Hedonic Hot Spots in the Brain

Abstract

Hedonic "liking" for sensory pleasures is an important aspect of reward, and excessive 'liking' of particular rewards might contribute to excessive consumption and to disorders such as obesity. The present review aims to summarize recent advances in the identification of brain substrates for food 'liking' with a focus on opioid hot spots in the nucleus accumbens and ventral pallidum. Drug microinjection studies have shown that opioids in both areas amplify the 'liking' of sweet taste rewards. Modern neuroscience tools such as Fos plume mapping have further identified hedonic hot spots within the accumbens and pallidum, where opioids are especially tuned to magnify 'liking' of food rewards. Hedonic hot spots in different brain structures may interact with each other within the larger functional circuitry that interconnects them. Better understanding of how brain hedonic hot spots increase the positive affective impact of natural sensory pleasures will help characterize the neural mechanisms potentially involved in 'liking' for many rewards.

Reward circuitry dysfunction in psychiatric and neurodevelopmental disorders and genetic syndromes: animal models and clinical findings

“…The mesolimbic DA system represents only one component of a very complex and integrated set of circuits, and although DA is clearly a crucial neurotransmitter in the reward-processing system, non-DA systems clearly also modulate reward responsibility [19,735]. Additionally, there are multiple brain regions not addressed in this review that contribute to reward processing, including the subthalamic nucleus and ventral pallidum, the subiculum, the lateral habenula, and the extended amygdala [736,737]. Additionally, multiple non-DA compounds have shown efficacy in improving reward responses, such as agents that affect glutamate circuits involved in regulating monoamine systems [19].…”

Affective neuroscience of pleasure: reward in humans and animals

“…There is a special need for better understanding of how pleasure is generated by brain systems, and so we will focus particularly on pleasure in this paper. Smith et al (2008), based on Kringelbach (2005), Peciña et al (2006), and Smith and Berridge (2007) From sensation to pleasure Pleasure is never merely a sensation (Frijda 2007;Kringelbach and Berridge 2008;Ryle 1954). Instead, it always requires the activity of hedonic brain systems to paint an additional "hedonic gloss" onto a sensation to make it 'liked'.…”

“…Food is one of the most universal routes to pleasure and is one of the most accessible experimental methods available to neuroscience studies of pleasure (Kringelbach 2005;Peciña et al 2006;Rozin 1999;Small et al 2001). The two most important senses involved in food intake are smell and taste, which must interact to facilitate human decision making and hedonic experience (Gottfried 2008;Small and Veldhuizen 2008).…”

“…Pleasurable subjective pain relief for chronic pain in a phantom limb in a patient was causally induced by effective deep brain stimulation in the PVG/ PAG part of the brainstem. When using MEG to directly measure the concomitant changes in the rest of the brain, a significant change in power was found in the mid-anterior OFC to enhance several aspects of reward (Cardinal et al 2002;Everitt and Robbins 2005;Kelley et al 2002;Kelley et al 2005;Koob and Le Moal 2006;Kringelbach and Berridge 2008;Peciña et al 2006;Robbins and Everitt 2002;Salamone et al 2007;Shizgal et al 2001;Szczypka et al 2001), yet damage to the nucleus accumbens may only subtly impair the hedonic impact or related components of natural rewards such as food (Balleine and Killcross 1994;Parkinson et al 1999;Setlow et al 2002;Whishaw and Kornelsen 1993). Core 'liking' reactions to pleasure may be relatively difficult to abolish absolutely by a single brain lesion or drug, which may be very good in evolutionary terms.…”

“…In most non-linguistic mammals, pleasure will also elicit affective 'liking' reactions, reflecting in a basic form the hedonic gloss to the sensation, which we experience as conscious pleasure (Berridge 2000;Kringelbach 2008;Peciña et al 2006).…”