Item repetition in short-term memory: Ranschburg repeated

In serial recall from short-term memory, repeated items are recalled well when close together (repetition facilitation), but not when far apart (repetition inhibition; the Ranschburg effect). These effects were re-examined with a new scoring scheme that addresses the possibility that repetitions are distinct tokens in memory. Repetition facilitation and repetition inhibition proved robust, and were shown to interact with the temporal grouping of items (Experiment 1), which affected the probability of detecting repetition (Experiments 2A and 2B). It is argued that detection of a repetition is necessary for repetition facilitation, attributable to the tagging of immediate repetition, whereas the failure to detect or remember a repetition results in repetition inhibition, attributable to an automatic suppression of previous responses and a bias against guessing repeated items (Experiment 3). The findings are discussed in relation to models of short-term memory and the phenomenon of repetition blindness.     

Defects of immediate memory in Broca''s and conduction aphasia

The effects of local anesthetic agents (lidocaine, procaine, cocaine) and diphenylhydantoin (DPH) were studied on the slow electrical responses induced by isoproterenol or caffeine in cardiac muscle preparations rendered inexcitable by tetrodotoxin (TTX) or by partial depolarization with elevated K+ (26 mM). In such inexcitable cells, we previously demonstrated that addition of some positive inotropic agents, such as catecholamines, histamine, and methylxanthines, rapidly increase the number of available slow Ca2+--Na+ channels, thus allowing slowly rising electrical responses resembling the plateau component of the cardiac action potential. In embryonic chick (16-20-day-old) myocardial cells (ventricular) studied as intact perfused hearts or as reaggregated cell cultures of trypsin-dispersed cells, high concentrations (10-(3) M) of all of the above drugs blocked the induced slow responses with their associated contractions; low concentrations (10-(5) M) of these agents reduced the maximal rate of rise (+Vmax) of the slow responses and depressed the contractions. For comparison with their effects on the slow response, the actions of these drugs on the normal action potential were also studied. As with the slow response, all of these drugs depressed the rate of rise of the action potential (10-(4) M) or blocked it at higher concentrations (10-(3) M); in contrast, low concentrations (10-(5) M) of lidocaine and DPH increased +V max. These findings suggest that local anesthetics, which interact with the lipid phase of the cell membrane, lead to blockade of the slow Ca2+--Na+ channels as well as of the fast Na+ channels in the myocardial sarcolemma.     

Long-term cognitive deficits following posterior fossa tumor resection: A neuropsychological and functional neuroimaging follow-up study.

The posterior fossa syndrome (PFS) consists of transient cerebellar mutism, cognitive symptoms, and neurobehavioral abnormalities that typically develop in children following posterior fossa (PF) tumor resection. The pathophysiological substrate of the syndrome remains unclear. We investigated eight children of whom five presented with a variety of clinically relevant non-motor language symptoms associated with cognitive and behavioral disturbances after PF tumor resection. Four children developed transient cerebellar mutism followed by dysarthric speech. Non-motor language symptoms consisted of agrammatism, anomia, impaired verbal fluency, comprehension deficits, and aspontaneous speech. Neurocognitive deficits included executive dysfunctions, concentration deficits, and visuo-spatial disorders. In addition, all children presented with behavioral and affective disturbances. Functional neuroimaging studies during the phase of mutism by means of SPECT showed perfusional deficits in the anatomo-clinically suspected supratentorial areas subserving language dynamics, syntax, naming, executive functioning, affective regulation, and behavior. A significant improvement of frontal perfusional deficits paralleled the clinical remission of mutism. These results add to the view that the PFS might represent a cerebello-cerebral diaschisis phenomenon, reflecting the metabolic impact of the cerebellar lesion on supratentorial cognitive and affective functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Drug-induced amnesia: Implications for cognitive neuropsychological investigations of memory.

