Assessment of adverse events associated with antiretroviral regimens for postexposure prophylaxis for occupational and nonoccupational exposures to prevent transmission of human immunodeficiency virus.

OBJECTIVE: To assess adverse events associated with antiretroviral regimens for human immunodeficiency virus (HIV) postexposure prophylaxis (PEP), with a particular focus on the treatment combination of zidovudine, lamivudine, and tenofovir (ZDV-3TC-TDF). METHODS: Retrospective chart review for individuals who received HIV PEP for occupational and nonoccupational exposure, and multivariate analyses to identify risk factors for noncompletion of PEP and adverse events associated with PEP. SETTING: University of Rochester Health Service Occupational Health Program and University of Rochester AIDS Center. PARTICIPANTS: Healthcare workers who received HIV PEP for occupational exposure from January 1, 1999, to December 31, 2004, and individuals who received HIV PEP for nonoccupational exposure from January 1, 2002, to December 31, 2004.Results. We found increased rates of nausea among subjects who received treatment with ZDV-3TC-TDF and subjects who received treatment with zidovudine, lamivudine, and indinavir (ZDV-3TC-IDV). Analyses showed that female sex was a risk factor for nausea. Compared with subjects who received treatment with ZDV-3TC-TDF, subjects who received treatment with ZDV-3TC-IDV were less likely to not complete the HIV PEP for occupational exposure. CONCLUSION: Preventive treatment of adverse events may be necessary to ensure completion of HIV PEP.

Response biases in auditory forebrain regions of female songbirds following exposure to sexually relevant variation in male song.

In many species of songbirds, individual variation between the songs of competing males is correlated with female behavioral preferences. The neural mechanisms of song based female preference in songbirds are not known. Working with female European starlings (Sturnus vulgaris), we used immunocytochemistry for ZENK protein to localize forebrain regions that respond to sexually relevant variation in conspecific male song. The number of ZENK-ir cells in ventral caudo-medial neostriatum [NCMv] was significantly higher in females exposed to longer songs than in those exposed to shorter songs, whereas variation in the total duration of song exposure yielded no significant differences in ZENK expression. ZENK expression in caudo-medial ventral hyperstriatum [cmHV] was uniformly high in all subjects, and did not vary significantly among the three groups. These results suggest that subregions of NCM in female starlings are tuned to variation in male song length, or to song features correlated therewith. Female starlings exhibit robust behavioral preferences for longer over shorter male songs (Gentner and Hulse; Anim Behav 59:443-458, 2000). Therefore, the results of this study strongly implicate NCM in at least a portion of the perceptual processes underlying the complex natural behavior of female choice.

Music perception and octave generalization in rhesus monkeys.

Two rhesus monkeys were tested for octave generalization in 8 experiments by transposing 6- and 7-note musical passages by an octave and requiring same or different judgments. The monkeys showed no octave generalization to random-synthetic melodies, atonal melodies, or individual notes. They did show complete octave generalization to childhood songs (e.g., "Happy Birthday") and tonal melodies (from a tonality algorithm). Octave generalization was equally strong for 2-octave transpositions but not for 0.5- or 1.5-octave transpositions of childhood songs. These results combine to show that tonal melodies form musical gestalts for monkeys, as they do for humans, and retain their identity when transposed with whole octaves so that chroma (key) is preserved. This conclusion implicates similar transduction, storage, processing, and relational memory of musical passages in monkeys and humans and has implications for nature-nurture origins of music perception.

Perceptual classification based on the component structure of song in European starlings.

