The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Zachary F. Mainen - One of the best experts on this subject based on the ideXlab platform.
-
speed and accuracy of Olfactory Discrimination in the rat
Nature Neuroscience, 2003Co-Authors: Naoshige Uchida, Zachary F. MainenAbstract:The sense of smell is typically thought of as a 'slow' sense, but the true temporal constraints on the accuracy of Olfactory perception are not known. It has been proposed that animals make finer odor Discriminations at the expense of additional processing time. To test this idea, we measured the relationship between the speed and accuracy of Olfactory Discrimination in rats. We found that speed of Discrimination was independent of odor similarity, as measured by overlap of glomerular activity patterns. Even when pushed to psychophysical limits using mixtures of two odors, rats needed to take only one sniff (<200 ms at theta frequency) to make a decision of maximum accuracy. These results show that, for the purpose of odor quality Discrimination, a fully refined Olfactory sensory representation can emerge within a single sensorimotor or theta cycle, suggesting that each sniff can be considered a snapshot of the Olfactory world.
-
Speed and accuracy of Olfactory Discrimination in the rat
Nature Neuroscience, 2003Co-Authors: Naoshige Uchida, Zachary F. MainenAbstract:The sense of smell is typically thought of as a 'slow' sense, but the true temporal constraints on the accuracy of Olfactory perception are not known. It has been proposed that animals make finer odor Discriminations at the expense of additional processing time. To test this idea, we measured the relationship between the speed and accuracy of Olfactory Discrimination in rats. We found that speed of Discrimination was independent of odor similarity, as measured by overlap of glomerular activity patterns. Even when pushed to psychophysical limits using mixtures of two odors, rats needed to take only one sniff (
Matthias Laska - One of the best experts on this subject based on the ideXlab platform.
-
Olfactory Discrimination Learning in an Outbred and an Inbred Strain of Mice.
Chemical senses, 2015Co-Authors: Matthias LaskaAbstract:The present study compared Olfactory Discrimination learning in CD-1 mice, a widely used outbred strain of mice with that of C57BL/6J mice, one of the most widely used inbred mouse strains. Using an automated olfactometer and a standard operant conditioning procedure, I found that CD-1 mice needed 60 trials to reach learning criterion in an initial 2-odor Discrimination task. They improved in learning speed in subsequent Discrimination tasks in which either the rewarded or the unrewarded stimulus was replaced for a new stimulus. C57BL/6J mice, in contrast, needed 120 trials to reach learning criterion in an initial 2-odor Discrimination task and also needed significantly more trials than the CD-1 mice in 3 of the 4 subsequent Discrimination tasks. Further, the results showed that Discrimination learning performance of both mouse strains was largely unaffected by the odor stimuli used. The results of the present study demonstrate differences between an outbred and an inbred strain of mice with regard to odor Discrimination learning, a classical measure of cognitive performance in comparative psychology. Thus, they emphasize the need to be careful with generalizing statements as to cognitive or sensory abilities of Mus musculus when inbred strains of mice are used.
-
Olfactory Discrimination Ability of Asian Elephants (Elephas maximus) for Structurally Related Odorants
Chemical senses, 2012Co-Authors: Alisa Rizvanovic, Mats Amundin, Matthias LaskaAbstract:Using a food-rewarded two-choice instrumental conditioning paradigm, we assessed the ability of Asian elephants, Elephas maximus, to discriminate between 2 sets of structurally related odorants. We found that the animals successfully discriminated between all 12 odor pairs involving members of homologous series of aliphatic 1-alcohols, n-aldehydes, 2-ketones, and n-carboxylic acids even when the stimuli differed from each other by only 1 carbon. With all 4 chemical classes, the elephants displayed a positive correlation between Discrimination performance and structural similarity of odorants in terms of differences in carbon chain length. The animals also successfully discriminated between all 12 enantiomeric odor pairs tested. An analysis of odor structure–activity relationships suggests that a combination of molecular structural properties rather than a single molecular feature may be responsible for the discriminability of enantiomers. Compared with other species tested previously on the same sets of odor pairs (or on subsets thereof), the Asian elephants performed at least as well as mice and clearly better than human subjects, squirrel monkeys, pigtail macaques, South African fur seals, and honeybees. Further comparisons suggest that neither the relative nor the absolute size of the Olfactory bulbs appear to be reliable predictors of between-species differences in Olfactory Discrimination capabilities. In contrast, we found a positive correlation between the number of functional Olfactory receptor genes and the proportion of discriminable enantiomeric odor pairs. Taken together, the results of the present study support the notion that the sense of smell may play an important role in regulating the behavior of Asian elephants.
