Figure 1.

Contextual fear conditioning and electrophysiology experimental paradigm. A, Schematic of day-dependent contextual design. B, Trial schematic. Rats progressed through a 4 d fear-conditioning paradigm in which acquisition in context A took place on day 1, fear extinction in context B took place on day 2, extinction retrieval in context B took place on day 3, and fear renewal in context A took place on day 4. See text in Materials and Methods for more detail. C, In a subset of behaviorally characterized animals, extracellular recordings targeted the basal amygdaloid nucleus of the BLA complex. Topographical studies of the basolateral amygdala describe abundant corticohippocampal inputs to the anterior part, known as the BA, anterior part. To maximize stimulation of these inputs, the stimulating electrode was consistently placed toward the medioventral region of the basolateral amygdaloid nucleus anterior part, and the recording electrode was consistently placed within 1 mm lateral relative to the stimulating electrode. D, Procedure and timeline schematic describing electrophysiological experiments. LA, Lateral Amygdaloid Nucleus; BA, Basal Amygdaloid Nucleus; vHPC, Ventral HPC.