RESUMEN
Consumption of anthocyanins from fruit sources may exert protection against hypertension and improve cognition. However, the effect of dose timing in studies is rarely considered. We hypothesized that timed-dose consumption of juice from an anthocyanin-rich Japanese plum variety (Queen Garnet plum, QGP) will have acute and dose-timing effects on cardiovascular responses, cognition, and urinary anthocyanin excretion profiles. Our study objective was to investigate the impact of plum juice on these health parameters. Twelve older (65+ years) and 12 younger (18-45 years) adults participated in an acute crossover study. Participants received, randomly, either 1 × 300 mL or 3 × 100 mL plum juice over 3 hours on 2 different occasions with a 2-week washout period. A battery of cognitive tasks was administered at 0 and 6 hours on each study day. Blood pressure (BP) and urinary anthocyanin/metabolite excretion profiles were measured over 24 hours. Area under the curve for BP was calculated (0-6 hours). A significant reduction in BP and cardiovascular responses was observed in both age groups which was more obvious in the older age group on the single dose for systolic BP, diastolic BP, mean arterial pressure, and heart rate (P values = .035, .028, .017, and .006, respectively). No significant difference was observed between dose-timing regimens for either age group. There was no observed effect on cognition. Native QGP anthocyanins, as well as methylated/glucuronidated metabolites, were detected in urine with no significant differences between age groups or dose timing. High-anthocyanin plum juice significantly reduced BP, but dose timing did not appear to be a significant factor in the potential acute BP-lowering effect of QGP juice.
Asunto(s)
Antocianinas/administración & dosificación , Presión Sanguínea , Cognición , Jugos de Frutas y Vegetales , Prunus domestica/química , Adulto , Anciano , Anciano de 80 o más Años , Monitoreo Ambulatorio de la Presión Arterial , Índice de Masa Corporal , Estudios Cruzados , Dieta , Relación Dosis-Respuesta a Droga , Femenino , Frutas/química , Humanos , Hipertensión/prevención & control , Masculino , Proyectos Piloto , Adulto JovenRESUMEN
There is a growing body of literature that suggests that long-term memory (LTM) and short-term memory (STM) structures that were once thought to be distinct are actually co-dependent, and that LTM can aid retrieval from STM. The mechanism behind this effect is commonly argued to act on item memory but not on order memory. The aim of the current study was to examine whether LTM could exert an influence on STM for order by examining an effect attributed to LTM, the phonological neighbourhood effect, in a task that reduced the requirement to retain item information. In Experiment 1, 18 participants completed a serial reconstruction task where neighbourhood density alternated within the lists. In Experiment 2, 22 participants completed a serial reconstruction task using pure lists of dense and sparse neighbourhood words. In Experiment 3, 22 participants completed a reconstruction task with both mixed and pure lists. There was a significant effect of neighbourhood density with better recall for dense than sparse neighbourhood words in pure lists but not in mixed lists. Results suggest that LTM exerts an influence prior to that proposed by many models of memory for order.
Asunto(s)
Memoria a Corto Plazo/fisiología , Aprendizaje Seriado/fisiología , Aprendizaje Verbal/fisiología , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas , VocabularioRESUMEN
Children with attention deficit hyperactivity disorder (ADHD) display many behaviors consistent with an underlying deficit in executive processes. This study examines Norman and Shallice's (1986) supervisory attentional system (SAS) as an approximation of executive functioning thought to be impaired in ADHD. Fifteen ADHD children were compared to a clinical control sample of learning disabled (LD) children and control children matched for age, gender, and IQ on a series of tasks designed to tap the functions of the SAS. The tasks assessed either the inhibition of a strongly triggered response (Star Counting Test, Hayling Sentence Completion Test, and the Random Generation Test) or impulsive responding in the absence of strong trigger-schema contingencies (Brixton Spatial Anticipation Test). Analyses revealed that the ADHD group was significantly impaired, in comparison to the LD and control groups, on tasks requiring the inhibition of a strongly triggered response. Further support for the fractionation of the SAS is provided by the differential performance of the groups on these tasks.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Atención , Inhibición Psicológica , Pruebas Neuropsicológicas , Nivel de Alerta , Trastorno por Déficit de Atención con Hiperactividad/psicología , Niño , Femenino , Humanos , Conducta Impulsiva/diagnóstico , Conducta Impulsiva/psicología , Discapacidades para el Aprendizaje/diagnóstico , Discapacidades para el Aprendizaje/psicología , Masculino , Desempeño Psicomotor , Tiempo de ReacciónRESUMEN
Two experiments are reported which examine immediate serial recall for high- and low-frequency words. The words in each list were either repeatedly drawn from the same small pool of candidates (in the closed set conditions) or each word only ever occurred once during the experiment (in the open set conditions). The results consistently show an effect of word frequency but the effect of set size was only apparent for low-frequency words. It is argued that both frequency and set size effects reflect processes concerning the "clean-up" of degraded short-term memory traces.
