Article Figures & Data
Figures
- Figure 1.
Mutations in glr-1 do not impair short-term habituation at a 60 sec ISI. Mean response magnitude in pixels for wild-type (a) and n2461 (b) worms given 20 taps at a 60 sec ISI (ky176 does not respond to taps). Data are presented averaged into 10 bins of two responses each. Both groups show a similar gradual decrease in response magnitude with repeated stimulation. Mean response magnitude in pixels for wild-type (c), n2461 (d), and ky176 (e) worms given 20 trains of taps (1 train is equivalent to 6 taps within 600 msec) at a 60 sec ISI. Data are presented averaged into 10 bins of two responses each, as above. All groups show a similar gradual decrease in response magnitude with repeated stimulation. Paired comparisons between bin 1 (average response to the first two stimuli) and bin 10 (average response across the last two stimuli) were significant in all cases with adjustment for multiple comparisons (N2 taps, t(19) = 4.73, p < 0.01; n2461 taps, t(19) = 3.21, p < 0.05; N2 trains, t(17) = 3.82, p < 0.05; n2461 trains, t(18) = 5.11, p < 0.01; ky176 trains, t(15) = 4.33, p < 0.01).
- Figure 2.
The role of glr-1 glutamate receptors in memory. a, Mutations in glr-1 (results from 2 alleles, n2461 and ky176) eliminate long-term memory for habituation. Mean percentage of control response magnitude for LTM for habituation training of the tap withdrawal response in wild-type (WT) and glr-1(n2461) and glr-1(ky176). Average reversal magnitude across the test trial for trained groups (black bars) expressed as percentage of control response (top black line across graph; dotted lines represent average ± SEM for control groups). White numbers in bars represent the number of worms in each trained group. Both wild-type (WT) groups showed significant LTM; none of the glr-1 groups showed significant LTM to either taps or trains. b, Exposure to the non-NMDA glutamate receptor antagonist DNQX during training blocks LTM for habituation of the tap withdrawal response in wild-type worms, and exposure to the vehicle control NaOH during training does not affect formation of LTM.
- Figure 3.
Confocal images of GFP expression in trained and control worms. a, Confocal images of postsynaptic expression of glr-1 receptors on processes of the interneurons in the posterior ventral nerve cord visualized with GLR-1::GFPshowing a single-tap control worm (control) and a worm that received distributed habituation training 24 hr earlier (trained; same procedure as Fig. 2). The training produced behavioral LTM in another group of these transgenic worms (t(44) = 2.5; p = 0.02; data not shown). There were significantly smaller GFP clusters in the trained worms (x = 280.95 ± 32.37; n = 21) than in the single-stimulus control worms (x = 463.70 ± 43.74; n = 16; t(35) = 3.44; p = 0.002), although the number of clusters between groups did not differ (trained, 62.2 ± 7.14; control, 69.3 ± 10.3; t(35) = 0.59; p = 0.56). Scale bar, 20 μm. b, Confocal images of the vesicles in tap sensory neuron terminals visualized with a synaptobrevin GFP marker showing a single-tap control worm (control) and a worm that received distributed habituation training 24 hr earlier (trained). The training produced behavioral LTM in another group of these transgenic worms (t(44) = 2.45; p = 0.02; data not shown). There was no difference in measured GFP expression between the trained worms (x = 41.00 ± 3.47; n = 12) and the single-stimulus control worms (x = 42.5 ± 5.4; n = 12; t(22) = 0.41; p = 0.69). Scale bar, 20 μm.
