[[File:Scott & Bowne's Palatable Castor Oil.jpg|thumb |right|200px|Advertisement of [[ Castorcastor oil]] as a medicine by Scott & Bowne company, 19th century]] ▼'''Palatability''' (or '''palatableness''') is the [[Reward_system|hedonic]] [[reward system|reward]] (which is [[pleasure]] of [[taste]] in this case) provided by foods or fluidsdrinks that are agreeable to the "[[palate]]", inwhich often varies regardrelative to the [[homeostatic]] satisfaction of [[nutrition|nutritional]], [[Fluid_balance|water]],al and/or [[Food_energyFluid balance|energywater]] needs.<ref>{{Cite journal |last1=Friedman MI,|first1=Mark I. |last2=Stricker EM|first2=Edward M. (|date=1976). |title=The physiological psychology of hunger: aA physiological perspective. Psychol|journal=Psychological Rev.Review |language=en |volume=83( |issue=6):409 |pages=409–431 |doi=10.1037/0033-31295X.83.6.409 PMID|issn=1939-1471 |pmid=1005583}}</ref> The palatability of a fooddish or fluidbeverage, unlike its [[Flavor (taste)|flavor]] or [[taste]], varies with the state of an individual: it is lower after [[eating|consumption]] and higher when [[hunger|deprived]]. Palatability of foods, however, can be learned. It has increasingly been appreciated that this can create a hedonic hunger that is independent of homeostatic needs.<ref name="Lowe">{{Cite journal |last1=Lowe MR,|first1=Michael R. |last2=Butryn ML|first2=Meghan L. (|date=2007).-07-24 |title=Hedonic hunger: aA new dimension of appetite? Physiol|journal=Physiology Behav.& JulBehavior 24;|volume=91( |issue=4):432-9 |pages=432–439 |doi=10.1016/j.physbeh.2007.04.006 PMID|issn=0031-9384 |pmid=17531274 |s2cid=10704679}}</ref>
==Brain mechanism==
The palatability of a substance is determined by [[opioid receptor]]-related processes in the [[nucleus accumbens]] and ventral [[ ventral pallidum]].<ref name="Wassum"> {{Cite journal |last1=Wassum KM,|first1=K. M. |last2=Ostlund SB,|first2=S. B. |last3=Maidment NT,|first3=N. T. |last4=Balleine BW|first4=B. (2009)W. |date=2009-07-28 |title=Distinct opioid circuits determine the palatability and the desirability of rewarding events . Proc|journal=Proceedings Natlof Acadthe SciNational UAcademy Sof A.Sciences |language=en |volume=106 :12512–12517 PMID|issue=30 19597155|pages=12512–12517 {{doi| doi=10.1073/pnas.0905874106 |issn=0027-8424 |pmc=2718390 |pmid=19597155 |bibcode=2009PNAS..10612512W |doi-access=free }}</ref> The opioid processes involve [[mu opioid receptor]]s and are present in the rostromedial shell part of the nucleus accumbens<ref> {{Cite journal |last1=Peciña S,|first1=Susana |last2=Berridge KC|first2=Kent C. (|date=2005 ). [http://www.jneurosci.org/cgi/content/full/25/50/11777-12-14 |title=Hedonic hotHot spotSpot in nucleusNucleus accumbensAccumbens shellShell: whereWhere doDo muμ- opioidsOpioids causeCause increasedIncreased hedonicHedonic impactImpact of sweetnessSweetness? ] J|journal=The Neurosci.Journal of Neuroscience 14;|language=en |volume=25 ( |issue=50 ):11777-86. {{DOI| pages=11777–11786 |doi=10.1523/JNEUROSCI.2329-05.2005 }} PMID|issn=0270-6474 16354936|pmc=6726018 |pmid=16354936}}</ref> on its [[ Medium_spiny_neuronMedium spiny neuron|spiny neuron]]s.<ref> {{Cite journal |last1=Kelley AE,|first1=A. E. |last2=Bakshi VP,|first2=V. P. |last3=Haber SN,|first3=S. N. |last4=Steininger TL,|first4=T. L. |last5=Will MJ,|first5=M. J. |last6=Zhang |first6=M. (|date=2002 ).-07-01 |title=Opioid modulation of taste hedonics within the ventral striatum . Physiol|journal=Physiology Behav.& Behavior |volume=76 ( |issue=3 |pages=365–377 |doi=10.1016/s0031-9384(02) :36500751- 77.5 PMID|issn=0031-9384 |pmid=12117573 |s2cid=44258056 }}</ref> This area has been called the "opioid eating site".<ref> {{Cite journal |last1=Peciña S,|first1=Susana |last2=Berridge KC|first2=Kent C. (|date=2000 ).-04-28 |title=Opioid site in nucleus accumbens shell mediates eating and hedonic 'liking' for food: mapMap based on microinjection Fos plumes . |journal=Brain Res.Research |volume=863 (1 |issue=1–2 |pages=71–86 |doi=10.1016/s0006- 28993(00) :7102102- 86.8 PMID|issn=0006-8993 |pmid=10773195 |s2cid=1805234 }}</ref> ▼▲[[File:Scott & Bowne's Palatable Castor Oil.jpg|thumb|right|200px|Advertisement of [[Castor oil]] as a medicine by Scott & Bowne company, 19th century]]
