The periaqueductal gray as a critical site to mediate reward seeking during predatory hunting

A comparison of neural responses to appetitive and aversive stimuli in humans and other mammals

“…Nonetheless, a couple of studies have implicated the PAG in appetitive-related motivation, as dorsal PAG inactivation reduces defensive, and increases maternal, behaviours (Sukikara et al, 2010) while ventrolateral PAG inactivation reduces hunting motivation (Mota-Ortiz et al, 2012). Nonetheless, the increase in such behaviours could be interpreted as decreases in aversive behaviours; this is supported by the fact that large PAG lesions do not affect electrical brain self-stimulation in rats (Waraczynski et al, 1998).…”

“…Nonetheless, although PAG activity, for instance, is associated mainly with pain-related and defensive behaviours, its activity also appears to be involved in socially motivated actions such as maternal behaviour in the presence of threat and hunting and foraging (Mota-Ortiz et al, 2012;Sukikara et al, 2010), as well as in the appetitive effects of heroin (Flores et al, 2006). Moreover, PAG activity may be context-dependent as a recent human fMRI study showed that comparatively low levels of pain (the 'relief' condition) are perceived as pleasant and correspond to increased connectivity between the PAG and classical reward-related circuitry (Leknes et al, 2013).…”

The periaqueductal gray and primal emotional processing critical to influence complex defensive responses, fear learning and reward seeking

“…In addition, the lateral PAG is also well positioned to influence reward seeking through its projections to the lateral/perifornical orexinergic cell group of the lateral hypothalamus (see Fig. 3; Mota-Ortiz et al, 2012). Activation of lateral hypothalamic orexinergic neurons has been found to be strongly linked to preferences for drug and food reward-associated cues, which work as highly salient appetitive reinforcers (Harris and Aston-Jones, 2006).…”

Periaqueductal Gray

“…The rostral third which, at its most rostral point, at the level of the posterior commissure, adjoins the periventricular gray of the hypothalamus has received substantially less attention. The lateral column in this region (rlPAG) has been shown to be critical for the expression of predatory behaviors, such as hunting and foraging in both female and male rats (Sukikara et al, 2006;Mota-Ortiz et al, 2012). This rlPAG region is also targeted by afferent inputs, from some, but not all of the forebrain regions that project to the caudal two thirds of this column; specifically, PL, ACd, AId, AIv, as well as primary and secondary motor areas and the peri-and entorhinal cortices (Mota-Ortiz et al, 2009).…”