"On the same day that his successor signaled dramatic policy changes that would see the Federal Reserve "take away the punchbowl" before inflating yet another asset bubble, radically altering the way financial market regulators operate in the process, former Fed chairman Alan Greenspan was readying yet another in a long series of op-ed pieces aimed at defending his legacy."
taps65 at 04:29 2009-03-12 said:
Modality-specific retrograde amnesia of fear
JJ Kim and MS Fanselow
Department of Psychology, University of California, Los Angeles 90024.
Emotional responses such as fear are rapidly acquired through classical conditioning. This report examines the neural substrate underlying memory of acquired fear. Rats were classically conditioned to fear both tone and context through the use of aversive foot shocks. Lesions were made in the hippocampus either 1, 7, 14, or 28 days after training. Contextual fear was abolished in the rats that received lesions 1 day after fear conditioning. However, rats for which the interval between learning and hippocampal lesions was longer retained significant contextual fear memory. In the same animals, lesions did not affect fear response to the tone at any time. These results indicate that fear memory is not a single process and that the hippocampus may have a time-limited role in associative fear memories evoked by polymodal (contextual) but not unimodal (tone) sensory stimuli. Permalink