The ability to recognize individuals based on their vocalizations is common among many species of songbirds. Examining the psychological and neural basis of this functionally relevant behavior can provide insight into the perceptual processing of acoustically complex, real-world, communication signals. In one species of songbird, European starlings (Sturnus vulgaris), males sing long and acoustically complex songs composed of small stereotyped note clusters called motifs. Previous studies demonstrate that starlings are capable of individual vocal recognition, and suggest that vocal recognition results from the association of specific motifs with specific individuals. The present study tests this possibility by examining how variation among the motifs that comprise a song affect its discrimination and classification. Starlings were trained, using operant techniques, to associate multiple songs from a single male starling with one response, and songs from four other male starlings with another response. The level of stimulus control exerted by motif variation was then measured by having subjects classify three sets of novel song bouts in which motifs from the training songs were systematically recombined. The results demonstrate a significant, and approximately linear, relationship between song classification and the relative proportions of familiar motifs from different singers that compose a bout. The results also indicate that the motif proportion effects on song classification are primary to retroactive interference in the recall for specific motifs, and independent of any biases due to the syntactic organization of motifs within a bout. Together, the results of this study suggest that starlings organize the complex vocalizations of conspecifics by memorizing large numbers of unique song components (i.e., motifs) that are then associated with different classes. Because individual starlings tend to possess unique motif repertoires, it is likely that under natural conditions such classes will correspond to individual identity. Thus, it is likely that perceptual processing mechanisms similar to those described by the results of the present study form the basis for individual vocal recognition in starlings.

Individual vocal recognition and the effect of partial lesions to HVc on discrimination, learning, and categorization of conspecific song in adult songbirds.

Among songbirds, the capacity to associate particular songs with particular singers (i.e., vocal recognition) forms the cognitive basis for more complex communication behaviors such as female choice and territoriality. In the present study, we combine operant conditioning techniques and excitotoxic lesions to the forebrain nucleus HVc to examine the role of this region in the discrimination, associative learning, and categorization of conspecific song. We trained adult male and female European starlings, Sturnus vulgaris, to recognize simultaneously the songs of several conspecific males. Then, using a series of transfer procedures, we demonstrate that correct recognition does not generalize to song bouts containing novel motifs from familiar singers. This suggests that starlings do not make use of individually invariant source or filter characteristics for vocal recognition. We then lesioned a portion of HVc bilaterally with ibotenic acid, and exposed the birds to a series of manipulations testing the discrimination, associative learning, and categorization of conspecific song. The lesions attenuated song production among males, but retention of the basic recognition task (i.e., maintenance of the discrimination) was unaffected. However, when the response contingencies were reversed-as a test of associative learning independent of discrimination-the initial performance and subsequent learning rate were negatively correlated with the size of the HVc lesions. This suggests that HVc plays a role in the formation of associations between a song and some referent. The results of this study are discussed in light of earlier claims regarding the role of HVc in the perceptual processing of conspecific song.

Comparison of 241Am, (239,240)Pu and 137Cs concentrations in soil around rocky flats.

Gamma spectroscopy measurements were used to estimate concentrations of 241Am and 137Cs in soil profiles to depths of 21 cm at on-site and off-site locations around the Rocky Flats Environmental Technology Site and at regional background locations east of the Front Range between Colorado's borders with New Mexico and Wyoming. Concentrations of these radionuclides were compared with concentrations of (239,240)Pu in the same samples. Concentrations of 241Am in soil from depths of 0 to 3 cm decreased in an easterly direction from more than 5.3 kBq kg(-1) near the 903 pad to background levels of 1.3 Bq kg(-1) 5 to 7 km away at a rate that was nearly proportional to the inverse square of distance. Deposits of 137Cs were ubiquitous, averaging 0.12 kBq kg(-1) in soil from depths of 0 to 3 cm, but were unevenly distributed around Rocky Flats and the regional background locations. Deviations from the uniform exponential rate at which soil concentrations of 137Cs typically decreased with depth, -0.25 cm(-1) at undisturbed sites, enabled us to determine that about 10% of our sampling sites had been disturbed by erosion, tillage, or other factors. The mean rate at which (239,240)Pu decreased with depth was about the same, -0.23 cm(-1), throughout the study area. Soil concentrations of 241Am decreased with depth at a similar mean rate of -0.22 cm(-1) at locations close to the 903 pad where measurements were robust. Ratios between 241Am or (239,240)Pu and 137Cs proved more useful for delineating the extent and pattern of contamination from Rocky Flats than did activity concentrations in soil.

