Combined glossopharyngeal and chorda tympani nerve transection elevates quinine detection thresholds in rats (Rattus norvegicus).

Using a conditioned shock avoidance procedure, behavioral quinine hydrochloride thresholds were measured before and after glossopharyngeal (GLX), chorda tympani (CTX), or combined glossopharyngeal and chorda tympani (GLX?+?CTX) transection, as well as after sham surgery. In Experiment 1, thresholds in the sham, CTX, and GLX rats (Rattus norvegicus) either improved (lowered) or remained the same after surgery. In Experiment 2, GLX?+?CTX caused a pronounced 1.5 log?0 unit increase in presurgically measured thresholds. Neither the glossopharyngeal nor the chorda tympani nerve is necessary for normal sensitivity to low quinine concentrations provided the other is intact. When both of these nerves are transected, however, the remaining afferent input is not sufficient to maintain normal detection performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relative time course of semantic and phonological activation in reading Chinese.

The relative time course of semantic and phonological activation was investigated in the context of whether phonology mediates access to lexical representations in reading Chinese. Compound words (Experiment 1) and single-character words (Experiments 2 and 3) were preceded by semantic and phonological primes. Strong semantic priming effects were found at both short (57 ms) and long (200 ms) stimulus onset asynchrony (SOA), but phonological effects were either absent in lexical decision (Experiment 1), were present only at the longer SOA in character decision (Experiment 2) or were equally strong as semantic effects in naming (Experiment 3). Experiment 4 revealed facilitatory or inhibitory effects, depending on SOA, in phonological judgments to character pairs that were not phonologically but semantically related. It was concluded that, in reading Chinese, semantic information in the lexicon is activated at least as early and just as strongly as phonological information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stop-reaction time and the internal clock

In a stop-reaction-time (stop-RT) task, a subject is presented with a regular, isochronous sequence of brief signals separated by a constant time interval, or stimulus onset asynchrony (SOA). His/her task is to press a response key as fast as possible when the sequence stops. As the sequence unfolds, an internal representation of the SOA duration builds up. Stop-RT is assumed to be triggered when an internal clock, operating as an "alarm clock," reaches a time criterion. Criterion setting is contingent upon variability in the SOA's internal representation. In Experiment 1A, stop-RT was measured for isochronous sequences of brief tones, light flashes, and also sequences of tones and flashes presented in regular alternation (tone-light-tone ...). Stop-RT was a linear function of SOA duration (ranging from 250 to 1,000 msec), regardless of modality, supporting a "central-clock" hypothesis. On the other and, taken together, the results of Experiments 1A, 1B, 2, and 3 suggest that no internal representation of the bimodal (tone-light) SOA of alternating sequences builds up. Indeed, an alternating sequence is physically equivalent to two interlaced isochronous subsequences, one auditory and one visual. So, two internal representations, one for the auditory (tone-tone) and one for the visual (light-light) SOA, could build up, and two time criteria running "in parallel" could thus support stop-RT. To provide a critical test of parallel timing, stop-RT was measured for bimodal 5:3 polyrhythms formed by the superposition of auditory and visual isochronous sequences that had different SOA durations (Experiment 4). Parallel timing accounted for a large proportion of variance in polyrhythmic stop-RT data. Overall findings can be accounted for by assuming a functional architecture of an internal clock in which pulses emitted by a central pacemaker are available in parallel with two modality-specific switch-accumulator "timing modules."     

