Many studies have been carried out to assess the variability of sleep parameters. The first night effect is one of the most important factors in this variability and has been extensively studied. However, the readaptation phenomenon when subjects returned to the sleep laboratory after spending a certain period of time at home has been not systematically evaluated. To investigate this phenomenon across multiple sleep laboratory sessions, polysomnographic data from 12 healthy young subjects for 12 nights (three periods each of 4 consecutive nights, with a minimum of 1 month between them) were collected. The first night effect was present only in the first night of the first period (“very first night”) and was significant only for REM sleep-related variables. We conclude that the results from the first nights of consecutive periods within a specific protocol with healthy young subjects need not be discarded in subsequent analyses.

In a parity judgment task, the ERPs at parietal electrode sites become the more negative the more mental rotation has to be executed. In two experiments, it was investigated whether a temporal relationship exists between the onset of this amplitude modulation and the moment when mental rotation is executed. Therefore, the duration of processing stages located before mental rotation was manipulated. The amplitude modulation was delayed when either the perceptual quality of the stimulus was reduced (Experiment 1) or when character discrimination was more difficult (Experiment 2). The results suggest that the onset of the rotation-related negativity might be used as a chronopsychophysiological marker for the onset of the cognitive process of mental rotation.

Although Unibase cream has been an effective medium for electrodermal recordings, its production has recently been discontinued. This study compared alternative media to Unibase for effectiveness. Three base creams similar to Unibase were initially compared for in vitro viscosity and effectiveness. Based upon this analysis one cream was eliminated. A volunteer sample of 6 postmenopausal women with hot flashes and 6 young women without flashes was recruited. Media were evaluated for viscosity and effectiveness of skin conductance. Results indicated that one electrolyte media produced readings within the normal range, identified true positive hot flashes, and produced few false negative readings whereas the second produced largely unreadable results with many false negative hot flashes. An appropriate substitute for Unibase as an effective electrolyte medium for measurement of electrodermal activity was identified.

This study tested various sources of changes in respiratory sinus arrhythmia (RSA). Twenty-two healthy participants participated in three experimental conditions (mental stress, relaxation, and mild physical exercise) that each consisted of three breathing parts (normal breathing, breathing compressed room air, and breathing compressed 5% CO2-enriched air). Independent contributions to changes in RSA were found for changes in tonic vagal modulation of heart rate, central respiratory drive (i.e., PaCO2), respiratory depth, and respiratory frequency. The relative contributions to changes in RSA differed for mental stress and physical exercise. It is concluded that uncorrected RSA will suffice to index within-subject changes in tonic vagal modulation of heart rate in most situations. However, if the central respiratory drive is expected to change, RSA should ideally be corrected for changes in PaCO2, respiratory depth, and respiratory frequency.

Crossmodal links in spatial attention were studied in an experiment where participants had to detect peripheral tactile or visual targets on the attended side, while ignoring all stimuli on the unattended side and in the currently irrelevant modality. Both relevant locations and relevant modalities were specified on a trial-by-trial basis by auditory precues. Spatial orienting in the cue–target interval was reflected in anterior negativities and occipital positivities contralateral to the cued side, either when vision or touch was cued as relevant. These effects resembled previously reported ERP modulations during shifts of visual attention, implicating supramodal mechanisms in the control of spatial attention and demonstrating their independence of cue modality. Early effects of spatial attention on somatosensory and visual ERPs were of equivalent size for currently relevant and irrelevant modalities. Results support the idea that crossmodal links in spatial attention are mediated by supramodal control mechanisms.

Developmental psychophysiologists working with infants have no commonly accepted frequency definitions of EEG waves or rhythms. The purpose of this study was to investigate the task-related power changes in three infant EEG frequency bands during the performance of a spatial working memory task by 8-month-old infants. EEG data were divided into three frequency bands: 3–5 Hz, 6–9 Hz, and 10–12 Hz. Although all three frequency bands showed some level of discrimination of baseline from task and among different processing stages of cognitive activity, only the 6–9 Hz band consistently exhibited these capabilities and distinguished the correct from incorrect responses. These data may form the foundation for defining EEG frequency bands that are appropriate for use with infant research participants and for understanding the function of these frequencies during cognitive activity.

A probabilistic association task that manipulated the necessity to temporarily store information was combined with the recording of event-related potentials. In Experiment 1, scores obtained from a positive schizotypy scale were used to categorize participants as either low or high schizotypal individuals. Low, but not high, schizotypal individuals displayed evidence for selective associative learning in the working memory dependent (“trace”) version of the task. The amplitudes of the occipito-temporal N150 were attenuated in high schizotypal individuals. In Experiment 2, the intravenous administration of a single dose of haloperidol (0.04 mg/kg), but not of a placebo, strengthened the selectivity of associative learning in the trace version of the task. The amplitudes of the occipito-temporal N150 were augmented by haloperidol. Psychometrically identified schizotypal individuals and normal individuals under mild stress demonstrated defective prioritization of information in working memory and deficient visual encoding. These neurocognitive effects of schizotypy and stress seem to be mediated by the D2 family of dopamine receptors.

