► People with TLE show faster forgetting over 3-week but not 30-min delays. ► People with IGE show similar rates of forgetting to healthy controls.
Temporal lobe epilepsy (TLE) has been associated ...with the phenomenon of accelerated long-term forgetting (ALF), in which memories are retained normally over short delays but are then lost at an accelerated rate over days or weeks. The causes of ALF, and whether it represents a consolidation deficit distinct from the one associated with forgetting over short delays, remain unclear. In addition, methodological issues have made results of some previous studies difficult to interpret. This study used improved methodology to investigate the role of seizure activity in ALF. Forgetting was assessed in participants with TLE (who have involvement of temporal lobe structures) and idiopathic generalised epilepsy (IGE; in which seizures occur in the absence of identified structural pathology in the temporal lobes). Learning of novel stimuli was matched between patients with TLE, patients with IGE and healthy controls matched for age and IQ. Results indicated that the TLE group showed accelerated forgetting between 30-min and three-weeks, but not between 40-s and 30-min. In contrast, rates of forgetting did not differ between patients with IGE and controls. We conclude that (1) ALF can be demonstrated in TLE in the absence of methodological confounds; (2) ALF is unlikely to be related to the experience of epilepsy that does not involve the temporal lobes; (3) neither seizures during the three-week delay nor polytherapy was associated with ALF.
The medial temporal lobe plays a critical role in recognition memory but, within the medial temporal lobe, the precise neural structures underlying recognition memory remain equivocal. In this study, ...visual paired comparison (VPC) was used to investigate recognition memory in a human patient (YR), who had a discrete lesion of the hippocampus, and a group of monkeys with neonatal hippocampal lesions, which included the dentate gyrus, and a portion of parahippocampal region. Participants were required to view a picture of an object on a coloured background. Immediately afterwards, this familiar object was shown again, this time paired with a novel object. All participants displayed a novelty preference, provided the background on which the objects were shown was the same as the one used during the learning phase. When the background of the familiar object was changed between initial familiarization and test, only the control subjects showed a novelty preference; the hippocampal-lesioned monkeys and patient YR showed null preference. The results are interpreted within Eichenbaum and Bunsey's Eichenbaum, H., & Bunsey, M. (1995). On the binding of associations in memory: Clues from studies on the role of the hippocampal region in paired-associate learning.
Current Directions in Psychological Science,
4, 19–23 proposal that the hippocampus facilitates the formation of a flexible representation of the elements that make up a stimulus whereas the parahippocampal region is involved in the formation of a fused representation.
When is now? Perception of simultaneity Stone, J. V.; Hunkin, N. M.; Porrill, J. ...
Proceedings of the Royal Society. B, Biological sciences,
01/2001, Letnik:
268, Številka:
1462
Journal Article
Recenzirano
Odprti dostop
We address the following question: Is there a difference (D) between the amount of time for auditory and visual stimuli to be perceived? On each of 1000 trials, observers were presented with a ...light-sound pair, separated by a stimulus onset asynchrony (SOA) between-250 ms (sound first) and 250 ms. Observers indicated if the light-sound pair came on simultaneously by pressing one of two (yes or no) keys. The SOA most likely to yield affirmative responses was defined as the point of subjective simultaneity (PSS). PSS values were between-21 ms (i.e. sound 21ms before light) and 150 ms. Evidence is presented that each PSS is observer specific. In a second experiment, each observer was tested using two observerstimulus distances. The resultant PSS values are highly correlated (r = 0.954, p = 0.003) suggesting that each observer's PSS is stable. PSS values were significantly affected by observer-stimulus distance, suggesting that observers do not take account of changes in distance on the resultant difference in arrival times of light and sound. The difference RTd in simple reaction time to single visual and auditory stimuli was also estimated; no evidence that RTd is observer specific or stable was found. The implications of these findings for the perception of multisensory stimuli are discussed.
In this study, we have examined visual recognition memory in a patient, YR, with discrete hippocampal damage who has shown normal or nearly normal item recognition over a large number of tests. We ...directly compared her performance as measured using a visual paired comparison task (VPC) with her performance on delayed matching to sample (DMS) tasks. We also investigated the effect of retention interval between familiarisation and test. YR shows good visual recognition with the DMS task up to 10
s after the familiarisation period, but only shows recognition with the VPC task for the shortest retention interval (0
s). Our results are consistent with the view that hippocampal damage disrupts recollection and recall, but not item familiarity memory.
