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Neuropsychological Characteristics of Early Alzheimer Disease
Published in Robert E. Becker, Ezio Giacobini, Alzheimer Disease, 2020
Maura Mitrushina, Paula Altman Fuld
Another research paradigm purport to explore the role of semantic context utilizes semantic priming. Studies exploring the effect of semantic priming on efficiency of information processing suggested that priming with a semantically related context facilitates processing of the stimulus. Nebes and coworkers (Nebes, Martin, & Horn, 1984; Nebes, Brady, & Huff, 1989) used word-naming and lexical-decision tasks to examine effect of semantically-related context on the identification of the stimulus in normal elderly and AD subjects. The word-naming task requires the subject to name visually presented stimulus word, while a lexical-decision task requires the subject to determine whether a given string of letters constitutes an English word (Nebes, Brady & Huff, 1989). As was shown by Seidenberg, Waters, Sanders, & Langer (1984), priming effects in a word-naming task are due to the automatic spread of activation, while those in a lexical-decision task reflect attention-dependent processes, as well. Nebes and coworkers showed that in both studies (1984, 1989) AD patients revealed an equal or substantially larger priming effect (i.e. the difference in response time to a word precipitated by an unrelated vs. a semantically related word) on both tasks, in comparison to the normal controls. However, lexical access time was slower for the group of demented patients. The authors concluded that AD patients benefit from semantic context whether it is mediated by automatic or attention-dependent processes.
Adult Age Differences in Sensitivity to Semantic Satiation
Published in Experimental Aging Research, 2023
Sheila R. Black, Meagan M. Wood, Jaimie Choi, Barbara-Shae Jackson, Teairra Z. Evans
One way to conceptualize semantic satiation is within a spreading activation framework. Specifically, within the semantic activation framework, words and concepts are represented in semantic memory via nodes (Collins & Loftus, 1975; Neely, 1977a, 1977b). When a node is activated, either by the presence of a stimulus or by directed attention, activation spreads via interconnecting links to other nodes, which represent the meaning of associated words. Hence, if the node CAT were activated, activation would spread via interconnecting links from the node which represents CAT to other nodes representing associated concepts, i.e., DOG, KITTEN, FELINE, etc. Because of this preactivation, the word DOG would be recognized faster when it follows a related word such as CAT than when it follows an unrelated word such as CAR. This facilitation for words preceded by a related word is referred to as the semantic priming effect.
Memory Performance of People with Different Dementia Severity for Different Semantic Hierarchies
Published in Experimental Aging Research, 2019
Min-Sheng Chen, Wei-Ru Chen, Hao-Ming Lee
As for the associations in semantic memory, Collins and Loftus (1975) proposed a spreading-activation model to explain the strength of semantic links. They likened memory organization to a complex network of connections, where each node will respond to stimulation from its neighboring nodes, thus activation can spread easily from one node to other nodes. Gollan, Salmon, and Paxton (2006) investigated the effects of associative strength on performance in a word association task. Their results indicated that people with AD performed more poorly for strong word associations compared to healthy elderly persons, but showed similar performance for weak word associations. This result is consistent with the spread-activation theory, specifically that words with strong associations will have greater levels of activation. Chiu (2007) proposed that the strength of the semantic priming effect is based on the association between the primer and the target. Furthermore, the majority of psychologists have regarded the semantic priming effect produced by spread activation as evidence that the representation of semantic knowledge in memory processes exists in a network form.
Effects of a single short exposure to blue light on cognitive performance
Published in Chronobiology International, 2019
Lorenzo Tonetti, Vincenzo Natale
As regards the LDT, the main result was a stronger semantic priming with blue light than no light (large effect size). While the RTs to prime were similar among conditions, participants’ RTs to target (large effect size) were significantly faster under blue light. Semantic memory can be conceived as a network with the concepts as nodes; the nodes of concepts semantically related would be nearer and more strongly linked compared to the nodes of concepts not semantically related (Crestani 1997). The semantic priming would be the consequence of an automatic spreading activation process (e.g., Collins and Loftus 1975), with the activation of a node (prime) that would spread automatically to the more closely semantically related nodes (target), leading to a reduction of RT to the latter (target), being semantically preactivated by the former (prime). On the basis of the observed data, it is thus possible to speculate that even a single short exposure to blue light is able to boost such an automatic spreading activation process. A possible explanation of this result is grounded on the similar cortical activation observed during semantic priming and the exposure to blue light. More specifically, Rossell and colleagues (2003) have disclosed an increase in cortical activity in the left supramarginal gyrus in the temporal-parietal junction for target semantically preactivated by prime. Moreover, the supramarginal gyrus was activated, as were other areas, by exposure to blue light during a task of working memory (Vandewalle et al. 2007).