-
Olfactory Discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers
Journal of comparative physiology. A Neuroethology sensory neural and behavioral physiology, 2012Co-Authors: Sunghee Kim, Mats Amundin, Matthias LaskaAbstract:Using a food-rewarded two-choice instrumental conditioning paradigm we assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between 12 enantiomeric odor pairs. The results demonstrate that the fur seals as a group were able to discriminate between the optical isomers of carvone, dihydrocarvone, dihydrocarveol, menthol, limonene oxide, α-pinene, fenchone (all p 0.05). An analysis of odor structure-activity relationships suggests that a combination of molecular structural properties rather than a single molecular feature may be responsible for the discriminability of enantiomeric odor pairs. A comparison between the Discrimination performance of the fur seals and that of other species tested previously on the same set of enantiomers (or subsets thereof) suggests that the Olfactory Discrimination capabilities of this marine mammal are surprisingly well developed and not generally inferior to that of terrestrial mammals such as human subjects and non-human primates. Further, comparisons suggest that neither the relative nor the absolute size of the Olfactory bulbs appear to be reliable predictors of between-species differences in Olfactory Discrimination capabilities. Taken together, the results of the present study support the notion that the sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals.
-
Successful acquisition of an Olfactory Discrimination test by Asian elephants, Elephas maximus.
Physiology & behavior, 2011Co-Authors: Josefin Arvidsson, Mats Amundin, Matthias LaskaAbstract:article i nfo The present study demonstrates that Asian elephants, Elephas maximus, can successfully be trained to coop- erate in an Olfactory Discrimination test based on a food-rewarded two-alternative instrumental conditioning procedure. The animals learned the basic principle of the test within only 60 trials and readily mastered intra- modal stimulus transfer tasks. Further, they were capable of distinguishing between structurally related odor stimuli and remembered the reward value of previously learned odor stimuli after 2, 4, 8, and 16 weeks of recess without any signs of forgetting. The precision and consistency of the elephants' performance in tests of odor Discrimination ability and long-term odor memory demonstrate the suitability of this method for assessing Olfactory function in this proboscid species. An across-species comparison of several measures of Olfactory learning capabilities such as speed of initial task acquisition and ability to master intramodal stimulus transfer tasks shows that Asian elephants are at least as good in their performance as mice, rats, and dogs, and clearly superior to nonhuman primates and fur seals. The results support the notion that Asian elephants may use Olfactory cues for social communication and food selection and that the sense of smell may play an important role in the control of their behavior.
-
Olfactory Discrimination ability of CD-1 mice for a large array of enantiomers
Neuroscience, 2006Co-Authors: Matthias Laska, Gordon M. ShepherdAbstract:With use of a conditioning paradigm, the ability of eight CD-1 mice to distinguish between 15 enantiomeric odor pairs was investigated. The results demonstrate a) that CD-1 mice are capable of discriminating between all odor pairs tested, b) that the enantiomeric odor pairs clearly differed in their degree of discriminability and thus in their perceptual similarity, and c) that pre-training with the rewarded stimuli led to improved initial but not terminal or overall performance. A comparison between the proportion of discriminated enantiomeric odor pairs of the CD-1 mice and those of other species tested in earlier studies on the same Discrimination tasks (or on subsets thereof) shows a significant positive correlation between Discrimination performance and the number of functional Olfactory receptor genes. These findings provide the first evidence of a highly developed ability of CD-1 mice to discriminate between an array of non-pheromonal chiral odorants. Further, they suggest that a species’ Olfactory Discrimination capabilities for these odorants may be correlated with its number of functional Olfactory receptor genes. The data presented here may provide useful information for the interpretation of findings from electrophysiological or imaging studies in the mouse and the elucidation of odor structure-activity relationships.
John Larson - One of the best experts on this subject based on the ideXlab platform.
-
Endogenous siRNAs and noncoding RNA-derived small RNAs are expressed in adult mouse hippocampus and are up-regulated in Olfactory Discrimination training.
