Michael J. Herz

Waning of the aggressive response to male models in the three-spined stickleback (Gasterosteus aculeatus L.)

Abstract Territorial three-spined sticklebacks were presented with crude wooden models of conspecific males. The models differed only in the amount of red colour on the anterior ventral surface. Each model was presented for 2 min each day for 12 days. It was found that the amount of red colour did not significantly affect the amount of aggression elicited by the model. The aggressive response (‘biting’) decreased markedly from the high level observed on the initial presentations to a low level of responding at the termination of the experiment.

Amnesic effects of ether and electroconvulsive shock in mice

Mice were given a painful foot-shock upon stepping through a small hole into a dark chamber. Different groups were administered either ECS or 40 sec. or 70 sec. of ether following the learning trial. On a test trial 22 hr. later the 70 sec. etherization and ECS groups showed no memory for the foot-shock while the shocked but untreated control Ss evidenced good retention. The results support a consolidation disruption interpretation of retrograde amnesia.

Temperature and conditioning in the earthworm, Lumbricus terrestris☆

Abstract With light as the UCS, groups of warm and cold earthworms, Lumbricus terrestris, were conditioned to perform a withdrawal response to a vibratory CS. The results of the study confirm those of previous investigations utilizing similar conditions. In addition, the following findings are reported. 1. 1. Both the warm and cold conditioning groups evidenced increments in the percentage of conditioned responses over the 50 conditioning trials. The increase for the warm group was significant while that for the cold group was not, suggesting that reduction in responsiveness results from lowered body temperature. 2. 2. Neither the cold nor the warm sentization or pseudo-conditioning control groups gave evidence of increased responsiveness. All 4 groups continued to respond at a low irregular level throughout the CS presentations. The cold sensitization group gave significantly fewer responses than did the warm group, further supporting the temperature-reduced responsiveness hypothesis. 3. 3. In extinction, after the cold conditioning group had warmed to room temperature, the two conditioning groups did not differ in the number of responses given. These results are discussed in terms of the effects of reduced body temperature on conditioning and on neural transmission.

Classical conditioning of the extension response in the earthworm

Abstract Earthworms were observed to extend the anterior body segments reliably during the presentation of a strong vibratory stimulus. The response was classically conditioned and subsequently extinguished. Backward conditioning and contiguity control groups indicated that learning was possible only with a forward conditioning order of stimuli. The extension response was observed to be relatively unaffected by central nervous system lesions leading to the conclusion that future studies of the role of the earthworm nervous system in behavior utilize this response rather than the contraction response to bright light which is reversed by lesions.

Ganglia removal and photically driven activity in the earthworm (L. terrestris)

This experiment investigates the effect of removing the anterior ganglia on the earthworm’s locomotor response to light. Ss with their five anterior segments amputated, Ss with both pairs of ganglia surgically isolated, and Ss with only the supraoeosophageal ganglia removed showed increased locomotor activity during a period of exposure to intermittent light as compared with periods of darkness. Normal and sham operated Ss also showed increased reactivity to light but were significantly less reactive than two of the operated groups.