Odour conditioning of positive affective states: Rats can learn to associate an odour with being tickled.
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Abstract
Most associative learning tests in rodents use negative stimuli, such as electric shocks. We investigated if young rats can learn to associate the presence of an odour with the experience of being tickled (i.e. using an experimenter's hand to mimic rough-and-tumble play), shown to elicit 50 kHz ultrasonic vocalisations (USVs), which are indicative of positive affect. Male, pair-housed Wistar rats (N = 24) were all exposed to two neutral odours (A and B) presented in a perforated container on alternate days in a test arena. Following 60s of exposure, the rats were either tickled on days when odour A (n = 8) or odour B (n = 8) was present, or never tickled (n = 8). When tickled, rats produced significantly more 50 kHz USVs compared to the days when not being tickled, and compared to control rats. The level of anticipatory 50 kHz USVs in the 60s prior to tickling did not differ significantly between the tickled and control rats. As a retrieval test following the odour conditioning, rats were exposed successively in the same arena to three odours: an unknown neutral odour, extract of fox faeces, and either odours A or B. Compared to controls, 50 kHz USVs of tickled rats increased when exposed to the odour they had previously experienced when tickled, indicating that these rats had learned to associate the odour with the positive experience of being tickled. In a test with free access for 5 min to both arms of a T-maze, each containing one of the odours, rats tickled with odour A spent more time in the arm with this odour. This work is the first to test in a fully balanced design whether rats can learn to associate an odour with tickling, and indicates that positive odour conditioning has potential to be used as an alternative to negative conditioning tests.
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Wistar rats have been shown to be reliably responsive to tickling and PH.
“This outbred albino strain has been shown to be reliably responsive to tickling and PH ( Bombail et al., 2019; Hammond et al., 2019) and is one of the commonly used strains for such experiments (23% of rat tickling studies used Wistar rats; LaFollette et al., 2017).”
From Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats (2025) · cites this paper as Bombail et al., 2019
Materials and methods (Animals and housing; page unavailable) identifies the subjects as Wistar rats. The Results report that all tickled rats emitted significantly more 50 kHz vocalisations when tickled, supporting responsiveness to tickling. The tickling procedure included play with the rats, but the paper does not test responsiveness to PH as a separate procedure. (LLM, conf=0.82)
Experimental — accuracy not yet measuredBy the 5th session, all PH rats showed an increase in USV production in contrast to the standard protocol where some rats show little or no increase in USVs.
“By the 5th session, all PH rats showed an increase in USV production in contrast to Figure 2(ii), which used the standard protocol and where some rats show little or no increase in USVs.”
From Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats (2025) · cites this paper as Bombail et al., 2019
The Results (page not available) report higher average 50 kHz USV production in the fifth than the first tickling session and note individual differences, but do not establish that some rats had little or no increase. The General discussion (page not available) explicitly says the authors did not standardise their tickling method, so this paper does not support describing its procedure as the standard protocol. The statement about all PH rats appears to describe the citing study’s own results, not a finding attributed to this source. (LLM, conf=0.82)
Experimental — accuracy not yet measuredThe PH protocol resulted in a more uniform increase in USVs across individuals relative to the standard protocol.
“Our data suggest that the PH protocol resulted in a more uniform increase in USVs across individuals relative to the standard protocol.”
From Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats (2025) · cites this paper as Bombail et al., 2019
In the General discussion (page unavailable), the authors say that adapting tickling to each rat appeared to reduce individual variation in responses compared with a standardized approach. They do not report a comparison showing that a PH protocol produced a more uniform increase in USVs than a standard protocol; the Results instead report that USV response levels varied by individual rat. (LLM, conf=0.83)
Experimental — accuracy not yet measuredThe PH protocol is intended to better mimic the dynamic nature of play, giving the rat more choice over how it is tickled.
“Due to our experiences using the standard tickling protocol we have developed a refined tickling protocol we refer to as playful handling (PH), intended to better mimic the dynamic nature of play, giving the rat more choice over how it is tickled ( Bombail et al., 2019), Figure 1(iii).”
