The counting function and its representation in the parietal cortex in humans and animals.

Current data provide evidence that the ability to assess numbers is present not only in adult humans, but also in animals and children of preverbal age. Studies of behavior in infants and animals have demonstrated that the perception of number, the discrimination of quantities, and elementary addition and subtraction appear during onto- and phylogenesis before the appearance of speech. Number perception in humans and animals has common features: the greater the difference between numbers, the easier they are to discriminate; for a given difference between numbers, increases in size lead to increased difficulty in discrimination. Clinical data on counting impairments in patients and functional tomography studies of number operations in healthy subjects have shown that the key structures involved in number perception in humans are located in the parietal cortex. As demonstrated by experiments on monkeys and dogs, recognition of number in these species is also associated with the parietal area of the cortex. The similarity of the morphofunctional bases of "counting behavior" in humans and animals suggests that counting can be regarded as a functional mechanism of adaptive behavior which formed during evolution.

[Computing function and its representation in the parietal cortex in humans and animals].

The currently available evidence suggests that not only adults but children of preverbal age and animals possess the ability to define numbers. The behavioral studies in infants and animals show that number perception, quantity discrimination, and elementary adding and subtraction appear in onto- and phylogenesis prior to language. There are parallels between number processing in animals and humans: a) the ability to discriminate between two numbers improves as the numerical distance between them increases; b) for equal numerical distance, discrimination of two numbers worsens as their numerical size increases. Disorders of "number sense" in brain-lesioned patients and brain-imaging of number processing in healthy subjects showed that the parietal cortex includes the key structures involved in number perception. These structures include the intraparietal sulcus area, angular gyrus and superior lobule. Animal experiments showed that the parietal cortex is also important for "counting behavior" in monkeys (area of the intraparietal sulcus and area 5), dogs (area 5) and cats (area 7). Parallels between functional and morphological bases of number perception in humans and animals suggest that they endow it in evolution as the usual fundamental mechanism of adaptive behavior.

Role of the parietal associative area of the cortex for "counting" behavior in dogs.

Experiments were performed on six dogs to study the effects of simultaneous and separate ablation of fields 5 and 7 of the parietal cortex on "counting" behavior. Dogs were trained to discriminate series of five sound clicks presented with variable interstimulus intervals from similar series consisting of three clicks. A food-related operant response (elevation of the right forepaw to place it on the feeder) was used to develop asymmetrical differentiation; the positive signal was a series of five clicks with variable interstimulus intervals and the negative (unreinforced) stimulus was a series of three clicks. Simultaneous bilateral ablation of fields 5 and 7 of the parietal cortex, like bilateral ablation only of field 5, produced profound impairment of differentiation lasting 2-3 months. Isolated bilateral ablation of field 7 produced no impairment of differentiation. These data led to the conclusion that field 5 of the parietal cortex is important for discriminating the numbers of sequential signals.

[Role of the parietal associative cortex in "counting" behavior of dogs].

Influence of the combined and isolated lesions of areas 5 and 7 of the parietal cortex on the counting behavior was studied in experiments with 6 dogs. Instrumental feeding reaction (lifting and placing the forepaw on the foodwell) was established. The positive conditioned stimulus was a series of 5 clicks with variable interclicks intervals and the negative (non-reinforced) conditioned stimulus was a series of 3 clicks, so that asymmetrical differentiation was elaborated. Combined bilateral lesions of areas 5 and 7 and an isolated lesion of area 5 resulted in a severe impairment of the numerical discrimination for two months, whereas the isolated lesion of area 7 did not lead to any problems in differentiation. The conclusion was made that area 5 is critical for numerical discrimination of sequential stimuli.

[Forward and backward conditioning]. / Priamye i obratnye uslovnye refleksy.

A discussion. The evolution of the concept of the forward and backward conditioning is traced. An attempt to define more precisely the widely distributed term such as a "feedback", is made.

Effect of castration method and the provision of local anesthesia on plasma cortisol, scrotal circumference, growth, and feed intake of bull calves.