Studies of drug effects on memory represent a large body of literature that, for the most part, has not had an impact on psychological theories of memory and amnesia produced by cognitive psychologists, who tend to theorize independently of information about the brain. Recently, however, there has been a movement toward cognitive neuropsychological approaches to memory in which theorists have begun to consider, and even focus on, neuroanatomical realities. This approach currently relies on data from organic amnesic patients and normal Ss. This article suggests that studies of drug-induced amnesia complement these current lines of investigation and therefore merit consideration from cognitive neuropsychologists interested in memory. To this end, the drugs and memory literature is reviewed, and its potential relationship with more mainstream cognitive neuropsychology is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Beyond the single study: function/location metanalysis in cognitive neuroimaging

Subject selection and exclusion criteria employed in typical clinical effectiveness trials of investigational new drugs have two fundamental aims: (1) to ensure that patients entering a study are truly suffering from the condition the drug is intended to treat and (2) to maximize the likelihood that the study will detect an effect of the drug if, in fact, one exists. Typical protocol selection criteria not only specify exacting procedures for establishing and documenting the diagnosis of those recruited for a study but also seek to increase, relative to the prevalence in the general population, the proportion of individuals in the sample likely to respond to pharmacological treatment. Because it is ordinarily impossible to learn prior to extensive clinical experience with a new drug which, if any, patient characteristics reliably predict a consistent treatment response, strategies for sample "enrichment" typically operate by excluding patients (for example, those with very advanced and/or complicated illness, those with serious concomitant illness, those at the extremes of age, those with very mild illness, and so forth) in whom a dependable response to treatment seems unlikely on logical and/or generic grounds. Some studies use positive strategies for sample "enrichment." In studies evaluating drugs intended to treat recurrent episodes of psychiatric illnesses, many protocols recommend selective recruitment of patients with a history of meaningful positive responses to antipsychotic treatment during prior episodes. Sample selection procedures of these kinds impose limits on the generalizability of a study's results (i.e., external validity), but the use of nonrandom patient samples is ordinarily held to have no effect on the internal validity of the results. In short, studies employing highly selected patient samples are, despite their limited external validity, regularly accepted as valid sources of evidence bearing on a drug's effectiveness. There are exceptions, however; this paper describes one in which the use of a seemingly innocuous sample enrichment maneuver proved highly damaging to the ultimate credibility of an important multicenter trial. In particular, exposure to an experimental treatment during an open qualification phase may invalidate drug-placebo comparisons made during a later randomized, blinded, controlled phase. Our review of the trial also reveals that the enrichment maneuver employed probably failed to accomplish its intended aims, selecting patients whose improvements on the outcome variable may be as reasonably ascribed to chance as to drug effect. This is all the more surprising because the method of sample enrichment employed has much in common with those long recommended in the clinical trial literature.     

A neuropsychological study of fact memory and source amnesia.

We investigated the ability of amnesic patients to learn new facts (e.g., Angel Falls is located in Venezuela) and also to remember where and when the facts were learned (i.e., source memory). To assess the susceptibility of fact and source memory to retrograde amnesia, patients prescribed electroconvulsive therapy were presented facts prior to the first treatment and were tested after their second treatment. All amnesic patients exhibited marked fact memory impairment. In addition, some amnesic patients exhibited source amnesia (i.e., they recalled a few facts but then could not remember where or when those facts had been learned). Source amnesia was unrelated to the severity of the memory deficit itself, because patients who exhibited source amnesia recalled as many facts as the patients who did not. These results show that the deficit in amnesia includes an impairment in acquiring and retaining new facts. Source amnesia can also occur, but it is dissociable from impaired recall and recognition and appears to reflect difficulty in remembering the specific context in which information is acquired. The findings are discussed in terms of their significance for how memory is organized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verb generation in patients with focal frontal lesions: a neuropsychological test of neuroimaging findings

What are the neural bases of semantic memory? Traditional beliefs that the temporal lobes subserve the retrieval of semantic knowledge, arising from lesion studies, have been recently called into question by functional neuroimaging studies finding correlations between semantic retrieval and activity in left prefrontal cortex. Has neuroimaging taught us something new about the neural bases of cognition that older methods could not reveal or has it merely identified brain activity that is correlated with but not causally related to the process of semantic retrieval? We examined the ability of patients with focal frontal lesions to perform a task commonly used in neuroimaging experiments, the generation of semantically appropriate action words for concrete nouns, and found evidence of the necessity of the left inferior frontal gyrus for certain components of the verb generation task. Notably, these components did not include semantic retrieval per se.     

