[Abstract Title]. - Society for Neuroscience

new paradigm for rainbow trout that combines elements of fear conditioning and spatial learning.
Utilizing social aggression from a large conspecific as our unconditioned stimulus (US), paired
with cessation of water inflow to the tank as our neutral conditioned stimulus (CS), we can
reliably induce approximately half of the test fish to escape into an empty tank chamber, a spatial
learning task that may be dependent on BDNF in the hippocampus. Those fish that do not learn
to escape from the US remain in their home tank and are subjected to social aggression for the
duration of the 15 minute daily interaction. Following 7 days of CS+US pairings, presentation of
the CS alone on Day 8 induced a significant increase in plasma cortisol in non-escapers, but had
no effect on fish that reliably escaped. This is a conditioned response and not an artifact of the
paradigm, as control groups exposed to both CS and US alone for 7 days did not show an
increase in plasma cortisol compared to basal levels. In escaping fish, over 7 days of CS+US
pairings, latency to escape decreases drastically. Presumably, this decrease in escape latency is
mediated not only by fear conditioning to the aggressive US, but also through circuits related to
spatial learning, which includes not only important contextual information but also exactly where
the escape hole is located. The dorsolateral pallium (hippocampus) was microdissected from
brains of escaping, non-escaping, and control fish, and BDNF mRNA levels were measured by
quantitative rtPCR and normalized to GAPDH. Hippocampal BDNF mRNA expression in trout
was significantly up-regulated by escaping, a 3-D spatial learning task.
Disclosures: R.E. Carpenter , None; D.H. Arendt, None; J.P. Smith, None; I. Sabirzhanov,
None; T.G. Clark, None; C.H. Summers, None.
Poster
292. Acetylcholine, Neurotrophins, and Cognition
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 292.12/SS25
Topic: F.02.f. Fear and aversive learning and memory
Support: NIH/NCRR (P51RR000165)
NSF (IBN-987675)
NIH (MH069884, DA019624, NS055077
Kirschstein NRSA (MH77420)
NSF (GRFP DGE-0234618)