From Stage 2 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats (2025) · cites this paper as Bombail et al., 2019
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Cites
Assessment of positive emotions in animals to improve their welfare
Boissy, A., Manteuffel, G., Jensen, M. B., Moe, R. O., Spruijt, B., Keeling, L. J., Winckler, C., Forkman, B., Dimitrov, I., Langbein, J., et al. (2007) · Physiology & Behavior · doi:10.1016/j.physbeh.2007.02.003 · Cited by 1,486 · see citing works
The neurobiology of positive emotions
Burgdorf, J., & Panksepp, J. (2006) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2005.06.001 · Cited by 677 · see citing works
Ultrasonic vocalizations as indices of affective states in rats
Knutson, B., Burgdorf, J., & Panksepp, J. (2002) · Psychological Bulletin · doi:10.1037/0033-2909.128.6.961 · Cited by 618 · see citing works
Poor human olfaction is a 19th-century myth
McGann, J. P. (2017) · Science · doi:10.1126/science.aam7263 · Cited by 500 · see citing works
Anticipation of play elicits high-frequency ultrasonic vocalizations in young rats.
Knutson, B. D., Burgdorf, J. S., & Panksepp, J. (1998) · Journal of comparative psychology · doi:10.1037/0735-7036.112.1.65 · Cited by 461 · see citing works
Blanchard, R. J., Blanchard, D. C., Agullana, R., & Weiss, S. M. (1991) · Physiology & Behavior · doi:10.1016/0031-9384(91)90423-l · Cited by 461 · see citing works
Wöhr, M., & Schwarting, R. K. W. (2013) · Cell and Tissue Research · doi:10.1007/s00441-013-1607-9 · Cited by 371 · see citing works
Burgdorf, J., Panksepp, J., & Moskal, J. R. (2011) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2010.11.011 · Cited by 258 · see citing works
Anxiolytic and Sedative Effects of Extracts and Essential Oil from Citrus aurantium L.
Carvalho-Freitas, M. I. R., & Costa, M. (2002) · Biological and Pharmaceutical Bulletin · doi:10.1248/bpb.25.1629 · Cited by 245 · see citing works
Moriceau, S., Wilson, D. A., Levine, S. D., & Sullivan, R. M. (2006) · Journal of Neuroscience · doi:10.1523/jneurosci.0499-06.2006 · Cited by 240 · see citing works
Schwarting, R. K. W., Jegan, N. R. A., & Wöhr, M. (2007) · Behavioural Brain Research · doi:10.1016/j.bbr.2007.01.029 · Cited by 176 · see citing works
Olfactory perception of chemically diverse molecules
Keller, A., & Vosshall, L. B. (2016) · BMC Neuroscience · doi:10.1186/s12868-016-0287-2 · Cited by 172 · see citing works
Rygula, R., Pluta, H., & Popik, P. (2012) · PLoS ONE · doi:10.1371/journal.pone.0051959 · Cited by 146 · see citing works
Olfactory memory networks: from emotional learning to social behaviors
Sullivan, R. M., Wilson, D. A., Ravel, N., & Mouly, A. (2015) · Frontiers in Behavioral Neuroscience · doi:10.3389/fnbeh.2015.00036 · Cited by 143 · see citing works
Tonoue, T., Ashida, Y., Makino, H., & Hata, H. (1986) · Psychoneuroendocrinology · doi:10.1016/0306-4530(86)90052-1 · Cited by 131 · see citing works
Breeding for 50-kHz Positive Affective Vocalization in Rats
Burgdorf, J. S., Panksepp, J., Brudzyński, S. M., Kroes, R. A., & Moskal, J. R. (2005) · Behavior Genetics · doi:10.1007/s10519-004-0856-5 · Cited by 115 · see citing works
Choi, J.-S., & Brown, T. H. (2003) · Journal of Neuroscience · doi:10.1523/jneurosci.23-25-08713.2003 · Cited by 106 · see citing works
Mällo, T., Matrov, D., Herm, L., Kõiv, K., Eller, M., Rinken, A., & Harro, J. (2007) · Behavioural Brain Research · doi:10.1016/j.bbr.2007.06.015 · Cited by 100 · see citing works
Laughing Rats? Playful Tickling Arouses High-Frequency Ultrasonic Chirping in Young Rodents
Panksepp, J., & Burgdorf, J. S. (2010) · American journal of play · Cited by 84 · see citing works
Rat tickling: A systematic review of applications, outcomes, and moderators.
