Assessing visual memory disorders.

The Biber Figure Learning Test (BFLT) was administered to 19 patients with right- and 20 with left-hemisphere cerebrovascular accidents, 11 severe amnesics and 42 controls. Results indicate that the BFLT reliably assesses impairments in long-term visual memory independent of primary visuoperceptual, visuoconstructional, and language deficits. Healthy controls showed no effects of education and minimal age effects on the BFLT. Normal learning curves were found for cortical lesions patients, but their overall scores were below those of normals. Amnesics with subcortical-limbic pathology showed grossly impaired acquisition, retention, and recognition memory, but normal short-term visual memory and primary visuoperceptual/visuoconstructional abilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cued recall and discrimination of memory deficit.

Reports the elimination of some ambiguities in the scoring procedure for the Logical Memory (LM) subtest of the Wechsler Memory Scale using a cued recall technique for eliciting responses. A cued recall technique discriminated significantly better than the LM subtest between memory-impaired and control groups. All Ss were 50–64 yr old males. This appears to have been due to the fact that on LM, controls showed worse performance on the final sections of the memory passages, whereas this did not occur in cued recall. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Change in visual memory following discrimination learning.

Studied visual recognition memory for the size of circles for evidence of active memory change in 3 experiments with 34 paid volunteers and 83 undergraduates. In Exp. I the remembered difference in size between 2 circles which had been discriminated on the basis of size increased, while the remembered difference in size between the same 2 circles discriminated on the basis of brightness did not. In Exp. II, the remembered size of the smallest of 4 circles discriminated by size changed from 1 day to 1 wk. Each S in Exp. III inspected either 1 or 2 circles and was asked to remember their size. There was more memory distortion when 2 circles were remembered, but the distortion did not change over time. The evidence suggests that memory will actively change after a visual discrimination task. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval dynamics of priming in recognition memory: Bias and discrimination analysis.

We investigated semantic priming effects on item recognition from short (8-word) lists in one reaction-time (RT) and three interruption speed–accuracy trade-off (SAT) experiments. SAT priming conditions included modest (0.35-s) prime durations; prime as a final list member; and long (1.5-s) prime durations with special instructions. Analyses tested for constant increment (bias) priming (an equivalent increase in both hits and false alarms) and enhanced discrimination priming (differential priming for targets and lures). Constant increment (bias) priming was ubiquitous, but some subjects showed enhanced early discrimination in restricted conditions. In constant increment (bias) priming, the semantic relations between prime and test either additively increase familiarity or lower criterion. Only enhanced discrimination must imply an interaction between the prime and the retrieval process, due to either interaction or use of compound cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in visual recall memory following discrimination learning.

Trained 100 undergraduates to discriminate among 4 visual stimuli on either 1 of the 2 dimensions which differentiated them: area (large or small circles) or dot density (thickly or lightly filled with dots). Recall was tested immediately or after delay of 4 hrs, 1 day, 1 wk, or 2 wks by having each S draw all 4 stimuli at 1 of these intervals. Differences in recall along the dimension which was discriminated were exaggerated relative to differences on the other dimension. The relative exaggeration was large immediately following testing, declined to a minimum after 1 wk, and increased again after 2 wks. Results are consistent with previously reported changes in visual recognition memory, and suggest a 2-process interpretation. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing recognition memory for surface forms in discourse: A methodological note.

Two different experimental procedures have been advocated for testing recognition memory for surface forms in discourse. One involves using a reversed-text control group that reverses the roles of recognition targets and distractors. Experiments using this procedure have led some researchers to conclude that surface memory is a fairly robust phenomenon. The alternative procedure, which makes use of a no-text (or guessing) control group, has produced inconsistent results, leading other researchers to question the status of surface memory. The goals of this inquiry are to (1) explore the strengths and weaknesses of each approach, (2) assess alternative explanations for the inconsistency between them, and (3) evaluate the available evidence for better-than-chance recognition of surface forms in discourse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing the roles of change discrimination and luminance integration: Evidence for a hybrid race model of perceptual decision making in luminance discrimination.

Many models of perceptual processing assume that participants integrate stimulus evidence over time, for example, random walk models. This class of models is tested in a luminance discrimination paradigm in which the onsets of the stimuli are either instantaneous (stepped) or slowly ramped. The ramped portion of ramped stimuli occurs prior to the stepped stimuli onsets. Consequently, there is more luminance energy in ramped stimuli. Therefore, if participants integrate luminance energy, they should perform better to ramped stimuli. This did not occur in 4 experiments. Participants performed better to stepped stimuli than ramped stimuli in earlier foreperiods and the reverse in later foreperiods. A new model is proposed in which participants monitor both integrated luminance energy and quick temporal changes in luminance, but they do so in a serial fashion. First, participants monitor temporal changes in luminance; later, they monitor integrated luminance energy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Narrative comprehension in Alzheimer's disease: Assessing inferences and memory operations with a think-aloud procedure.

