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PubMed2003

[An investigation of the unit of activation in on-line inferences during text processing: word-unit or proposition-unit?].

This study investigated the unit of activation in on-line inferences. To explore whether the activation of inferences is a word-unit or a proposition-unit, a meaningfulness-decision task was devised as a priming measure. The task required participants to decide whether a series of short sentences was meaningful or not. The result of Experiment 1 suggested that only proposition-units were activated. A priming effect was observed in targets which described inferences both at word-level and proposition-level, but not in targets which described inferences at word-level only. In Experiment 2, a meaningfulness-decision task was administered to investigate word-based priming and to make sure that the result of Experiment 1 was not caused by characteristics of the task. In Experiment 3, a priming effect was found in targets which described inferences using alternative perspectives and words. These results suggest that the unit of activation in on-line inferences is proposition-units and that these activations relate to the proposition-semantic level, not the word or single-concept level.

Mental Processes↗
PubMed2006

Acute effects of the ampakine farampator on memory and information processing in healthy elderly volunteers.

Ampakines act as positive allosteric modulators of AMPA-type glutamate receptors and facilitate hippocampal long-term potentiation (LTP), a mechanism associated with memory storage and consolidation. The present study investigated the acute effects of farampator, 1-(benzofurazan-5-ylcarbonyl) piperidine, on memory and information processes in healthy elderly volunteers. A double-blind, placebo-controlled, randomized, cross-over study was performed in 16 healthy, elderly volunteers (eight male, eight female; mean age 66.1, SD 4.5 years). All subjects received farampator (500 mg) and placebo. Testing took place 1 h after drug intake, which was around Tmax for farampator. Subjects performed tasks assessing episodic memory (wordlist learning and picture memory), working and short-term memory (N-back, symbol recall) and motor learning (maze task, pursuit rotor). Information processing was assessed with a tangled lines task, the symbol digit substitution test (SDST) and the continuous trail making test (CTMT). Farampator (500 mg) unequivocally improved short-term memory but appeared to impair episodic memory. Furthermore, it tended to decrease the number of switching errors in the CTMT. Drug-induced side effects (SEs) included headache, somnolence and nausea. Subjects with SEs had significantly higher plasma levels of farampator than subjects without SEs. Additional analyses revealed that in the farampator condition the group without SEs showed a significantly superior memory performance relative to the group with SEs. The positive results on short-term memory and the favorable trends in the trail making test (CTMT) are interesting in view of the development of ampakines in the treatment of Alzheimer's disease and schizophrenia.

Adult↗
PubMed2003

Semantic priming in the name retrieval of objects and famous faces.

Researchers interested in face processing have recently debated whether access to the name of a known person occurs in parallel with retrieval of semantic-biographical codes, rather than in a sequential fashion. Recently, Schweinberger, Burton, and Kelly (2001) took a failure to obtain a semantic context effect in a manual syllable judgment task on names of famous faces as support for this position. In two experiments, we compared the effects of visually presented categorically related prime words with either objects (e.g. prime: animal; target: dog) or faces of celebrities (e.g. prime: actor; target: Bruce Willis) as targets. Targets were either manually categorized with regard to the number of syllables (as in Schweinberger et al.), or they were overtly named. For neither objects nor faces was semantic priming obtained in syllable decisions; crucially, however, priming was obtained when objects and faces were overtly named. These results suggest that both face and object naming are susceptible to semantic context effects.

Adult↗
PubMed2000

[An examination of retrieval processes in implicit and explicit memory tests].

The purpose of this study was to examine the retrieval processes in implicit and explicit memory tests by manipulating study tasks and test types. Ninety-six students wrote down target words embedded in the sentences and generated target words using 2-letter cues embedded in the sentences. Students in one test group were asked to recall the target words using the 2-letter cues and then recognize them from the words recalled. Students in the second group were asked to generate words using the 2-letter cues. Students in the third test group were asked to generate words using the 2-letter cues and then recognize the target words from the words generated. The results showed the generation effects in the cued recall test, but in the other test groups, there were no differences between the writing and the generation tasks. The results of the recognition test also showed the interaction between study task and test type. The results suggest that the targets generated are accessed differently between implicit and explicit memory tests.

Adult↗
PubMed1995

Biphasic patterns of memory deficits following moderate-dose partial-brain irradiation: neuropsychologic outcome and proposed mechanisms.

