hydration status and ingestive behavior.
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effect of aging on regional cerebral blood flow responses associated with osmotic Thirst and its satiation by water drinking a pet study
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Michael Farrell, M J Mckinley, D A Denton, Paddy A Phillips, Robert E Shade, Peter T Fox, Frank Zamarripa, J R Blairwest, Gary F EganAbstract:Levels of Thirst and ad libitum drinking decrease with advancing age, making older people vulnerable to dehydration. This study investigated age-related changes in brain responses to Thirst and drinking in healthy men. Thirst was induced with hypertonic infusions (3.1 ml/kg 0.51M NaCl) in young (Y) and older (O) subjects. Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET). Thirst activations were identified by correlating rCBF with Thirst ratings. Average rCBF was measured from regions of interest (ROI) corresponding to activation clusters in each group. The effects of drinking were examined by correlating volume of water drunk with changes in ROI rCBF from maximum Thirst to postdrinking. There were increases in blood osmolality (Y, 2.8 ± 1.8%; O, 2.2 ± 1.4%) and Thirst ratings (Y, 3.1 ± 2.1; O, 3.7 ± 2.8) from baseline to the end of the hypertonic infusion. Older subjects drank less water (1.9 ± 1.6 ml/kg) than younger subjects (3.9 ± 1.9 ml/kg). Thirst-related activation was evident in S1/M1, prefrontal cortex, anterior midcingulate cortex (aMCC), premotor cortex, and superior temporal gyrus in both groups. Postdrinking changes of rCBF in the aMCC correlated with drinking volumes in both groups. There was a greater reduction in aMCC rCBF relative to water drunk in the older group. Aging is associated with changes in satiation that militate against adequate hydration in response to hyperosmolarity, although it is unclear whether these alterations are due to changes in primary afferent inflow or higher cortical functioning.
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the physiological regulation of Thirst and fluid intake
Physiology, 2004Co-Authors: M J Mckinley, Alan Kim JohnsonAbstract:Thirst is important for maintaining body fluid homeostasis and may arise from deficits in either intracellular or extracellular fluid volume. Neural signals arising from osmotic and hormonal influences on the lamina terminalis may be integrated within the brain, with afferent information relayed from intrathoracic baroreceptors via the hindbrain to generate Thirst.
Takashi Matsuda - One of the best experts on this subject based on the ideXlab platform.
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distinct neural mechanisms for the control of Thirst and salt appetite in the subfornical organ
Nature Neuroscience, 2017Co-Authors: Takashi Matsuda, Takeshi Y Hiyama, Fumio Niimura, Taiji Matsusaka, Akiyoshi Fukamizu, Kenta Kobayashi, Kazuto Kobayashi, Masaharu NodaAbstract:Body fluid conditions are continuously monitored in the brain to regulate Thirst and salt-appetite sensations. Angiotensin II drives both Thirst and salt appetite; however, the neural mechanisms underlying selective water- and/or salt-intake behaviors remain unknown. Using optogenetics, we show that Thirst and salt appetite are driven by distinct groups of angiotensin II receptor type 1a-positive excitatory neurons in the subfornical organ. Neurons projecting to the organum vasculosum lamina terminalis control water intake, while those projecting to the ventral part of the bed nucleus of the stria terminalis control salt intake. Thirst-driving neurons are suppressed under sodium-depleted conditions through cholecystokinin-mediated activation of GABAergic neurons. In contrast, the salt appetite-driving neurons were suppressed under dehydrated conditions through activation of another population of GABAergic neurons by Nax signals. These distinct mechanisms in the subfornical organ may underlie the selective intakes of water and/or salt and may contribute to body fluid homeostasis.
Gary F Egan - One of the best experts on this subject based on the ideXlab platform.
