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 - See this specific section in the following text: **Neurobiology of Sensation and Reward.** Gottfried JA, editor. Boca Raton (FL): CRC Press; 2011. **Chapter 11 Neuroanatomy of Reward: A View from the Ventral Striatum. By Suzanne N. Haber.** - See this specific section in the following text: **Neurobiology of Sensation and Reward.** Gottfried JA, editor. Boca Raton (FL): CRC Press; 2011. **Chapter 11 Neuroanatomy of Reward: A View from the Ventral Striatum. By Suzanne N. Haber.**
-Most important references cited here (see below).+Most important references cited here (see below). COPY LINK.
  
-- See also **The Ventral Striatum as an Interface Between the Limbic and Motor Systems** By **Henk J. Groenewegen.** CNS Spectr 12:12. 2007+- See also **The Ventral Striatum as an Interface Between the Limbic and Motor Systems** By **Henk J. Groenewegen.** CNS Spectr 12:12. 2007. COPY PAPER HERE.
  
-The nucleus accumbens (and the VS in general) ​has been a central site for studying reward and drug reinforcement and for the transition between drug use as a reward and as a habit (Olds and Milner, 1954; Kalivas, Volkow, and Seamans 2005; Taha and Fields 2006).+The nucleus accumbens (and the VS in general)
  
-Human imaging studies demonstrate the involvement of the VS in reward prediction and reward prediction errors (Knutson et al. 2001; O’Doherty et al. 2004; Pagnoni et al. 2002; Tanaka et al. 2004) andconsistent with physiological non-human primate studies, the region is activated during ​reward ​anticipation ​(Schultz 2000). Collectively,​ these studies demonstrate its key role in the acquisition ​and development of reward-based behaviors and its involvement in drug addiction and drug-seeking behaviors (Belin and Everitt 2008; Everitt and Robbins 2005; Porrino et al. 2007; Volkow et al. 2006).+• Involved ​in **reward prediction, reward anticipation ​and reward prediction errors, reward evaluation and incentive-based learning** ​(Knutson et al. 2001; O’Doherty et al. 2004; Pagnoni et al. 2002; Tanaka et al. 2004; Schultz2000; Corlett et al. 2004; Elliott et al. 2003; Knutson et al. 2001; Schultz Tremblayand Hollerman 2000; Tanaka et al. 2004). Central site for studying ​ **drug reinforcement** and for the transition between drug use as a reward ​and as a habit (Olds and Milner, 1954; Kalivas, Volkow, and Seamans 2005; Taha and Fields 2006). Acquisition ​and development of **drug addiction and drug-seeking behaviors** (Belin and Everitt 2008; Everitt and Robbins 2005; Porrino et al. 2007; Volkow et al. 2006; Kuhnen and Knutson 2005; Volkow et al. 2005). 
 +• Based on the character of the afferents of the nucleus accumbens, this part of the ventral striatum may be viewed as a **site for integration** of signals with **emotional** content (amygdala); **contextual** information (hippocampus);​ **motivational** significance (dopaminergic inputs); information about the state of **arousal** (midline thalamus); and **executive/​cognitive** information (prefrontal cortex). 
 +• The accumbens’ outputs, directly or via ventral pallidal and dopaminergic and non- dopaminergic nigral relays, lead to brain areas involved in basic functions, such as feeding and drinking behavior (lateral hypothalamus);​ motivational behavior (VTA and nigral dopaminergic neurons); locomotor behavior (caudal mesencephalon);​ and more complex cognitive and executive functions (via medial thalamic nuclei to the prefrontal cortex). Thus, Morgenson and colleagues original concept of the **nucleus accumbens as a functional interface between the limbic and motor systems, in general** terms, is still valid. 
 +• The VS contains a subterritory,​ the **Shell*,* which plays a particularly important role in the circuitry underlying **goal-directed behaviors, behavioral sensitization,​ and changes in affective states** (Carlezon and Wise 1996; Ito, Robbins, and Everitt 2004), **expression of certain innate, unconditioned behaviors, such as feeding or defensive behavior** ( **SEARCH REFS** 33-39 in Groenewegen et al. 2007). The shell and core subregions play important but distinct roles in **Pavlovian and instrumental conditioned learning** that may be potentiated by psychostimulants (40-48 in Groenewegen et al. 2007). The **core** subregion seems to be preferentially involved in **response-reinforcement learning**, whereas the **shell** is not involved in motor or response learning, per se, rather, it **integrates basic biological “drives” with the viscero- limbic and motor-effector systems.**  
 +• Electrical or chemical stimulation of the nucleus accumbens → **analgesic action** (inhibition of the nociceptive jaw opening reflex) mediated by activation of its dopamine D2 receptors and transmitted through the indirect pathways of the basal ganglia and the medullary dorsal reticular nucleus (RVM) to the sensorial nuclei of the trigeminal nerve. Its mechanism of action was by inhibition of the nociceptive response of the second order neurons of the nucleus caudalis of the V par (Barcelo et al. 2012. Cell Mol Neurobiol).
  
