Coupling of the human Y2 receptor for neuropeptide Y and peptide YY to guanine nucleotide inhibitory proteins in permeabilized SMS-KAN cells

This study of location information involved in information persistence used the partial-report paradigm. Six subjects were asked on 144 trials to recall positions of dots presented in a display. The subjects were instructed to maintain only information on location (but not on identity information) of the presented dots until a partial-report cue was introduced. The effects of display duration (50, 200, and 350 msec.) and cue delay (interval between the display offset and the onset of the partial-report cue: 50, 250, and 500 msec.) were examined. Analysis showed effect of cue delay on partial-report performance decreased as the duration of display increased so performance was negatively affected by the cue delay only when the subject was exposed to the presented dots for 50 msec. Contrarily, partial-report performance did not decline much for a 200-msec. duration and showed little variation in a 350-msec. duration, even though the cue delay increased. Consequently, the decay of the information on location mediating partial-report performance about dots varies with duration of display.     

Short-term consolidation of individual identities leads to Lag-1 sparing.

A rapid serial visual presentation (RSVP) technique was used to investigate the role of the nature of processing carried out on targets in the Lag-1 sparing phenomenon. Lag-1 sparing refers to a higher accuracy in the task associated with the 2nd target when the 2 targets are immediately successive in the RSVP stream relative to when there are 1 or 2 intervening items between the targets. In 5 experiments, 0, 1, or 2 digits were embedded with equal probability in RSVP streams of letter distractors. In 4 of the experiments, subjects identified the digits in some blocks of trials, and they counted the number of presented digits in other blocks. In a 5th experiment, the counting task was replaced with a digit-sum task. The most interesting results were those from trials with 2 digits. Lag-1 sparing was always evident when the task involved the explicit identification of the digits. In addition, Lag-1 sparing was evident when subjects were required to sum 2 digits or to count digits of a prespecified parity subclass (e.g., count only even digits). In striking contrast, Lag-1 sparing was absent when subjects were required to count the digits independent of their parity subclass. These results suggest that the occurrence of Lag-1 sparing depends on the type of mental representation that must be generated on the basis of target information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Input control processes in rapid serial visual presentations: Target selection and distractor inhibition.

The attentional blink refers to the finding that the 2nd of 2 targets embedded in a stream of rapidly presented distractors is often missed. Whereas most theories of the attentional blink focus on limited-capacity processes that occur after target selection, the present work investigates the selection process itself. Identifying a target letter caused an attentional blink for the enumeration of subsequent dot patterns, but this blink was reduced when the dots shared their color with the target letter. In contrast, performance worsened when the color of the dots matched that of the remaining distractors in the stream. Similarity between the targets also affected competition between different sets of dots presented simultaneously within a single display. The authors conclude that the selection of targets from a rapid serial visual presentation stream is mediated by both excitatory and inhibitory attentional control mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of organizer nucleolar regions by the argyrophil technique in cervical intraepithelial neoplasias

Thirty three biopsies of the uterine cervix were studied by the AgNOR method, that identifies the nucleolar organizer regions. These comprised 9 cases of cervicitis (with or without squamous metaplasia), 9 cases of cervical intraepithelial neoplasia grade I (CIN I), 8 CIN II and 10 CIN III. A hundred cells were counted and classified according to the number of AgNOR dots. We use a more practical and fast method of AgNOR dots counting in cervical intraepithelial neoplasia, in that we exclude the two basal layers and count only cells with 4 or more dots. Statistically significant differences for AgNOR dots were found between cervicitis or CIN I and CIN II cases (p < 0.02) and between CIN II and CIN III cases (p < 0.001). No statistical difference was found between the cases of cervicitis and CIN I. It was concluded that this method of AgNOR counting can be useful in the identification and classification of individual cases intraepithelial neoplasia and their differentiation from eventual difficult cases of cervicitis.     

Processing time and memory for pictures.

Postexposure processing of an iconic memory following the presentation of pictures of complex, colored, naturalistic scenes was assessed in 3 experiments which examined the effects of exposure duration and mask delay upon recognition memory. Ss were 50 undergraduates. Exposure durations ranged from 50 to 550 msec and mask delays from 0 to 500 msec. For exposure durations of 300 msec and longer, recognition accuracy was primarily determined by exposure duration, and mask delay had no significant effect. For exposure durations of less than 300 msec, postexposure processing continued for up to 250 msec following the offset of a target picture, and recognition accuracy was a function of total processing time (i.e., the total time separating target and mask onsets.) This reciprocity between exposure duration and mask delay was similar to that previously demonstrated for verbal materials. The processing-time/recognition memory relationship was also shown to be due to differences in initial encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The visible persistence of illusory contours.

