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Seeed Aufstehn Instrumental __LINK__


What began as a sandbar is now Sanibel, a barrier island fringed with mangrove trees, shallow bays, and white sandy beaches located off the southwest coast of Florida. For over 2,000 years the Calusa Indians made the lush island, with its ready source of food from the sea, their home. By the mid-1800s, European settlers arrived and soon displaced the Calusa tribe. For years, the island was mainly used by farmers until a fierce hurricane in 1926 destroyed the agriculture industry. Construction of the Sanibel causeway in 1963 opened way for tourism on the island. Jay Norwood Darling was instrumental in the effort to block the sale of a parcel of environmentally valuable land to developers on Sanibel Island. At Darling's urging, President Harry S. Truman signed an Executive Order creating the Sanibel National Wildlife Refuge in 1945.




Seeed aufstehn instrumental



Lesions of the BLA (Blundell et al., 2001; Balleine et al., 2003), the NAc (Corbit et al., 2001), the IC (Balleine and Dickinson, 2000), or the DMS (Yin et al., 2005), performed both before or after instrumental training, impair IDE, i.e., the ability of recalling actions differentially based on the current value associated to their outcomes. The same work showing the importance of NAc (Corbit et al., 2001) also shows that nucleus accumbens shell (NAs) is not needed for IDE. Interestingly, lesions of PL (or the MD, through which PL forms loops with BGv) impair IDE only when the lesion is made before the instrumental training but not after it, thus showing that the PL is needed for the acquisition but not for the expression of IDE (Corbit and Balleine, 2003; Ostlund and Balleine, 2008; Tran-Tu-Yen et al., 2009). Instead, the lesion of the orbitofrontal cortex (OFC) does not impair IDE, even though it impairs Pavlovian outcome devaluation effects (PDE), namely it prevents the reduction of Pavlovian responses to conditioned stimuli after the devaluation of the related unconditioned stimuli (Ostlund and Balleine, 2007). Lesions of the hippocampus (Hip) before or after instrumental learning do not impair IDE, both in rats (Corbit and Balleine, 2000) and in monkeys (Chudasama et al., 2008). Using a disconnection technique involving a combined controlateral lesion of two connected brain structures, Coutureau et al. (2009) showed that disrupting the recurrent projections between BLA and PL does not impair IDE, thus demonstrating that the direct interaction between the two is not necessary for IDE.


The retrieval of the incentive value of outcomes during instrumental behavior has been shown to involve the gustatory region of the anterior insular cortex (IC; Balleine and Dickinson, 2000). In particular, in devaluation experiments bilateral lesions of IC abolish IDE with satiety outcome devaluation when assessed in extinction tests (but not if food is delivered), suggesting that the IC is critical for recalling the incentive value of outcomes during choice. The roles of BLA and IC in learning and storing information on incentive value of outcomes might be based on their strong reciprocal connections (Yamamoto et al., 1984; Augustine, 1996; Nieuwenhuys, 2012). These connections suggest the existence of a close interplay of the two structures as also shown by the direct test for which the stimulation of the BLA affects the response of IC neurons (Piette et al., 2012). The importance of BLA for learning and IC for storing information is in particular supported by evidence showing that a tetanic stimulation of BLA causes an NMDA receptor-dependent long term potentiation in the ipsilateral IC (Escobar et al., 1998; Jones et al., 1999; Escobar and Bermúdez-Rattoni, 2000). Disconnecting BLA and NAc by lesioning the BLA of one brain emisphere and the controlateral NAc abolishes IDE (Shiflett and Balleine, 2010; Parkes and Balleine, 2013) so suggesting that BLA-IC-NAc might form a three-stage circuit responsible for encoding, storing, and dispatching the value of outcomes. Indeed, the technique for disconnecting two brain structures based on the lesion of their controlateral components is equivalent to ruling out not only their direct connections but also their indirect ones, so it also eliminates the functions played by intermediate stages (e.g., IC) of the circuit starting and ending with the two targeted regions (e.g., BLA and NAc). More direct evidence on the importance of the synergistic action of the two structures comes from another devaluation experiment (Parkes et al., 2015). Here the disconnection of the two structures, performed after satiation and before the devaluation test by injecting IC with GABAA agonist muscimol and NAc with a μ-opioid receptor antagonist, again abolished IDE. Notwithstanding this evidence, the specific mechanisms through which BLA and IC specifically contribute to support their interdependent functioning and learning processes are not well understood (Parkes and Balleine, 2013). For this reason, and also for its focus on the system-level aspects of IDE, the model presented here abstracts over the specific roles of BLA and IC and considers them as a whole structure. The specific mechanisms through which the two structures play their differential functions in IDE might be addressed in a future targeted research.


