Person:
Ramirez, Franchesca

Profile Picture

Email Address

AA Acceptance Date

Birth Date

Research Projects

Organizational Units

Job Title

Last Name

Ramirez

First Name

Franchesca

Name

Ramirez, Franchesca
Author's Publications: search.filters.isAuthorOfPublication.090939a1-403c-46e7-b4be-89ae51d5ddd0

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Publication
    Active Avoidance Requires a Serial Basal Amygdala to Nucleus Accumbens Shell Circuit
    (Society for Neuroscience, 2015) Ramirez, Franchesca; Moscarello, J. M.; LeDoux, J. E.; Sears, R. M.
    Freezing is a species-typical defensive reaction to conditioned threats. While the neural circuitry of aversive Pavlovian behavior has been extensively studied, less is known about the circuitry underlying more active responses to danger. Here we show that the flow of information between the basal amygdala (BA) and the nucleus accumbens (NAcc) is necessary for signaled active avoidance behavior. Rats trained to avoid shock by shuttling during an auditory conditioned stimulus showed increased expression of the activity-dependent protein c-Fos in the NAcc, specifically the shell subregion (NAccSh). Silencing neural activity in the NAccSh, but not in the adjacent NAcc core, disrupted avoidance behavior. Disconnection of the BA and the NAccSh was just as effective at disrupting avoidance behavior as bilateral NAccSh inactivations, suggesting learned avoidance behavior requires an intact BA-NAccSh circuit. Together, these data highlight an essential role for the amygdalar projection to the ventral striatum in aversively motivated actions.
  • Thumbnail Image
    Publication
    Stressor controllability modulates fear extinction in humans
    (Elsevier BV, 2014) Hartley, Catherine A.; Gorun, Alyson; Reddan, Marianne C.; Ramirez, Franchesca; Phelps, Elizabeth A.
    Traumatic events are proposed to play a role in the development of anxiety disorders, however not all individuals exposed to extreme stress experience a pathological increase in fear. Recent studies in animal models suggest that the degree to which one is able to control an aversive experience is a critical factor determining its behavioral consequences. In this study, we examined whether stressor controllability modulates subsequent conditioned fear expression in humans. Participants were randomly assigned to an escapable stressor condition, a yoked inescapable stressor condition, or a control condition involving no stress exposure. One week later, all participants underwent fear conditioning, fear extinction, and a test of extinction retrieval the following day. Participants exposed to inescapable stress showed impaired fear extinction learning and increased fear expression the following day. In contrast, escapable stress improved fear extinction and prevented the spontaneous recovery of fear. Consistent with the bidirectional controllability effects previously reported in animal models, these results suggest that one's degree of control over aversive experiences may be an important factor influencing the development of psychological resilience or vulnerability in humans.