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Title: Device for measuring a nociceptive reaction of laboratory animals
Claims: What is claimed is: 1. In an apparatus for objectively determining a nociceptive reaction of a caged laboratory animal to an irritating stimulus applied to a first paw of the animal, wherein the reaction is manifested by lifting of the first paw from the base of the cage, the improvement wherein substantially the entire floor of the cage is formed from a planar array which comprises, in combination, a plurality of parallel, dielectrically spaced elongated conductors, the spacing between adjacent ones of the conductors being selected to provide contact between the paw and a pair of adjacent conductors except when the paw is lifted from the floor, first and second mutually insulated bus bars, means for connecting alternate ones of the conductors to the first bus bar, and means for connecting the remaining conductors to the second bus bar; wherein an electroconductive layer is applied over the plantar surface of the first paw whereby the contact of the first paw with the floor normally connects the first and second bus bars through a high-conductivity path, the first and second bus bars being disconnected from each other when the first paw is lifted from the floor; and wherein the apparatus further comprises, in combination, two-state comparator means having an output normally in a first state and operable into a second state upon a prescribed change of state at its input, means for coupling the first and second bus bars to the input of the comparator means for operating the comparator means from its first state to its second state when the first and second bus bars are disconnected, the comparator means reverting to its first state when the bus bars are reconnected, and first means operable over a selected first interval and coupled to the output of the comparator means for measuring the total time over which the comparator means output is in its first state over the first interval. 2. Apparatus as defined in claim 1, in which the comparator means further comprises threshold-operated means for inhibiting the operation of the comparator means from its first to its second state when the conductivity of the path across the first and second bus bars is below a predetermined value. 3. Apparatus as defined in claim 1, in which the apparatus further comprises second means operable over the prescribed first interval and coupled to the output of the comparator means for recording the total number of times during said first interval that the comparator means is operated from its first to its second output state. 4. Apparatus as defined in claim 1, in which the first recording means comprises means for periodically sampling the output of the comparator means, and means coupled to the output of the sampling means for counting the number of the resulting samples. Other info: Inventors: Halek, Jan (Olomouc, CS) Jezdinsky, Jaroslav (Olomouc, CS) Application Number: 575502 Filing Date: 1975-05-08 Publication_date: 1977-02-08 Assignee: Rektorat University Palackeho v Olomouci (Olomouc, CS) Primary Class(es): 346/141 324/415, 324/692, 368/113, 968/846, 968/DIG1 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Demeo, Palmer C. Assistant Examiner: Tokar, Michael J. Attorney: |
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