Objective: To further understanding of text comprehension abilities in Alzheimer's disease (AD), a think-aloud protocol was used to examine the role of inferencing and the memory operations used to produce inferences. Method: Twenty participants with AD and 20 cognitively healthy older adults (OA) read narratives, pausing to talk aloud after each sentence. A verbal protocol analysis developed by Trabasso and Magliano (1996a) was used to code participants' utterances into inferential and noninferential clause types; inferential statements were then coded to identify the memory operation used in their generation. Results: Compared with OA controls, the AD participants showed poorer story comprehension, d = 2.0, produced fewer inferences, d = .67, and were less skilled at providing explanations of story events, d = 1.27, and in using prior text information to explain outcomes, d = .90. The AD group also appeared to rely more on the activation of world knowledge, d = .58, which contributed to less effective inferences and produced more incoherent noninferential statements, d = 1.05. Poorer text comprehension for the AD group was associated with poorer verbal memory abilities, r's > .55, and poorer use of prior text events when producing explanatory inferences, r = .42. Conclusions: The findings suggest that the memory difficulties of the AD group appear to be an important cognitive factor interfering with their ability to integrate story events through the use of inferences and to create a global coherence to support text comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing remote memory with an improved public events questionnaire.

In the present research, public events recall and recognition tests were developed that appear to be psychometrically stronger than those used in the past. Following test construction, these tests were administered to older and middle-aged participants in order to examine the effects of chronological age and historical time period on memory for remote news events. Results indicated that middle-aged participants generally exhibited a better memory for news events than did older participants for the time periods that both age groups lived through. Across the life span, a common pattern was observed. Specifically, there was an increase in memory for events until the teenage years and fairly constant performance thereafter for both age groups. From these findings, we can clearly argue against a loss theory of remote memory. Some gender differences were observed on the recall and recognition tasks, but they were not as global or as frequent as Botwinick and Storandt (1980) suggested. The clinical potential of the remote memory tests is briefly considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Involvement of entorhinal cortex or parietal cortex in long-term spatial discrimination memory in rats: Retrograde amnesia.

Twenty-four rats assigned to 1 of 3 matched groups (control, entorhinal cortex [EC], and parietal cortex [PC]) were trained on 6 successive discrimination problems (2 in an 8-arm for pretraining and 4 in a 12-arm radial maze for training per se). The training on the 12-arm maze started 6, 4, 2 and 0.5 weeks before surgery. On the day after the rats learned the last problem, they were given surgery according to groups. Postoperative retention was measured by presenting 16 trials per session for each of the problems during 4 sessions. Results indicate that the EC lesions produced a retention deficit for problems learned immediately and up to 4 weeks before surgery, but not for the problem acquired 6 weeks before the lesions. The PC lesions produced a significant retrograde amnesia that was not temporally graded. Results demonstrate that the EC and PC make important, albeit distinct, contributions to spatial memory storage and retrieval in rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Central cholinergic involvement in working memory: Effects of scopolamine on continuous nonmatching and discrimination performance in the rat.

In 4 experiments, male Sprague-Dawley rats (N?=?37) were trained to stable baselines of leverpressing on a variable intertrial interval continuous nonmatching-to-sample schedule (CNM) or on an analogous discrimination schedule. Scopolamine HBr (0.125, 0.25, and 0.50 mg/kg) reduced the accuracy of CNM performance to a similar extent over the 3 intertrial (retention) intervals: 2.5, 5, and 10 sec, indicating that the drug did not affect the time-dependent process of retention in working memory. When baseline levels of performance accuracy were similar in the CNM and discrimination tasks (but stimulus discriminability was greater in the CNM task), scopolamine reduced accuracy equally in the 2 procedures. The effects of scopolamine on the accuracy of noncorrection trial CNM performance were simulated by reducing stimulus discriminability; however, scopolamine disrupted CNM correction trial performance much more than did reductions in stimulus discriminability. It is concluded that scopolamine's effects on working memory are not limited to the possible effects on stimulus discrimination—scopolamine may also affect the retrieval of response rules from reference memory. (52 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial frequency discrimination: visual long-term memory or criterion setting?