LaFollette, M. R., O’Haire, M. E., Cloutier, S., Blankenberger, W. B., & Gaskill, B. N. (2017) · PLOS ONE · doi:10.1371/journal.pone.0175320 · Cited by 84 · see citing works
Opioid mediation of odor preferences induced by sugar and fat in 6-day-old rats
Shide, D. J., & Blass, E. M. (1991) · Physiology & Behavior · doi:10.1016/0031-9384(91)90422-k · Cited by 81 · see citing works
Raineki, C., Shionoya, K., Sander, K., & Sullivan, R. M. (2009) · Learning & Memory · doi:10.1101/lm.977909 · Cited by 71 · see citing works
The noradrenergic system of the amygdala and aversive information processing.
Ellis, M. E., & Kesner, R. P. (1983) · Behavioral Neuroscience · doi:10.1037//0735-7044.97.3.399 · Cited by 70 · see citing works
Varlet, M., Marín, L., Capdevielle, D., Del-Monte, J., Schmidt, R. C., Salesse, R. N., Boulenger, J., Bardy, B. G., & Raffard, S. (2014) · Frontiers in Behavioral Neuroscience · doi:10.3389/fnbeh.2014.00029 · Cited by 66 · see citing works
Olfactory fear conditioning paradigm in rats: Effects of midazolam, propranolol or scopolamine
Kroon, J. A. V., & Carobrez, A. P. (2008) · Neurobiology of Learning and Memory · doi:10.1016/j.nlm.2008.10.007 · Cited by 65 · see citing works
Lawrence, A. B., Newberry, R. C., & Špinka, M. (2017) · Elsevier eBooks · doi:10.1016/b978-0-08-101012-9.00014-9 · Cited by 54 · see citing works
Self-citationTickling, a Technique for Inducing Positive Affect When Handling Rats.
Cloutier, S., LaFollette, M. R., Gaskill, B. N., Panksepp, J., & Newberry, R. C. (2018) · Journal of Visualized Experiments · doi:10.3791/57190 · Cited by 52 · see citing works
Burgdorf, J., Moskal, J. R., Brudzynski, S. M., & Panksepp, J. (2013) · Behavioural Brain Research · doi:10.1016/j.bbr.2013.04.022 · Cited by 43 · see citing works
Brenes, J. C., & Schwarting, R. K. W. (2015) · Physiology & Behavior · doi:10.1016/j.physbeh.2015.05.012 · Cited by 42 · see citing works
Practical rat tickling: Determining an efficient and effective dosage of heterospecific play.
LaFollette, M. R., O’Haire, M. E., Cloutier, S., & Gaskill, B. N. (2018) · Applied Animal Behaviour Science · doi:10.1016/j.applanim.2018.08.005 · Cited by 40 · see citing works
Odor preferences shape discrimination learning in rats.
Devore, S., Lee, J. K., & Linster, C. (2013) · Behavioral Neuroscience · doi:10.1037/a0033329 · Cited by 35 · see citing works
Wolffenbüttel, A. N., Zamboni, A., Becker, G., dos Santos, M. K., Borille, B. T., Mariotti, K. D. C., Fagundes, A. C., Salomón, J. L. D. O., Coelho, V. R., Virto, L., et al. (2017) · Phytotherapy Research · doi:10.1002/ptr.5964 · Cited by 34 · see citing works
Importance of retronasal and orthonasal olfaction for odor aversion memory in rats.
