ERPs in schizophrenia: effects of antipsychotic medication

Thirty unmedicated schizophrenics were compared to 29 age-matched controls on auditory and visual event-related brain potential (ERP) paradigms. Twenty-one of these patients were tested again after 1 week on placebo and after 4 weeks on antipsychotic medication. Before treatment, N1, N2, and P3 components of the auditory ERP were smaller in the schizophrenics than in the controls. Although visual N2 was smaller in schizophrenics, visual P3 was not. In spite of significant clinical improvement with antipsychotic treatment, amplitudes of auditory and visual N1, N2, and P3 were not significantly changed. Higher blood levels of antipsychotic medication were related to reductions in auditory P3 latency, however. In addition, higher levels of cerebrospinal fluid (CSF) MHPG (methoxyhydroxyphenylglycol) were associated with larger auditory N1s and larger auditory and visual P3s, suggesting an influence of arousal on these components in schizophrenics. In spite of this influence, reduction of the auditory P3 in schizophrenia is an enduring trait of the disease, which is not affected by antipsychotic medication or clinical improvement.     

The role of inhibitory processes in part-list cuing.

Providing a subset of studied items as retrieval cues can have detrimental effects on recall of the remaining items. In 2 experiments, the authors examined such part-list cuing impairment in a repeatedtesting situation. Participants studied exemplars from several semantic categories and were given 2 successive cued-recall tests separated by a distractor task of several minutes. Part-list cues were provided in the 1st test but not the 2nd. Noncue item recall was tested with the studied category cues (same probes) in the 1st test, but novel, unstudied retrieval cues (independent probes) in the 2nd test. The authors found detrimental effects of part-list cues in both the 1st (same-probe) test and the 2nd (independent-probe) test. These results show that part-list cuing impairment can be lasting and is not eliminated with independent probes. The findings support the view that the impairment was caused by retrieval inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of attributional processes concerning medication taking on return of fear.

In this investigation, the authors examined the effect of attributional processes concerning medication taking on return of fear following exposure-based treatment. Participants (87% undergraduate students and 13% community volunteers) displaying marked claustrophobic fear (N = 95) were randomly allocated to a waitlist condition, a psychological placebo condition, a 1-session exposure-based treatment, or the same exposure treatment given in conjunction with an inactive pill. Attributions concerning medication taking were manipulated by further randomly assigning participants in the exposure-based treatment plus pill condition to 1 of 3 instructional sets immediately following treatment completion and posttreatment assessment: (1) The pill was described as a sedating herb that likely made exposure treatment easier; (2) the pill was described as a stimulating herb that likely made exposure treatment more difficult; or (3) the pill was described as a placebo that had no effect on exposure treatment. Return of fear rates for the 3 conditions were 39%, 0%, and 0%, respectively. Moreover, the deleterious effects of the sedation instructions were mediated by reduced self-efficacy. These findings highlight the importance of assessing patient attributions regarding the improvements achieved with combined exposure-based and pharmacological treatments for anxiety disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The psychophysiology of confession: Linking inhibitory and psychosomatic processes.

We investigated the short-term autonomic correlates of disclosing personal and traumatic experiences among two samples of healthy undergraduates. In Experiment 1, subjects talked into a tape recorder about extremely stressful events that had occurred in their lives, as well as what they planned to do following the experiment. Skin conductance, blood pressure, and heart rate were continuously measured. Based on judges' ratings of subjects' depth of disclosure, subjects were classified as high or low disclosers. Talking about traumatic events was associated with decreased behavioral inhibition, as measured by lower skin conductance levels among high disclosers. Disclosing traumatic material was also associated with increased cardiovascular activity. In Experiment 2, subjects both talked aloud and thought about a traumatic event and about plans for the day. Half of the subjects were alone in an experimental cubicle and talked into a tape recorder; the remaining subjects talked to a silent "confessor" who sat behind a curtain. Among high disclosers, both talking and thinking about traumatic events produced lower skin conductance levels than did thinking or talking about plans for the day. The presence of a confessor inhibited subjects' talking. Implications for understanding the nature of confession and the development of an inhibitory model for psychosomatic processes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of three types of aggression on vascular processes.