Neural bases of song preferences in female zebra finches (Taeniopygia guttata).

We examined the neural bases of song preferences in female zebra finches (Taeniopygia guttata). Females performed more courtship displays in response to conspecific songs than to heterospecific songs. Following electrolytic lesion to the HVc (sometimes referred to as high vocal center), females maintained normal song preferences. However, following lesion to cHV (caudal hyperstriatum ventrale, an auditory area) females performed courtship displays at high rates in response to both conspecific and heterospecific song. Thus cHV, but not HVc, must be intact for female zebra finches to exhibit normal song preferences. Differences between this study and those showing HVc lesions disrupting song preferences in female canaries (Serinus canaria) indicate interspecific variation in the function of HVc in female songbirds.

Neural correlates of singing behavior in male zebra finches (Taeniopygia guttata).

This study examined the relationship between the volumes of four song control nuclei: the high vocal center (HVC), the lateral part of the magnocellular nucleus of the anterior neostriatum (IMAN), Area X, and the robust nucleus of the archistriatum (RA), as well as syrinx mass, with several measures of song output and song complexity in male zebra finches (Taeniopygia guttata). Male zebra finches' songs were recorded in standardized recording sessions. The syrinx and brain were subsequently collected from each bird. Volumes of the song control nuclei were reconstructed by measuring the cross-sectional area of serial sections. Syrinx mass was positively correlated with RA volume. The volume of IMAN was negatively related to element repertoire size and the number of elements per phrase. We found no other correlations between brain and behavioral measures. This study, combined with others, indicates that the evidence for a general relationship among songbirds between HVC volume and song complexity is equivocal. There are clear species differences in this brain-behavior correlation.

Auditory scene analysis by European starlings (Sturnus vulgaris): perceptual segregation of tone sequences.

Like humans, animals that use acoustic stimuli to perceive their world ought to be able to parse the auditory scene into functionally significant sounds. The ability to do so ought to have significant adaptive value when, for example, an animal can identify the sounds of a predator among other natural noises. In earlier work it was shown that a species of songbird, the European starling, can identify excerpts of both its own song and songs from other avian species when the songs are mixed concurrently with other natural signals. In this experiment it is demonstrated that starlings can segregate two synthetic pure-tone sequences when the sequences differ in frequency. Taken together, the experiments show that at least one nonhuman species is capable of auditory scene analysis both for natural and for non-natural acoustic stimuli. This suggests in turn that auditory scene analysis may be a general perceptual process that occurs in many species that make use of acoustic information.

Birdsong.

Vocalizations used by birds for territory defense, mate attraction, or both are often referred to as a given species' song. Birdsong refers to the often complex vocalizations produced most frequently by males of species that are members of the songbird order (passeriformes). Unlike most species-typical vocalizations produced by nonhuman animals, some songbird vocalizations are learned. Studies of birdsong learning, production, and perception address issues of fundamental interest to psychologists and others interested in behavior and its physiological underpinnings and provide the basis for this review. This article highlights recent advances in knowledge as illustrations of the utility of birdsong as an arena for significant new developments in experimental psychology and behavioral neuroscience.

Auditory scene analysis by songbirds: stream segregation of birdsong by European starlings (Sturnus vulgaris).

Three experiments examined the capacity of European starlings to segregate perceptually 2 superimposed, intermixed auditory stimuli. The stimuli were 10-s song samples from 2 of 4 songbird species: European starling, brown thrasher, mockingbird, and nightingale. The birds first learned a discrimination between the intermixed song pairs. Then, they maintained the discrimination with novel song exemplars in the mixtures and when song stimuli for each species were presented alone. Performance fell, but remained above chance, when song pairs were mixed with the dawn chorus of bird song. The results show that starlings were identifying the songs of individual species within the baseline superimposed song pairs, a process of auditory stream segregation and scene analysis (A. S. Bregman, 1990).