Chapuis, J., Messaoudi, B., Ferreira, G., & Ravel, N. (2007) · Behavioral Neuroscience · doi:10.1037/0735-7044.121.6.1383 · Cited by 33 · see citing works
Avvisati, R., Contu, L., Stendardo, E., Michetti, C., Montanari, C., Scattoni, M. L., & Badiani, A. (2016) · Psychopharmacology · doi:10.1007/s00213-016-4247-4 · Cited by 32 · see citing works
Exercise reward induces appetitive 50-kHz calls in rats
Heyse, N. C., Brenes, J. C., & Schwarting, R. K. W. (2015) · Physiology & Behavior · doi:10.1016/j.physbeh.2015.04.021 · Cited by 24 · see citing works
Tickling, a Technique for Inducing Positive Affect When Handling Rats
Cloutier, S., LaFollette, M. R., Gaskill, B. N., Panksepp, J., & Newberry, R. C. (2018) · Journal of Visualized Experiments · doi:10.3791/57190-v · Cited by 24 · see citing works
Nielsen, B. L., Jérôme, N., Saint-Albin, A., Rampin, O., & Maurin, Y. (2013) · Physiology & Behavior · doi:10.1016/j.physbeh.2013.07.012 · Cited by 24 · see citing works
Self-citationBrenes, J. C., & Schwarting, R. K. W. (2014) · PLoS ONE · doi:10.1371/journal.pone.0102414 · Cited by 23 · see citing works
Positive welfare: What does it add to the debate over pig welfare?
Lawrence, A. B., Newberry, R. C., & Špinka, M. (2023) · Elsevier eBooks · doi:10.1016/b978-0-323-85676-8.00009-2 · Cited by 19 · see citing works
Self-citationRelationships between play and responses to tickling in male juvenile rats.
Hammond, T., Bombail, V., Nielsen, B. L., Meddle, S. L., Lawrence, A. B., & Brown, S. M. (2019) · Applied Animal Behaviour Science · doi:10.1016/j.applanim.2019.104879 · Cited by 18 · see citing works
Self-citationCaffrey, M. K., & Febo, M. (2013) · Drug and Alcohol Dependence · doi:10.1016/j.drugalcdep.2013.09.032 · Cited by 14 · see citing works
Nielsen, B. L., Jérôme, N., Saint-Albin, A., Ouali, C., Rochut, S., Zins, É., Briant, C., Guettier, E., Reigner, F., Couty, I., et al. (2016) · Applied Animal Behaviour Science · doi:10.1016/j.applanim.2016.01.014 · Cited by 13 · see citing works
Self-citationPopik, P., Kos, T., Pluta, H., Nikiforuk, A., Rojek-Sito, K., & Ryguła, R. (2013) · Behavioural Brain Research · doi:10.1016/j.bbr.2013.11.029 · Cited by 12 · see citing works
Ultrasonic Vocalizations as an Index of Positive Emotional State.