Hormonal responses of male gerbils to stimuli from their mate and pups

Following copulation and cohabitation with a pregnant female, male gerbils show high levels of parental behavior toward their pups. The initiation of male parental behavior may be the result of neuroendocrine changes induced by cohabiting with the pregnant female or by pup stimuli. Experiment 1 examines the changes in androgen and prolactin levels in male gerbils cohabiting with females over the reproductive cycle. Gerbils were mated and blood samples taken from males for hormone analysis 1, 10, and 20 days after pairing and 3, 10, and 20 days after pups were born. A group of unmated male gerbils served as controls. Plasma prolactin levels of males were elevated throughout the female's pregnancy and lactation periods, but were only statistically significantly higher than those of unmated males 20 days after pups were born. Androgen levels rose during pregnancy and dropped significantly after the birth of the pups. These hormonal changes are similar to those found in males of monogamous birds and differ from those found in males of polygynous rodents such as the rat. Experiment 2 examined the hormonal responses of male and female gerbils to pup replacement after 4 hr of parent-pup separation. Female gerbils showed a significant elevation of prolactin levels 1 hr after pup replacement, but males did not. Males with pups returned showed no difference in androgen levels from males who did not have pups returned. Thus, male gerbils show neuroendocrine changes following long-term cohabitation with their mate and pups, but do not show acute hormone responses to pup removal and replacement. These results indicate that parental males have neuroendocrine changes associated with parental behavior and these differ from the neuroendocrine changes underlying female parental behavior.     

The Locus of Redundant-Targets and Nontargets Effects: Evidence From the Psychological Refractory Period Paradigm.

In target detection tasks, responses are faster when displays have 2 targets (redundant-targets effect; RTE) and slower when they have no targets (nontargets effect; NTE) relative to displays with a single target. The psychological refractory period paradigm was used to localize these effects. In Experiment 1, participants classified tones as high or low and then classified letters as targets or nontargets after a short or long stimulus onset asynchrony (SOA). The magnitudes of the RTE and NTE did not depend on SOA. In Experiment 2, the order of the tasks was reversed, and at short SOAs the RTE and NTE had similar magnitudes for both tone discrimination and target detection responses. These findings suggest that the RTE and NTE arise during response selection. Interactive effects of tone pitch with the number and type of target features were also observed, and these were tentatively interpreted as synesthetic effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative analysis of the gustatory evoked potentials in the guinea pig

Gustatory evoked potentials were studied in anesthetized guinea pigs to develop an objective and quantitative taste examination for patients with taste disorders. A positive wave was recorded by the application of NaCl, HCl or quinine hydrochloride solution. There was little difference in latency, duration and waveform among these three solutions. No apparent change in activity was seen after the application of sucrose solution or distilled water. The gustatory evoked potentials that excluded the influence of the trigeminal nerve innervating the tongue surface were able to be reproducibly recorded on either the cortical surface or the skull surface. There was a linear relationship between logarithmic values of potential amplitude and those of taste solution concentration. Therefore, it is suspected that the quantitative evaluation of taste detection is possible by measuring the taste solution concentration-potential amplitude relationship.     

Social learning of a food preference in male and female Mongolian gerbils is facilitated by the anxiolytic, chlordiazepoxide

Social transmission of a food preference in Mongolian gerbils (Meriones unguiculatus) depends on the presence of a social bond between the interacting animals. An "observer" gerbil can acquire a preference for a novel food item from a familiar and, or related "demonstrator" animal. However, exposure to an unfamiliar and unrelated demonstrator gerbil does not lead to acquisition of a food preference, even though the extent of social interaction and likelihood of transmission of food information is unaffected. Likewise, individual preexposure to a novel food does not affect diet preference in individual animals. Here we show that oral, nongavage, administration of the benzodiazepine anxiolytic, chlordiazcpoxide (CDP, 2.5, 5, and 10 mg/kg) has significant dose-associated differential facilitatory effects on social learning in male and female gerbils, while having no significant effects on either individual learning or total food consumption. These results suggest that the CDP mediated reduction of the anxiety associated with the interactions between unfamiliar/unrelated gerbils facilitates social learning. These findings also rise the possibility of sex differences in socially related anxiety and the effects of CDP on social learning in gerbils.     

