Prospective/intentional and incidental everyday memory: Effects of age and passage of time.

Investigated the effects of age and passage of time on incidental and prospective/intentional everyday memory. 79 23–93 yr old volunteers were tested twice, and 33 of the Ss were tested 3 times over an 18-mo period. They were asked to recognize or recall, either in writing or orally, experiences from a 3-day period in which they served as research Ss. Results demonstrate that incidental, but not prospective/intentional, memory appeared to be influenced by age and passage of time. Results imply that salience and context are important factors in aging memory performance and that certain types of everyday retrospective reports may be reliable. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of intentional versus incidental learning on explicit and implicit tests of memory.

In Experiment 1, subjects monitored and responded to the termination of words displayed for 1, 3, or 6.5 sec. Anticipation of an unspecified memory test facilitated subsequent recognition memory, but not priming of word-fragment completion. In Experiment 2, subjects repeated the words aloud for the duration of each word's exposure. Recognition memory was facilitated by anticipation of either a recognition memory test or a fragment-completion test on the studied words, as well as by lengthened rehearsal duration. Priming of fragment-completion was facilitated only by anticipation of a fragment-completion test on the studied words. The results indicate that subjects can adopt encoding strategies which enhance performance on implicit memory tests. A transfer-appropriate processing account applies most parsimoniously to the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human sequence learning under incidental and intentional conditions.

This research explored the role that dissociable associative learning and hypothesis-testing processes may play in human sequence learning. Two 2-choice serial reaction time (SRT) tasks were conducted, 1 under incidental conditions and the other under intentional conditions. In both cases an experimental group was trained on 4 subsequences (i.e., XXX, XYY, YYX, and YXY). To control for sequential effects, sequence learning was assayed by comparing their performance to a control group that had been trained on a pseudorandom ordering, during a test phase in which both groups experienced effectively the same trial order. Under incidental conditions participants demonstrated learning of the subsequences that ended in an alternation, but not of those that ended in a repetition. In contrast, under intentional conditions XXX showed the greatest evidence of learning. This dissociation is explained using a 2-process model of learning, with an associative process (the augmented simple recurrent network [SRN]) capturing the incidental pattern, and a rule-based process explaining the advantage for XXX under intentional conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Knowing what to remember and forget: a developmental study of cue memory in intentional forgetting

These experiments are the first to investigate children's encoding and use of information about a memory cue in Bjork's (1972) intentional forgetting task. In Experiment 1, children in Grades 2, 4, and 6 and college students were given cues to either remember or forget after the presentation of each picture. Recall and recognition tests of pictures and cues followed. The procedure in Experiment 2 was identical to that in Experiment 1 except that the list of presentation pictures was altered for some children (Grades 3 and 4) and adolescents (Grades 8 and 9) so that remember and forget cues were associated with particular taxonomic categories. In Experiment 3, the testing component was modified so that children (Grades 2, 3, and 4) and college students were asked to recall only the cue associated with each picture. The results indicated that (1) children as young as second graders encode the cue associated with each picture, although to a lesser extent than do college students, (2) much improvement in intentional forgetting is still occurring during adolescence, (3) only adults adequately cluster their recall by cue, (4) associating remember and forget cues with items from different categories does not increase the differentiation between cues, and (5) eliminating picture recall and recognition has minimal effects on the magnitude of cue judgments. These results suggest that children's difficulties on intentional forgetting tasks stem, at least in part, from their poorer encoding of information about whether an item should be remembered or forgotten.     

Generation and precision of elaboration: Effects on intentional and incidental learning.

Across three experiments adults were presented either base sentences containing arbitrary relations (e.g., The fat man read the sign) or base sentences accompanied by a precise elaboration that made clear the significance of the particular type of man doing the action (e.g., The fat man read the sign warning about thin ice). Subjects either read the sentence alone or answered a question accompanying the sentence. Why did that particular man do that? accompanied base sentences; How does the last part of the sentence make clear why that particular man did that? accompanied precisely elaborated sentences. Both intentional and incidental learning were studied. The positive effects of providing precise elaborations were moderate in size and confined to incidental learning. Much larger incidental and intentional learning gains followed generation of elaborations in response to questions, with generated precise elaborations facilitating acquisition slightly better than generated imprecise elaborations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Young children's incidental and intentional retention of televised events.