RNA, 2010Co-Authors: Neil R. Smalheiser, Giovanni Lugli, Jyothi Thimmapuram, Edwin H. Cook, John LarsonAbstract:We previously proposed that endogenous siRNAs may regulate synaptic plasticity and long-term gene expression in the mammalian brain. Here, a hippocampal-dependent task was employed in which adult mice were trained to execute a nose-poke in a port containing one of two simultaneously present odors in order to obtain a reward. Mice demonstrating Olfactory Discrimination training were compared to pseudo-training and nose-poke control groups; size-selected hippocampal RNA was subjected to Illumina deep sequencing. Sequences that aligned uniquely and exactly to the genome without uncertain nucleotide assignments, within exons or introns of MGI annotated genes, were examined further. The data confirm that small RNAs having features of endogenous siRNAs are expressed in brain; that many of them derive from genes that regulate synaptic plasticity (and have been implicated in neuropsychiatric diseases); and that hairpin-derived endo-siRNAs and the 20- to 23-nt size class of small RNAs show a significant increase during an early stage of training. The most abundant putative siRNAs arose from an intronic inverted repeat within the SynGAP1 locus; this inverted repeat was a substrate for dicer in vitro, and SynGAP1 siRNA was specifically associated with Argonaute proteins in vivo. Unexpectedly, a dramatic increase with training (more than 100-fold) was observed for a class of 25- to 30-nt small RNAs derived from specific sites within snoRNAs and abundant noncoding RNAs (Y1 RNA, RNA component of mitochondrial RNAse P, 28S rRNA, and 18S rRNA). Further studies are warranted to characterize the role(s) played by endogenous siRNAs and noncoding RNA-derived small RNAs in learning and memory.
-
Olfactory Discrimination training up-regulates and reorganizes expression of microRNAs in adult mouse hippocampus
ASN neuro, 2010Co-Authors: Neil R. Smalheiser, Giovanni Lugli, Angela L Lenon, John M. Davis, Vetle I. Torvik, John LarsonAbstract:Adult male mice (strain C57Bl/6J) were trained to execute nose-poke responses for water reinforcement; then they were randomly assigned to either of two groups: Olfactory Discrimination training (exposed to two odours with reward contingent upon correctly responding to one odour) or pseudo-training (exposed to two odours with reward not contingent upon response). These were run in yoked fashion and killed when the Discrimination-trained mouse reached a learning criterion of 70% correct responses in 20 trials, occurring after three sessions (a total of approximately 40 min of training). The hippocampus was dissected bilaterally from each mouse (N = 7 in each group) and profiling of 585 miRNAs (microRNAs) was carried out using multiplex RT-PCR (reverse transcription-PCR) plates. A significant global up-regulation of miRNA expression was observed in the Discrimination training versus pseudo-training comparison; when tested individually, 29 miRNAs achieved significance at P = 0.05. miR-10a showed a 2.7-fold increase with training, and is predicted to target several learning-related mRNAs including BDNF (brain-derived neurotrophic factor), CAMK2b (calcium/calmodulin-dependent protein kinase IIβ), CREB1 (cAMP-response-element-binding protein 1) and ELAVL2 [ELAV (embryonic lethal, abnormal vision, Drosophila)-like; Hu B]. Analysis of miRNA pairwise correlations revealed the existence of several miRNA co-expression modules that were specific to the training group. These in vivo results indicate that significant, dynamic and co-ordinated changes in miRNA expression accompany early stages of learning.
-
impaired Olfactory Discrimination learning and decreased Olfactory sensitivity in aged c57bl 6 mice
Neurobiology of Aging, 2009Co-Authors: Roseanne C. Patel, John LarsonAbstract:Young (4 months) and old (24 months) C57Bl/6J mice were tested in an automated simultaneous-cue, two-odor Discrimination task. The mice were first pre-trained to execute trial-structured nose poke responses in a straight alley. They were then trained to criterion on a series of eight novel Olfactory Discrimination problems. Old mice required slightly more shaping sessions to acquire the nose poke response. The old mice required many more sessions and made 70% more errors than young mice before reaching criterion performance on the series of eight Olfactory Discrimination problems. Young and old mice did not differ in retention of the last odor Discrimination when tested 2 weeks after training. Old mice had significantly higher thresholds for discriminating ethyl acetate vapor from non-odorized air. The results suggest that mice may be a good model for study of Olfactory dysfunction and cognitive deficits with aging.
