Life in the oceanic realms

The marine environment includes the nutrient-rich coastal waters, relatively nutrient-poor open oceanic waters, coral reef atolls, metal-rich hydrothermal vent fluids with temperatures of 200–350°C, cold-seeps, estuaries, mangrove swamps, intertidal beaches and rocky shores. Oceans are home to some of themost diverse and unique life forms. This article is an attempt to introduce some of the fundamentals of biologicaloceanography andmarine biologyto describe life in the sea.     

Modulation of an activity response with associative and nonassociative fear in the rat: A lighting differential influences the form of defensive behavior evoked after fear conditioning

Rats confronted with the onset of a light gradient display a transient increase in locomotion called theactivity response (AR) and a dark preference (Godsil & Fanselow, 2004). These experiments demonstrate that the magnitude of the AR can be blunted with Pavlovian fear-conditioning procedures via associative and nonassociative fear. Although manifested in decreased locomotion, the blunted AR effect was not due to increased freezing or immobility behaviors. Instead, rats displayed reduced rearing and an increase in a class of behaviors calledstationary activity. These results suggest that the lighting differential supplied by the cue influences the topography of defensive behavior and reduces the expression of freezing. This procedure provides a means by which to examine learned and unlearned defensive responses to the same stimulus.