Terson''s syndrome in a patient with acute promyelocytic leukemia on all-trans retinoic acid treatment

Hypothermia induced by surface cooling has shown to protect vulnerable regions of the brain during an ischemic insult. This study evaluated the neuroprotective efficacy of neurotensin, a potent hypothermic agent, using a 5-min carotid occlusion procedure in the gerbil. In Experiment 1, the dose-response and time course of neurotensin-induced hypothermia were evaluated (n = 5/dose). Central infusion of 10, 20, and 30 micrograms neurotensin were found to significantly decrease core body temperature of conscious gerbils within 30 min of administration. In Experiment 2, gerbils pretreated with 30 micrograms neurotensin were permitted to become hypothermic or were maintained at 37 degrees-38 degrees C (rectal) during ischemic insult. Other gerbils were pretreated with peptide vehicle prior to ischemic insult (at 37 degrees -38 degrees C) or underwent a sham procedure (n = 6/condition). At 24 h after surgery, gerbils were tested for increased locomotor activity in an open-field apparatus. Gerbils pretreated with peptide vehicle or neurotensin and maintained at 37 degrees-38 degrees C during ischemia had significantly higher activity levels compared to the other treated groups. In contrast, gerbils made hypothermic with neurotensin exhibited activity levels similar to sham gerbils. Histological assessment revealed that neurotensin-induced hypothermia protected the CA1 region from ischemic damage.     

Reading aloud is not automatic: Processing capacity is required to generate a phonological code from print.

The present experiments tested the claim that phonological recoding occurs "automatically" by assessing whether it uses central attention in the context of the psychological refractory period paradigm. Task 1 was a tone discrimination task and Task 2 was reading aloud. The joint effects of long-lag word repetition priming and stimulus onset asynchrony (SOA) were underadditive in Experiment 1, suggesting that an early component of lexical processing does not use central attention. In contrast, nonword letter length and grapheme-phoneme complexity yielded additive effects with SOA in Experiments 2, 3, and 4, suggesting that assembled phonology uses central attention. Further, orthographic neighborhood density also yielded additive effects with SOA in Experiments 5, 6, and 7, suggesting that lexical contributions to phonological recoding use central attention. Taken together, the results of these experiments are inconsistent with the widespread claim that phonological codes are assembled and/or addressed automatically. It is suggested that "automaticity" should be replaced by accounts that make more specific claims about how processing unfolds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioned preferences in the rat with an unnatural need state: Morphine withdrawal.

Placed 30 morphine addicted and 15 nonaddicted female albino rats on a 21-day conditioning regimen which involved the daily alternation of access to either water, sucrose-octa-acetate (SOA), or no liquid for 1 hr. The addicted Ss received injections of morphine after either the SOA sessions or the no-liquid sessions. Nonaddicted Ss were injected with morphine after the SOA sessions. Following the last injection, Ss were given a 2-bottle preference test between SOA and water. Results show that the addicted Ss that received morphine-SOA pairings had an increased preference for SOA, whereas the nonaddicted Ss showed a decrease in SOA preference after the same conditioning treatments. Addicted Ss that received the morphine injections on the no-liquid days showed no change in SOA preference. (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the role of eye movements and saccade preparation in generating auditory inhibition of return.

Examined whether the suggestion that "the eccentricity of signals which are effective in activating inhibition of return is restricted to the eccentricity to which accurate saccades can be made" is consistent with the necessary conditions for the occurrence of location-based auditory inhibition of return in a total of 24 volunteers. In 3 experiments, listeners were required to either localize or identify the 2nd of 2 successive sounds. The 1st sound and the 2nd sound could originate from either the same or different locations, and the interval between the onsets of the 2 sounds (Stimulus Onset Asynchrony, SOA) was varied. Sounds were presented out of visual range at 135 azimuth left or right. In Exp 1, localization responses were made more quickly at 100 ms SOA when the target sounded from the same location as the cue, and at 700 ms SOA when the target and cue sounded from different locations. In Exps 2 and 3, Ss monitored visual information presented directly in front of them at the same time as the auditory cue and target were presented behind them. Results indicate that in both experiments, a transition from facilitation at a brief SOA to inhibition at a longer SOA was observed for the auditory task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the temporal dynamics of digit comparison processes.

