scholarly journals Cardiac response in aversive and appetitive olfactory conditioning: Evidence for a valence‐independent CS‐elicited bradycardia

2021 ◽  
Author(s):  
Anna Exner ◽  
Isabell Tapia León ◽  
Erik M. Mueller ◽  
Tim Klucken
2003 ◽  
Vol 17 (2) ◽  
pp. 61-68 ◽  
Author(s):  
Michal Kuniecki ◽  
Robert Barry ◽  
Jan Kaiser

Abstract The effect of stimulus valence was examined in the evoked cardiac response (ECR) elicited by the exposition of neutral and negative slides as well as by an innocuous auditory stimulus presented on the affective foregrounds generated by the slides. The exposition of the aversive slide produced prolonged cardiac deceleration in comparison with the neutral slide. Similar prolonged deceleration accompanied exposition of the neutral auditory stimulus on the negative visual foreground in comparison with the neutral foreground. We interpret these results as an autonomic correlate of extended stimulus processing associated with the affective stimulus. The initial deceleration response, covering two or three slower heart beats, may be prolonged for several seconds before HR reaches the baseline level again. In such a case the evoked cardiac deceleration can be functionally divided into two parts: the reflexive bradycardia (ECR1) elicited by neutral stimuli and a late decelerative component (LDC). We can speculate that the latter is associated with an additional voluntary continuation of processing of the stimulus. This must involve some cognitive aspect different from the mental task performance which leads to the accelerative ECR2, and we suggest that processing of a stimulus with negative valence is involved in generating the LDC.


2001 ◽  
Vol 281 (5) ◽  
pp. E1029-E1036 ◽  
Author(s):  
Raymond R. Russell ◽  
Deborah Chyun ◽  
Steven Song ◽  
Robert S. Sherwin ◽  
William V. Tamborlane ◽  
...  

Insulin-induced hypoglycemia occurs commonly in intensively treated patients with type 1 diabetes, but the cardiovascular consequences of hypoglycemia in these patients are not known. We studied left ventricular systolic [left ventricular ejection fraction (LVEF)] and diastolic [peak filling rate (PFR)] function by equilibrium radionuclide angiography during insulin infusion (12 pmol · kg−1 · min−1) under either hypoglycemic (∼2.8 mmol/l) or euglycemic (∼5 mmol/l) conditions in intensively treated patients with type 1 diabetes and healthy nondiabetic subjects ( n = 9 for each). During hypoglycemic hyperinsulinemia, there were significant increases in LVEF (ΔLVEF = 11 ± 2%) and PFR [ΔPFR = 0.88 ± 0.18 end diastolic volume (EDV)/s] in diabetic subjects as well as in the nondiabetic group (ΔLVEF = 13 ± 2%; ΔPFR = 0.79 ± 0.17 EDV/s). The increases in LVEF and PFR were comparable overall but occurred earlier in the nondiabetic group. A blunted increase in plasma catecholamine, cortisol, and glucagon concentrations occurred in response to hypoglycemia in the diabetic subjects. During euglycemic hyperinsulinemia, LVEF also increased in both the diabetic (ΔLVEF = 7 ± 1%) and nondiabetic (ΔLVEF = 4 ± 2%) groups, but PFR increased only in the diabetic group. In the comparison of the responses to hypoglycemic and euglycemic hyperinsulinemia, only the nondiabetic group had greater augmentation of LVEF, PFR, and cardiac output in the hypoglycemic study ( P < 0.05 for each). Thus intensively treated type 1 diabetic patients demonstrate delayed augmentation of ventricular function during moderate insulin-induced hypoglycemia. Although diabetic subjects have a more pronounced cardiac response to hyperinsulinemia per se than nondiabetic subjects, their response to hypoglycemia is blunted.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Daniele Carlesso ◽  
Stefania Smargiassi ◽  
Elisa Pasquini ◽  
Giacomo Bertelli ◽  
David Baracchi

AbstractFloral nectar is a pivotal element of the intimate relationship between plants and pollinators. Nectars are composed of a plethora of nutritionally valuable compounds but also hundreds of secondary metabolites (SMs) whose function remains elusive. Here we performed a set of behavioural experiments to study whether five ubiquitous nectar non-protein amino acids (NPAAs: β-alanine, GABA, citrulline, ornithine and taurine) interact with gustation, feeding preference, and learning and memory in Apis mellifera. We showed that foragers were unable to discriminate NPAAs from water when only accessing antennal chemo-tactile information and that freely moving bees did not exhibit innate feeding preferences for NPAAs. Also, NPAAs did not alter food consumption or longevity in caged bees over 10 days. Taken together our data suggest that natural concentrations of NPAAs did not alter nectar palatability to bees. Olfactory conditioning assays showed that honey bees were more likely to learn a scent when it signalled a sucrose reward containing either β-alanine or GABA, and that GABA enhanced specific memory retention. Conversely, when ingested two hours prior to conditioning, GABA, β-alanine, and taurine weakened bees’ acquisition performances but not specific memory retention, which was enhanced in the case of β-alanine and taurine. Neither citrulline nor ornithine affected learning and memory. NPAAs in nectars may represent a cooperative strategy adopted by plants to attract beneficial pollinators.


2007 ◽  
Vol 58 ◽  
pp. S170
Author(s):  
Chihiro Sato ◽  
Yukihisa Matsumoto ◽  
Midori Sakura ◽  
Hidehiro Watanabe ◽  
Makoto Mizunami

2003 ◽  
Vol 65 (1) ◽  
pp. 123-130 ◽  
Author(s):  
Maki Ikebuchi ◽  
Miho Futamatsu ◽  
Kazuo Okanoya

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