Translational approach to studying panic disorder in rats: Hits and misses

In a rat model of panic, corticotropin responses to dorsal periaqueductal gray stimulation depend on physical exertion

“…These findings were corroborated by c-fos immunohistochemistry data showing the activation of both the nucleus of the solitary tract (NTS) and the DPAG in rats that developed escape reactions to 8% hypoxia (Casanova et al, 2013). Overall, these data endorse extensive research suggesting the DPAG mediation of panic (Deakin and Graeff, 1991;Schenberg et al, 2001Schenberg et al, , 2014Mobbs et al, 2007;Quintino-Dos-Santos et al, 2014).…”

The neural circuits of innate fear: detection, integration, action, and memorization

“…Moreover, slice electrophysiology experiments have shown that the PAGd harbors hypoxia-responding neurons (Kramer et al 1999). Taken together, these findings indicate that the dorsal PAG may serve as a central node in the processing of hypoxiainduced fear (Schenberg et al 2014).…”

“…First, neuronal activation in the PAG has been observed upon exposure to a wide variety of threats, including live predator or predator odor (Cezario et al 2008), aggressive conspecifics (Motta et al 2009), loud ultrasound stimuli (Mongeau et al 2003), and electrical footshock (Johansen et al 2010). Second, impairment of PAG function diminishes the expression of defensive behaviors including freezing, risk assessment, flight, analgesia, and autonomical arousal (Hunsperger et al 1963, Schenberg et al 2014Sukikara et al 2006;Silva et al 2013). Third, stimulation of the PAG is sufficient to induce defensive responses of various types, including freezing, escape, and jumping (Bandler and Shipley 1994;Schenberg et al 2014).…”

“…Second, impairment of PAG function diminishes the expression of defensive behaviors including freezing, risk assessment, flight, analgesia, and autonomical arousal (Hunsperger et al 1963, Schenberg et al 2014Sukikara et al 2006;Silva et al 2013). Third, stimulation of the PAG is sufficient to induce defensive responses of various types, including freezing, escape, and jumping (Bandler and Shipley 1994;Schenberg et al 2014). …”

“…The dorsal columns of the PAG (PAGd) represent the main output structures of the medial hypothalamic defensive system (Canteras et al 1994;Canteras 2002;Gross and Canteras 2012) as well as of the SC and IC (Canteras et al 1992) and mediate active defensive responses to imminent threats like predators and aggressive conspecifics (Sukikara et al 2006;Motta et al 2009;Silva et al 2013). Such active defensive strategies include escape, freezing associated with muscular tension, tachycardia, hypertension, hypervigilance, and hyperreactivity (Schenberg et al 2014;Sukikara et al 2006;Wang et al 2015). The dorsal columns of the PAG project to downstream brain stem structures, including the cuneiform nucleus, periabducens region of the rostral dorsomedial pons, the locus coeruleus, and the ventromedial, ventrolateral, and dorsal medulla (Bandler and Shipley 1994).…”