Influence of preoperative anxiety on hypotension after spinal anaesthesia in women undergoing Caesarean delivery.

BACKGROUND: We designed a prospective observational study to assess the effect of preoperative anxiety on hypotension after spinal anaesthesia. METHODS: After IRB approval and signed informed consent, 100 healthy term parturients undergoing elective Caesarean delivery under spinal anaesthesia were enrolled. Direct psychological assessments of preoperative anxiety were verbal analogue scale (VAS) (0-10) anxiety score and State-Trait Anxiety Inventory questionnaire (STAI-s); salivary amylase was measured as an indirect physical assessment of anxiety. Direct and indirect anxiety data were transformed into ordinal groups for low, medium, and high anxiety (VAS: low 0-3, medium 4-6, high 7-10; STAI-s: low <40, medium 40-55, high >55; log(10) salivary amylase: low <3, medium 3-4, high >4). Spinal anaesthesia was performed using hyperbaric bupivacaine 10 mg and fentanyl 20 µg. All patients received i.v. crystalloid 500 ml prehydration and 500 ml cohydration. Hypotension was treated by standardized protocol (fluid bolus and ephedrine or phenylephrine depending on maternal heart rate). Systolic arterial pressure (SAP) was measured at baseline and every minute after spinal anaesthesia. The effect of low, medium, and high anxiety groups on the maximum percentage change in SAP (%ΔSAP) was assessed (one-way analysis of variance, Tukey's honestly significant difference). RESULTS: Ninety-three patients were included in analysis. There was a significant effect of direct psychological measures of anxiety on %ΔSAP (VAS P=0.004; STAI-s P=0.048). There was a significant difference between low and high anxiety groups (VAS P=0.003; STAI-s P=0.038), but not between other anxiety groups. Salivary amylase did not correlate with %ΔSAP. CONCLUSIONS: Preoperative anxiety assessed by VAS had a significant effect on hypotension after spinal anaesthesia.

Electrophysiological and haemodynamic correlates of face perception, recognition and priming.

Face perception, recognition and priming were examined with event-related functional magnetic resonance imaging (fMRI) and scalp event-related potentials (ERPs). Face perception was associated with haemodynamic increases in regions including bilateral fusiform and right superior temporal cortices, and a right posterior negativity (N170), most likely generated in the superior temporal region. Face recognition was associated with haemodynamic increases in fusiform, medial frontal and orbitofrontal cortices, and with a frontocentral positivity from 550 ms poststimulus. Face repetition was associated with a positivity from 400 to 600 ms and behavioural priming. Repetition of familiar faces was also associated with earlier onset of the ERP familiarity effect, and haemodynamic decreases in fusiform cortex. These data support a multi-component model of face-processing, with priming arising from more than one stage.

Probing memory with conceptual cues at multiple retention intervals: a comparison of forgetting rates on implicit and explicit tests.

The time courses for implicit and explicit conceptual tests of memory were compared in two experiments. In Experiment 1, participants encoded target words by judging the apparent pleasantness of their meaning. Immediately thereafter or 48 h later, retrieval cues were presented to different groups of participants for either an implicit or an explicit free-association task. Whereas explicit test performance showed a decline over the 48-h delay, implicit test performance was statistically unaltered. In Experiment 2, memory was tested at five retention intervals, lasting up to 3 weeks. The forgetting functions of both implicit and explicit tests conformed to a logarithmic function. Despite the large conceptual priming effect, which resulted from relational encoding instructions, implicit memory performance still declined at a much slower rate than did performance on the cued-recall test. We argue that because nominal conceptual cues were held constant across the implicit and the explicit conditions, the observed dissociation in performance supports a memory systems approach.

Intact implicit memory for newly formed verbal associations in amnesic patients following single study trials.

This study examines the ability of amnesic patients to recover newly formed associations implicitly after a single study trial. Fifteen amnesic patients with various etiologies studied pairs by forming a sentence containing both words. At test, all participants saw 40 intact pairs, 40 rearranged pairs, and 40 new words. All pairs appeared side by side both at study and at test. For the implicit lexical-decision task, 40 nonwords were intermixed with the other pairs, and participants indicated whether both items were words. For the explicit speeded-recognition test, participants were asked to indicate whether both words had appeared at study. Despite being severely impaired on the explicit test, amnesic patients performed like healthy controls on the implicit test, with faster and more accurate responses to intact pairs than to recombined pairs. Contrary to existing theories, the results suggest that amnesic patients can form and retain new associations.