A long-term sensory memory is believed to account for spatial frequency discrimination when reference and test stimuli are separated by long intervals. We test an alternative proposal: that discrimination is determined by the range of test stimuli, through their entrainment of criterion-setting processes. Experiments 1 and 2 show that the 50% point of the psychometric function is largely determined by the midpoint of the stimulus range, not by the reference stimulus. Experiment 3 shows that discrimination of spatial frequencies is similarly affected by orthogonal contextual stimuli and parallel contextual stimuli and that these effects can be explained by criterion-setting processes. These findings support the hypothesis that discrimination over long intervals is explained by the operation of criterion-setting processes rather than by long-term sensory retention of a neural representation of the stimulus.     

Spatial working memory and reference memory of Brown Norway and WAG rats in a holeboard discrimination task

PURPOSE: To investigate the effects of bradykinin (BK) on the outflow facility (C) of human and bovine perfused anterior segments, the [Ca2+]i of cultured bovine trabecular meshwork (BTM) cells, and the area and major axis of BTM cells. METHODS: Cellular studies were performed using first- through third-passage cultures of BTM cells. For [Ca2+]i and shape change assessment, BTM cells were loaded with fura-2 acetoxymethyl ester, and individual fluorescence images were analyzed after the different experimental manipulations. C studies were performed in vitro using human and bovine anterior segments perfused at constant pressure. RESULTS: Bradykinin at 10(-6) M elicited a [Ca2+]i increase of 8 to 10 times the basal levels in 90% of the studied cells. From the responder cells, 60% elicited a 15%+/-1% reduction of the initial cell area, and 37% showed a 13%+/-2% reduction of their major axis. Bradykinin failed to induce any effect in the presence of the BK-B2 receptor antagonist HOE-140. Zero [Ca2+]o the depletion of intracellular stores with thapsigargin, or the presence of the calmodulin antagonist W13, decreased the BK response significantly (P < 0.001; P < 0.001; and P < 0.05). A second application of BK elicited a significantly lower (P < 0.001) response than the previous one. Perfusion with 10(-6) M BK decreased CD, calculated as the area under the curve, by 13%+/-4% (P < 0.05) in human anterior segments and 12%+/-4% (P < 0.05) in bovine anterior segments. The presence of 10(-6) M HOE-140, a BK-B2 receptor antagonist, completely blocked the decrease in C after perfusion with BK. CONCLUSIONS: The C of human and bovine trabecular meshwork (perfused anterior segments) is decreased by BK, acting through BK-B2 receptors. Primary cultured BTM cells respond to BK stimulation by increasing their [Ca2+]i by mobilization of extracellular and intracellular Ca2+. Moreover, these cells are reduced in area and their major axis shortened after the [Ca2+]i peak elicited by BK through BK-B2 receptors. The [Ca2+]i mobilization and shape changes are calmodulin dependent. Taking into account the [Ca2+]i mobilization, the BTM shape changes, the decrease of C, and the temporal sequence of these parameters, a contraction of trabecular meshwork cells related to the functional role of trabecular meshwork is discussed.     

Decision making and memory: A critique of Juslin and Olsson's (1997) sampling model of sensory discrimination.

P. Juslin and H. Olsson's (see record 1997-03612-006) distinction between Thurstonian and Brunswikian uncertainty is examined and their sampling model of sensory discrimination analyzed as a representative of the class of memoryless decision processes. The separate characteristics and combined behavior of 4 main components of the model are explored: (a) the basic decision process, (b) the assumption of deadline responding, (c) the moving window model of memory, and (d) the hypothesized basis for confidence. It is argued that grafting a moving window memory onto a memoryless decision process has several undesirable consequences. Moreover, the suggested basis for confidence leads to predictions that are counterintuitive and unsupported by empirical evidence. It is concluded that the window-sampling model is a maladapted combination of inappropriate elements, which is implausible as a model of decision making, memory, or confidence, in sensory discrimination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel memory retrieval in dual-task situations: II. Episodic memory.

Three experiments asked whether subjects could retrieve information from a 2nd stimulus while they retrieved information from a 1st stimulus. Ss performed recognition judgments on each of 2 words that followed each other by 0, 250, and 1,000 msec (Experiment 1) or 0 and 300 msec (Experiments 2 and 3). In each experiment, reaction time to both stimuli was faster when the 2 stimuli were both targets (on the study list) or both lures (not on the study list) than when 1 was a target and the other was a lure. Each experiment found priming from the 2nd stimulus to the lst when both stimuli were targets. Reaction time to the 1st stimulus was faster when the 2 targets came from the same memory structure at study (columns in Experiment l; pairs in Experiment 2; sentences in Experiment 3) than when they came from different structures. This priming is inconsistent with discrete serial retrieval and consistent with parallel retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel memory retrieval in dual-task situations: I. Semantic memory.