▲The palatability of a substance is determined by [[opioid receptor]]-related processes in the [[nucleus accumbens]] and ventral [[pallidum]].<ref name="Wassum">Wassum KM, Ostlund SB, Maidment NT, Balleine BW. (2009). Distinct opioid circuits determine the palatability and the desirability of rewarding events. Proc Natl Acad Sci U S A. 106:12512–12517 PMID 19597155 {{doi|10.1073/pnas.0905874106}}</ref> The opioid processes involve [[mu opioid receptor]]s and are present in the rostromedial shell part of the nucleus accumbens<ref>Peciña S, Berridge KC. (2005). [http://www.jneurosci.org/cgi/content/full/25/50/11777 Hedonic hot spot in nucleus accumbens shell: where do mu-opioids cause increased hedonic impact of sweetness?] J Neurosci. 14;25(50):11777-86. {{DOI|10.1523/JNEUROSCI.2329-05.2005}} PMID 16354936 </ref> on its [[Medium_spiny_neuron|spiny neuron]]s.<ref>Kelley AE, Bakshi VP, Haber SN, Steininger TL, Will MJ, Zhang M. (2002). Opioid modulation of taste hedonics within the ventral striatum. Physiol Behav. 76(3):365-77. PMID 12117573</ref> This area has been called the "opioid eating site".<ref>Peciña S, Berridge KC. (2000).Opioid site in nucleus accumbens shell mediates eating and hedonic 'liking' for food: map based on microinjection Fos plumes. Brain Res. 863(1-2):71-86. PMID 10773195</ref>
The rewardfulness of consumption associated with palatability is dissociable from desire or incentive value which is the motivation to seek out a specific commodity.<ref name="Wassum"/> Desire or incentive value is processed by [[opioid receptor]]-related processes in the [[basolateral amygdala]].<ref name="Wassum"/> Unlike the liking palatability for food, the [[incentive salience]] wanting is not downregulated by the physiological consequences of food consumption and may be largely independent of homoeostatic processes influencing food intake.<ref>{{Cite journal |last1=Finlayson G,|first1=Graham |last2=King N,|first2=Neil |last3=Blundell J.|first3=John (|date=2008). -01-01 |title=The role of implicit wanting in relation to explicit liking and wanting for food: implications for appetite control. |journal=Appetite. |volume=50( |issue=1):120-7 |pages=120–127 |doi=10.1016/j.appet.2007.06.007 PMID|issn=0195-6663 |pmid=17655972|s2cid=54347866 |url=http://eprints.whiterose.ac.uk/96699/2/finlayson%20et%20al%202008%20appetite%20manuscript.pdf }}</ref>
Though the wanting of incentive salience may be informed by palatability, it is independent and not necessarily reduced to it.<ref name="Wassum"/> It has been suggested that a third system exists that links opioid processes in the two parts of the brain: "Logically this raises the possibility that a third system, with which the accumbens shell, ventral pallidum, and basolateral amygdala are associated, distributes the affective signals elicited by specific commodities across distinct functional systems to control reward seeking... At present we do not have any direct evidence for a system of this kind, but indirect evidence suggests it may reside within the motivationally rich circuits linking [[Hypothalamus|hypothalamic]] and [[brainstem]] viscerogenic structures such as the [[Parabrachial nuclei|parabrachial nucleus]].<ref name="Wassum"/>
It has also been suggested that "[[hedonic hunger"]] can be driven both in regard to “wanting”"wanting" and “liking”"liking"<ref name="Lowe"/> and that a palatability subtype of neuron may also exist in the basolateral amygdala.<ref>{{Cite journal |last1=Fontanini A,|first1=Alfredo |last2=Grossman SE,|first2=Stephen E. |last3=Figueroa JA,|first3=Joshua A. |last4=Katz DB|first4=Donald B. (|date=2009).-02-25 |title=Distinct subtypes of basolateral amygdala taste neurons reflect palatability and reward. J|journal=The Neurosci.Journal of Neuroscience |volume=29( |issue=8):2486 |pages=2486–2495 |doi=10.1523/JNEUROSCI.3898-9508.2009 PMID|issn=1529-2401 |pmc=2668607 |pmid=19244523}}</ref>
==Satiety and palatability==
