Thermography reveals emotional arousal in rats encountering highly preferred food

Research output: Conference materialsPosterResearchpeer-review

Abstract

Thermography is increasingly used in studies on animal emotions. To gain information on physiological processes linked to emotions, an infrared camera can be used to measure subtle changes in skin and eye temperatures that correlate with changes in blood flow and muscle activity. Most thermographic studies on animal emotions have focused on detecting a temperature decrease in the nose and eyes, which indicates vasoconstriction caused by sympathetic activity during emotional arousal. Development of further thermographic methods to measure animal emotions will require identifying indicators for other physiological processes during emotional arousal as well, as they may be linked to partly different emotional experiences. The aim of this study was to test a potential indicator for which there is evidence from human studies: temperature increase on the forehead. It is thought to be caused by a rise in core body temperature due to increased thermogenesis (“emotional fever”) and by increased blood flow to periorbital muscles. Another aim was to contribute to practical design of thermographic experiments for freely moving animals. We tested whether exposing rats to highly preferred food would elicit a measurable rise in their forehead temperature. The animals were six outbred female rats, living in a large enriched communal cage, fed ad libitum. Each rat was tested separately, moving freely while it was presented alternatingly with ordinary food (whole grains) or highly preferred food (salmon paté). Three repetitions per rat were carried out for each type of food, counterbalanced for the order of presentation. During the first 60 seconds of eating, the facial temperature was recorded with a FLIR T620 thermal video camera. Data were collected from the thermal videos at 5-second intervals (+- 2.5 s) from the forehead and from a standard reference point on the nose bridge. During the first 30 seconds, exposure to preferred food elicited a significantly higher forehead temperature than exposure to ordinary food: the mean differences from the reference point were 3.0°C (SEM 0.2) vs. 2.6°C (SEM 0.2), respectively (F=8.4, p<0.01, linear mixed-effects model). From 35 seconds onwards the difference was no longer significant. This change may reflect a transition from an appetitive to a consummative phase of pleasure; the former is more plausible to elicit arousal. In conclusion, our results suggest forehead temperature is a promising indicator for emotional arousal in rats. The experimental setup proved to be successful and contributes to the practical design of thermographic experiments for fast-moving unrestrained animals.
Original languageEnglish
Number of pages1
Publication statusPublished - 2017
MoE publication typeNot Eligible
EventMeasuring animal welfare and applying scientific advances - Why is it still so difficult? - Surrey, United Kingdom
Duration: 27 Jun 201729 Jun 2017

Conference

ConferenceMeasuring animal welfare and applying scientific advances - Why is it still so difficult?
CountryUnited Kingdom
CitySurrey
Period27/06/201729/06/2017

