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Electrophysiological and neuroimaging studies suggest that our actions are initiated by unconscious mental processes long before awareness of intention to act. The time window between the awareness of the intention to move and the movement onset, which normally permits to exert a conscious "veto" on the impending action, is modulated by individual differences in trait impulsivity. In particular, trait impulsive people show a delayed awareness of the intention to act, probably exceeding the "point of no return", after which the action can no longer be inhibited. In order to investigate if individual differences in the "veto" interval might be explained by differences in the readiness potential (RP) dynamics, nineteen healthy participants underwent an impulsivity trait assessment using the Barratt Impulsiveness Scale (BIS-11) and performed a task based on Libet's clock paradigm, during EEG recordings of pre-movement neural activity. We observed a positive relationship between impulsive personality trait and motor system excitability during the preparation of self-initiated movements. In particular, the RP showed an earlier negative rising phase and a greater amplitude, with the increasing of BIS-11 scores. Based on present results, we conclude hypothesizing that trait impulsivity might be characterized by less effective preparatory inhibition mechanisms, which have a fundamental role in the control of behavior., (Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.)

In time processing, the role of different cortical areas is still under investigation. Event-related potentials (ERPs) represent valuable indices of neural timing mechanisms in the millisecond-to-second domain. We used an interference approach by repetitive TMS (rTMS) on ERPs and behavioral performance to investigate the role of different cortical areas in processing basic temporal information. Ten healthy volunteers were requested to decide whether time intervals between two tones (S1-S2, probe interval) were shorter (800ms), equal to, or longer (1200ms) than a previously listened 1000-ms interval (target interval) and press different buttons accordingly. This task was performed at the baseline and immediately after a 15-min-long train of 1-Hz rTMS delivered over the supplementary motor area, right posterior parietal cortex, right superior temporal gyrus, or an occipital control area. Task accuracy, reaction time, and ERPs during (contingent negative variation, CNV) and after the presentation of probe intervals were analyzed. At the baseline, CNV amplitude was modulated by the duration of the probe interval. RTMS had no significant effect on behavioral or ERP measures. These preliminary data suggest that stimulated cortical areas are less crucially involved than other brain regions (e.g. subcortical structures) in the explicit discrimination of auditory time intervals in the range of hundreds of milliseconds., (Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.)

At different times post-lesion, the excitotoxically lesioned striatum has been shown to undergo significant neuroanatomical and neurochemical changes, which could be expressed behaviorally. Gender and dose of excitotoxin are other variables that may modify the behavioral effects of the lesion. Consequently, the purpose of this study was to determine the effect of dose, gender, and time post-lesion on spontaneous and drug-induced locomotor behavior after intrastriatal KA lesions. Results showed that dose and time post-lesion had a significant effect on the deficits observed. Hyperactivity induced by the lesion with KA (5 nm) subsided as time post-lesion increased. Both the pattern of spontaneous and MK-801-induced locomotor activity were different for male and female rats. In female animals with KA lesions (5 nm), MK-801 did not stimulate ambulatory activity nor reduce vertical activity. Both female and male rats lesioned with KA (5 nm) showed an exaggerated response to amphetamine, at a time when spontaneous locomotor activity was reduced to control levels. Haloperidol significantly reduced locomotor activity in all groups.

The effects on ovulation of a specific anti-oxytocin rabbit serum (anti-OT) (50.0 microliters) given by intrabursal injection into the right ovaries of etherized adult female rats at proestrus, were explored by counting the number of ovulated ova present within the right oviducts. Left ovaries were not treated and served as control ovaries. Control rats were treated with male normal rabbit serum (NRS) (50.0 microliters) given by intrabursal injections into the right ovaries of animals at proestrus. Ovulation was induced by injection of human chorionic gonadotrophin (hCG). Anti-OT administered into the right ovarian bursae of proestrous rat ovaries evoked a significant 51% inhibition of ovulation in comparison with that observed in control non-injected left ovaries (p less than 0.01). Also, when the ovulation of right ovaries injected with anti-OT was compared with that of left ovaries injected with NRS, the number of ovulated ova in the right side was significantly smaller (30%) than on the contralateral side (p less than 0.02). However, in rats pre-treated with hCG the intrabursal injection of oxytocin (OT) (50.0 mU/ml) into right and left ovaries failed to alter the number of ovulated ova compared with that of rats receiving intrabursal injections of saline. The basal control and the OT-evoked synthesis and release of endogenous prostaglandin E2 (PGE2) and PGF2 alpha were explored in ovaries isolated from prepuberal rats injected with pregnant mare's serum gonadotrophin (PMSG), two days prior to sacrifice. OT augmented the basal release of PGF2 alpha but did not influence that of PGE2. Moreover, the conversion of exogenous 14C-arachidonic acid (14C-AA) into different prostanoids and into 5-HETE, in the presence and in the absence of added OT (50.0 mU/ml), was studied in rat ovaries isolated in proestrus. The challenge with OT augmented the basal synthesis and release of PGF2 alpha and of 5-HETE from 14C-AA, but failed to influence the formation of products generated via the cyclo-oxygenase pathway, namely 6-keto-PGF1 alpha, PGE2 and thromboxane B2 (TXB2). Therefore, the present results suggest that ovarian OT may play a role in the ovulatory process, via generation of PGF2 alpha to enhance contractions of ovarian smooth muscle and of 5-HETE to promote follicular collagenolysis.

