Heat exposure in female rats elicits abnormal fear expression and cellular changes in prefrontal cortex and hippocampus.

Despite a twofold higher prevalence of fear-related disorders in women, the neurobiological factors that modulate and drive fear expression are rarely studied in female animals. Fear conditioning and extinction are useful tools for dissecting these mechanisms, and here we tested the effects of environmental manipulations - four days of exposure to 31°C temperatures in the animal housing facility - on fear learning and memory exclusively in female rats. We found that heat exposure disrupted freezing to tone during fear conditioning, and elicited enhanced freezing during extinction and extinction retrieval.

Dopamine D1 receptor activation rescues extinction impairments in low-estrogen female rats and induces cortical layer-specific activation changes in prefrontal-amygdala circuits.

Post-traumatic stress disorder (PTSD) is twice as common in women as in men; it is a major public health problem whose neurobiological basis is unknown. In preclinical studies using fear conditioning and extinction paradigms, women and female animals with low estrogen levels exhibit impaired extinction retrieval, but the mechanisms that underlie these hormone-based discrepancies have not been identified. There is much evidence that estrogen can modulate dopaminergic transmission, and here we tested the hypothesis that dopamine-estrogen interactions drive extinction processes in females.

Cognitive mapping in humans and its relationship to other orientation skills.

Human orientation in novel and familiar environments is a complex skill that can involve numerous different strategies. To date, a comprehensive account of how these strategies interrelate at the behavioural level has not been documented, impeding the development of elaborate systems neuroscience models of spatial orientation. Here, we describe a virtual environment test battery designed to assess five of the core strategies used by humans to orient.