Repetition priming for familiar and unfamiliar faces in a sex-judgment task: evidence for a common route for the processing of sex and identity.

Repetition priming for faces was examined in a sex-judgment task given at test. Priming was found for edited, hair-removed photos of unfamiliar and familiar faces after a single presentation at study. Priming was also observed for the edited photos when study and test faces were different exemplars. Priming was not observed, however, when sex judgments were made at test to photos of complete, hair-included faces. These findings were interpreted by assuming that, for edited faces, internal features are attended, thereby activating face-recognition units that support performance. With complete faces, however, participants provided speeded judgments based primarily on the hairstyle. It is suggested that, for both familiar and unfamiliar faces, a common locus exists for the processing of the identity of a face and its sex. A single face-recognition model for the processing of familiar and unfamiliar faces is advocated.

Automatic Retrieval of New Associations under Shallow Encoding Conditions

In two experiments during the study phase participants read unrelated context-target word pairs presented below a line drawing of the context word. During test the strong cue group was presented with context words, line drawings, and stems of target words. The line drawings were not presented in the weak cue group. Stems were paired with the same context words as at study (intact), paired with different context words (recombined), or corresponded to unstudied words (control). In Experiment 1 participants were instructed to complete stems with the first word that came to mind (indirect). The priming effect for new associations was twice as large in the strong cue group. In Experiment 2 the process dissociation procedure was applied and participants completed stems with studied words (inclusion) or with unstudied words (exclusion). Results indicated that consciously controlled and automatic retrieval processes mediated the associative effect in both groups.

Automatic retrieval of new associations under shallow encoding conditions.

In two experiments during the study phase participants read unrelated context-target word pairs presented below a line drawing of the context word. During test the strong cue group was presented with context words, line drawings, and stems of target words. The line drawings were not presented in the weak cue group. Stems were paired with the same context words as at study (intact), paired with different context words (recombined), or corresponded to unstudied words (control). In Experiment 1 participants were instructed to complete stems with the first word that came to mind (indirect). The priming effect for new associations was twice as large in the strong cue group. In Experiment 2 the process dissociation procedure was applied and participants completed stems with studied words (inclusion) or with unstudied words (exclusion). Results indicated that consciously controlled and automatic retrieval processes mediated the associative effect in both groups.

Repetition priming for newly formed and preexisting associations: perceptual and conceptual influences.

Three experiments demonstrate that association-specific repetition effects can be obtained for both newly formed and preexisting associations and that these effects are sensitive to modality of presentation. After studying a list of word pairs, participants were shown the original intact pairs and pairs formed by recombining the original pairs. In a lexical-decision task in which participants were asked to indicate whether both items were words, responses were faster to newly formed associations in the intact than in the recombined condition. This association-specific repetition priming effect was also observed for preexisting associations when a speeded relatedness judgment task was used. Both effects were found to be attenuated under cross-modal presentation. Finally, an explicit speeded recognition task revealed an associative effect that was not attenuated when modality was crossed for newly formed associations and was actually exaggerated for preexisting associations, suggesting that the repetition priming effects were not produced by conscious recollection. Results are discussed in terms of frameworks that are based either on perceptual representation systems or on a transfer-appropriate processing model.

Repetition priming effects for newly formed associations are perceptually based: evidence from shallow encoding and format specificity.

This article is concerned with memory for newly formed associations as displayed on implicit and explicit tests of memory. After studying a list of word pairs, participants were shown the original intact pairs and pairs formed by recombining the original pairs. Pairs were simultaneously presented both at study and at test. In a lexical-decision task in which participants were asked to indicate whether both items were words, responses to intact pairs were faster than to recombined pairs. The size of this association-specific repetition effect was relatively unaffected by a levels-of-processing manipulation, indicating that conceptual processes did not likely contribute to the production of the effect. Furthermore, the effect was not produced when pairs were presented simultaneously at study but sequentially at test, thus highlighting the importance of format of presentation. Finally, in an explicit speeded-recognition task the size of the association-specific effect was largely affected by levels-of-processing manipulation and was revealed even under sequential test presentation suggesting that the associative repetition effects were not contaminated by conscious recollection. Together, the results show that perceptual factors are involved in both storage and retrieval of associative information in data-driven implicit tests of memory.