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influence of anterior midcingulate cortex on drinking behavior during Thirst and following satiation
Proceedings of the National Academy of Sciences of the United States of America, 2018Co-Authors: Pascal Saker, Michael Farrell, Gary F Egan, M J Mckinley, D A DentonAbstract:In humans, activity in the anterior midcingulate cortex (aMCC) is associated with both subjective Thirst and swallowing. This region is therefore likely to play a prominent role in the regulation of drinking in response to dehydration. Using functional MRI, we investigated this possibility during a period of "drinking behavior" represented by a conjunction of preswallow and swallowing events. These events were examined in the context of a Thirsty condition and an "oversated" condition, the latter induced by compliant ingestion of excess fluid. Brain regions associated with swallowing showed increased activity for drinking behavior in the Thirsty condition relative to the oversated condition. These regions included the cingulate cortex, premotor areas, primary sensorimotor cortices, the parietal operculum, and the supplementary motor area. Psychophysical interaction analyses revealed increased functional connectivity between the same regions and the aMCC during drinking behavior in the Thirsty condition. Functional connectivity during drinking behavior was also greater for the Thirsty condition relative to the oversated condition between the aMCC and two subcortical regions, the cerebellum and the rostroventral medulla, the latter containing nuclei responsible for the swallowing reflex. Finally, during drinking behavior in the oversated condition, ratings of swallowing effort showed a negative association with functional connectivity between the aMCC and two cortical regions, the sensorimotor cortex and the supramarginal gyrus. The results of this study provide evidence that the aMCC helps facilitate swallowing during a state of Thirst and is therefore likely to contribute to the regulation of drinking after dehydration.
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regional brain responses associated with drinking water during Thirst and after its satiation
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Pascal Saker, Michael Farrell, Faiz R M Adib, Gary F Egan, M J Mckinley, D A DentonAbstract:The instinct of Thirst was a cardinal element in the successful colonization by vertebrates of the dry land of the planet, which began in the Ordovician period about 400 million y ago. It is a commonplace experience in humans that drinking water in response to Thirst following fluid loss is a pleasant experience. However, continuing to drink water once Thirst has been satiated becomes unpleasant and, eventually, quite aversive. Functional MRI experiments reported here show pleasantness of drinking is associated with activation in the anterior cingulate cortex (Brodmann area 32) and the orbitofrontal cortex. The unpleasantness and aversion of overdrinking is associated with activation in the midcingulate cortex, insula, amygdala, and periaqueductal gray. Drinking activations in the putamen and cerebellum also correlated with the unpleasantness of water, and the motor cortex showed increased activation during overdrinking compared with drinking during Thirst. These activations in motor regions may possibly reflect volitional effort to conduct compliant drinking in the face of regulatory mechanisms inhibiting intake. The results suggestive of a specific inhibitory system in the control of drinking are unique.
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cortical activation and lamina terminalis functional connectivity during Thirst and drinking in humans
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2011Co-Authors: Michael Farrell, Robin M. Mcallen, M J Mckinley, D A Denton, Tharushini K Bowala, Maria Gavrilescu, Paddy A Phillips, Gary F EganAbstract:The pattern of regional brain activation in humans during Thirst associated with dehydration, increased blood osmolality, and decreased blood volume is not known. Furthermore, there is little information available about associations between activation in osmoreceptive brain regions such as the organum vasculosum of the lamina terminalis and the brain regions implicated in Thirst and its satiation in humans. With the objective of investigating the neuroanatomical correlates of dehydration and activation in the ventral lamina terminalis, this study involved exercise-induced sweating in 15 people and measures of regional cerebral blood flow (rCBF) using a functional magnetic resonance imaging technique called pulsed arterial spin labeling. Regional brain activations during dehydration, Thirst, and postdrinking were consistent with the network previously identified during systemic hypertonic infusions, thus providing further evidence that the network is involved in monitoring body fluid and the experience of Thirst. rCBF measurements in the ventral lamina terminalis were correlated with whole brain rCBF measures to identify regions that correlated with the osmoreceptive region. Regions implicated in the experience of Thirst were identified including cingulate cortex, prefrontal cortex, striatum, parahippocampus, and cerebellum. Furthermore, the correlation of rCBF between the ventral lamina terminalis and the cingulate cortex and insula was different for the states of Thirst and recent drinking, suggesting that functional connectivity of the ventral lamina terminalis is a dynamic process influenced by hydration status and ingestive behavior.
