1966 ◽  
Vol 6 (10) ◽  
pp. 463-464 ◽  
Author(s):  
Norman R. Ellis ◽  
Walter W. Porter

2006 ◽  
Vol 95 (6) ◽  
pp. 3391-3400 ◽  
Author(s):  
Roger D. Santer ◽  
F. Claire Rind ◽  
Richard Stafford ◽  
Peter J. Simmons

Flying locusts perform a characteristic gliding dive in response to predator-sized stimuli looming from one side. These visual looming stimuli trigger trains of spikes in the descending contralateral movement detector (DCMD) neuron that increase in frequency as the stimulus gets nearer. Here we provide evidence that high-frequency (>150 Hz) DCMD spikes are involved in triggering the glide: the DCMD is the only excitatory input to a key gliding motor neuron during a loom; DCMD-mediated EPSPs only summate significantly in this motor neuron when they occur at >150 Hz; when a looming stimulus ceases approach prematurely, high-frequency DCMD spikes are removed from its response and the occurrence of gliding is reduced; and an axon important for glide triggering descends in the nerve cord contralateral to the eye detecting a looming stimulus, as the DCMD does. DCMD recordings from tethered flying locusts showed that glides follow high-frequency spikes in a DCMD, but analyses could not identify a feature of the DCMD response alone that was reliably associated with glides in all trials. This was because, for a glide to be triggered, the high-frequency spikes must be timed appropriately within the wingbeat cycle to coincide with wing elevation. We interpret this as flight-gating of the DCMD response resulting from rhythmic modulation of the flight motor neuron's membrane potential during flight. This means that the locust's escape behavior can vary in response to the same looming stimulus, meaning that a predator cannot exploit predictability in the locust's collision avoidance behavior.


1966 ◽  
Vol 71 (5) ◽  
pp. 629-633 ◽  
Author(s):  
Henry C. Ellis ◽  
Douglas G. Muller ◽  
Donald T. Tosti
Keyword(s):  

Konturen ◽  
2010 ◽  
Vol 2 (1) ◽  
pp. 43
Author(s):  
Samuel C. Wheeler III

This essay argues that what Livingston calls the “structuralist” project, combined with a naturalistic, external approach to language, does not in fact lead to a paradoxical failure to match lived language. Quine’s indeterminacy argument is not a consequence of naturalism and structuralism, but is rather a consequence of thorough anti-essentialism, a thesis he shares with Derrida and Davidson. Contemporary naturalism is in fact not committed to Quine’s thesis. Davidson’s views are a purification of the views of Quine, removing Quine’s empiricist appeal to stimulus meaning and Quine’s scientism. Davidson abandons the conventionalist conception of language but retains the “structuralist” conception of language, as captured by a truth-definition. The indeterminacy thesis is a consequence of anti-essentialism applied to semantics, that is, the denial of transcendental signifieds. The essay concludes by arguing that Quine’s aporia (which is also Davidson’s and Derrida’s aporia) is a discovery rather than a paradox.


1985 ◽  
Vol 21 (2) ◽  
pp. 159-168 ◽  
Author(s):  
Jerome I. Gellman

When are sentences A and B the same belief? Following Quine, observation sentences A and B are the same belief when they share the same stimulus–meaning, similar patterns of assent and dissent by subjects when the sentences are queried in the presence of the same non–linguistic stimuli. As for non–observation sentences we note a suggestion of Karl Schick: apply linguistic stimuli in the form of utterances of the language, and map the connections between sentences in the language in terms of linguistic conditioned–responses to utterances. The mapping will yield a network of relations between non–observation sentences themselves, and between the latter and observation sentences at the ‘periphery’. Thus, each sentence receives its place in the overall criss–crossing of relations in the network of the language. Out of a commitment to the ‘autonomy of meaning’, we can say that when A and B are non–observational, they are the same belief when they occupy similar places in the network of sentences in a given language, or corresponding places in corresponding networks of two languages. (Since we can identify the place of sentences in the language network, and since the present suggestion identifies the sameness of belief with location identity, it turns out that there needn't be indeterminacy of translocation.)


1970 ◽  
Vol 79 (1) ◽  
pp. 63 ◽  
Author(s):  
Paul Ziff
Keyword(s):  

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