To determine the effects of castration of calves, with or without local anesthesia, on plasma cortisol, scrotal circumference, ADG, and ADFI, 56 Friesian bulls (5.5 mo of age; mean +/- SE BW = 173 +/- 2 kg) were randomly assigned to each of seven treatments: 1) control (CON); 2) s.c. injection of .1 mg of a human serum albumin-GnRH conjugate with DEAE-dextran adjuvant (HSA-GnRH); 3) burdizzo castration without local anesthetic (BURD); 4) burdizzo castration following local anesthetic administration (BURD + LA); 5) surgical castration without local anesthetic (SURG); 6) surgical castration following local anesthetic administration (SURG + LA); and 7) local anesthetic administration alone (LAA). Blood samples for cortisol analyses were taken via jugular catheter from -2 to 10 h and at 24, 48, and 72 h relative to treatment. Average daily feed intakes were recorded for 5-d periods and calves weighed at 7-d intervals before and after treatment. Local anesthetic alone had no effect (P > .10) on any variable. The HSA-GnRH calves had elevated (P < .05) plasma cortisol from 2 to 6 h compared with CON calves. Peak plasma cortisol was elevated (P < .01) in BURD, BURD + LA, SURG, and SURG + LA compared with CON calves. The SURG calves (46.0 ng/mL) had higher (P < .03) peak cortisol than BURD (31.4 ng/mL) and SURG + LA (35.4 ng/mL) calves. There was no difference in peak cortisol between BURD and BURD + LA (26.5 ng/mL) calves. The ADG from d 0 to 7 was reduced (P < .05) in calves in BURD + LA, SURG, and SURG + LA treatments (-.01, -.83 and -.24 kg, respectively) compared with CON calves (.54 kg). The ADFI were reduced (P < .05) in BURD and BURD + LA calves during d 1 to 5 and in BURD + LA, SURG, and SURG + LA calves during d 6 to 10 compared with CON calves. The scrotal circumferences of BURD and BURD + LA calves were greater (P < .05) than those of CON calves for 7- and 35-d periods post-castration, respectively. Castration induced increases in cortisol and decreases in ADG and ADFI. Surgical castration induced a greater plasma cortisol response than burdizzo castration, and the administration of local anesthetic reduced the cortisol response of surgical castrates but was less effective for burdizzo castrates.

[The characteristics of the discrimination of the number of sequential signals in dogs]. / Osobennosti razlicheniia chisla posledovatel'nykh signalov u sobak.

Food instrumental asymmetrical differentiation (discrimination) between the reinforced train of five identical clicks administered with variable interstimulus intervals and the non-reinforced train of the same three clicks was elaborated in six dogs. At the stable stage of conditioning, the number of instrumental reactions to five clicks was twice higher than to three clicks. Temporal parameters of such kind of counting reactions are analyzed. A conclusion is made that dogs, can discriminate the number of identical signals in the consecutive train and use this parameter in their adaptive behaviour. Types of the internal inhibition which participate in the above-described differentiation are considered.

Physiological role of GlpB of anaerobic glycerol-3-phosphate dehydrogenase of Escherichia coli.

Anaerobic sn-glycerol-3-phosphate dehydrogenase of Escherichia coli is encoded by an operon of three genes, glpACB. The promoter distal gene, glpB, encodes a 44-kilodalton polypeptide that is not part of the purified soluble dehydrogenase. By recombinant plasmid complementation, in a strain harboring a chromosomal deletion of glpACB, we found that all three genes were essential for anaerobic growth on glycerol-3-phosphate (G3P). By isolation of inner membrane preparations we confirmed the cytoplasmic membrane localization of GlpB. GlpB displayed an electron paramagnetic resonance spectrum that suggested the presence of iron-sulfur center(s) within GlpB. We used this spectrum to show that the center(s) were reduced by the artificial reductant dithionite and by the physiological substrate G3P but not by lactate or formate. The center(s) were oxidized by fumarate. These data indicated that GlpB mediates electron transfer from the soluble GlpAC dimer to the terminal electron acceptor fumarate via the membrane-bound menaquinone pool.

[The dynamic changes in somatosensory input into the cortical motor area after damage to the somatosensory cortical zones in dogs]. / Dinamika izmenenii somatosensornogo vkhoda v motornuiu oblast' kory posle povrezhdeniia somatosensornykh korkovykh zon u sobak.