Barker, D. J. (2018) · Handbook of Behavioral Neuroscience · doi:10.1016/b978-0-12-809600-0.00024-x · Cited by 12 · see citing works
Olfactory preference conditioning changes the reward value of reinforced and non-reinforced odors
Torquet, N., Aimé, P., Messaoudi, B., Garcia, S., Ey, E., Gervais, R., Julliard, A., & Ravel, N. (2014) · Frontiers in Behavioral Neuroscience · doi:10.3389/fnbeh.2014.00229 · Cited by 12 · see citing works
Lowen, S. B., Rohan, M. L., Gillis, T. E., Thompson, B. S., Wellons, C. B. W., & Andersen, S. L. (2015) · NeuroImage: Clinical · doi:10.1016/j.nicl.2015.06.012 · Cited by 11 · see citing works
Nielsen, B. L., Jérôme, N., Saint-Albin, A., Joly, F., Rabot, S., & Meunier, N. (2018) · Behavioural Brain Research · doi:10.1016/j.bbr.2018.09.018 · Cited by 8 · see citing works
Self-citationRat 22-kHz Ultrasonic Vocalizations as a Measure of Emotional Set Point During Social Interactions
Burgdorf, J. S., Panksepp, J., & Moskal, J. R. (2018) · Handbook of behavioral neuroscience · doi:10.1016/b978-0-12-809600-0.00025-1 · Cited by 5 · see citing works
Revillo, D., Fernández, G., Castelló, S., Paglini, M. G., & Arias, C. (2012) · Behavioural Brain Research · doi:10.1016/j.bbr.2012.03.018 · Cited by 4 · see citing works
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Research works printed but not linked: 2
- [9]Deehan GA Jr, Ding Z-M, Hauser SR, Engleman EA, Wilden JA, McBride WJ, et al Conditioned odor cues associated with the access to or the absence of alcohol differentially modulate dopmamine efflux in the nucleus accumbens shell. Alcohol Clin Exp Res. 2012; 36: 186A.
- [36]Lam H. Can odour be associated with positive affective states in rats (Rattus norvegicus)? MSc thesis, University of Edinburgh; 2017. 45 pp.
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Self-citationBehavioral analysis in laboratory rats: Challenges and usefulness of 50-kHz ultrasonic vocalizations
Schwarting, R. K. W. (2023) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2023.105260 · Cited by 39 · see citing works
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Schild, S.-L. A., & Rørvang, M. V. (2023) · Frontiers in Animal Science · doi:10.3389/fanim.2023.1215206 · Cited by 19 · see citing works
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Hammond, T., Bombail, V., Nielsen, B. L., Meddle, S. L., Lawrence, A. B., & Brown, S. M. (2019) · Applied Animal Behaviour Science · doi:10.1016/j.applanim.2019.104879 · Cited by 18 · see citing works
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“The PH protocol is described by Bombail et al., (2019) as the handler using one hand to touch, tickle, and play with the rat for 20 second periods interspersed with 20 second pauses.”
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Is Tickling a Reinforcer for Adult Rats?
Bruce, K. E. M., Collins, R., Reese, C., Cariveau, T., & Galizio, M. (2025) · The Psychological Record · doi:10.1007/s40732-025-00633-4
- Authors
- Bombail, V., Jerôme, N., Lam, H., Muszlak, S., Meddle, S. L., Lawrence, A. B., & Nielsen, B. L.
- Affiliations
- Université Paris-Saclay (FR)
- Roslin Institute (GB)
- AgroParisTech (FR)
- Venue
- PLOS ONE
- Publisher
- Public Library of Science (PLoS)
- Published
- 2019-06-12
- Volume
- 14
- Issue
- 6
- Pages
- e0212829
- ISSN
- 1932-6203 (ISSN-L)
- PMC
- PMC6561538
- OpenAlex
- W2949794481
- Cited by
- 17
- References
- 49
- Citations by year
- 2026: 2 · 2025: 2 · 2024: 1 · 2023: 4 · 2022: 3 · 2021: 3 · 2020: 1 · 2019: 1
- FWCI
- 1.16
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- PLoS ONE (publishedVersion, cc-by)
- bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- HAL (submittedVersion, cc-by)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Edinburgh Research Explorer (University of Edinburgh) (submittedVersion, cc-by)
- Funders
- RESAS
- Biotechnology and Biological Sciences Research Council
- Department of Animal Physiology and Livestock Systems
- Topics
- Life Sciences › Neuroscience › Cognitive Neuroscience › Memory and Neural Mechanisms
- Life Sciences › Neuroscience › Sensory Systems › Olfactory and Sensory Function Studies
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neurotransmitter Receptor Influence on Behavior
- Keywords
- positive affective states, tickling, associative learning, rats, rough-and-tumble play
- MeSH terms
- Animals, Conditioning, Psychological, Learning, Male, Odorants, Physical Stimulation, Ultrasonics, Rats, Wistar, Rats
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