Measured the visible persistence of illusory contours (ICs) in 2 experiments. In Exp 1, persistence was determined among 12 Ss for IC squares presented for 50 msec. Exp 2, with 10 Ss, varied target duration from 50 to 1,000 msec. For the control figures, visible persistence decreased with increasing target duration. However, with the IC targets, persistence increased sharply with increasing target duration and then decreased. Results suggest that the time it takes for the visual system to construct the subjective contour yields an overall increase in persistence, and this ongoing processing can be seen over long target durations. Data support the existence of cortical components of visible persistence. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limitations on preschool children's knowledge about counting: Using counting to compare two sets.

Possible limitations on preschool children's understanding of counting were examined by asking twenty 3-year-olds and twenty 4-year-olds to judge the appropriateness of counting carried out by a puppet. The puppet was asked to count either to find out how many objects were present altogether or to find out whether every object in one subset could have a corresponding object from the other subset. Within each counting task, half of the time the puppet counted all of the objects together and half of the time it counted the two subsets separately. Children at both ages showed some differentiation between the two counting tasks and performed at an above-chance level on the how-many task but not on the compare-sets task. The most common individual response pattern among the 3-year-olds was to judge both kinds of counts to be appropriate on both tasks, whereas the most common individual response pattern among the 4-year-olds was to judge counting of all the objects together to be appropriate and counting of the two subsets separately to be inappropriate on both tasks. The fact that children managed to differentiate appropriately between the two counting tasks despite using these basically undifferentiated strategies suggests that correct judgment processes coexisted with their predominant strategies and competed with them to determine performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motion integration with dot patterns: effects of motion noise and structural information

To better understand how local motion detectors merge their responses so as to permit the global determination of objects' movements in the visual field, direction discrimination of performance was measured using a flexible class of moving dots--two sets of dots translating sinusoidally 90 deg out of phase along orthogonal axes. When dots' velocities are combined, a global motion along a circular trajectory emerges, clockwise or counter-clockwise depending on the sign of the phase lag. However, the results of the present experiments indicate that dot patterns are segregated into distinct, but interacting, streams when each dot motion can be accurately determined. In contrast, perceptual coherence of the global motion occurs when each local motion signal is "blurred" by a "motion noise". Direction discrimination performance then increases regularly with both noise amplitude and noise frequency, i.e., noise speed. Performance also increases when relative motion between dots is added. Testing different dot configurations indicates that performance is better for spatial arrangements that display structural properties (a square shape), as compared to overlapping random distributions. Interestingly, when the delay between stimulus onset and motion onset increases up to 300 msec, performance improves when dot patterns convey come form of structural organization but not when the dots are distributed at random. Relations of these results to existing models of motion integration are considered.     

Distributed and focused attention: Neuropsychological evidence for separate attentional mechanisms when counting and estimating.

Evidence is presented for 2 modes of attention operating in simultanagnosia. The authors examined visual enumeration in a patient, GK, who has severe impairments in serially scanning across a scene and is unable to count the numbers of items in visual displays. However, GK's ability to judge the relative magnitude of 2 displays was consistently above chance, even when overall luminosity did not vary with the number of items present. In addition, several variables had a differential impact on GK's counting and magnitude estimation. Magnitude estimation but not counting was facilitated by using elements that grouped more easily and by presenting the elements in regular configurations. In contrast, counting was facilitated by placing the elements in different colors while magnitude estimation was disrupted. Also GK's performance on magnitude estimation tasks was disrupted by asking him to count the elements present. The data suggest that GK can process visual stimuli in either a focused or distributed attention mode. When in a focused attention mode, performance is limited by poor serial scanning of attention due to an impaired explicit representation of visual space. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociable mechanisms of subitizing and counting: Neuropsychological evidence from simultanagnosic patients.