Dynamics of changes in the somatosensory evoked potentials (EPs) in the foreleg motor cortex (MI) was studied in awake dogs in chronic experiments following lesions of the forelimb area in the somatosensory cortex (SI) or in area 5. Cortical ablations reduced the amplitude of the primary positive-negative wave of the EPs in ipsilateral MI down to 28-63% of the original one. Within three weeks recovery of the EPs was insignificant or was absent at all. So there was no correlation between the EPs changes and spontaneous recovery of precise avoidance movements of the foreleg which takes place two weeks after local ablation of the SI. After area 5 lesion the EPs in the MI did not recover in spite of complete recovery of the EPs in the adjoining area of SI after its initial reduction down to 53%. The long-lasting EPs reduction was apparently a result of destruction of somatotopic sensory inputs from SI (or area 5) to MI, since EPs in MI of the intact hemisphere and in the hindlimb area of MI on the side of the lesion either did not change or recovered during one or two weeks.

[Formation of conditioned reflexes to number of sequential stimuli in the dog]. / Formirovanie uslovnykh refleksov na chislo posledovatel'nykh razdrazhitelei u sobak.

The present experimental study deals with question, whether dogs are able to orient their behaviour to stimuli which differ only by the number of identical clicks presented in successive series with variable interstimulus interval. Some dogs elaborated alimentary or defensive motor conditioned reflexes nd differentiations to them being in classical conditions in experimental chamber. In other dogs running to the feeding trough was elaborated and a differentiation to it in response to series of clicks differing only by one signal. It was established that the parameters of conditioned positive and negative reactions (latency, rate and realization frequency) statistically depended on the number of clicks in the series and did not depend upon its temporal characteristics (interstimulus intervals and duration). The conclusion is made that in CNS of dogs, elementary form of counting a signals takes place, and that the integrated result of this count might serve as a key to evoke positive or negative conditioned reaction.

The number of consecutive clicks in the train as positive or differential conditioned stimulus in dogs.

Conditioned reflexes were elaborated to trains of identical signals (clicks) of a constant number with variable interstimulus interval. The negative conditioned stimulus differed from the positive one only by the number of elements in the train. In classical defensive conditioned reflexes the latent period of motor conditioned responses to the positive stimulus was shorter than to the negative one. There were differences in the latent periods and in the speed of running to the feeding box to the positive and negative stimuli when alimentary instrumental reflexes were elaborated. The dogs ran faster to the feeding box after the positive stimuli. In 30 percent of the total number of negative stimulus presentations they did not run to the feeding box at all. There was no correlation between the reaction parameters and duration of the trains. These parameters correlate only with the number of elements in the train. Experimental data suggest that the quantitative assessment of signal trains effected in the dogs’ central nervous system, i.e. the simple count of elements may be used in its adaptive behavior.

[Reflection of quantitative parameters of a series of nonreinforced heteromodal signals in cortical evoked potentials]. / Otrazhenie v korkovykh vyzvannykh potentsialakh kolichestvennykh parametrov riadov nepodkrepliaemykh signalov raznoi modal'nosti.

Systematic presentation to dogs of series, standard in number of sound, electro-cutaneous or visual stimuli, leads to a development of U-shaped dependence of cortical evoked potentials (EPs) on the stimulus position in the series. This indicates that in the dog's CNS an estimation is formed of the quantitative structure of the applied series, shaped in a similar way for stimuli of all of these modalities. Singling-out of the stimulus quantitative property results from a simple repetition of the series without any reinforcement, i.e. in the course of perceptual learning. Dependence of the EP on its position in the series appears earlier and with a greater stability in the projection of the stimulus modality than in cortical areas of other modalities. The dependence of the EP on signal position in a series of unimodal stimuli is relatively rapidly reproduced following a transition to similar series of other modalities. This suggests a possibility of transfer of the estimation of quantitative series structure from one modality analyser to another one.

[Evoked potentials in the auditory cortex with systematic use of standard series of stimuli on the internal geniculate body]. / Vyzvannye potentsialy v slukhovoi kore pri sistematicheskom primenenii standartnykh riadov razdrazhenii vnutrennego kolenchatogo tela.

Standard series of short electrical stimuli of the medial geniculate body were systematically applied to dogs with chronically implanted electrodes. Gradual formation was observed of a dependence of amplitudes of averaged EPs in the auditory cortex on the consecutive place of the stimulus in the series. This points to the existence in the dog's central nervous system of an elementary form of counting not only adequate signals, as has been previously shown, but also electrical stimuli of the thalamic nucleus. In contrast to what was observed in response to clicks, the EPs amplitude of MGB electrical stimulations increases by the middle of the series and diminishes by its end. It has been assumed that the cortical level of the analyser to which the stimulation was applied, suffices for the formation of the above phenomenon.