Table 2.

Effects of lesions on components of anxious temperament in primates.

Region	Lesion age	Freezing	Cooing	HPA axis	Other
Amygdala	neonatal	↑ at 2 months - at 2.5 months - at 4 months ↓ at 12 months ↓ as young adults	↑ at 2.5 months ↑ at 12 months	- ACTH release at 12 months - ACTH release as young adults ↓ cortisol release at 2.5 months ↓ cortisol afternoon release at 5 months ↑ cortisol release at 12 months ↓ cortisol release as young adults
Amygdala (central nucleus)	young adult	↓	↑	↓ ACTH release ↓ CRF release -↓ cortisol release	↓ snake fear - left frontal EEG asymmetry
Amygdala	Young adult	-↓	↓	↓ cortisol release	↓↓↓ snake fear -left frontal EEG asymmetry
Orbitofrontal cortex	Young adult	↓↓↓		- ACTH release - CRF release ↓ cortisol release	-↓ snake fear ↑ left frontal EEG asymmetry ↓ BNST and entorhinal cortex metabolism
Hippocampus	Young adult	-		- cortisol release	- snake fear

Note: data from (Fox et al., 2010; Izquierdo and Murray, 2004; Kalin et al., 2007, 2004, 2001; Machado et al., 2009; Machado and Bachevalier, 2008; Raper et al., 2013a, 2013b, 2013c). HPA = hypothalamic-pituitary-adrenal axis; ACTH = adrenocorticotropic hormone; CRF = corticotropin-releasing hormone; ↑ = one study showing a significant increase; - = one study showing no effect; ↓ = one study showing a significant decrease