Median raphe region stimulation alone generates remote, but not recent fear memory traces

The median raphe region (MRR) is believed to control the fear circuitry indirectly, by influencing the encoding and retrieval of fear memories by amygdala, hippocampus and prefrontal cortex. Here we show that in addition to this established role, MRR stimulation may alone elicit the emergence of remote but not recent fear memories. We substituted electric shocks with optic stimulation of MRR in C57BL/6N male mice in an optogenetic conditioning paradigm and found that stimulations produced agitation, but not fear, during the conditioning trial. Contextual fear, reflected by freezing was not present the next day, but appeared after a 7 days incubation. The optogenetic silencing of MRR during electric shocks ameliorated conditioned fear also seven, but not one day after conditioning. The optogenetic stimulation patterns (50Hz theta burst and 20Hz) used in our tests elicited serotonin release in vitro and lead to activation primarily in the periaqueductal gray examined by c-Fos immunohistochemistry. Earlier studies demonstrated that fear can be induced acutely by stimulation of several subcortical centers, which, however, do not generate persistent fear memories. Here we show that the MRR also elicits fear, but this develops slowly over time, likely by plastic changes induced by the area and its connections. These findings assign a specific role to the MRR in fear learning. Particularly, we suggest that this area is responsible for the durable sensitization of fear circuits towards aversive contexts, and by this, it contributes to the persistence of fear memories. This suggests the existence a bottom-up control of fear circuits by the MRR, which complements the top-down control exerted by the medial prefrontal cortex

MRI screening for breast cancer in women at high risk; isthe Australian breast MRI screening access program addressing the needs of women at high risk of breast cancer?

Breast magnetic resonance imaging (MRI) screening of women under 50 years old at high familial risk of breast cancer was given interim funding by Medicare in 2009 on the basis that a review would be undertaken. An updated literature review has been undertaken by the Medical Services Advisory Committee but there has been no assessment of the quality of the screening or other screening outcomes. This review examines the evidence basis of breast MRI screening and how this fits within an Australian context with the purpose of informing future modifications to the provision of Medicare-funded breast MRI screening in Australia. Issues discussed will include selection of high-risk women, the options for MRI screening frequency and measuring the outcomes of screening

Evaluation of the rat defense reaction as a model of panic attack in man: Pharmacological and neuroendocrine evidence

Univ Fed Espirito Santo, Dept Physiol Sci, CBM, BR-29040090 Vitoria, ES, BrazilUniversidade Federal de São Paulo, Dept Psychopharmacol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychopharmacol, São Paulo, BrazilWeb of Scienc