Effects of social interaction on the development of starling song and the perception of these effects by conspecifics.

To examine the effects of contact with a conspecific in the absence of species-typical song models, the authors raised starlings in male-male pairs in acoustic isolation. The songs of these birds differed significantly from those of either individual isolates or wild adults and resembled in some respects the songs of starlings tutored by live conspecifics. Operant conditioning techniques were used to demonstrate that these differences among songs were perceptually salient to conspecifics. The results indicated that (a) wild-caught adult starlings are capable of forming open-ended categories for isolate and wild song, (b) starlings perceive the songs of isolated pairs as more "isolatelike" than "wildlike," and (c) starlings can distinguish the songs of isolated pairs from those of individual isolates. Both experiments point to the importance of social factors in avian song development.

Interactive method of informing patients of the risks of intravenous contrast media.

PURPOSE: To evaluate interactive computer-based informed consent for use of contrast material versus the same information in a written format. MATERIALS AND METHODS: Patients (n = 160) referred for radiologic examination with intravenous contrast material were block randomized (sex, age, and previous exposure to contrast material) into two groups and were provided either written or computer-based (video) informed consent. RESULTS: The female patients in the video group scored better on the test than those in the group with the written consent form. Male patients attained equivalent scores with both types of consent. The video took an average of 1.6 minutes longer to complete, probably because the majority of patients chose to be informed of every risk of intravenous contrast material. CONCLUSION: This project demonstrates that a video format for informed consent before use of intravenous contrast material offers a good alternative to the written consent form.

The other side of the coin: Cognitive properties of nonreward.

In this comment, I examine Amsel's theory in the light of rats' reaction not to frustrative non-reward per se, but to the more complicated case in which frustrative nonreward is part of a rule-based sequence of reward quantities. The discussion goes beyond Amsel's emphasis on dispositional memory to consider cognitive and representational memory-the signaling properties of reinforcement and nonreinforcement. The strengths and weaknesses of Amsel's theory are discussed with the fresh perspective that this viewpoint provides, and some issues emerge that may be fruitful for further study.

Perceptual organization of auditory temporal patterns in European starlings (Sturnus vulgaris).

The perception of continuously repeating auditory patterns by European starlings was explored in seven experiments. In Experiment 1, 4 starlings learned to discriminate between two continuously repeating, eight-element, auditory patterns. Each eight-element pattern was constructed from different temporal organizations of two elements differing in timbre. In Experiments 2-7, the repeating patterns were transformed in ways designed to identify the starlings' perceptual organization of the patterns. In Experiment 2, the starlings identified patterns beginning with novel starting points. In Experiment 3, discrimination performance was adversely affected by reorganizing the elements in the patterns. In Experiments 4 and 5, the pattern elements were altered. In Experiment 4, the patterns were constructed from two novel elements. In Experiment 5, the temporal location of the two pattern elements was reversed. The transformations of the patterns in Experiments 4 and 5 affected discrimination performance for some, but not all, of the starlings. In Experiments 6 and 7, replacing either of the two elements with silent intervals had no effect on discrimination performance. The results of these experiments identify basic grouping principles that starlings use when they perceive auditory patterns.

Absolute pitch.

Absolute pitch (AP) is the ability to identify a tone's pitch or to produce a tone at a particular pitch without the use of an external reference pitch. AP exists in varying degrees among people generally described as AP possessors. AP possessors vary not only in the accuracy with which they can identify pitches but also in their ability to produce pitches absolutely and in their ability to identify tones of various timbers and in various pitch registers. AP possessors' memory for pitches is mediated by verbal pitch names; they do not have superior memory for pitches per se. Although the etiology of AP is not yet completely understood, evidence points toward the early-learning theory. This theory states that AP can be learned by anyone during a limited period early in development, up to about age 6, after which a general developmental shift from perceiving individual features to perceiving relations among features makes AP difficult or impossible to acquire.