QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online May 30, 2008
Journal of Experimental Biology 211, 1992-1998 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.018531

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in JEB Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Crook, R. Articles by Basil, J. Search for Related Content PubMed PubMed Citation Articles by Crook, R. Articles by Basil, J. Social Bookmarking                         What's this?

A biphasic memory curve in the chambered nautilus, Nautilus pompilius L. (Cephalopoda: Nautiloidea)

Robyn Crook^1,2,* and Jennifer Basil^1,2

¹ Brooklyn College, The City University of New York, Brooklyn, NY 11210, USA
² City University of New York Graduate School and University Center, Ecology, Evolution and Behavior subprogram, 365 Fifth Avenue, New York, NY 10016, USA

View larger version (46K): [in this window] [in a new window]   Fig. 1. Diagram of the conditioning apparatus. (A) The restraint harness. (B) The restraint harness with a nautilus in situ. (C) The recording set-up for experimental trials, with a restrained animal in the experimental arena, surrounded by a blind, with a camera recording behaviour. The boxed area is shown in detail in B.

View larger version (18K): [in this window] [in a new window]   Fig. 2. The scoring system for tentacle extension response (TER) in chambered nautilus. TER was graded every 5 s from a minimum score of 0 to a maximum score of 3. Each level corresponds to a range of percentage extension relative to the length of the animal's hood. Zero is recorded when all tentacles are retracted into their sheaths. A score of 1 corresponds to an extension of <33% of the hood length. A score of 2 corresponds to extension between 34% and 66%, and 3 is given when tentacles are extended beyond 67% of hood length.

View larger version (13K): [in this window] [in a new window]   Fig. 3. There was a latency to respond to the light pulse during testing in conditioned (CS+) animals (N=6, black line) but not control (CS–) animals (N=6, grey line). In the first 30 s of the 1 min test period (intervals 1–6) behaviours were similar in the two treatments, but in the latter half of the test period (intervals 7–12, black double-headed arrow) the tentacle extension response (TER) of conditioned animals (A) and ventilation rate (B) increased. Graphs show the means ± 1 s.e.m. of behaviour in each 5 s interval in the 6 h retention test.

View larger version (17K): [in this window] [in a new window]   Fig. 4. N. pompilius expresses a bi-phasic memory curve. There was expression of two distinct memory peaks in animals conditioned with a light pulse plus food odour association (CS+, black bars; N=6) for both behaviours we measured: (A) tentacle extension response (TER), and (B) ventilation rate. The short-term memory peak was expressed at 3 and 30 min after training, whereas a long-term memory peak was apparent at 6 and 12 h after training, and persisted for less than 24 h. The control group (CS–, white bars; N=6) received a light pulse combined with home-tank water during training and showed little change in behaviour over the six test periods. Graphs show the mean ± 1 s.e.m. Asterisks above the bars denote a significant difference (P0.05) between CS+ and CS– measures at each time interval. The linking bars below the x-axis show significant differences (P0.05) within the CS+ group compared across test procedures at each retention interval. There were no significant differences in the CS– group across test periods.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

Twitter