[[Appetite]] is controlled by a direct loop and an indirect one. In both the direct and indirect loops there are two feedback mechanisms. First a positive feedback involving its stimulation by palatability food cues, and second, a [[negative feedback]] due to satiation and satiety cues following ingestationingestion.<ref>{{Cite journal |last=Smith GP.|first=Gerard (2000)P. |date=2000-10-01 |title=The controls of eating: a shift from nutritional homeostasis to behavioral neuroscience. |journal=Nutrition. |volume=16( |issue=10 |pages=814–820 |doi=10.1016/s0899-9007(00):81400457-20.3 PMID|issn=0899-9007 |pmid=11054585}}</ref> In the indirect loop these cues are learnt by association such as meal plate size and work by modulating the potency of the cues of the direct loop.<ref>{{Cite journal |last=Smith GP|first=Gerard P. (|date=1996).-01-01 |title=The direct and indirect controls of meal size. Neurosci|journal=Neuroscience Biobehavand Rev.Biobehavioral Reviews |volume=20( |issue=1 |pages=41–46 |doi=10.1016/0149-7634(95):4100038-6.g PMID|issn=0149-7634 |pmid=8622828|s2cid=8313724 |doi-access=free }}</ref> The influence of these processes can exist without subjective awareness.<ref>{{Cite journal |last=Berridge KC|first=Kent C. (|date=1996).-01-01 |title=Food reward: brainBrain substrates of wanting and liking. Neurosci|journal=Neuroscience Biobehavand Rev.Biobehavioral ;Reviews |volume=20( |issue=1 |pages=1–25 |doi=10.1016/0149-7634(95):100033-25.b PMID|issn=0149-7634 |pmid=8622814 |s2cid=18707849}}</ref>
The cessation of a desire to eat after a meal "satiation" is likely to be due to different processes and cues.<ref>Blundell{{Citation JE|last1=Dalton |first1=M. |title=Hedonics, Rogerssatiation PJ.and (1991).satiety Hunger,|date=2013-01-01 hedonics|work=Satiation, Satiety and the controlControl of satiationFood andIntake satiety.|pages=221–237 pp.|editor-last=Blundell 127–148.|editor-first=John In: M.IE. Friedman,|series=Woodhead M.G.Publishing TordoffSeries andin M.R.Food KareScience, (Editors) AppetiteTechnology and nutrition,Nutrition Dekker,|publisher=Woodhead NewPublishing York ISBN|doi=10.1533/9780857098719.4.221 |isbn=978-0-824785709-8371543-65 |last2=Finlayson |first2=G. |editor2-last=Bellisle |editor2-first=France}}</ref> More palatable foods reduce the effects of such cues upon satiation causing a larger food intake, exploited in [[hyperpalatable food]].<ref>{{Cite journal |last1=Yeomans MR,|first1=M. R. |last2=Lee MD,|first2=M. D. |last3=Gray RW,|first3=R. W. |last4=French SJ|first4=S. (2001)J. [http://www.nature.com/ijo/journal/v25/n8/pdf/0801653a.pdf|date=2001-08-01 |title=Effects of test-meal palatability on compensatory eating following disguised fat and carbohydrate preloads.] Int|journal=International JJournal Obesof RelatObesity Metaband Disord.Related Metabolic Disorders |volume=25( |issue=8):1215-24. PMID|pages=1215–1224 |doi=10.1038/sj.ijo.0801653 |pmid=11477507|s2cid=37835293 }}</ref><ref>{{Cite journal |last1=Robinson TM,|first1=Tristan M. |last2=Gray RW,|first2=Richard W. |last3=Yeomans MR,|first3=Martin R. |last4=French SJ|first4=Stephen J. (|date=2005).-02-15 |title=Test-meal palatability alters the effects of intragastric fat but not carbohydrate preloads on intake and rated appetite in healthy volunteers. Physiol|journal=Physiology Behav.& Behavior |volume=84( |issue=2):193-203 |pages=193–203 |doi=10.1016/j.physbeh.2004.11.004 PMID|issn=0031-9384 |pmid=15708771|s2cid=33711162 }}</ref> In contrast, unpalatability of certain foods can serve as a deterrent from feeding on those foods in the future. For example, the [[Euphydryas chalcedona|Variablevariable Checkerspotcheckerspot butterfly]] contains [[iridoid]] compounds that are unpalatable to avian predators, thus reducing the risk of [[predation]].<ref>{{Cite journal |last=Bowers, |first=M. D.Deane "|date=1981 |title=Unpalatability as a Defense Strategy of Western Checkerspot Butterflies (Euphydryas Scudderscudder, Nymphalidae)." |jstor=2407845 |journal=Evolution |volume=35. |issue=2 (1981):|pages=367–375 367-75|doi=10.2307/2407845 |pmid=28563381 |issn=0014-3820}}</ref>
==See also==
*[[Acquired taste]]
*[[ Flavor (taste)|Flavor]] ▼*[[Appetite]]
*[[Food craving]]
*[[Motivation]]
*[[Nutrition]]
*[[Pleasure center]]
*[[Taste]]
==References==
{{reflist|2}}
==External links==
*[http://www.nutrition.org.uk/upload/Prof%20Martin%20Yeomans_The%20effect%20of%20palatability%20on%20satiety.pdf The effect of palatability on satiety] Martin R Yeomans
[[Category:Behavioral neuroscience]]
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