-The ventral striatal region is also involved in various aspects of reward evaluation and incentive-based learning (Corlett et al. 2004; Elliott et al. 2003; Knutson et al. 2001; Schultz Tremblay, and Hollerman 2000; Tanaka et al. 2004), and is associated with pathological risk-taking and addictive behaviors (Kuhnen and Knutson 2005; Volkow et al. 2005) 
- 
- 
-The VS contains a subterritory,​ the shell,* which plays a particularly important role in the circuitry underlying goal-directed behaviors, behavioral sensitization,​ and changes in affective states (Carlezon and Wise 1996; Ito, Robbins, and Everitt 2004). 
- 
-Based on the character of the afferents of the nucleus accumbens, this part of the ventral striatum may be viewed as a site for integration of signals with emotional content (amygdala); contextual information (hippocampus);​ motivational significance (dopaminergic inputs); information about the state of arousal (midline thalamus); and executive/​cognitive information (prefrontal cortex). 
- 
- The accumbens’ outputs, directly or via ventral pallidal and dopaminergic and non- dopaminergic nigral relays, lead to brain areas involved in basic functions, such as feeding and drinking behavior (lateral hypothalamus);​ motivational behavior (VTA and nigral dopaminergic neurons); locomotor behavior (caudal mesencephalon);​ and more complex cognitive and executive functions (via medial thalamic nuclei to the prefrontal cortex). Thus, Morgenson and colleagues original concept of the nucleus accumbens as a functional interface between the limbic and motor systems, in general terms, is still valid. 
- 
- ​However,​ current insights are, of course, much more differentiated. In particular, the functional differentiation between the shell and core has received much attention in the past 2 decades. Primarily based on animal experimental work, it may be concluded that **the shell** stands out from the core and the rest of the striatum through its involvement in the expression of certain innate, unconditioned behaviors, such as feeding or defensive behavior (33-39 in Groenewegen et al. 2007). The shell and core subregions play important but distinct roles in Pavlovian and instrumental conditioned learning that may be potentiated by psychostimulants (40-48 in Groenewegen et al. 2007). The **core** subregion seems to be preferentially involved in response-reinforcement learning, whereas the **shell** is not involved in motor or response learning, per se, rather, it integrates basic biological “drives” with the viscero- limbic and motor-effector systems. Dopamine in the nucleus accumbens may have a role in enhancing the gain by which conditioned stimuli and contexts exert control over behavior. 
- 
-From Barcelo et al. 2012. Cell Mol Neurobiol. 
- 
-"We analyse the effect of electrical and chemical stimulation of the striatum on the orofacial pain, especially that produced by tooth pulp stimulation of the lower incisors. We demonstrated specific sites within the nucleus which electrical or chemical stimulation produced inhibition of the nociceptive jaw opening reflex. This analgesic action of the striatum was mediated by activation of its dopamine D2 receptors and transmitted through the indirect pathways of the basal ganglia and the medullary dorsal reticular nucleus (RVM) to the sensorial nuclei of the trigeminal nerve. Its mechanism of action was by inhibition of the nociceptive response of the second order neurons of the nucleus caudalis of the V par." 
 === Effects of stimulation === === Effects of stimulation ===