"Eighty college-age-subjects underwent either a frustrating or nonfrustrating experience and subsequently were placed in one of four aggression-conditions: Physical, Verbal, Fantasy, or No Aggression. The intent of this 2 X 4 factorial design experiment was to measure the effects of each type of aggression on frustration-produced-elevations in systolic blood pressure and heart rate. The results indicated that frustrated subjects who were given an opportunity to physically or verbally aggress against the frustrator, manifested returns on both physiological measures to the levels of the Low Frustration control subjects. Frustrated subjects in the Fantasy and No Aggression conditions exhibited significantly elevated systolic pressures and heart rates at the post-aggression-recording of these measures." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of an "anxiety-reducing" medication on group behavior under threat.

Three member teams worked on a group task under three experimental conditions: a threat condition in which Ss received an anxiety reducing medication, a threat condition with Ss receiving no medication, and a control nonthreat condition. Threat was imposed by structuring the sessions as evaluative tests whose results would become part of the Ss ROTC records. The Bales category system was used to obtain behavioral indices and the S's perception of their group and motivational state were obtained from an adjective check list. The results indicate that medication produces changes in the emotional and motivational state of the Ss along three dimensions, anxiety, elation, and assertion. "Medicated groups may be characterized as having an active, non-aggressive 'good time' with no especial concern for effective performance on the task." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The duality of selection: Excitatory and inhibitory processes in auditory selective attention.

Behavioral and event-related potential (ERP) measurements were made in an auditory selective-attention paradigm, both before and after a series of inhibition or discrimination training sessions. The presence of distractors caused poor perceptual sensitivity, weak P3 responses, conservative responding, and slow reaction times relative to baseline. Distraction prompted a frontal enhancement of ERP components occurring 100-250 ms after the onset of attended signals (N1, P2, and N2). Training ameliorated behavioral interference from distraction. Participants receiving inhibition training acquired improved inhibitory processing of distractors, an effect that peaked 200 ms after distractor onset, In a proposed model, distinct excitatory and inhibitory mechanisms work interactively to maintain sensitivity to environmental change in the fare of disruption from the contextual integration of irrelevant events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The selective effects of alcohol on automatic and effortful memory processes.

Automatic and effortful memory processes were evaluated in a 2-session, within-subjects design involving an alcohol challenge and a no-alcohol condition. Free recall of a 90-word list measured effortful processing. Estimation of word frequency from the same list measured automatic processing. Acute intoxication was hypothesized to diminish effortful but not automatic memory processes. Healthy, male volunteers (n?=?36) completed the 2 conditions 1 week apart. Presentation frequency influenced both free recall and frequency estimation, with both measures increasing as presentation frequency increased. Free recall was significantly lower in the alcohol than in the no-alcohol condition, but frequency estimation was not differentially affected. The data showed that an alcohol challenge dissociated automatic and effortful memory processes in volunteers. The authors discuss potential neurobiological substrates that may account for alcohol's selective disruption of effortful, verbal, episodic memory processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anchoring effects in sequential clinical judgments.

To clarify further the nature of assimilation and contrast effects, serial judgments of clinical stimuli were studied using a 4-phase alternation of anchor design. Judgments of pathology of equivalent moderate clinical stimuli across the sequence of anchor contexts were made by 176 Ss. 2 types of behavior were judged, aggression and dependency. The results indicated significant anchoring effects on 3 of the 4 phases. Contrast on the initial phase was followed by a trend toward assimilation on the succeeding phases. It is concluded that assimilation effects using alternated anchors may be facilitated by the limited capacity of judges to discriminate clinical stimuli and by perceptual grouping effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Speed and sequential effects in reaching.

To investigate the impact of future task demands on reaching, participants performed repetitive sagittal-plane reaches at low and high speeds. In a control condition, they reached from a start location to a target and back. In the experimental conditions, they reached from the start to the target, then to a second target (the location of which varied between trials), then back to the first target, and finally back to the start. Contributions of the hip, shoulder, and elbow to reaches made to the first target depended on the second target's location, on movement speed, and on repetition. Participants combined sustained and transient postural adjustments to minimize effort. The results support the knowledge model of movement selection (D. A. Rosenbaum, L. D. Loukopoulos, R. G. M. Meulenbroek, J. Vaughan, & S. E. Engelbrecht, 1995) but also call for its elaboration. Variants of the model are explored through simulations of the above study. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Partial delay extinction effects within-subjects based on sequential manipulations.