The effects of exogenous histamine (H) on prostaglandin (PG) generation and release in uteri isolated from diestrous rats and the influences of H2-receptors blockers (cimetidine and metiamide) on the output of uterine PGs, were explored. Moreover, the action of H on the uterine 9-keto-reductase, was also studied. Histamine (10(-4) M) failed to alter the basal output of PGE1 but reduced significantly the generation and release of PGE2 and augmented the output of PGF2 alpha. On the other hand, cimetidine (10(-5) M) enhanced the basal release of PGE2 but had no action on the outputs of PGs E1 or F2 alpha. The enhancing effect of H on the production and release of PGF2 alpha was abolished in the presence of cimetidine. Also, the antagonist reversed the influence of H on the output of PGE2. Metiamide, another H2-receptor antagonist, did not alter the basal control generation and release of uterine PGs, but antagonized the augmenting influence of H on PGF2 alpha uterine output, as much as cimetidine did, and prevented the depressive action of H on the release of PGE2 from uteri. Histamine (10(-4) M) significantly stimulated uterine formation of cyclic-adenosine monophosphate, an action which was antagonized by the presence of cimetidine (10(-5) M), a blocker of H2 receptors. Also, histamine (10(-5) M) and dibutyrylcyclic-adenosine monophosphate (DB-cAMP) at 10(-3) M, enhanced significantly the formation 3H-PGF2 alpha from 3H-PGE2. Results presented herein demonstrate that H is able to diminish the generation of PGE2 in uteri from rats at diestrus augmenting the synthesis of PGF2 alpha, apparently via the activation of H2-receptors, enhancing adenylate-cyclase. These effects appear to increase uterine 9-keto-reductase activity which transforms PGE2 into PGF2 alpha. Relationships between the foregoing results and those evoked by estradiol, are also discussed.

The output of prostaglandins (PGs) E1, E2 and F2 alpha, from ampullary and isthmic portions of sow oviducts isolated during proestrus, estrus and metestrus, was explored. Moreover, in vitro cumulative dose-response curves for the contractile effect of these three PGs, on identical oviductal segments, were constructed. Isthmic preparations from proestrous and metestrous animals released more PGE1 and PGF2 alpha than PGE2 "like material". During estrus, the outputs of PGE1, PGE2 and PGF2 alpha were similar, whereas, oviducts from proestrous and metestrous sows released less PGE1 and PGF2 alpha than during estrus. Although the output of PGE2 "like material" from isthmic and ampullary segments did not differ significantly during the three stages of the sex cycle, ampullary metestrous preparations released more PGE1 and PGF2 alpha, than estrous or proestrous ones. The addition of PGE1, PGE2 or PGF2 alpha, consistently stimulated the amplitude of contractions of isthmic oviductal segments isolated from proestrous and metestrous sows. Within the concentration-range explored, dose-response curves for PGE2 and PGE1 were to the left of those for PGF2 alpha in the isthmus obtained before ovulation (proestrus) but not in segments isolated at later times (2-3 days) of the cycle (metestrus). The stimulatory dose-response curves for PGE1, or PGE2, in isthmic segments of metestrous preparations incubated with phentolamine (10(-6)M) were shifted to the right of controls not exposed to the adrenoreceptor blocker, whereas, the curve for PGF2 alpha without phentolamine, was identical to that obtained in its presence. PGE1 and PGE2 did not evoke significant contractile effects on oviductal ampullary portions from proestrous sows, whereas, PGF2 alpha was clearly stimulatory at concentrations of 10(-9)M and higher. In ampullary segments isolated after ovulation (metestrus) the threshold for contractile enhancement following PGF2 alpha was greater than during proestrus, whereas, PGE1 elicited a significant inhibition of contractions. The spontaneous contractile pattern exhibited by isthmic and ampullary oviductal regions, prior to and after ovulation, is discussed in terms of tissue PG generation and output and is compared with results regarding tubal motility following the exposure to exogenous PGs.