Regional brain responses to pleasant and unpleasant IAPS pictures: Different networks

Negative Emotional Experiences during Navigation Enhance Parahippocampal Activity during Recall of Place Information

“…Similar to previous studies that have shown memory enhancement for negative emotional stimuli (Schwarze et al, 2012;Keightley, Chiew, Anderson, & Grady, 2011;Humphreys, Underwood, & Chapman, 2010;Mickley Steinmetz, Addis, & Kensinger, 2010;Mickley & Kensinger, 2008), our finding suggests that affectively modulated place memory is valence-specific. Our findings are also consistent with previous studies that have shown that the parahippocampal gyrus is specifically involved in the processing of negative emotional stimuli but not positive emotional stimuli (Aldhafeeri, Mackenzie, Kay, Alghamdi, & Sluming, 2012;Gosselin et al, 2006). Valencespecific effects may reflect a natural bias of emotion regulation networks toward automatic processing of threatrelated information.…”

Negative emotional stimulation decreases respiratory sensory gating in healthy humans

“…It might be induced by the action of epinephrine, a neuromodulator that is strongly released during emotional processes, directly on thalamic cells and/or via the prefrontal-thalamic system . Unpleasant IAPS pictures have been shown to activate the hippocampus as well as the prefrontal cortex (Aldhafeeri et al, 2012), suggesting a role for both structures in the modulation of the respiratory sensory gating observed in our study. The thalamus is not activated by unpleasant IAPS pictures but it has strong interconnections with the amygdala, the anterior cingulate and the prefrontal cortex which are activated by viewing unpleasant pictures (Aldhafeeri et al, 2012).…”

Effect of d-amphetamine on emotion-potentiated startle in healthy humans: implications for psychopathy and antisocial behaviour

“…Given consistent evidence from both animal (review, Davis et al 1993) and human studies (e.g. Aldhafeeri et al 2012;Buchanan et al 2004;Funayama et al, 2001) that startle potentiation by aversive stimuli is mediated by the amygdala, which has a high density of dopamine receptors (Missale et al 1998), and is influenced by dopamine transmission (Kroner et al 2005), our findings point to two possible explanations: (a) that d-amphetamine directly antagonises fear-related processes; or (b) this effect is secondary to a primary effect on pleasurerelated processes (there is a long and well-established literature showing mutually reciprocal inhibition of appetitive and aversive systems; Gray 1987). In support of the latter possibility, there is evidence of neurochemical and neurophysiological hyperactivity in the mesolimbic dopamine reward system in psychopathic individuals (Buckholtz et al 2010).…”