Biology subjects

Acca, G. M.

Publications and source records attributed to Acca, G. M..

2 recordsLinked to original sources

bioRxiv2019

Threat imminence dictates the role of the bed nucleus of the stria terminalis in contextual fear

Previous work indicates that the bed nucleus of the stria terminalis (BNST) is involved in defensive freezing to unpredictable Pavlovian conditioned stimuli (Goode et al., 2019). Here we show that the BNST mediates freezing to contexts paired with remote (unpredictable), but not imminent (predictable), footshock. Rats underwent a fear conditioning procedure in which a single footshock unconditioned stimulus (US) was delivered either 1 (imminent) or 9 minutes (remote) after placement in the context; each rat received a total of four conditioning trials over two days. Contexts associated with either imminent or remote USs produced distinct patterns of freezing and shock-induced activity but freezing in each case was context-dependent. Reversible inactivation of the BNST reduced the expression of contextual freezing in the context paired with remote, but not imminent, footshock. Implications of these data are discussed in light of recent conceptualizations of BNST function, as well as for anxiety behaviors.

neuroscience↗

bioRxiv2018

Bed nucleus of the stria terminalis mediates fear to ambiguous threat signals

The bed nucleus of the stria terminalis (BNST) has been implicated in fear and anxiety, but the specific factors that engage the BNST in defensive behavior are unclear. Here we explore the possibility that ambiguous threats recruit the BNST during Pavlovian fear conditioning in rats. We arranged a conditioned stimulus (CS) to either precede or follow an aversive unconditioned stimulus (US), a procedure that established reliable (forward) or ambiguous (backward) signals for US onset. After conditioning, reversible inactivation of the BNST selectively reduced freezing to the backward CS; BNST inactivation did not affect freezing to the forward CS even when that CS predicted a variable magnitude US. Backward CSs increased Fos in the ventral BNST and in BNST-projecting neurons in the infralimbic cortex, but not the hippocampus or amygdala. These data reveal that BNST circuits process ambiguous threat signals central to the etiology and expression of anxiety.

neuroscience↗