The authors studied the temporal dynamics of digit comparison processes by presenting the digits with a stimulus onset asynchrony (SOA) of 0, 70, 140, or 210 ms. Experiment 1 used the standard complete paired comparison design that confounds numerical and probabilistic information in the digit presented first. The results showed large effects of SOA that differed characteristically for different digit pairs. These results changed considerably in Experiment 2, using a design that removed any probabilistic contingencies. Experiment 3 examined a form of congruity effect related to the temporal order of the digits. The authors formulated and compared to the data 2 models that differed in their assumptions about the loci of digit-specific and SOA-specific effects: Either the participants use partial numerical advance information to prepare for the suggested response, or they start to process numerical information only after both digits are presented. When probabilistic contingencies were removed, the data favored the latter model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploiting degrees of inflectional ambiguity: Stem form and the time course of morphological processing.

The authors compared sublexical and supralexical approaches to morphological processing with unambiguous and ambiguous inflected words and words with ambiguous stems in 3 masked and unmasked priming experiments in Finnish. Experiment 1 showed equal facilitation for all prime types with a short 60-ms stimulus onset asynchrony (SOA) but significant facilitation for unambiguous words only with a long 300-ms SOA. Experiment 2 showed that all potential readings of ambiguous inflections were activated under a short SOA. Whereas the prime-target form overlap did not affect the results under a short SOA, it significantly modulated the results with a long SOA. Experiment 3 confirmed that the results from masked priming were modulated by the morphological structure of the words but not by the prime-target form overlap alone. The results support approaches in which early prelexical morphological processing is driven by morph-based segmentation and form is used to cue selection between 2 candidates only during later processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogenesis of monoamine oxidase in the thyroid gland of rats

Mongolian gerbils (Meriones unguiculatus) were exposed to Mycobacterium paratuberculosis by intraperitoneal and oral routes. Fourteen weeks after exposure, the gerbils were necropsied and tissues were cultured and examined microscopically. Results of the study showed that gerbils can be infected with M paratuberculosis but are not suitable for studies of paratuberculosis.     

Comparison of nutritive and nonnutritive stimuli in intestinal and oral conditioned taste aversion paradigms.

The intestinal taste aversion paradigm has previously demonstrated that animals could orally discriminate between carbohydrate and fat subsequent to pairing a gastrointestinal (GI) infusion of 1 nutrient with lithium chloride (LiCl), whereas they could not discriminate between 2 nonnutritive flavors (A. L. Tracy, R. J. Phillips, M. M. Chi, T. L. Powley, & T. L. Davidson, 2004). The present experiments assessed the relative salience of nutritive and nonnutritive stimuli when presented either intestinally or orally. Two compound stimuli, each comprising 1 nutrient and 1 nonnutritive flavor, were presented in training and were paired with LiCl or saline. Subsequent oral intake of the nutrients alone, the flavors alone, or the compounds was measured. Results showed that rats discriminated both nutrients and flavors independently after GI or oral training, whereas the compounds were discriminated only after oral training, indicating substantive differences in the processing of these stimuli. This suggests that nutrient activation of the GI tract may potentiate learning about nonnutritive flavors analogously to taste-potentiated odor conditioning. The ability to learn about the oral properties of stimuli in the GI tract suggests a new account of delayed taste aversion learning as well as learning about the positive nutritive consequences of food consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulating the interference effect in timing with varying stimulus onset asynchrony.