Encoding, repetition, and the mirror effect in recognition memory: symmetry in motion

The entrapment of loperamide hydrochloride (LPM) in biodegradable polymeric drug carriers such as nanoparticles might enable its passage across the blood-brain barrier. The optimization of the preparation of the LPM-loaded PLA nanoparticles was performed employing high pressure emulsification-solvent evaporation. The resulting nanoparticles were characterized by particle size, distribution, thermal analysis, and drug release profiles. The partition of LPM into the organic phase increased with an increase in pH of the aqueous phase and with addition of lipophilic surfactants such as sorbitan fatty acid esters, resulting in an increase in the drug entrapment in the nanoparticles. Evaporation of the organic phase under reduced pressure and the addition of ethanol in the organic phase yielded a high drug entrapment due to the rapid polymer precipitation. The addition of the sorbitan fatty acid esters further increased the drug entrapment even at higher LPM concentrations. The results of thermal analysis suggest that LPM was homogeneously dispersed in the amorphous polymer matrix. The in vitro release of the drug from nanoparticles was biphasic, with a fast initial phase, followed by a second slower phase. Different drug release profiles from nanoparticles can be achieved by addition of sorbitan fatty acid esters, or the employment of different solvents as the organic phase.     

Errors in short-term memory for speech: A developmental study.

In a previous study (R. Treiman & C. Danis, 1988), adults who were presented with lists of spoken consonant-vowel-consonant (CVC) nonsense syllables for immediate recall produced many errors that combined the initial consonant onset of one to-be-remembered syllable with the vowel-consonant rime of another to-be-remembered syllable. These onset-rime recombination errors were more common than other types of recombination errors and also more common than serial position errors. These findings suggest that nonwords are remembered in terms of smaller phonological units. To replicate the previous results and to determine whether they generalize to children, the author tested kindergartners, 3rd graders, 6th graders, and adults on lists of nonsense CVCs. Onset-rime conjunction errors were the most frequent type of recombination error, even among kindergartners, suggesting that children code spoken syllables in terms of onset and rime units from a young age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial-order short-term memory predicts vocabulary development: Evidence from a longitudinal study.

Serial-order short-term memory (STM), as opposed to item STM, has been shown to be very consistently associated with lexical learning abilities in cross-sectional study designs. This study investigated longitudinal predictions between serial-order STM and vocabulary development. Tasks maximizing the temporary retention of either serial-order or item information were administered to kindergarten children aged 4 and 5. At age 4, age 5, and from age 4 to age 5, serial-order STM capacities, but not item STM capacities, were specifically associated with vocabulary development. Moreover, the increase of serial-order STM capacity from age 4 to age 5 predicted the increase of vocabulary knowledge over the same time period. These results support a theoretical position that assumes an important role for serial-order STM capacities in vocabulary acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory, short-term memory, and general fluid intelligence: A latent-variable approach.

A study was conducted in which 133 participants performed 11 memory tasks (some thought to reflect working memory and some thought to reflect short-term memory), 2 tests of general fluid intelligence, and the Verbal and Quantitative Scholastic Aptitude Tests. Structural equation modeling suggested that short-term and working memories reflect separate but highly related constructs and that many of the tasks used in the literature as working memory tasks reflect a common construct. Working memory shows a strong connection to fluid intelligence, but short-term memory does not. A theory of working memory capacity and general fluid intelligence is proposed: The authors argue that working memory capacity and fluid intelligence reflect the ability to keep a representation active, particularly in the face of interference and distraction. The authors also discuss the relationship of this capability to controlled attention, and the functions of the prefrontal cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Higher touch and kinesthetic functions in children with former speech/language development disorders: a neuropsychological study