Two groups of patients with global amnesia resulting either from Korsakoff’s syndrome (KS) or from medial temporal lobe (MTL) damage were compared with groups of matched healthy control subjects on a ...list discrimination paradigm. Item recognition memory was matched across the amnesic and control groups in order to determine whether KS, but not MTL amnesics are disproportionately impaired on list discrimination as predicted by Parkin’s Functional significance of etiological factors in human amnesia. In: Squire LR, Butters N, editors. Neuropsychology of memory, 2nd ed. New York: The Guilford Press, 1992 hypothesis. However, both patient groups were impaired disproportionately on the temporal order memory task, which is inconsistent with Parkin’s hypothesis. It remains possible that the KS patients are more disproportionately impaired than those with MTL damage because both patient groups performed at floor on the list discrimination task. The results are consistent with theories that postulate a critical role for the hippocampus in the kind of associative memory which underlies memory for temporal order, but not in recognition of single items or arbitrary associations between items of similar kinds.
The effectiveness of errorless and errorful learning methods was compared in two experiments in which a group of memory-impaired individuals learned lists of single words. In both experiments, error ...prevention during learning resulted in higher levels of cued recall performance than trial-and-error learning. Experiment 1 showed that the beneficial effects of the errorless learning method extended over a delay of up to 48hr and were also observed in free recall. The hypothesis that the benefits of errorless learning rely upon implicit memory was tested in Experiment 2. No evidence was found to support the hypothesis. Implicit memory was observed following both errorless and errorful learning, but there was no indication that enhanced performance in the errorless condition could be accounted for by implicit memory. There was no correlation between performance on a direct test (cued recall) and performance on an indirect test (fragment completion) for the same materials. Furthermore, the extent of priming was no greater for recalled items than non-recalled items in the cued recall test. It is proposed that the benefits of errorless learning in this paradigm stem from the effects of error prevention on residual explicit memory.
In two experiments involving verbal association learning by people with memory impairments, the effectiveness of errorless learning (EL) was compared with errorful learning (EF). Experiment 1 ...examined the effectiveness of both methods in learning remotely linked word pairs. There was an advantage for items learned by EL at immediate test which was not sustained over a delay of 1 hr. Learning appeared to be stable over this delay in the EF condition. Analysis of responses at delayed cued recall showed more evidence of spontaneous recovery in EF than in EL. Elimination of these items from analysis resulted in a similar pattern of forgetting in both methods. Experiment 2 examined the effectiveness of EL and EF in teaching novel associations, and showed an advantage for EL at immediate and delayed test. Forgetting was apparently observed following EL, but not EF. As in Experiment 1, this discrepancy was attributed to recovered responses at delayed test in EF. Eliminating these responses showed a similar pattern of forgetting in both methods for items correctly recalled at immediate test. The study shows an advantage for EL techniques in learning novel associations. The two methods also differ in that learning via EF is associated with more spontaneous recovery.
One kind of between-list and two kinds of within-list temporal order memory were examined in a patient with selective bilateral hippocampal lesions. This damage disrupted memory for all three kinds ...of temporal order memory, but left item and word pair recognition relatively intact. These findings are inconsistent with claims that (1) hippocampal lesions, like those of the medial temporal lobe (MTL) cortex, disrupt item and word pair recognition, and that (2) hippocampal lesions disrupt temporal order memory and item recognition to the same degree. Not only was word pair recognition intact in the patient, but further evidence indicates that her recognition of other associations between items of the same kind is also spared so retrieval of such associations cannot be sufficient to support within-list temporal order recognition. Rather, as other evidence indicates that the patient is impaired at recognition of associations between different kinds of information, within-list (and possibly between-list) temporal order memory may be impaired by hippocampal lesions because it critically depends on retrieving associations between different kinds of information.
Young and old participants were evaluated on tests of frontal lobe function, recognition memory, and memory for temporal and spatial information. Older participants showed significant impairments on ...memory for temporal order, and this impairment was found to correlate with deficits on frontal lobe tests measuring spontaneous flexibility but not reactive flexibility. However, spatial memory showed no evidence of an age effect. An interpretation of this latter finding based on the differential availability of contextual cues is ruled out because similar results were obtained when spatial memory was assessed in a different context to that used during learning. The researchers concluded that memory for temporal order and spatial memory are affected differentially by age. Theoretical interpretations of this difference are discussed.
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