PURPOSE: To identify the longitudinal neurobehavioral characteristics of the early-delayed and late-delayed effects of partial-brain radiotherapy for patients with supratentorial brain tumors with favorable histology. This study improves on previous attempts to identify radiation effects, because of the inclusion of baseline measures and the use of subjects as their own controls. PATIENTS AND METHODS: Ten neuropsychologic domains were measured in 12 patients at baseline (post-surgery and immediately before initiation of radiotherapy), and followed trimonthly for 1 year. Four to six patients were examined at 2 and 3 years postbaseline. RESULTS: Patients were impaired at baseline compared with controls only in visual memory and sentence recall, but demonstrated significant improvement in visual memory by 2 years postbaseline. Speed of processing information also showed a slope of improvement over 2 years. Retrieval from verbal long-term memory was impaired at 1.5 months postcompletion of radiotherapy, but recovered to baseline levels by 1 year. At 2 years postbaseline, long-term memory retrieval demonstrated a decline, but remained unchanged at 3 years. CONCLUSION: Long-term memory appears to be sensitive to the effects of radiotherapy. We confirmed our previous findings of a decrement with rebound during the early-delayed period, and propose that these findings are consistent with demyelination/remyelination. Decrement was observed again at 2 years postbaseline, which suggests that memory retrieval may be the earliest marker of late-delayed effects. These neurocognitive patterns are consistent with leukoencephalopathy. Confirmation of these observations will be possible if neuropsychologic testing with the same sensitivity can be incorporated into national collaborative trials.

Adult↗
PubMed1982

Psychiatric patient denial of mental illness as a normal process.

The self-perceptions of 50 first-admission psychiatric patients are compared with their perceptions of the mentally ill and psychiatric staff's views of the mentally ill but do not characterize themselves in terms of this stereotype. On the other hand they do view themselves as being much more like the mentally ill than usual. Two common perspectives on patient denial of mental illness, the sociological and the medical/clinical, are examined with respect to their ability to accommodate these results and it is concluded that a third perspective on patient denial of mental illness is required. This perspective views patient denial of mental illness as a normal process dependent on two mechanisms: rational rejection of self-stereotype identity and minor self-deception resulting from egocentric biases which play an important integrative role within the personality.

Adult↗
PubMed2004

[The neuroanatomy of motivation in man].

To relate motivation, a psychological concept, to a neurobiological substrate requires that this concept should be translated in operations relevant at the biological level. The term of motivation includes mental elementary processes decoding the emotional value of a stimulus (endogenous or exogenous) and integrating it into the elaboration, control and execution of goal-directed behaviors in order to ensure the maintenance of homeostasis, the well-being and survival of the individual and the species. Thus, in experimental condition, responses to aversive or appetitive situations are the classical markers of motivation. Consequently, the cerebral network of motivation particularly relates to the limbic system, i.e., the amygdala, the orbital and ventromedial prefrontal cortex, the anterior cingulum and the ventral striatum. Within this network, it is possible to distinguish: on one part structures such as the orbital and ventromedial prefrontal cortex, which are essential for the highest level of adaptive responses, allowing the individual to decode the variations of the emotional contingencies in real time, to integrate them into the behavior, and to maintain a behavioral choice during a long course, regardless of endogenous or environmental constraints; on the other part structures like the amygdala allow to build stable and invariants behaviors, that can be automatically activated and are essential for survival and avoidance of noxious situations.

Animals↗
PubMed2004

Analogical reasoning and prefrontal cortex: evidence for separable retrieval and integration mechanisms.

The present study examined the contributions of prefrontal cortex (PFC) subregions to two component processes underlying verbal analogical reasoning: semantic retrieval and integration. Event-related functional magnetic resonance imaging data were acquired while subjects performed propositional analogy and semantic decision tasks. On each trial, subjects viewed a pair of words (pair 1), followed by an instructional cue and a second word pair (pair 2). On analogy trials, subjects evaluated whether pair 2 was semantically analogous to pair 1. On semantic trials, subjects indicated whether the pair 2 words were semantically related to each other. Thus, analogy--but not semantic--trials required integration across multiple retrieved relations. To identify regions involved in semantic retrieval, we manipulated the associative strength of pair 1 words in both tasks. Anterior left inferior PFC (aLIPC) was modulated by associative strength, consistent with a role in controlled semantic retrieval. Left frontopolar cortex was insensitive to associative strength, but was more sensitive to integration demands than was aLIPC, consistent with a role in integrating the products of semantic retrieval to evaluate whether distinct representations are analogous. Right dorsolateral PFC exhibited a profile consistent with a role in response selection rather than retrieval or integration. These findings indicate that verbal analogical reasoning depends on multiple, PFC-mediated computations.