Can participants retrieve information about the 2nd of 2 stimuli while they are processing the 1st? Four experiments suggest they can. Reaction times to the 1st stimulus were faster if it came from the same category as the 2nd than if it came from a different category. This category-match effect was observed for letter-digit discrimination (Experiment 1), magnitude and parity judgments about digits (Experiment 2), and lexical decisions (Experiment 3). Experiment 4 showed that the 2nd stimulus could semantically prime the 1st. The category-match effect was observed only when the same task was performed on the 2 stimuli. When the task changed from the Ist stimulus to the 2nd, there was no advantage of a category match. This dependence on task set may explain previous failures to find parallel retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imprinting: Monocular and binocular cues in object discrimination.

Conducted 2 experiments with a total of 200 Peking ducklings (Anas platyrhyncos) which predicted that under monocular conditions an imprinted preference for a 3-dimensional object should be eliminated or reduced. Results show that binocular viewing was not essential for the establishment of imprinted preferences, contrary to expectations raised by the failure to imprint the Ss to 2-dimensional images. It is suggested that ducklings rely on a hierarchy of cues when making discriminations and that the order within the hierarchy may vary from one situation to the next. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ethnicity and perceived discrimination in Toronto: Another look at the personal/group discrimination discrepancy.

Perceptions of personal and group discrimination in 5 domains (jobs, pay, loans, promotions, and clubs) were investigated via telephone interviews with 902 respondents from different ethnic groups in Toronto. The reported analyses concern 6 ethnic groups, representing "visible," racial minorities (Blacks, Chinese, and South Asians) as well as White minorities (Italians, Jews, and Portuguese). The personal/group discrimination discrepancy (i.e., perceiving greater discrimination toward one's group than oneself personally) was observed to varying extent across all domains and ethnic groups, though with some exceptions. Visible minorities perceived greater discrimination toward their group than did White minorities, especially in the economic domains of jobs, pay, and promotions. Among visible minorities, Black respondents perceived higher levels of group and personal discrimination than most other ethnic groups across domains, followed in turn by Chinese and South Asian respondents. By contrast, White minority group members perceived considerably less group or personal discrimination than members of visible minorities, except for Jewish respondents who reported greater group discrimination in joining clubs than any other ethnic group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is the hippocampus involved in temporal discrimination and the memory of short intervals?

Rats with lesions to the hippocampus proper and the subiculum were tested for timing behavior and temporal memory. Using the peak procedure, they were trained to discriminate a 40 s interval and a retention gap tested the memory for time. Results were interpreted within the theoretical framework of the internal clock and with respect to current theories on hippocampal function. Timing behavior was unaffected by either lesion and no shifts in the temporal discrimination functions were observed. The lesions also failed to show a deficit in the memory for temporal events. For all groups, the retention gap increased the mean peak time by the time of the gap. This indicated that all rats used the stop rule which required the use of working memory. Thus, it was concluded that the hippocampus is neither necessary for accurate timing behavior nor for the memory of temporal events.     

Frequency discrimination of stylized synthetic vowels with a single formant

Just-noticeable differences (jnd's) in the center frequency of bandlimited harmonic complexes were measured for normal-hearing subjects. A triangular and a rounded spectral envelope were used. The center frequency ranged from 500 to 600 Hz in a region representing the first formant of vowels, and from 2000 to 2100 Hz in a second formant region. The slope of the spectral envelope was either 50 or 100 dB/oct for the first formant region and 100 or 200 dB/oct for the second formant region. For the fundamental frequency of the complexes 100 and 200 Hz were used. The jnd's were determined for various phase relations between the individual components of the complexes. For comparison we also determined jnd's for a Gaussian white noise that was filtered with the same spectral envelopes as the harmonic complexes. A three-interval, three-alternative forced-choice task was used. All measurements were performed with roving stimulus level. The jnd's found for center frequencies that were halfway between two harmonics were smaller than those found for center frequencies that coincided with a harmonic. The jnd's for the noise bands were mostly between those of the two aforementioned groups. Except for a small group of stimuli, the phase relations had little effect on the jnd's. The majority of the results for both the harmonic and the noise band stimuli can be described by a model using a spectral profile comparison. Most of the remaining data can be explained in the temporal domain from changes in the temporal envelope of the stimuli.