Describes an experiment with 4 groups of 10 male albino Sprague-Dawley rats. 3 groups received partial delay of reward in 1 runway and immediate reward in a discriminably different runway followed by extinction to both runways. Group 1, which received transitions from delay to immediate reward in the partial-delay alley, showed greater resistance to extinction in the partial-delay alley than in the immediate alley. Groups that received transitions from delay to immediate reward in the immediate alley (Group 2) and in both partial-delay and immediate alleys (Group 3) showed no differential within-S extinction performance. A between-group, partial-delay extinction effect was found; all Ss experiencing delay showed greater resistance to extinction than Group 4 (controls) that received only immediate reward. Data are interpreted within the framework of E. J. Capaldi's sequential theory. However, an extension of sequential theory was needed to account for the nondifferential extinction performance of Group 2. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical assessment of extrapyramidal signs in nursing home patients given antipsychotic medication

BACKGROUND: We sought to quantify the relationship between antipsychotic drug use and clinical evidence of extrapyramidal dysfunction in a large population of elderly nursing home patients. METHODS: Subjects were 251 residents (mean age, 84.1 years; range, 65 to 105 years) who were taking psychoactive drugs in 12 long-term care facilities. Patient characteristics and all medication use (both scheduled and as needed) were measured during a 1-month observation period. We then performed neuropsychological and functional testing on residents who received any psychoactive medications during the study month. The presence of rigidity, bradykinesia, or masklike facies was assessed in each patient by a research assistant who was unaware of diagnoses and medication use. RESULTS: The parkinsonian signs studied were found in 127 (50.6%) of these residents. Using logistic regression modeling to adjust for potential confounding, we found this outcome to be increased more than threefold in patients who took low-potency neuroleptics (odds ratio [OR], 3.49 for > or = 50 mg/d of chlorpromazine-type drugs; 95% confidence interval [CI], 1.28 to 9.57) and more than sixfold for use of 1 mg/d or more of haloperidol (OR, 6.42; 95% CI, 2.16 to 19.04). Age, gender, and use of nonneuroleptic psychoactive drugs were not associated with an increase in parkinsonian signs. CONCLUSIONS: Clinical evidence of extrapyramidal dysfunction is three to six times more common in institutionalized elderly patients given antipsychotic medication than in comparable patients not using such drugs. Its risk is substantially increased even in patients given low-potency chlorpromazine-type drugs, as well as those taking haloperidol. The effect is not explained by age or mental status and is not seen with other psychoactive medications. The expected frequency of parkinsonian symptoms can help to inform the balancing of risks vs therapeutic effect when the use of all drugs in this class is considered.     

Encoding and external-storage effects on writing processes.

Across 4 experiments, undergraduate students viewed a 19-min videotape lecture about types of creativity and then wrote a compare-and-contrast essay for 25 min. In Exps 1 (immediate writing) and 2 (delayed writing), Ss either listened or took notes under 1 of 3 note-taking formats and then wrote with or without notes. In both experiments, Ss writing from their own notes (encoding plus external storage) composed more organized and lengthier essays than Ss writing without their notes (encoding only). Exps 3 and 4 examined the external-storage effect separately from the encoding effect. In delayed writing (Exp 4), Ss composing from provided notes wrote lengthier essays than Ss composing without notes. Results support the effects of external storage and encoding plus external storage on writing processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The indispensability of medication.

Contends that psychiatrists who are medication oriented can generally earn more money with less specialized training than can psychotherapy-oriented pychiatrists and that there is a tendency for them to believe that what they have not been trained in does not exist. The author cautions society against allowing medication-oriented psychiatrists to be the sole decision makers. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic integration as a boundary condition on inhibitory processes in episodic retrieval.

Recalling an experience often impairs the later retention of related traces, a phenomenon known as retrieval-induced forgetting (RIF). Research has shown that episodic associations protect competing memories from RIF (Anderson & McCulloch, 1999). We report 4 experiments that examined whether semantic associations also protect against RIF. In all experiments, robust RIF occurred when there were few associations between practiced and nonpracticed sets, but RIF was abolished when there were many. The benefits of semantic integration were independent of episodic integration strategies and were not mediated by intentional use of the associations. Rather, these results establish a new boundary condition on RIF—semantic integration—that has a potent impact on the magnitude of RIF and may explain variability in the RIF phenomenon. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The effects of a sequential behavior analysis protocol on the teaching practices of undergraduate trainees.