Fields of Science

  • 413 Veterinary science

Cite this

Telkanranta, H., Koskela, A. M., Somppi, S., Kujala, M. V., Törnqvist, H. M. J., Vainio, O., & Vainionpää, M. H. (2017). Thermography reveals emotional arousal in rats encountering highly preferred food. Poster session presented at Measuring animal welfare and applying scientific advances - Why is it still so difficult? , Surrey, United Kingdom.
Telkanranta, Helena ; Koskela, Aija Mariama ; Somppi, Sanni ; Kujala, Miiamaaria Viktoria ; Törnqvist, Heini Marketta Johanna ; Vainio, Outi ; Vainionpää, Mari Helena. / Thermography reveals emotional arousal in rats encountering highly preferred food. Poster session presented at Measuring animal welfare and applying scientific advances - Why is it still so difficult? , Surrey, United Kingdom.1 p.
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title = "Thermography reveals emotional arousal in rats encountering highly preferred food",
abstract = "Thermography is increasingly used in studies on animal emotions. To gain information on physiological processes linked to emotions, an infrared camera can be used to measure subtle changes in skin and eye temperatures that correlate with changes in blood flow and muscle activity. Most thermographic studies on animal emotions have focused on detecting a temperature decrease in the nose and eyes, which indicates vasoconstriction caused by sympathetic activity during emotional arousal. Development of further thermographic methods to measure animal emotions will require identifying indicators for other physiological processes during emotional arousal as well, as they may be linked to partly different emotional experiences. The aim of this study was to test a potential indicator for which there is evidence from human studies: temperature increase on the forehead. It is thought to be caused by a rise in core body temperature due to increased thermogenesis (“emotional fever”) and by increased blood flow to periorbital muscles. Another aim was to contribute to practical design of thermographic experiments for freely moving animals. We tested whether exposing rats to highly preferred food would elicit a measurable rise in their forehead temperature. The animals were six outbred female rats, living in a large enriched communal cage, fed ad libitum. Each rat was tested separately, moving freely while it was presented alternatingly with ordinary food (whole grains) or highly preferred food (salmon pat{\'e}). Three repetitions per rat were carried out for each type of food, counterbalanced for the order of presentation. During the first 60 seconds of eating, the facial temperature was recorded with a FLIR T620 thermal video camera. Data were collected from the thermal videos at 5-second intervals (+- 2.5 s) from the forehead and from a standard reference point on the nose bridge. During the first 30 seconds, exposure to preferred food elicited a significantly higher forehead temperature than exposure to ordinary food: the mean differences from the reference point were 3.0°C (SEM 0.2) vs. 2.6°C (SEM 0.2), respectively (F=8.4, p<0.01, linear mixed-effects model). From 35 seconds onwards the difference was no longer significant. This change may reflect a transition from an appetitive to a consummative phase of pleasure; the former is more plausible to elicit arousal. In conclusion, our results suggest forehead temperature is a promising indicator for emotional arousal in rats. The experimental setup proved to be successful and contributes to the practical design of thermographic experiments for fast-moving unrestrained animals.",
keywords = "413 Veterinary science",
author = "Helena Telkanranta and Koskela, {Aija Mariama} and Sanni Somppi and Kujala, {Miiamaaria Viktoria} and T{\"o}rnqvist, {Heini Marketta Johanna} and Outi Vainio and Vainionp{\"a}{\"a}, {Mari Helena}",
year = "2017",
language = "English",
note = "Measuring animal welfare and applying scientific advances - Why is it still so difficult? ; Conference date: 27-06-2017 Through 29-06-2017",

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Telkanranta, H, Koskela, AM, Somppi, S, Kujala, MV, Törnqvist, HMJ, Vainio, O & Vainionpää, MH 2017, 'Thermography reveals emotional arousal in rats encountering highly preferred food' Measuring animal welfare and applying scientific advances - Why is it still so difficult? , Surrey, United Kingdom, 27/06/2017 - 29/06/2017, .

Thermography reveals emotional arousal in rats encountering highly preferred food. / Telkanranta, Helena; Koskela, Aija Mariama; Somppi, Sanni; Kujala, Miiamaaria Viktoria; Törnqvist, Heini Marketta Johanna; Vainio, Outi; Vainionpää, Mari Helena.

2017. Poster session presented at Measuring animal welfare and applying scientific advances - Why is it still so difficult? , Surrey, United Kingdom.

Research output: Conference materialsPosterResearchpeer-review

TY - CONF

T1 - Thermography reveals emotional arousal in rats encountering highly preferred food