Reduced pain perception has been observed in hypertensive individuals and normotensive individuals at risk for high blood pressure and may involve increased endogenous opioid release or receptor sensitivity. The present study examined the issue by administering two subjectively similar but physiologically different forms of the pain-reducing procedure transcutaneous electrical nerve stimulation (TENS). Men varying in resting blood pressure and parental history of hypertension participated in three testing sessions during which was presented (a) high-frequency (100 Hz) TENS; (b) low-frequency (2 Hz) TENS, the type believed to elicit endogenous opioid activity; or (c) no-TENS stimulation. Measurements of blood pressure (BP) and other physiological variables were obtained during this period. Afterwards, two pain stimuli were presented: a series of electric shocks and 5 min of arm ischemia. There was a significant negative association between pain and resting systolic blood pressure (SBP), and pain and parental history of hypertension in the no-TENS and high-frequency TENS conditions that was significantly strengthened by administration of low-frequency TENS. As well, low-frequency TENS produced a modest but significant acute reduction in SBP, especially among those with higher resting levels. These results provide further evidence that opioid mechanisms are involved in blood pressure-related hypoalgesia and blood pressure regulation.

Categorization is a basic means of organizing the world around us and offers a simple way to process the mass of stimuli one perceives every day. The ability to categorize appears early in infancy, and has important ramifications for the acquisition of other cognitive capacities, but little is known of its development during childhood. We studied 48 children (7–15 years of age) and 14 adults using an animal/nonanimal visual categorization task while event-related potentials (ERPs) were recorded. Three components were measured: P1, N2, and P3. Behaviorally, the children performed the task very similarly to adults, although the children took longer to make categorization responses. Decreases in latencies (N2, P3) and amplitudes (P1, N2, P3) with age indicated that categorization processes continue to develop through childhood. P1 latency did not differ between the age groups. N2 latency, which is associated with stimulus categorization, reached adult levels at 9 years and P3 latency at 11 years of age. Age-related amplitude decreases started after the maturational changes in latencies were finished.

Many adverse effects commonly associated with chemotherapy, such as nausea, vomiting, and fatigue, are also characteristic of adrenal insufficiency. It is conceivable that chemotherapy drugs may directly or indirectly impact the activity of the hypothalamic-pituitary-adrenal axis. We examined this conjecture by characterizing temporal changes in blood cortisol concentrations in women with ovarian carcinoma given chemotherapy. Twenty-three chemotherapy-naïve women with histologically confirmed ovarian cancer underwent serial blood sampling for determination of cortisol levels prior to and every hour for 6 hr following two chemotherapy treatments with cisplatin or carboplatin. Samples were also taken for 4 hr on a comparison day when all study procedures were performed except chemotherapy administration. A significant reduction in serum cortisol was found immediately following infusion of either cisplatin or carboplatin. No progressive reduction in cortisol was found over the two treatment cycles. Because the reduction in cortisol was seen only in the presence of the cytotoxic drug, it is likely that the effect of the drug is “direct” and does not involve overt psychological or circadian mechanisms. The possible role of this reduction in cortisol is discussed in relation to induction of chemotherapy-induced nausea and vomiting.

We investigated the inhibitory regulation of perceptual–motor processing streams in a task that switched between spatially compatible and incompatible stimulus–response mappings. Thirty male and female college-aged participants performed a reaction time (RT) task in which the response was either spatially compatible or not depending on a cue immediately preceding the stimulus. The cue-to-stimulus interval (CI) was either 50 or 500 ms. Incompatible mapping yielded the typical slower responses than compatible mapping at 500 ms, but not at 50 ms. Changes in cardiac interbeat interval (IBI) and performance suggested that automatic responses to compatible stimuli were suppressed at 50 ms. Both performance and IBI changes as well as individual differences in these measures suggested a precue preparatory schema or set biased toward suppressing the compatible mapping. An alternate hypothesis of a cue-induced suppression was questioned. The results illustrate the operation of different supervisory processes in the anticipatory and online control of action.

Differential aversive Pavlovian conditioning with a foul odor as unconditioned stimulus (US) and neutral faces as conditioned stimuli (CS) was compared between 9 noncriminal psychopaths as defined by the Hare Psychopathy Checklist Revised and 12 healthy controls. Event-related potentials (ERP), heart rate, skin conductance response, corrugator EMG, and startle response potentiation as well as valence, arousal, and contingency of the CS were assessed. Whereas the healthy controls (HC) showed significant CS+/CS− differentiation, the psychopaths (PP) failed to exhibit a conditioned response although unconditioned responses were comparable between the groups. N100, P200, and P300 to the CSs revealed that psychopaths were not deficient in information processing and showed even better anticipatory responding than the HC group indicated by the terminal contingent negative variation (tCNV), that lacked, however, CS+ and CS− differentiation. These data indicate a deficit in association formation in psychopaths that may be related to deficient interaction of limbic-subcortical and cortical structures.

Two experiments addressed the following issues concerning modulation of the acoustic startle reflex during emotional imagery: (1) Is startle inhibited or potentiated during imagery of pleasurable events? (2) Does startle modulation differ for personal versus standard imagery scenes? (3) Is startle modulated differently during anger versus fear? For standard scenes, startle was greater during aversive than pleasant imagery, with both exceeding neutral. Blink potentiation was greater during imagery of personal pleasant than nonpersonal pleasant scenes. Startle potentiation did not differ for anger versus fear material, but differences were found in self-report, corrugator EMG, and HR response. These results suggest that in addition to the emotional valence of imagined material, startle reactivity is influenced by the degree of engagement or active disengagement from the sensory environment. The findings also indicate that fear and anger are differentiable in terms of affective report, cardiac mobilization, and expressive behavior, but not at the primary motivational level at which reflex priming occurs.

Though many studies suggest that fine acoustic details fade from memory after 15 s or even less, everyday experience tells us that the voice of a person or a musical instrument can be recognized long after it was last heard. We wished to determine whether tones leave a lasting memory trace using an experimental model of implicit recognition and testing whether exact pitch information can be retrieved even after 30 s. Event-related brain potentials demonstrated the survival of an accurate representation of tone pitch in the auditory cortex. This result provides a link between short-duration buffering and permanent storage of acoustic information.