The interference effect on time judgments, when subjects are also required to perform a concurrent nontemporal task, is one of the most reliable findings in the time perception literature. In the present study, the interference between a time discrimination task (short or long tone) and a digit classification task (even or odd digit) was analysed using the overlapping tasks paradigm. Reaction times in the digit task were shorter at longer values of stimulus onset asynchrony (SOA) in Experiment 1, showing a clear modulation of interference with varying the relative position of the tasks. Using longer tone durations in Experiment 2, reaction times in the digit task were affected not only by the overlap between the tasks but also by the temporal proximity of responses in the timing and digit tasks. In Experiment 3, the effect of varying the SOA on performance on the digit task was abolished when the auditory tone was irrelevant, thus eliminating an interpretation in terms of distraction from the tone offset. We conclude that the interference effect in concurrent time discrimination and digit classification may be modulated by the degree of overlap between the tasks as well as by the overlap between late processing stages related to decision and response components in the 2 tasks. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The time course of competition for attention: Attention is initially labile.

Competition for attention between 2 written words was investigated by presenting the words briefly in a single stream of distractors (Experiment 1) or in different streams (Experiment 2- 6), using rapid serial visual presentation at 53 ms/item. Stimulus onset asynchrony (SOA) was varied from 0 to 213 ms. At all SOAs there was strong competition, but which word was more likely to be reported shifted markedly with SOA. At SOAs in the range of 13-53 ms the second word was more likely to be reported, but at 213 ms, the advantage switched to the first word, as in the attentional blink. A 2-stage competition model of attention is proposed in which attention to a detected target is labile in Stage 1. Stage 1 ends when one target is identified, initiating a serial Stage 2 process of consolidation of that target. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does PAULA prime PAUL? Does WAITER prime WAITRESS? Implicit transfer across gender forms of verbal stimuli

Repetition-priming effects were investigated with a speeded verification task as an indirect or implicit test. Subjects were asked to verify whether items were instances of the categories "first name" and "profession." In Experiment 1, instances were repeated in their alternate gender form (e.g., PAUL as PAULA, or WAITRESS as WAITER) and performance was compared to new instances. Facilitation in terms of faster response latencies for old instances (i.e., repetitions in the alternative gender form) was restricted to the category "profession." In Experiment 2, facilitation was found for names studied and tested in the same gender form (e.g., PAUL-PAUL). Instances of professions were repeated in either the same or the alternative gender form; the amount of facilitation was identical for the two repetition conditions. However, transfer across gender forms was affected by the study-test order (facilitation was larger from male to female than from female to male) and by the gender dominance of specific instances. In Experiment 3, the interfering effect of gender dominance was not replicated. Response accuracy tended to parallel the latency results in all experiments, but without reaching statistical reliability. Therefore, the faster response latencies for old items are by no means the result of a speed-accuracy trade-off. The central finding of the experiments reported is the material-dependent dissociation of repetition transfer across gender forms that occurred for instances of professions, but was absent for names. This dissociation is interpreted to indicate that the stimulus-driven speeded verification test is sensitive to conceptual, but not to perceptual, processing aspects of a study event.     

Effects of single oral administrations of haloperidol and d-amphetamine on prepulse inhibition of the acoustic startle reflex in healthy male volunteers

The effects of acute administration of an indirect dopamine-agonist, d-amphetamine, and a non-selective dopamine receptor antagonist, haloperidol, were investigated in normal male volunteers on habituation and prepulse inhibition (PPI) of the acoustic startle reflex in two experiments. In Experiment 1, 40 male non-smoker volunteers were tested for habituation and PPI (defined as percentage reduction of the pulse-alone amplitude; prepulses 9 dB above background) before and after double-blind administration of either 2 mg haloperidol or placebo. No influence of haloperidol was observed on either habituation or PPI of the startle reflex in this experiment. In Experiment 2, 60 male volunteers underwent startle testing before and after double-blind administration of a single oral dose of 5 mg haloperidol, 5 mg d-amphetamine or placebo. Habituation and PPI (prepulses 15 dB above background) for the placebo group did not differ significantly from that observed for the d-amphetamine or for the haloperidol group. However, in a subgroup of smoking subjects, both d-amphetamine and haloperidol reduced PPI as compared to that observed prior to drug administration. The implications of these findings in relation to animal pharmacological studies and observed sensorimotor gating deficits in schizophrenia are discussed.