1. The affinities of 10 selective muscarinic receptor antagonists against [3H]-quinuclidinyl benzilate (QNB) binding were determined to characterize the muscarinic receptors present in guinea-pig gallbladder smooth muscle. The highest correlation was obtained for the comparison between the pKi values for the gallbladder smooth muscle and M2 sites. Pirenzepine revealed two binding sites with affinities indicating the presence of muscarinic M2 receptors in abundance and a minor population of an additional site(s). 2. Carbachol produced gallbladder contractions, stimulated phosphoinositide (PI) hydrolysis and inhibited cAMP formation concentration-dependently with pD2 values of 6.12 +/- 0.11, 5.18 +/- 0.33 and 7.19 +/- 0.15, respectively. 3. Pirenzepine, 4-DAMP, HHSiD, pF-HHSiD, AF-DX 116, methoctramine, AQ-RA 741, guanylpirenzepine and AF-DX 384 showed competitive antagonism against carbachol-induced gallbladder contractions. There was no correlation between the pA2 values for the gallbladder and pKi values for the M2 sites, whereas significant correlations were found for the M1, M3 and M4 sites, the best correlation being between the pA2 values for the gallbladder and M4 subtypes. 4. Finally, the presence of both m2 and m4 receptor proteins were demonstrated by Western blot analysis. It is concluded that guinea-pig gallbladder smooth muscle has both muscarinic M2 and M4 receptors, which are coupled to adenylate cyclase inhibition and PI hydrolysis. 5. Although it seems likely that M2 receptors do not play a primary role in carbachol-induced guinea-pig gallbladder contraction, the characterization of the muscarinic subtypes which mediate these contractile responses needs further evidence.     

Problems of method in the study of short-term memory.

Considerations of design which have been problems in the study of long-term memory are discussed in the context of short-term memory research. These problems include the type of experimental design (independent versus repeated measures), the measurement of immediate retention, and the means by which the retention interval is filled. This review indicates that these methodological problems are also present in the investigation of short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A developmental study of categorical organization in short-term memory.

Studied 3rd and 4th graders and college undergraduates to investigate the development of the ability to use taxonomic, phonemic, and sense impression categories as dimensions. Results indicate that the more sophisticated the level of encoding needed to discriminate between 2 opposing classes of information, the older the child must be before he can accomplish the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Benefits of immediate repetition versus long study presentation on memory in amnesia.

Objective: This study aimed to resolve discrepant findings in the literature regarding the effects of massed repetition and a single long study presentation on memory in amnesia. Method: Experiment 1 assessed recognition memory in 9 amnesic patients and 18 controls following presentation of a study list that contained items shown for a single short study presentation, a single long study presentation, and three massed repetitions. In Experiment 2, the same encoding conditions were presented in a blocked rather than intermixed format to all participants from Experiment 1. Results: In Experiment 1, control participants showed benefits associated with both types of extended exposure, and massed repetition was more beneficial than long study presentation, F(2, 34) = 14.03, p F F(2, 50) = 4.80, p = .012, partial η2 = .16. Amnesic patients showed significant and equivalent benefit associated with both types of extended exposure, F(2, 16) = 5.58, p = .015, partial η2 = .41, but control participants again benefited more from massed repetition than from long study presentation, F(2, 34) = 23.74, p     

Bias in a neuropsychological test classification related to education, age, and ethnicity.

159 brain-damaged or non-brain-damaged male inpatients (mean age 47.5 yrs) were classified by the Background Interference Procedure version of the Bender-Gestalt Test. Correctly and incorrectly classified Ss were compared in age, education, IQ, and racial-ethnic group. Differences were consistent with the hypothesis that certain S characteristics would lead to classification as neurologically impaired regardless of neurological condition. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Everyday memory compensation: The impact of cognitive reserve, subjective memory, and stress.

To determine the potential importance of several unexplored covariates of everyday memory compensation, the authors examined relations between responses on the Memory Compensation Questionnaire (a self-report measure of everyday memory compensation) and cognitive reserve (education and verbal IQ), subjective memory, and life stress in 66 older adults (mean age = 70.55 years). Key results indicated that compensation occurred in people (a) whose IQ level was greater than their education level (representing cognitive reserve “discordance”) but not in people whose IQ was commensurate with their education (representing cognitive reserve “concordance”); (b) who had greater perceived memory errors; and (c) who experienced heightened stress. Further, high-stress older adults compensated whether perceived memory errors were low or high, but low-stress older adults compensated only if they perceived high memory errors. Bootstrapped confidence intervals around model betas provided further support for estimate reliability. These results suggest boundary conditions for the concept of cognitive reserve, and highlight the importance of subjective memory and life stress for defining contexts in which compensation may occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)