AU - Telkanranta, Helena

AU - Koskela, Aija Mariama

AU - Somppi, Sanni

AU - Kujala, Miiamaaria Viktoria

AU - Törnqvist, Heini Marketta Johanna

AU - Vainio, Outi

AU - Vainionpää, Mari Helena

PY - 2017

Y1 - 2017

N2 - Thermography is increasingly used in studies on animal emotions. To gain information on physiological processes linked to emotions, an infrared camera can be used to measure subtle changes in skin and eye temperatures that correlate with changes in blood flow and muscle activity. Most thermographic studies on animal emotions have focused on detecting a temperature decrease in the nose and eyes, which indicates vasoconstriction caused by sympathetic activity during emotional arousal. Development of further thermographic methods to measure animal emotions will require identifying indicators for other physiological processes during emotional arousal as well, as they may be linked to partly different emotional experiences. The aim of this study was to test a potential indicator for which there is evidence from human studies: temperature increase on the forehead. It is thought to be caused by a rise in core body temperature due to increased thermogenesis (“emotional fever”) and by increased blood flow to periorbital muscles. Another aim was to contribute to practical design of thermographic experiments for freely moving animals. We tested whether exposing rats to highly preferred food would elicit a measurable rise in their forehead temperature. The animals were six outbred female rats, living in a large enriched communal cage, fed ad libitum. Each rat was tested separately, moving freely while it was presented alternatingly with ordinary food (whole grains) or highly preferred food (salmon paté). Three repetitions per rat were carried out for each type of food, counterbalanced for the order of presentation. During the first 60 seconds of eating, the facial temperature was recorded with a FLIR T620 thermal video camera. Data were collected from the thermal videos at 5-second intervals (+- 2.5 s) from the forehead and from a standard reference point on the nose bridge. During the first 30 seconds, exposure to preferred food elicited a significantly higher forehead temperature than exposure to ordinary food: the mean differences from the reference point were 3.0°C (SEM 0.2) vs. 2.6°C (SEM 0.2), respectively (F=8.4, p<0.01, linear mixed-effects model). From 35 seconds onwards the difference was no longer significant. This change may reflect a transition from an appetitive to a consummative phase of pleasure; the former is more plausible to elicit arousal. In conclusion, our results suggest forehead temperature is a promising indicator for emotional arousal in rats. The experimental setup proved to be successful and contributes to the practical design of thermographic experiments for fast-moving unrestrained animals.

AB - Thermography is increasingly used in studies on animal emotions. To gain information on physiological processes linked to emotions, an infrared camera can be used to measure subtle changes in skin and eye temperatures that correlate with changes in blood flow and muscle activity. Most thermographic studies on animal emotions have focused on detecting a temperature decrease in the nose and eyes, which indicates vasoconstriction caused by sympathetic activity during emotional arousal. Development of further thermographic methods to measure animal emotions will require identifying indicators for other physiological processes during emotional arousal as well, as they may be linked to partly different emotional experiences. The aim of this study was to test a potential indicator for which there is evidence from human studies: temperature increase on the forehead. It is thought to be caused by a rise in core body temperature due to increased thermogenesis (“emotional fever”) and by increased blood flow to periorbital muscles. Another aim was to contribute to practical design of thermographic experiments for freely moving animals. We tested whether exposing rats to highly preferred food would elicit a measurable rise in their forehead temperature. The animals were six outbred female rats, living in a large enriched communal cage, fed ad libitum. Each rat was tested separately, moving freely while it was presented alternatingly with ordinary food (whole grains) or highly preferred food (salmon paté). Three repetitions per rat were carried out for each type of food, counterbalanced for the order of presentation. During the first 60 seconds of eating, the facial temperature was recorded with a FLIR T620 thermal video camera. Data were collected from the thermal videos at 5-second intervals (+- 2.5 s) from the forehead and from a standard reference point on the nose bridge. During the first 30 seconds, exposure to preferred food elicited a significantly higher forehead temperature than exposure to ordinary food: the mean differences from the reference point were 3.0°C (SEM 0.2) vs. 2.6°C (SEM 0.2), respectively (F=8.4, p<0.01, linear mixed-effects model). From 35 seconds onwards the difference was no longer significant. This change may reflect a transition from an appetitive to a consummative phase of pleasure; the former is more plausible to elicit arousal. In conclusion, our results suggest forehead temperature is a promising indicator for emotional arousal in rats. The experimental setup proved to be successful and contributes to the practical design of thermographic experiments for fast-moving unrestrained animals.

KW - 413 Veterinary science

M3 - Poster

ER -

Telkanranta H, Koskela AM, Somppi S, Kujala MV, Törnqvist HMJ, Vainio O et al. Thermography reveals emotional arousal in rats encountering highly preferred food. 2017. Poster session presented at Measuring animal welfare and applying scientific advances - Why is it still so difficult? , Surrey, United Kingdom.