Do people have to count to determine visual numerosity, or is there a fast "subitizing" procedure dedicated to small sets of 1 to 3 items? Numerosity naming time and errors were measured in 5 simultanagnosic patients who suffered from severe difficulties in serial counting. Although these patients made close to 100% errors in quantifying sets comprising more than 3 items, they were excellent at quantifying sets of 1, 2, and sometimes 3 items. Their performances in visual search tasks suggested that they suffered from a deficit of serial visual exploration, due to a fundamental inability to use spatial tags to keep track of previously explored locations. The present data suggest that the patients' preserved subitizing abilities were based not on serial processing but rather on a parallel algorithm dedicated to small numerosities. Several ways in which this parallel subitizing algorithm might function are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A mode control model of counting and timing processes.

In Exp I, 10 male albino Norway rats initially learned a discrimination between a 2-cycle auditory signal of 2-sec duration and an 8-cycle auditory signal of 8-sec duration. In a number discrimination test, the number of cycles was varied, and the signal duration was held constant at an intermediate value. In a duration discrimination test, the signal duration was varied, and the number of cycles was held constant at an intermediate value. Ss were equally sensitive to a 4:1 ratio of counts (with duration controlled) and a 4:1 ratio of times (with number controlled). The point of subjective equality for the psychophysical functions that related response classification to signal value was near the geometric mean of the extreme values for both number and duration discriminations. Exp II demonstrated that methamphetamine (1.5 mg/kg, ip) shifted the psychophysical functions for both number and duration leftward by approximately 10%. Exp III demonstrated that the magnitude of cross-modal transfer from auditory to cutaneous signals was similar for number and duration. In Exp IV (6 Ss), the mapping of number onto duration demonstrated that a count was approximately equal to 200 msec. The psychophysical functions for number and duration were fit with a scalar expectancy model with the same parameter values for each attribute. It is concluded that the same internal mechanism is used for counting and timing. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual masking and visual integration across saccadic eye movements.

Studied visual masking and visual integration across saccadic eye movements in 4 experiments. In a 5th experiment, 4 randomly chosen dots from a 3?×?5 dot matrix were presented in 1 fixation, and 4 different dots from the matrix were presented in a 2nd fixation. Ss reported the location of the missing dot. When the 1st display was presented just before the saccade (as in Exps I–III), Ss accurately specified the missing dot location when the dots were presented to the same region of the retina but not when they were presented in the same place in space. When the 1st display was presented well before the saccade (as in Exp IV), Ss performed poorly regardless of retinal or spatial overlap. Results indicate the existence of a short-lived retinotopic visual persistence but provide no support for a spatiotopic visual persistence capable of fusing the contents of successive fixations. It is concluded that transsaccadic integration depends instead on an abstract memory that accumulates position and identity information about the contents of successive fixations. Results are discussed in relation to the work by M. L. Davidson et al (see record 1974-10245-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing acoustically presented time intervals of seconds duration: an expression of the phonological loop of the working memory?

Working memory has been proposed to contribute to the processing of time, rhythm and music; the question which component of working memory is involved is under discussion. The present study tests the hypothesis that the phonological loop component (Baddeley, 1986) is involved in the processing of auditorily presented time intervals of a few seconds' duration. Typical effects well known with short-term retention of verbal material could be replicated with short-term retention of temporal intervals: The immediate reproduction of time intervals was impaired under conditions of background music and articulatory suppression. Neither the accuracy nor the speed of responses in a (non-phonological) mental rotation task were diminished under these conditions. Processing of auditorily presented time intervals seems to be constrained by the capacity of the phonological loop: The immediate serial recall of sequences of time intervals was shown to be related to the immediate serial recall of words (memory span). The results confirm the notion that working memory resources, and especially the phonological loop component, underlie the processing of auditorily presented temporal information with a duration of a few seconds.     

Counting in rats: Its functional significance and the independent cognitive processes that constitute it.

Four major conclusions were supported in 7 runway experiments: Rats count; rats routinely and perhaps automatically count reinforcing events; counting reinforcing events is of importance for understanding instrumental learning and performance; and counting is the result of several independent coordinated cognitive processes. The results suggested counting rather than some simpler numerical ability because (a) they cannot be ascribed to other mechanisms (e.g., an identical–nonidentical discrimination or subitizing; (b) qualitatively different reinforcers were categorized as both similar and different for counting purposes; (c) the order-irrelevance principle was followed; (d) abstract tags were assigned on the basis of number of events; and (e) assignment occurred according to complex and situationally determined rules that were themselves abstract. Number cues associated with reinforcing events are often valid in learning investigations but are invariably confounded with various, equally valid number and duration cues (related to trials, responses, etc.). Reinforcers were counted when confounded with these other cues, which supported the sequential view that rats are highly disposed to using number cues associated with reinforcers and normally do so in instrumental situations. There was some evidence that one or more of the confounded events (unidentified) provided cues that were used by the rat, but this was of minor significance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Velocity decomposition and surface decomposition--reciprocal interactions between motion and form processing