-
Olfactory Discrimination learning in mice lacking the fragile X mental retardation protein.
Neurobiology of learning and memory, 2008Co-Authors: John Larson, Roseanne C. Patel, Daniel Kim, Christina FloreaniAbstract:An automated training system was used to compare the behavior of knockout (KO) mice lacking the fragile X mental retardation protein with that of wild-type (WT) mice (C57Bl/6 strain) in the acquisition and retention of Olfactory Discriminations. KO and WT mice did not differ in the acquisition of a four-stage nose poke shaping procedure. In two separate experiments, mutant mice required substantially more training to acquire a series of novel Olfactory Discrimination problems than did control mice. The KO mice required significantly more sessions to reach criterion performance, made significantly more errors during training, and more often failed to acquire Discriminations. Both KO and WT mice showed similar error patterns when learning novel Discriminations and both groups showed evidence of more rapid learning of later Discriminations in the problem series. Both groups showed significant long-term memory two or four weeks after training but WT and KO mice did not differ in this regard. A group of well-trained mice were given training on novel odors in sessions limited to 20-80 trials. Memory of these problems at two day delays did not differ between WT and KO mice. Tests using ethyl acetate demonstrated that WT and KO mice had similar odor detection thresholds.
-
Impaired Olfactory Discrimination learning and decreased Olfactory sensitivity in aged C57Bl/6 mice.
Neurobiology of aging, 2007Co-Authors: Roseanne C. Patel, John LarsonAbstract:Young (4 months) and old (24 months) C57Bl/6J mice were tested in an automated simultaneous-cue, two-odor Discrimination task. The mice were first pre-trained to execute trial-structured nose poke responses in a straight alley. They were then trained to criterion on a series of eight novel Olfactory Discrimination problems. Old mice required slightly more shaping sessions to acquire the nose poke response. The old mice required many more sessions and made 70% more errors than young mice before reaching criterion performance on the series of eight Olfactory Discrimination problems. Young and old mice did not differ in retention of the last odor Discrimination when tested 2 weeks after training. Old mice had significantly higher thresholds for discriminating ethyl acetate vapor from non-odorized air. The results suggest that mice may be a good model for study of Olfactory dysfunction and cognitive deficits with aging.
Naoshige Uchida - One of the best experts on this subject based on the ideXlab platform.
-
speed and accuracy of Olfactory Discrimination in the rat
Nature Neuroscience, 2003Co-Authors: Naoshige Uchida, Zachary F. MainenAbstract:The sense of smell is typically thought of as a 'slow' sense, but the true temporal constraints on the accuracy of Olfactory perception are not known. It has been proposed that animals make finer odor Discriminations at the expense of additional processing time. To test this idea, we measured the relationship between the speed and accuracy of Olfactory Discrimination in rats. We found that speed of Discrimination was independent of odor similarity, as measured by overlap of glomerular activity patterns. Even when pushed to psychophysical limits using mixtures of two odors, rats needed to take only one sniff (<200 ms at theta frequency) to make a decision of maximum accuracy. These results show that, for the purpose of odor quality Discrimination, a fully refined Olfactory sensory representation can emerge within a single sensorimotor or theta cycle, suggesting that each sniff can be considered a snapshot of the Olfactory world.
-
Speed and accuracy of Olfactory Discrimination in the rat
Nature Neuroscience, 2003Co-Authors: Naoshige Uchida, Zachary F. MainenAbstract:The sense of smell is typically thought of as a 'slow' sense, but the true temporal constraints on the accuracy of Olfactory perception are not known. It has been proposed that animals make finer odor Discriminations at the expense of additional processing time. To test this idea, we measured the relationship between the speed and accuracy of Olfactory Discrimination in rats. We found that speed of Discrimination was independent of odor similarity, as measured by overlap of glomerular activity patterns. Even when pushed to psychophysical limits using mixtures of two odors, rats needed to take only one sniff (
Rui D S Prediger - One of the best experts on this subject based on the ideXlab platform.
-
Lithium and valproate prevent Olfactory Discrimination and short-term memory impairments in the intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) rat model of Parkinson's disease.
