Browsing by Author "Torrealba, Fernando"
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- ItemA Review on Electron Microscopy and Neurotransmitter Systems(2004) Torrealba, Fernando
- ItemA Role for the Insular Cortex in Long-Term Memory for Context-Evoked Drug Craving in Rats(2012) Contreras, Marco; Billeke, Pablo; Vicencio, Sergio; Madrid, Carlos; Perdomo, Gueton; Gonzalez, Marcela; Torrealba, FernandoDrug craving critically depends on the function of the interoceptive insular cortex, and may be triggered by contextual cues. However, the role of the insula in the long-term memory linking context with drug craving remains unknown. Such a memory trace probably resides in some neocortical region, much like other declarative memories. Studies in humans and rats suggest that the insula may include such a region. Rats chronically implanted with bilateral injection cannulae into the high-order rostral agranular insular cortex (RAIC) or the primary interoceptive posterior insula (pIC) were conditioned to prefer the initially aversive compartment of a 2-compartment place preference apparatus by repeatedly pairing it to amphetamine. We found a reversible but long-lasting loss (ca. 24 days) of amphetamine-conditioned place preference (CPP) and a decreased expression in the insula of zif268, a crucial protein in memory reconsolidation, when anisomycin (ANI) was microinjected into the RAIC immediately after the reactivation of the conditioned amphetamine/context memory. ANI infusion into the RAIC without reactivation did not change CPP, whereas ANI infusion into pIC plus caused a 15 days loss of CPP. We also found a 24 days loss of CPP when we reversibly inactivated pIC during extinction trials. We interpret these findings as evidence that the insular cortex, including the RAIC, is involved in a context/drug effect association. These results add a drug-related memory function to the insular cortex to the previously found role of the pIC in the perception of craving or malaise. Neuropsychopharmacology (2012) 37, 2101-2108; doi:10.1038/npp.2012.59; published online 25 April 2012
- ItemA tribute to Dr. Teresa Pinto-Hamuy(2008) Robles, L.; Torrealba, Fernando
- ItemAn Inescapable Cat Odor Exposure Protocol for Studying Innate and Contextual Threat Conditioning in Rats(2021) Rodriguez, Maria; Contreras, Marco; Domic-Siede, Marcos; Ceric, Francisco; Torrealba, FernandoAnimals respond to threatening situations by exhibiting a number of defensive behaviors, including avoidance, freezing, and risk assessment. An animal model with an ethological approach offers a deeper insight into the biological mechanisms underlying threat responses. This paper describes a methodology to measure defensive behaviors toward both innate and learned aversive stimuli in rats. Animals were individually exposed to predator odor in an inescapable chamber to elicit a measurable, sustained, defensive state. The experimental design involved placing a rat in a familiar chamber for 10 min followed by exposure to cat odor for another 10 min in the same context. The next day, the rats were
- ItemAnatomical Substrate for Separate Processing of Ascending and Descending Visceral Information in the Nucleus of the Solitary Tract of the Rat(2000) Acuña-Goycolea, C.; Torrealba, Fernando
- ItemAntiribosomal-P autoantibodies from psychiatric lupus target a novel neuronal surface protein causing calcium influx and apoptosis(2007) Matus, Soledad; Torrealba, Fernando; Massardo Vega, Loreto; González de la Rosa, Alfonso
- ItemArousal and Differential Fos Expression in Histaminergic Neurons of the Ascending Arousal System During a Feeding-Related Motivated Behaviour(2005) Valdés, J.; Serón Ferré, María; Torrealba, Fernando; Valdés, J.; Serón Ferré, María; Torrealba, Fernando
- ItemCentral Proyections of Coarse and Fine Vagal Axons of the Cat(1990) Calderón, F.; Torrealba, Fernando
- ItemClock gene expression in adult primate suprachiasmatic nuclei and adrenal: Is the adrenal a peripheral clock responsive to melatonin?(2008) Valenzuela, F.; Campino Johnson, María del Carmen; Torrealba, Fernando; Serón Ferré, María; Valenzuela, F.; Campino Johnson, María del Carmen; Torrealba, Fernando; Serón Ferré, María
- ItemComparative Study of Visual Inter and Intrahemispheric Cortico-Cortical Connections in Five Native Chilean Rodents(1990) Bravo Contreras, Hermes; Torrealba, Fernando
- ItemLa Corteza Prefrontal Medial Controla el Alerta Conductual y Vegetativo: Implicancias en Desórdenes de la Conducta(2006) Valdés, José Luis; Torrealba, Fernando
- ItemCytochrome Oxidase Activity in the Nucleus of the Tractus Solitarius of the Cat(1992) Muñoz, M.; Torrealba, Fernando
- ItemDay-night changes in c-fos expression in the fetal sheep suprachiasmatic nucleus at late gestation(1995) Constandil, L.; Torrealba, Fernando; Serón Ferré, María
- ItemDifferential Effects of Infralimbic Cortical Lesions on Temperature and Locomotor Activity Responses to Feeding in Rats(2005) Recabarren, M.; Serón Ferré, María; Torrealba, Fernando; Recabarren, M.; Serón Ferré, María; Torrealba, Fernando
- ItemEffect of insular cortex inactivation on autonomic and behavioral responses to acute hypoxia in conscious rats(2013) Casanova, José Patricio; Contreras Abarca, Marco; Moya, Esteban A.; Torrealba, Fernando; Iturriaga Agüera, Rodrigo
- ItemEffort Displayed During Appetitive Phase of Feeding Behavior Requires Infralimbic Cortex Activity and Histamine H1 Receptor Signaling(2019) Riveros, Maria E.; Ines Forray, Maria; Torrealba, Fernando; Valdes, Jose L.The chances to succeed in goal-directed behaviors, such as food or water-seeking, improve when the subject is in an increased arousal state. The appetitive phase of these motivated behaviors is characterized by high levels of behavioral and vegetative excitation. The key decision of engaging in those particular behaviors depends primarily on prefrontal cortical areas, such as the ventromedial prefrontal cortex. We propose that the infralimbic cortex (ILC) located in the medial prefrontal cortex induces an increase in arousal during the appetitive phase of motivated behavior, and that this increase in arousal is, in turn, mediated by the activation of the brain histaminergic system, resulting in higher motivation for getting food rewards. To test this hypothesis, we conduct a progressive ratio operant conditioning to test the degree of motivation for food, while simultaneously manipulating the histaminergic system through pharmacologic interventions. We found that the behavioral responses to obtain food in hungry rats were disrupted when the ILC was inhibited through muscimol infusion, blocking brain H1 histamine receptors by intracerebroventricular infusion of pyrilamine or by satiety. In contrast, the consummatory behavior was not affected by ILC inhibition. The extracellular histamine levels in the ILC were increased in direct correlation with the degree of motivation measured in the progressive ratio test. ILC inhibition also prevented this increase in histamine levels. The rise in extracellular histamine levels during the progressive ratio test was similar (ca. 200%) during the active or the resting period of the day. However, different basal levels are observed for these two periods. Our findings suggest that increased histamine levels during this behavior are not simply explained by the awaked state, but instead, there is a motivation-related release of histamine, suggestive of a specific form of brain activation. Serotonin (another critical component of the ascending arousal system) was also tested. Interestingly, changes in levels of this neuromodulator were not detected during the progressive ratio test. In conclusion, our results suggest that ILC activation and subsequent increase in brain histamine release are both necessary for the normal performance of a motivated behavior such as feeding.
- ItemHistamine and motivation(2012) Torrealba, Fernando
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