Asunto(s)
Memoria a Corto Plazo/fisiología , Recuerdo Mental , Adulto , Femenino , Humanos , Masculino , Fonética , Tamaño de la MuestraRESUMEN
Four experiments investigated the mechanisms responsible for the advantage enjoyed by high-frequency words in short-term memory tasks. Experiment 1 demonstrated effects of word frequency on memory span that were independent of differences in speech rate. Experiments 2 and 3 showed that word frequency has an increasing effect on serial recall across serial positions, but Experiment 4 showed that this effect was abolished for backward recall. A model that includes a redintegration process that operates to "clean up" decayed short-term memory traces is proposed, and the multinomial processing tree model described by R. Schweickert (1993) is used to provide a quantitative fit to data from Experiments 2, 3, and 4.
Asunto(s)
Memoria a Corto Plazo , Semántica , Aprendizaje Seriado , Adulto , Atención , Femenino , Humanos , Masculino , Fonética , Práctica Psicológica , Tiempo de Reacción , Conducta VerbalRESUMEN
Working memory refers to the systems responsible for the temporary storage and manipulation of information during the performance of cognitive tasks. There is a good deal of evidence that verbal short-term memory functions as a working memory system. We review advances in our understanding of the nature and limitations of verbal short-term memory and the reasons for its development with age, and go on to consider the common association between impairments of verbal short-term memory and other impairments of cognitive development. We conclude by considering the relationship between short-term memory development and cognitive development.
Asunto(s)
Discapacidades para el Aprendizaje/diagnóstico , Memoria a Corto Plazo , Percepción del Habla , Aprendizaje Verbal , Adolescente , Atención , Niño , Humanos , Discapacidades para el Aprendizaje/psicología , Retención en Psicología , Aprendizaje SeriadoRESUMEN
The experiments reported examine the effects of two highly related variables, word frequency and age of acquisition, on short-term memory span. Short-term memory span and speech rate were measured for sets of words which independently manipulated frequency and age of acquisition. It was found that frequency had a considerable effect on short-term memory span, which was not mediated by speech rate differences--although frequency did affect speech rate in one experiment. For age of acquisition, this situation was reversed; there was a small but significant effect of age of acquisition on speech rate, but no effect on memory span. This occurred despite results confirming that the stimuli used in the experiments produce an effect of age of acquisition on word naming. The results are discussed in terms of a two-component view of performance on short-term memory tasks.
Asunto(s)
Envejecimiento , Memoria a Corto Plazo , Vocabulario , Humanos , Medición de la Producción del Habla , Aprendizaje VerbalRESUMEN
We report an experiment investigating the mechanisms responsible for short-term memory span and its development by examining the relationship between memory span and speech rate for words and nonwords of differing spoken lengths. Linear functions related memory span to speech rate for both words and nonwords in children of different ages. The functions for nonwords had equivalent slopes (interpreted as reflecting a contribution from a speech-based process) but lower intercepts (interpreted as reflecting a contribution from a long-term memory component) than the functions for words. Children in both age groups studied showed evidence of a relationship between speech rate and memory span and part of the difference in memory span between age groups appears to reflect a difference in speech rate. However, there is also evidence that the long-term memory component of memory span shows greater efficiency in older children.