A small number of studies have investigated the role of ACh signaling in the hypothalamus, which receives input from the PPTg and LDTg (Hallanger and Wainer, 1988; Jones and Beaudet, 1987). Activity in both these areas adapts quickly to environmental changes (Majkutewicz et al., 2010; Woolf, 1991) and is linked to peripheral control of feeding behavior (Phillis, 2005). There are also intrinsic neurons within the hypothalamus that express cholinergic markers (Tago et al., 1987) as well as the pro-opiomelanocortin (POMC) peptide (Meister et al., 2006), and nAChRs in the hypothalamus are critical for feeding behavior (Jo et al., 2002). It has also been suggested that neurons in the median eminence could project to the hypothalamus (Schafer et al., 1998). Corticotropin-releasing hormone-expressing neurons in this area can affect metabolism. In non-human primates, neurons in the substantia innominata and LH, most of which express cholinergic markers, were activated in response to presentation of food when the animals were hungry (Rolls et al., 1979). Consistent with a potential role for ACh in coordinating caloric need with food-seeking behaviors, long-term maintenance on a high-fat/high-sugar