Adult↗
PubMed2002

Implicit memory for words played during isoflurane- or propofol-based anesthesia: the lexical decision task.

BACKGROUND: Unconscious processing of words during general anesthesia has been suggested after surgery with several tests of implicit memory. Patients can neither recall those words nor do they have explicit memories of other intraoperative events. It is unclear to what degree information is processed during general anesthesia and which tests are best suited to detect implicit memory. In the current study, a lexical decision paradigm not previously used to demonstrate implicit memory during anesthesia was used. METHODS: Sixty patients undergoing lumbar disc surgery were assigned to receive isoflurane infusion- or propofol infusion-based anesthesia combined with alfentanil infusions and a nitrous oxide-oxygen mixture. A control group of 10 medical students listened to tapes without receiving anesthesia. Two tapes, each containing a list of 30 low-frequency German nouns repeated for 15 min, were prepared, with half of the patients listening to tape A and the other half listening to tape B during the operation. Exposure time was 15 min from the time of skin incision onward. In the test phase, approximately 7 h later, words from lists A and B plus 60 nonwords were presented in random order by a computer program. Subjects were asked to indicate, by pressing one of two response buttons, whether the spoken word was or was not a legal German word (lexical decision). RESULTS: A recognition test revealed chance recognition for words presented during anesthesia. Lexical decision responses, however, were slightly faster to primed (previously presented) words than to unprimed (not previously presented) words when the entire group of patients was tested, suggesting a small implicit memory effect, which barely failed to reach the significance level. When the two medication groups were tested separately, no significant implicit memory effect could be ascertained statistically. The effects of previous exposure were much more pronounced in the control group. CONCLUSIONS: Balanced anesthesia techniques with isoflurane or propofol lead to only a minimal, statistically borderline implicit memory effect in the lexical decision paradigm.

Acoustic Stimulation↗
PubMed2006

Uncertainty of illness relationships with mental health and coping processes in fibromyalgia patients.

Fibromyalgia syndrome (FMS) is a chronic musculoskeletal pain condition poorly understood in terms of etiology and treatment by both physicians and patients. This condition of "uncertainty of illness" was examined as a variable involved in the adjustment of FMS patients, relating it to their depression, anxiety, affect, and coping styles. Fifty-one community-residing FMS patients provided self-report information on subsets of adjustment variables. Both cross-sectional and more dynamic longitudinal analyses showed that illness uncertainty was significantly associated with anxiety, negative affect, and avoidant and passive coping. Its positive relationship with depression was eliminated when a control variable, pain helplessness, was included as a covariate. Longitudinally, illness uncertainty interacted with interpersonally stressful daily events in predicting reports of reduced positive affect, suggesting that illness uncertainty acts as a risk factor for affective disturbances during stressful times. Implications of these results for therapeutic interventions are discussed.

Adaptation, Psychological↗
PubMed2006

The effects of mild and severe traumatic brain injury on speed of information processing as measured by the computerized tests of information processing (CTIP).

In spite of the fact that reaction time (RT) measures are sensitive to the effects of traumatic brain injury (TBI), few RT procedures have been developed for use in standard clinical evaluations. The computerized test of information processing (CTIP) [Tombaugh, T. N., & Rees, L. (2000). Manual for the computerized tests of information processing (CTIP). Ottawa, Ont.: Carleton University] was designed to measure the degree to which TBI decreases the speed at which information is processed. The CTIP consists of three computerized programs that progressively increase the amount of information that is processed. Results of the current study demonstrated that RT increased as the difficulty of the CTIP tests increased (known as the complexity effect), and as severity of injury increased (from mild to severe TBI). The current study also demonstrated the importance of selecting a non-biased measure of variability. Overall, findings suggest that the CTIP is an easy to administer and sensitive measure of information processing speed.

Adolescent↗
PubMed1999

Individual differences in information-processing rate and amount: implications for group differences in response latency.

Research on group differences in response latency often has as its goal the detection of Group x Treatment interactions. However, accumulating evidence suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditive interactions in which the slower group produces a larger treatment effect. The authors propose a rate-amount model that predicts linear relationships between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global processing parameters may be used to linearly transform response latencies from different individuals to a common information-processing scale so that small-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may be used to augment traditional analyses of raw response latencies.

Adult↗