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When exposed to light, planarians display a distinctive light avoidance behavior known as negative phototaxis. Such behavior is temporarily suppressed when animals are decapitated, and it is restored once the animals regenerate their heads. Head regeneration and the simple but reproducible phototactic response of planarians provides an opportunity to study(More)
We have investigated the morphology and physiology of the genitalia of the male cricket to establish a basis for neuroethological study of its reproductive behaviour. First, the structure of the phallic complex, including the dorsal pouch, guiding rod, epiphallus, ventral lobes and median pouch, are described, as are the muscles, cuticle, membranes and(More)
We have found that the cricket Gryllus bimaculatus shows an immobile posture, so-called thanatosis. Thanatosis was reflexly elicited by gently holding the forelegs and pronotum of the cricket. During thanatosis, the respiration rate decreased markedly while the heart rate doubled compared with the resting state. Animals in the state of extreme rigidity were(More)
1. Responses evoked by stimulation of the cerebellar and thalamic nuclei were recorded by microelectrodes introduced at various depths in the cerebral cortex of monkeys (Macaca mulatta) under light Nembutal anaesthesia. 2. Stimulation of the medial (fastigial) cerebellar nucleus produced, at a latency of 4–5 msec, deep thalamo-cortical (T-C) responses(More)
The cricket Gryllus bimaculatus displayed freezing (thanatosis) after struggling while the femoro-tibial joints of the walking legs were forcibly restrained. Myographic recording indicated that strong contraction of the flexor tibia muscle “leg flexion response” occurred under this restrained condition. During thanatosis, when the femoro-tibial joint was(More)
The suitability of ejaculated and epididymal stallion spermatozoa for cooled storage (5 degrees C) and cryopreservation was examined in 5 ejaculates from each of 6 stallions and in spermatozoa recovered from the cauda epididymidis after castration of these stallions. The percentage of progressively motile spermatozoa, examined by subjective estimation(More)
The location of the reproductive timer for the post-copulatory, time-fixed, sexually refractory stage was investigated in the male cricket Gryllus bimaculatus. This stage was defined as the interval between spermatophore protrusion and recommencement of copulation or a calling song. To inactivate the central nervous system locally and reversibly, different(More)
To understand the neural mechanisms of reproductive behaviour in the male cricket, we identified motor neurones innervating the muscles in each genital organ by backfilling with cobalt/nickel and recording their extracellular spike activity from nerve bundles of the terminal abdominal ganglion during tethered copulation and spermatophore formation. During(More)
This study addresses a potentially general basis of measuring time in a biological timer. Here, we examined the effects of biogenic amines on the time-fixed post-copulatory sexually refractory stage (ca. 1 h) which is defined as the time interval between spermatophore protrusion and the onset of a calling or a mating response in the reproductive cycle of(More)