Behavioural brain research, 2012Co-Authors: Adalberto A. Castro, Karina Ghisoni, Alexandra Latini, João Quevedo, Carla I. Tasca, Rui D S PredigerAbstract:We have recently demonstrated that rodents treated intranasally with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) display time-dependent impairments in Olfactory, emotional, cognitive and motor functions associated with disruption of dopaminergic neurotransmission in different brain structures conceivably analogous to those observed during different stages of Parkinson's disease (PD). On the other hand, lithium (Li) and valproate (VPA) are two primary drugs used to treat bipolar mood disorder that have recently emerged as promising neuroprotective agents. The present data indicates that the pretreatment with Li (47.5 mg/kg) or VPA (200 mg/kg) by intraperitoneal route during 7 consecutive days was able to prevent Olfactory Discrimination and short-term memory impairments evaluated in the social recognition and step-down inhibitory avoidance tasks in rats infused with a single intranasal (i.n.) administration of MPTP (0.1 mg/nostril). Despite the absence of clear depressive-like responses following the current MPTP dose, Li and VPA treatment presented an antidepressant profile reducing the immobility time in the forced swimming test. Importantly, at this time no significant alterations on the locomotor activity of the animals were observed in the open field test. Moreover, Li and VPA prevented dopamine depletion in the Olfactory bulb and striatum of MPTP-infused rats. These results provide new insights in experimental models of PD, indicating that Li and VPA may represent new therapeutic tools for the management of Olfactory and cognitive symptoms associated to early preclinical phases of PD, together with their neuroprotective potential demonstrated in previous research.
-
Pilocarpine improves Olfactory Discrimination and social recognition memory deficits in 24 month-old rats.
European journal of pharmacology, 2006Co-Authors: Rui D S Prediger, Nelson De-mello, Reinaldo N TakahashiAbstract:Muscarinic receptor agonists have been suggested as potential drugs to counteract age-related cognitive decline since critical changes in cholinergic system occur with aging. Recently, we demonstrated that single administration of the non-selective muscarinic receptor agonist pilocarpine prevents age-related spatial learning impairments in rats. In addition, increasing evidence suggests that areas in the central nervous system processing Olfactory information are affected at the early stages of age-related diseases, such as Alzheimer's disease, and that specific Olfactory testing may represent an important tool in the diagnosis of these diseases. In the present study, Olfactory Discrimination and short-term social memory of 3 and 24 month-old rats were assessed with the Olfactory Discrimination and social recognition memory tasks, respectively. The actions of the repeated treatment with pilocarpine (30 mg/kg, i.p.; once per day for 21 days) in relation to age-related effects on Olfactory and cognitive functions were also studied. The 24 month-old rats exhibited significantly impaired performance in both models, demonstrating deficits in their odour Discrimination and in their ability to recognize a juvenile rat after a short period of time. The treatment with pilocarpine improved in a specific manner these age-related deficits in 24 month-old rats without altering their motor performance. The present results extend the notion of the participation of muscarinic receptors in control of Olfactory functions and reinforce the potential of muscarinic receptor agonists for the treatment of age-related cognitive decline.
-
Caffeine reverses age-related deficits in Olfactory Discrimination and social recognition memory in rats. Involvement of adenosine A1 and A2A receptors.
Neurobiology of aging, 2005Co-Authors: Rui D S Prediger, Luciano C. Batista, Reinaldo N TakahashiAbstract:Caffeine, a non-selective adenosine receptor antagonist, has been suggested as a potential drug to counteract age-related cognitive decline since critical changes in adenosinergic neurotransmission occur with aging. In the present study, Olfactory Discrimination and short-term social memory of 3, 6, 12 and 18 month-old rats were assessed with the Olfactory Discrimination and social recognition tasks, respectively. The actions of caffeine (3.0, 10.0 and 30.0 mg/kg, i.p.), the A1 receptor antagonist DPCPX (1.0 and 3.0 mg/kg, i.p.) and the A2A receptor antagonist ZM241385 (0.5 and 1.0 mg/kg, i.p.) in relation to age-related effects on Olfactory functions were also studied. The 12 and 18 month-old rats exhibited significantly impaired performance in both models, demonstrating deficits in their odor Discrimination and in their ability to recognize a juvenile rat after a short period of time. Acute treatment with caffeine or ZM241385, but not with DPCPX, reversed these age-related Olfactory deficits. The present results suggest the participation of adenosine receptors in the control of Olfactory functions and confirm the potential of caffeine for the treatment of aged-related cognitive decline.