Physically unidirectional motion of short-lived random dot arrays was found to perceptually decompose into two motion components (velocity decomposition) in a configuration in which two squares appear to partially overlap transparently (surface decomposition). In the experiments in which the velocity of the short-lived random dots in the overlapping area was varied, both the velocity decomposition and the surface decomposition were found to be strongest when the velocity of the overlapping area was close to the vector sum of the velocities of random dots in adjacent non-overlapping areas. On the other hand, neither velocity decomposition nor surface decomposition was found either when random dot arrays were put in occlusion configurations or when continuous random dots were used. While previous studies have indicated a one-way influence either from motion to form processing, or from form to motion processing, the present study further suggests that there is a strong reciprocal interaction between motion and form processing. A possibility is that the reciprocal interaction is iterative so that the representations for velocity and surface decomposition are gradually formed.     

Children's counting strategies for time quantification and integration.

This study investigated whether and how children spontaneously employ counting to measure and integrate the duration of events. A total of 180 children, 5 to 7 years old, judged the overall duration of two successive events, which were varied in a factorial design. For half of the children, the continuous events were accompanied by rhythmic beats of a metronome. This implicit hint of a segmentation of time enhanced the use of counting, particularly in younger children. By the age of 7 years, almost all children counted spontaneously, even without the hint of the rhythm. Several sensible counting strategies were observed and were closely related to an integration rule. The normative additive rule was found to predominate in children as young as 6 years, in contrast to previous studies. These results, which evidence a surprising potential for time quantification in young children, are discussed in terms of knowledge accessibility in different contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal dynamics of the rabbit's nictitating membrane response in serial compound conditioned stimuli.

Two experiments, with 88 female albino rabbits, investigated conditioning of the nictitating membrane response to a reinforced serial compound stimulus. The serial compound was composed of a 400-msec CS (CSA), a trace interval of at least 2 sec, and a brief 2nd CS (CSB) prior to the UCS. The CSB duration was either 150, 250, or 400 msec in Exp I, and the CSB duration in Exp II was 400 msec. Exp I compared serial compound training to an "uncoupled" condition, which contained intermixed CSA–UCS trials and CSB–UCS trials. Exp II compared serial compound training with uncoupled training, 2nd-order conditioning (CSA–CSB/CSB–UCS), trace conditioning (CSA–UCS), and generalization testing that entailed CSB–UCS training and unreinforced tests with CSA. The serial compound, uncoupled, and 2nd-order conditioning procedures all produced high levels of responding during CSA, but only the reinforced serial compound procedure yielded an appreciable likelihood of CR initiation during the trace interval between CSA and CSB. The CRs during the trace interval were temporally distinct from the CRs during CSA and did not appear to be belated CRs to CSA itself. Results are discussed in connection with stimulus selection phenomena, for example, overshadowing and potentiation of toxicosis conditioning. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Which attention is needed for implicit sequence learning?

The role of attention in implicit sequence teaming was investigated in 3 experiments in which participants were presented with a serial reaction time (SRT) task under single- or dual-task conditions. Unlike previous studies using this paradigm, these experiments included only probabilistic sequences of locations and arranged a counting task performed on the same stimulus on which the SRT task was being carried out. Another sequential contingency was also arranged between the dimension to be counted and the location of the next stimulus. Results indicate that the division of attention barely affected teaming but that selective attention to the predictive dimensions was necessary to learn about the relation between these dimensions and the predicted one. These results are consistent with a theory of implicit sequence teaming that considers this teaming as the result of an automatic associative process running independently of attentional load, but that would associate only those events that are held simultaneously in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance demands in the selection of objects for counting

This paper considers the visual processes in object counting among children. Experiment 1 presented identical objects to 7- and 8-year-old children and found that spatially random configurations were counted more quickly than linear arrays, illustrating the difficulty of isolating objects grouped together in rows. However, the younger children were more prone to miscounting these random arrays than rows. The study also established a spatial proximity effect, with a dense arrangement of items being difficult to count. Experiment 2 revealed that this proximity effect can be removed by differentiating objects by color, providing further evidence that object counting involves overcoming Gestalt grouping forces and arguing against fine-motor control as a limiting factor in counting.