Behavioural brain research
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We investigated global motion detection in binocularly deprived cats (BD cats) and control cats (C cats). The cats were trained in the two-choice free running apparatus for a food reward. The positive stimulus was a moving random-dot pattern with all dots moving in one direction, the negative stimulus was the same random-dot pattern but stationary. ⋯ In contrast, their level of performance in a simple relative motion detection task (one square) did not differ from that in the C cats. However, in more complex relative motion detection task (two squares) the performance of the BD cats was impaired. The deficit in the detection of global motion in BD cats may be due to impairments of their Y-pathway.
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The present study was conducted to establish a simple method for measuring muscular rigidity in rats, which could be used for screening and is able to discriminate between rigidity and akinesia/catalepsy. Therefore, we treated rats with morphine (30 mg/kg i.p.), since large doses of morphine lead to muscular rigidity and akinesia. We measured muscular rigidity with a new method by determining the resistance of the hindlimb to passive flexion in the 'balance test' and also checked haloperidol (3 mg/kg i.p.) treated rats for muscular rigidity. ⋯ The results showed that morphine, but not haloperidol led to muscular rigidity, whereas both drugs led to positive scores in the catalepsy test. The dopaminergic drugs partly antagonized the morphine-induced muscular rigidity in the doses applied, but not the catalepsy. Apparently, rigidity, akinesia/catalepsy produced by morphine can be discriminated from that produced by haloperidol in simple and quick tests.
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The purpose of the present study was to investigate the effects on the duration of imagined movements of changes in timing and order of performance of actual and imagined movement. Two groups of subjects had to actually execute and imagine a walking and a writing task. The first group first executed 10 trials of the actual movements (block A) and then imagined the same movements at different intervals: immediately after actual movements (block I-1) and after 25 min (I-2), 50 min (I-3) and 75 min (I-4) interval. ⋯ The duration of imagined movements was very similar to those of actual movements, for both tasks, regardless of either the interval elapsed from the actual movements (first group) or the order of performance (second group). However, the variability of imagined movement duration was significantly increased compared to variability of the actual movements, for both motor tasks and groups. The findings give evidence of similar cognitive processes underlying both imagination and actual performance of movement.
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Prior research has revealed that treatments that elevate the level of the pro-inflammatory cytokine IL-1beta in the brain, if given after training, impair contextual but not auditory-cue fear conditioning. The present experiments add to these finding by showing that, (a) IL-1beta exerts its effect on contextual fear conditioning by impairing consolidation processes that support the storage of the memory representation of the context; (b) the dorsal hippocampus is a critical site for the effect of IL-1beta; (c) the effect of IL-1beta cannot be attributed to its effect on glucocorticoid levels; and (d) IL-1beta injected into dorsal hippocampus either, immediately, 3, or 24 h, but not 48 h, after training produces this impairment. At this time the mechanisms responsible for this impairment are not understood, but may involve late-phase protein synthesis processes associated with LTP, because later consolidation processes are being disrupted.