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effect of aging on regional cerebral blood flow responses associated with osmotic Thirst and its satiation by water drinking a pet study
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Michael Farrell, M J Mckinley, D A Denton, Paddy A Phillips, Robert E Shade, Peter T Fox, Frank Zamarripa, J R Blairwest, Gary F EganAbstract:Levels of Thirst and ad libitum drinking decrease with advancing age, making older people vulnerable to dehydration. This study investigated age-related changes in brain responses to Thirst and drinking in healthy men. Thirst was induced with hypertonic infusions (3.1 ml/kg 0.51M NaCl) in young (Y) and older (O) subjects. Regional cerebral blood flow (rCBF) was measured with positron emission tomography (PET). Thirst activations were identified by correlating rCBF with Thirst ratings. Average rCBF was measured from regions of interest (ROI) corresponding to activation clusters in each group. The effects of drinking were examined by correlating volume of water drunk with changes in ROI rCBF from maximum Thirst to postdrinking. There were increases in blood osmolality (Y, 2.8 ± 1.8%; O, 2.2 ± 1.4%) and Thirst ratings (Y, 3.1 ± 2.1; O, 3.7 ± 2.8) from baseline to the end of the hypertonic infusion. Older subjects drank less water (1.9 ± 1.6 ml/kg) than younger subjects (3.9 ± 1.9 ml/kg). Thirst-related activation was evident in S1/M1, prefrontal cortex, anterior midcingulate cortex (aMCC), premotor cortex, and superior temporal gyrus in both groups. Postdrinking changes of rCBF in the aMCC correlated with drinking volumes in both groups. There was a greater reduction in aMCC rCBF relative to water drunk in the older group. Aging is associated with changes in satiation that militate against adequate hydration in response to hyperosmolarity, although it is unclear whether these alterations are due to changes in primary afferent inflow or higher cortical functioning.
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neuroimaging evidence implicating cerebellum in support of sensory cognitive processes associated with Thirst
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Lawrence M Parsons, Gary F Egan, M J Mckinley, D A Denton, Robert E Shade, Jack L Lancaster, Peter T FoxAbstract:Recent studies implicate the cerebellum, long considered strictly a motor control structure, in cognitive, sensory, and affective phe- nomenon. The cerebellum, a phylogenetically ancient structure, has reciprocal ancient connections to the hypothalamus, a struc- ture important in vegetative functions. The present study investi- gated whether the cerebellum was involved in vegetative func- tions and the primal emotions engendered by them. Using positron emission tomography, we examined the effects on the cerebellum of the rise of plasma sodium concentration and the emergence of Thirst in 10 healthy adults. The correlation of regional cerebral blood flow with subjects' ratings of Thirst showed major activation in the vermal central lobule. During the development of Thirst, the anterior and posterior quadrangular lobule, lingula, and the vermis were activated. At maximum Thirst and then during irrigation of the mouth with water to alleviate dryness, the cerebellum was less activated. However, 3 min after drinking to satiation, the anterior quadrangular lobule and posterior cerebellum were highly acti- vated. The increased cerebellar activity was not related to motor behavior as this did not occur. Instead, responses in ancient cerebellar regions (vermis, fastigal nucleus, archicerebellum) may be more directly related to vegetative and affective aspects of Thirst experiences, whereas activity in neocerebellar (posterior) regions may be related to sensory and cognitive aspects. More- over, the cerebellum is apparently not involved in the computation of Thirst per se but rather is activated during changes in Thirsty satiation state when the brain is ''vigilant'' and is monitoring its sensory systems. Some neocerebellar activity may also reflect an intentionality for gratification by drinking inherent in the con- sciousness of Thirst.