Determined whether young children show a visual-superiority effect (i.e., higher retention of visual than auditory information) only when they view cartoons for entertainment. 24 preschoolers' short-term recognition of audio and video information was assessed under conditions of intentional and incidental learning. Off-task glancing was also measured while Ss were actually viewing the show. Contrary to expectations, forewarning Ss that they would be tested on the show's content increased the magnitude of the visual-superiority effect, even though more frequent off-task glancing occurred in conjunction with intentional than with incidental instructions. Findings are discussed in terms of S. Ward and D. B. Wackman's (1973) stage model for processing televised information. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain organization of language after early unilateral lesion: a PET study

Neuropsychological studies suggest that good long-term language outcome is possible following extensive early left-hemisphere damage. We explored the brain organization for language in children with early unilateral lesion, using [15O]-water PET. In 12 patients with left lesion (LL) and 9 patients with right lesion (RL), cerebral blood flow changes during listening to sentences and repetition were studied. A rightward shift of language activations in the LL group was found in perisylvian areas and multiple other, mostly temporo-parietal, regions. The hypothesis of intrahemispheric reorganization in the LL group found only limited support. The number of activated regions was overall greater in the RL group. Unexpected findings included a stronger subcortical and cerebellar language involvement in the RL group. We suggest that (a) early left lesion is associated with enhanced language participation of the right hemisphere in and beyond the classical language areas, and (b) postlesional effects are in part additive (recruitment of noncanonical areas), in part subtractive (functional depression in areas normally involved in language).     

Intentional and incidental memory: Order effects in clinical testing.

Clinicians sometimes worry that the administration of intentional memory tests early in a clinical battery might artificially enhance performance on subsequent incidental memory tests, with possible differential effects for younger vs. older adults. Eighty-one healthy adults (ages 30–80) were blindly assigned to 1 of 2 testing conditions (incidental followed by intentional and vice versa). Contrary to the concerns of some, administration of intentional tests prior to incidental tests did not affect performance on any measures, and there was no interaction with age. Order of administration did not affect performance in older or younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A role for the hippocampal formation in implicit memory: a 3-D PET study

The apparent preservation of word priming effects in amnesia has been interpreted as supporting the view that implicit memory depends on brain systems that are independent of mesial temporal lobe structures which are in part responsible for explicit memory disorders. Nevertheless, a number of studies have demonstrated word priming deficits in amnesic patients relatively to normal subjects, suggesting that such structures may also be involved in implicit memory. To determine whether one such structure, the hippocampal formation, is a component of the brain system subserving word priming, a 3-D PET study was carried out in 13 normal individuals. Encoding was carried out using the brief multiple presentation technique, a procedure that allows one to effectively circumvent contamination of implicit memory tasks by explicit memory strategies. Results revealed that word priming was indeed associated with an activation of the right hippocampal formation. This finding of an hippocampal involvement in word priming calls into question the notion of absolute dissociability between the brain systems underlying performance on various explicit and implicit memory tasks.     

Learner expectations induced by adjunct questions and the retrieval of intentional and incidental information.

150 undergraduates studied a passage with questions interspersed at different locations. 30 different randomized sets of adjunct questions were yoked to Ss across treatments. Answers were written when the reading of a paragraph was completed. Intentional performance in the prequestions treatment was lower than in the postquestions or combined pre/postquestions treatments but higher than performance in the no-question treatment. Incidental performance was lowest in the prequestions treatment and equal in the remaining treatments. Total level of acquisition was highest in those treatments involving the use of postquestions and no questions. The results are attributed to the influence of adjunct questions on learner expectations that affect the selective processing of information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic versus intentional uses of memory: Aging, attention, and control.

In 2 experiments, the authors used a process dissociation procedure by L. L. Jacoby (see record 1992-07943-001) to separately examine the effects of aging on automatic and consciously controlled memory processes. In Exp 1, a group of young adults in either a full-attention or divided-attention condition were compared with a group of elderly adults on a fame judgment task. Both age and divided attention had a detrimental effect on consciously controlled memory processing but left automatic processing intact. In Exp 2, the same age-related pattern was found using a more demanding forced-choice recognition paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental changes in incidental memory as a function of meaningfulness and encoding condition.