The connections of BLA and IC with other structures, and the evidence of focused lesions of such structures reviewed in Section 2.1, support the idea that BLA and IC are sufficient to store the current motivational values of outcomes in IDE experiments, and to transfer it to NAc for the selection of goals. BLA (Pitkänen et al., 1995; Savander et al., 1995, 1996) and IC (Augustine, 1996; Nieuwenhuys, 2012) exchange reciprocal connections with Hip, PL, and OFC but these areas are not necessary for IDE. In particular, BLA and IC are heavily connected with the Hip via reciprocal connections and through them they support Hip learning and recall of episodic memories, in particular in relation to their emotional aspects (Pitkänen et al., 1995; Augustine, 1996; McDonald, 1998; Janes, 2015). However, Corbit and Balleine (2000) showed that lesioning the Hip does not impair IDE. Second, the interaction between Amg and IC with various areas of PFC have a great role in complex decision making processes (Bechara et al., 1999; Sterzer and Kleinschmidt, 2010; Moraga-Amaro and Stehberg, 2012). However, the lesion of PL after instrumental learning does not impair the expression of IDE (Coutureau et al., 2009). Last, several studies show that OFC, another cortical region broadly connected with BLA in a reciprocal manner, has an important role in PDE (Ostlund and Balleine, 2007) and its connections with IC are important for several cognitive processes (Augustine, 1996; Nieuwenhuys, 2012). Notwithstanding this, Ostlund and Balleine (2007) showed that OFC is not needed for the expression of IDE. Overall, this evidence shows that BLA and IC can store and retrieve information on the value of outcomes in IDE experiments without the support of those other structures.


In the instrumental learning phase of the devaluation experiment, when BLA/IC recall the outcome representation in the presence of the CS, and at the same time the NAc-PL loop activates the representation of the possible effects of the selected actions, a third learning process can take place. This links the motivationally salient representations of outcomes in BLA/IC with the goal representations in the NAc (Figure 1(3)): the NAc thus becomes a nexus between incentive value information stored in BLA/IC and goal representations in PFC (Mannella et al., 2013). Later, in particular in the third phase of the devaluation experiment, this link allows the outcome value representation in BLA/IC, whose level of activation depends on the current internal state of the animal, to bias the goal-selection process taking place within the NAc-PL loop.


To empirically rule out a possible S-R interpretation of IDE experiments, Balleine and Ostlund (2007) carried out a devaluation experiment where, in the first instrumental phase, the rats learned (in separate experimental sessions) to perform two different actions on one manipulandum, and these actions led, as usual, to two different outcomes. The two different actions consisted in pushing a pole either toward one direction or toward the opposite direction. As in standard devaluation experiments, the experimenters later satiated the rats for one reward, performed the devaluation test using the unique manipulandum, and measured which action was performed more frequently. The results showed that the rats performed more frequently the action associated with the valued outcome notwithstanding they were exposed to the unique ambiguous stimulus (the pole).


The main architecture of the model is based on three loops: the motor loop, the associative loop, and the goal loop (Haber, 2003; Yin and Knowlton, 2006). The motor loop (Figure 2(1)) involves the dorsolateral striatum (DLS) and the primary motor cortex, the premotor cortex, and the supplementary motor areas (here referred to as motor cortex as a whole, MC) (Romanelli et al., 2005; Redgrave and Gurney, 2006). This loop learns by trial-and-error to select instrumental actions based on current stimuli (S-R). In the model, the motor loop selects one of the two available actions.


All simulations consisted of two instrumental training sessions followed by two devaluation test sessions. The satiation phase, happening between training and test, was simulated by suitably setting the satiation inputs of the model in the test sessions (see below). Each instrumental session lasted 20 min and was formed by multiple trials during which both satiety input units were set to zero. In the simulations with two manipulanda, in the first training session each rat experienced the first manipulandum and related reward (first food), whereas in the second session it experienced the second manipulandum and related reward (second food). In the simulations with one manipulandum, in the first training session only the first action could lead to a reward (first food) whereas in the second session only the second action could lead to a reward (second food).


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