Studied the effects of a sequential behavior feedback procedure on the practice teaching experiences of undergraduate teacher trainees. Teaching performances of 4 Ss were analyzed using Alternative Appropriate Instructional and Organizational Action measures within the ecological context of Instructional and Organizational challenges in the practice teaching setting. Data support the added utility of sequential information when using behavior analysis approaches to teacher training. One field-based undergraduate teaching practicum was monitored. The key elements summarized are (1) classroom instruction tied to the practicum experience, (2) practice teaching experience, and (3) sequential observation system used for evaluation and feedback, including multiple-baseline data to support this approach to teacher training. Results point to the strong relationship between sequential behavior feedback and (1) teacher-trainee improvement in meeting instructional and organizational challenges in the classroom, (2) teacher-trainee movement from an organizational to an instructional focus over the course of the experiment, and (3) positive changes in pupil practices as a function of changes in teacher-trainee instruction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Forgetting our facts: The role of inhibitory processes in the loss of propositional knowledge.

Seven experiments are reported that show that retrieving facts from long-term memory is accomplished, in part, by inhibitory processes that suppress interfering facts. When asked to repeatedly retrieve a recently learned proposition (e.g., recalling The actor is looking at the tulip, given cues such as Actor looking t__), subjects experienced a recall deficit for related facts (e.g., The actor is looking at the violin) on a recall test administered 15 min later. Importantly, this retrieval-induced forgetting was shown to generalize to other facts in which the inhibited concepts took part (e.g., The teacher is lifting the violin), replicating a finding observed by M. C. Anderson and B. A. Spellman (1995) with categorical stimuli. These findings suggest a critical role for suppression in models of propositional retrieval and implicate the mere retrieval of what we know as a source of forgetting of factual knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of guanosine-quartet inhibitory effects versus cytidine homopolymer inhibitory effects on rat neointimal formation

Biotinyl-oligosaccharides are a relatively new generation of saccharide probes that enable immobilization of desired oligosaccharides on streptavidin matrices for studies of carbohydrate-protein interactions. Here we describe the facile preparation of biotinyl-l-3-(2-naphthyl)-alanine hydrazide (BNAH) derivatives of oligosaccharides, containing a strong UV absorbing and fluorescent group, in which the ring of the reducing-end monosaccharide is nonreduced. We evaluate reactivities of immobilized BNAH- N -glycans with plant lectins that recognize aspects of the oligosaccharide core or outer-arms. We make some comparisons with 2-amino-6-amidobiotinyl-pyridine (BAP) derivatives obtained by reductive amination, and 6-(biotinyl)-aminocaproyl-hydrazide (BACH) derivatives which have a longer spacer-arm. N -Glycan-BNAH and-BAP derivatives have, overall, comparable reactivities with lectins which recognize N -glycan outer-arms or the trimannosyl core, but only BNAH and BACH derivatives are bound by lectins which recognize the non-reduced core. Moreover, with Pisum sativum agglutinin (PSA) which additionally requires the fucosyl- N- glycan-asparaginyl core for high affinity binding, the immobilized BNAH derivative (which is an alanine hydrazide beta-glycoside) can substitute for the natural beta-glycosylasparaginyl core, whereas the BACH derivative (aminocaproyl-hydrazide-beta-glycoside) is less effective. BNAH is a derivatization reagent of choice, therefore, for solid phase carbohydrate-binding experiments with immobilized N -glycans.     

Probability effects on stimulus evaluation and response processes.

Investigated the effects of probability information on response preparation and stimulus evaluation. Eight Ss responded with 1 hand to the target letter H and with the other to the target letter S. The target letter was surrounded by noise letters that were either the same as or different from the target letter. In 2 conditions, the targets were preceded by a warning stimulus unrelated to the target letter. In 2 other conditions, a warning letter predicted that the same letter or the opposite letter would appear as the imperative stimulus with .80 probability. Correct reactions times (RTs) were faster and error rates were lower when imperative stimuli confirmed the predictions of the warning stimulus. Probability information affected (1) the preparation of motor responses during the foreperiod, (2) the development of expectancies for a particular target letter, and (3) a process sensitive to the identities of letter stimuli but not to their locations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of divided attention on encoding and retrieval processes in human memory.

The authors examined the effects of divided attention (DA) at encoding and retrieval in free recall, cued recall, and recognition memory in 4 experiments. Lists of words or word pairs were presented auditorily and recalled orally; the secondary task was a visual continuous reaction-time (RT) task with manual responses. At encoding, DA was associated with large reductions in memory performance, but small increases in RT; trade-offs between memory and RT were under conscious control. In contrast, DA at retrieval resulted in small or no reductions in memory, but in comparatively larger increases in RT, especially in free recall. Memory performance was sensitive to changes in task emphasis at encoding but not at retrieval. The results are discussed in terms of controlled and automatic processes and speculatively linked to underlying neuropsychological mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)