Examined incidental memory for words in 30 2nd and 60 6th graders under acoustic- and semantic-processing conditions. When the same list of words (known from normative data to increase in meaningfulness with age) was presented to Ss of both grades, an age-related increase in recall was observed in the semantic but not in the acoustic condition. When meaningfulness of the lists was equivalent across grades, no developmental increase in recall was observed for either encoding condition. Findings were predicted by an associative-processing account of incidental memory previously advanced by the author (see record 1981-31937-001) and indicate that both knowledge base development and processing activity determine children's incidental memory for words. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The temporal dynamics of reading: a PET study

The temporal dynamics of evoked brain responses are normally characterized using electrophysiological techniques but the positron emission tomography study presented here revealed a temporal aspect of reading by correlating the duration a word remained in the visual field with evoked haemodynamic response. Three distinct types of effects were observed: in visual processing areas, there were linear increases in activity with duration suggesting that visual processing endures throughout the time the stimulus remains in the visual field. In right hemisphere areas, there were monotonic decreases in activity with increased duration which we relate to decreased attention for longer stimulus durations. In left hemisphere word processing areas there were inverted U-shaped dependencies between activity and word duration indicating that, after 400-600 ms, activity in word processing areas is progressively reduced if the word remains in the visual field. We conclude that these inverted U effects in left hemisphere language areas reflect the temporal dynamics of visual word processing and we highlight the implication of these effects for the design of activation studies involving reading.     

Receptive and expressive language activations for sentences: a PET study

Most language mapping studies have focussed on activations for single-word tasks. We examined activations for verbal auditory and generation tasks using sentence stimuli. [15O]-water PET was performed in 4 female and 5 male normal adults. Listening to sentences (minus rest) activated the superior and middle temporal gyri bilaterally, but mean activation was significantly stronger on the left. The strongest activation for sentence generation (minus repetition) was seen in the left middle and inferior frontal gyri (area 46). This focus appears to be anterior to activations reported for single-word generation, possibly due to greater verbal working memory demands of the sentential task. Additional activation of the left inferior temporal lobe can be attributed to lexicosemantic processing.     

Corticobasal degeneration: a combined clinical, PET and pathological study

OBJECTIVE: The purpose of this study was to evaluate the application of helical CT-generated three-dimensional images of the upper airway. MATERIALS AND METHODS: Thirty patients, 10 healthy and 20 with upper-airway disease, were studied with helical CT (5-mm collimation). Overlapping images at 2-mm intervals were retrospectively generated. In the group of healthy patients, two radiologists in independently compared overlapping with nonoverlapping images, ranked confidence in identifying small airway structures on a scale of 1-5, and tabulated the number of images demonstrating these structures. In the 20 patients with disease, three-dimensional (3D) surface models were rendered on an independent workstation and were reviewed by two radiologists and one otolaryngologist for image quality, appreciation of lesion morphology, and ability to judge lesion extent, using a similar scale. A phantom was used to optimize parameters for the 3D reconstructions. RESULTS: Viewing of the retrospectively generated overlapping images increased by 122% the number of images in which laryngeal and hypopharyngeal structures could be identified (p < .01). Image confidence scores for the radiologists averaged 3.3 for nonoverlapping and 4.0 for overlapping (p < .05). Radiologists and otolaryngologist rated the quality of the 3D images equally. The otolaryngologist's assessment of the value of the models for understanding the lesion morphology was 3.5 compared with the radiologists assessment of 2.5; and for judging the lesion extent, the otolaryngologist's assessment was 3.8 compared with 2.7 for the radiologist, a statistical significance of p < .01. CONCLUSION: Helical CT with the application of overlapping images and 3D reconstructions significantly assists the understanding of upper-airway disease.     

