Wind‐activated thoracic interneurons of the cockroach: I. Responses to controlled wind stimulation

Westin, Joanne; Ritzmann, Roy E.; Goddard, Donald J.

doi:10.1002/neu.480190702

Cited by 34 publications

(37 citation statements)

References 25 publications

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“…For wind stimulation, directional properties of TIAS are highly correlated with the presence or absence of ventral median (VM) branches which are probably the structures on which vGIs synapse (Casagrand and Ritzmann,199 1 ) . All TIAS that have unbiased left-right wind responses have bilateral VM branches (Westin et al, 1988). All TI,s with wind fields that are biased to their soma side or axon side have been found to have a single unilateral VM branch on that side.…”

Section: Tactile Maps Of Cuticlementioning

confidence: 98%

Response of thoracic interneurons to tactile stimulation in the cockroach, Periplaneta americana

Ritzmann

Pollack

1994

J. Neurobiol.

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Recent findings indicate that cockroaches escape in response to tactile stimulation as well as they do in response to the classic wind puff stimulus. The thoracic interneurons that receive inputs from ventral giant interneurons also respond to tactile stimulation and, therefore, represent a potential site of convergence between wind and tactile stimulation, as well as other sensory modalities. In this article, we characterize the tactile response of these interneurons, which are referred to as type-A thoracic interneurons (TIAs). In response to tactile stimulation of the body cuticle, TIAs typically respond with a short latency biphasic depolarization which often passes threshold for action potentials. The biphasic response is not typical of responses to wind stimulation nor of tactile stimulation of the antennae. It is also not seen in tactile responses of thoracic interneurons that are not part of the TIA group. The responses of individual TIAs to stimulation of various body locations were mapped. The left-right directional properties of TIAs are consistent with their responses to wind puffs from various different directions. Cells that respond equally well to wind from the left and right side also respond equally well to tactile stimuli on the left and right side of the animal's body. In contrast, cells that are biased to wind on one side are also biased to tactile stimulation on the same side. In general, tactile responses directed at body cuticle are phasic rather than tonic, occurring both when the tactile stimulator is depressed and released. The response reflects stimulus strength and follows repeated stimulation quite well. However, the first phase of the biphasic response is more robust during high-frequency stimulation than the second phase. TIAs also respond to antennal stimulation. However, here the response characteristics are complicated by the fact that movement of either antenna evokes descending activity in both left and right thoracic connectives. The data suggest that the TIAs make up a multimodal site of sensory convergence that is capable of generating an oriented escape turn in response to any one of several sensory cues.

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Section: Tactile Maps Of Cuticlementioning

confidence: 98%

Response of thoracic interneurons to tactile stimulation in the cockroach, Periplaneta americana

Ritzmann

Pollack

1994

J. Neurobiol.

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“…However, the fact that ETs of adult cockroaches (with 440 cercal sensory hairs) are almost identical to those of early-stage juveniles (with only 80) strongly suggests that it is centrally located ). Domenici et al (Domenici et al, 2008) suggest that the ET-generating mechanism could involve the many thoracic interneurons that are interposed between the ventral GIs and the motor neurons (Ritzmann and Pollack, 1990;Westin et al, 1988) or perhaps also the dorsal GIs. Alternatively, the possibility that the preferred directions of pliancy of the sensory hairs (Dagan and Camhi, 1979) may control ET 0 s cannot be ruled out.…”

Section: Insects Cockroachesmentioning

confidence: 99%

Animal escapology II: escape trajectory case studies

Domenici¹,

Blagburn

Bacon

2011

Journal of Experimental Biology

133

151

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Summary Escape trajectories (ETs; measured as the angle relative to the direction of the threat) have been studied in many taxa using a variety of methodologies and definitions. Here, we provide a review of methodological issues followed by a survey of ET studies across animal taxa, including insects, crustaceans, molluscs, lizards, fish, amphibians, birds and mammals. Variability in ETs is examined in terms of ecological significance and morpho-physiological constraints. The survey shows that certain escape strategies (single ETs and highly variable ETs within a limited angular sector) are found in most taxa reviewed here, suggesting that at least some of these ET distributions are the result of convergent evolution. High variability in ETs is found to be associated with multiple preferred trajectories in species from all taxa, and is suggested to provide unpredictability in the escape response. Random ETs are relatively rare and may be related to constraints in the manoeuvrability of the prey. Similarly, reports of the effect of refuges in the immediate environment are relatively uncommon, and mainly confined to lizards and mammals. This may be related to the fact that work on ETs carried out in laboratory settings has rarely provided shelters. Although there are a relatively large number of examples in the literature that suggest trends in the distribution of ETs, our understanding of animal escape strategies would benefit from a standardization of the analytical approach in the study of ETs, using circular statistics and related tests, in addition to the generation of large data sets.

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“…As we seek ultimately to relate behavioral effects to changes in circuitry, we focused on the type 1 response. Effects specific to type 2 responses would likely be due to effects of TI A s preferring wind from the front, and in all of the recordings of TI A s, such a cell has only been recorded once (Westin et al, 1988).…”

Section: Quantitative Analysis Of Joint Angle Excursions During Escapmentioning

confidence: 99%

Descending influences on escape behavior and motor pattern in the cockroach

Schaefer

Ritzmann

2001

J. Neurobiol.

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The escape behavior of the cockroach is a ballistic behavior with well characterized kinematics. The circuitry known to control the behavior lies in the thoracic ganglia, abdominal ganglia, and abdominal nerve cord. Some evidence suggests inputs may occur from the brain or suboesophageal ganglion. We tested this notion by decapitating cockroaches, removing all descending inputs, and evoking escape responses. The decapitated cockroaches exhibited directionally appropriate escape turns. However, there was a front-to-back gradient of change: the front legs moved little if at all, the middle legs moved in the proper direction but with reduced excursion, and the rear legs moved normally. The same pattern was seen when only inputs from the brain were removed, the suboesophageal ganglion remaining intact and connected to the thoracic ganglia. Electromyogram (EMG) analysis showed that the loss of or reduction in excursion was accompanied by a loss of or reduction in fast motor neuron activity. The loss of fast motor neuron activity was also observed in a reduced preparation in which descending neural signals were reversibly blocked via an isotonic sucrose solution superfusing the neck connectives, indicating that the changes seen were not due to trauma. Our data demonstrate that while the thoracic circuitry is sufficient to produce directional escape, lesion or blockage of the connective affects the excitability of components of the escape circuitry. Because of the rapidity of the escape response, such effects are likely due to the elimination of tonic descending inputs.

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Wind‐activated thoracic interneurons of the cockroach: I. Responses to controlled wind stimulation

Cited by 34 publications

References 25 publications

Response of thoracic interneurons to tactile stimulation in the cockroach, Periplaneta americana

Response of thoracic interneurons to tactile stimulation in the cockroach, Periplaneta americana

Animal escapology II: escape trajectory case studies

Descending influences on escape behavior and motor pattern in the cockroach

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