Nucleolar organizer regions in lymphomas: a quantitative study

Using a silver staining technique, nucleolar organizer region-associated proteins (Ag-NORs) have been studied in paraffin sections of 76 non-Hodgkin's lymphomas, five normal lymph nodes, and five lymph nodes. The mean number of nucleolar organizer regions per nucleus was 1.19 (SD:0.09) for normal lymphocytes, 3.04 (SD:0.14) for reactive lymph nodes, 2.79 (SD:0.44) for low-grade lymphomas, 6.33 (SD:1.58) for intermediate-grade lymphomas, and 10.53 (SD:1.97) for high-grade lymphomas. There were highly significant differences in Ag-NOR counts among the groups (p < 0.001). The Ag-NOR regions were often observed in nuclei in areas where nucleoli themselves were invisible. It is suggested that this method is useful in diagnostic histopathology and in differentiation of the grade of lymphomas.     

Task-related activations in heterotopic brain malformations: a PET study

Positron emission tomography (PET) studies have shown normal or elevated levels of glucose metabolism in neuronal heterotopia, raising the issue of potential participation of heterotopic neurons in cognitive processing. We studied three patients with heterotopic malformations, using [(15)O]water PET and experimental conditions selected according to the location of the malformations. Task performance was associated with blood flow increases of > 17% within the heterotopia in each patient. In two, these occurred in left frontal heterotopia during sentence generation. In the third patient, activations for facial and visuospatial discrimination and picture naming were found in a right posterior heterotopion. Our findings may reflect participation of heterotopia in cognitive function and suggest that heterotopic neurons synapse with neurons in other brain regions.     

Visual form discrimination from texture cues: a PET study

With the purpose of localising the cerebral cortical areas participating in the discrimination of visual form generated exclusively by texture cues, we measured changes in regional cerebral blood flow (rCBF) with positron emissions tomography (PET) and 15O-butanol as the tracer. The subjects performed two odd-one-out discrimination tasks: a form-from-texture discrimination task (in which a visual form was defined by differences in texture) and its reference task, the discrimination of texture. During task performance, activated fields were present bilaterally in the primary visual cortex and its immediate extrastriate cortex, the right lateral occipital gyrus, bilaterally in the fusiform and superior temporal gyri and posterior parts of the superior parietal lobules, along the medial bank of the right intraparietal sulcus, and in the right supramarginal gyrus. Other fields were found in the cingulate and prefrontal cortex. The findings demonstrate that the discrimination of visual form as defined by texture engages cortical fields that are widely distributed ion the human brain. In the visual cortex, the activated fields are present in both the occipito-temporal and occipito-parietal visual areas. These results suggest that the perception and discrimination of forms in the visual system requires the joint-activation of neuronal populations in the visual cortex.     

Short-term and long-term verbal memory: a positron emission tomography study

Short-term and long-term retention of experimentally presented words were compared in a sample of 33 healthy normal volunteers by the [15O]H2O method with positron emission tomography (PET). The design included three conditions. For the long-term condition, subjects thoroughly studied 18 words 1 week before the PET study. For the short-term condition, subjects were shown another set of 18 words 60 sec before imaging, with instructions to remember them. For the baseline condition, subtracted from the two memory conditions, subjects read a third set of words that they had not previously seen in the experiment. Similar regions were activated in both short-term and long-term conditions: large right frontal areas, biparietal areas, and the left cerebellum. In addition, the short-term condition also activated a relatively large region in the left prefrontal region. These complex distributed circuits appear to represent the neural substrates for aspects of memory such as encoding, retrieval, and storage. They indicate that circuitry involved in episodic memory has much larger cortical and cerebellar components than has been emphasized in earlier lesion studies.     

Variability of DA/DAPI and C heterochromatic regions: a population study

DA/DAPI and C chromosomal heteromorphic sites (1q, 9q, 15p, 16q, Yq) in a sample of 136 unrelated individuals from the Garfagnana valley (Tuscany, Italy) have been analyzed quantitatively and qualitatively. The variations in length, between-homolog heteromorphisms, and intensity of fluorescence of the heterochromatic bands have been compared in two subsamples of the population (upper and middle valley) individualized according to geodemographic criteria. DA/DAPI heterochromatin differed significantly from C heterochromatin, showing a lower average amount and a higher variability at each site. This suggests a differential staining of DNA of the two banding systems. Furthermore, DA/DAPI heterochromatin was less uniformly distributed in the population than C heterochromatin and the regions 16q and Yq discriminated better between subsamples. The variations of DA/DAPI fluorescence at the 15p site demonstrated an excess of homomorphic individuals in the upper valley, which could be related to the mating structure of the population living in this area.