Mathieu Lesourd

The Sensory Nature of Episodic Memory: Sensory Priming Effects Due to Memory Trace Activation

The aim of this study was to provide evidence that memory and perceptual processing are underpinned by the same mechanisms. Specifically, the authors conducted 3 experiments that emphasized the sensory aspect of memory traces. They examined their predictions with a short-term priming paradigm based on 2 distinct phases: a learning phase consisting of the association between a geometrical shape and a white noise and a priming phase examining the priming effect of the geometrical shape, seen in the learning phase, on the processing of target tones. In the 3 experiments, the authors found that only the prime associated with the sound in the learning phase had an effect on the target processing. The perceptual nature of the auditory component reactivated by the prime was shown in Experiments 1 and 2 via manipulation of the white noise duration in the learning phase and the stimulus onset asynchrony in the priming phase. Moreover, Experiment 3 highlighted the importance of the simultaneous association of sensory components in the learning phase, which makes it possible to integrate these components in a memory trace.

On the neurocognitive origins of human tool use : A critical review of neuroimaging data

Since more than a century, neuropsychological models have assumed that the left inferior parietal cortex is central to tool use by storing manipulation knowledge (the manipulation-based approach). Interestingly, recent neuropsychological evidence indicates that the left inferior parietal cortex might rather support the ability to reason about physical object properties (the reasoning-based approach). Historically, these two approaches have been developed from data obtained in left brain-damaged patients. This review is the first one to (1) give an overview of the two aforementioned approaches and (2) reanalyze functional neuroimaging data of the past decade to examine their predictions. Globally, we demonstrate that the left inferior parietal cortex is involved in the understanding of tool-use actions, providing support for the reasoning-based approach. We also discuss the functional involvement of the different regions of the tool-use brain network (left supramarginal gyrus, left intraparietal sulcus, left posterior temporal cortex). Our findings open promising avenues for future research on the neurocognitive basis of human tool use.

Apraxia and Alzheimer’s Disease: Review and Perspectives

Apraxia is one of the cognitive deficits that characterizes Alzheimer’s disease. Despite its prevalence and relevance to diagnosing Alzheimer’s disease, this topic has received little attention and is without comprehensive review. The review herein is aimed to fill this gap by first presenting an overview of the impairment caused in different clinical situations: pantomime of tool use, single tool use, real tool use, mechanical problem solving, function and manipulation knowledge tasks, and symbolic/meaningless gestures. On the basis of these results, we then propose alternative interpretations regarding the nature of the underlying mechanisms impaired by the disease. Also presented are principal methodological issues precluding firm conclusions from being drawn.

Act-In: An integrated view of memory mechanisms

The present article proposes a new memory model called Act-In (Activation-Integration). Act-In extends the multiple trace memory models by placing them within the situated cognition perspective. Act-In considers that the activation and integration mechanisms play a key role in memory processes. These mechanisms are involved in both the construction of memory traces and the emergence of knowledge. The model is based on four main assumptions: (1) Memory traces reflect all the components of past experiences and, in particular, their sensory properties, actions performed on the objects in the environment and the emotional states of individuals. Memory traces are therefore distributed across multiple neuronal systems which code the multiple components of the experiences. (2) Knowledge is emergent and is the product of the coupling of the present experience with past experiences. (3) The brain is a categorisation system which develops by accumulating experiences and which, by default, produces categorical knowledge. (4) The emergence of specific knowledge (memories or episodic knowledge) requires very simple mechanisms which occur during learning and/or during retrieval. These assumptions are defended and discussed in the light of the work reported in the literature.

Tool use disorders after left brain damage

In this paper we review studies that investigated tool use disorders in left-brain damaged (LBD) patients over the last 30 years. Four tasks are classically used in the field of apraxia: Pantomime of tool use, single tool use, real tool use and mechanical problem solving. Our aim was to address two issues, namely, (1) the role of mechanical knowledge in real tool use and (2) the cognitive mechanisms underlying pantomime of tool use, a task widely employed by clinicians and researchers. To do so, we extracted data from 36 papers and computed the difference between healthy subjects and LBD patients. On the whole, pantomime of tool use is the most difficult task and real tool use is the easiest one. Moreover, associations seem to appear between pantomime of tool use, real tool use and mechanical problem solving. These results suggest that the loss of mechanical knowledge is critical in LBD patients, even if all of those tasks (and particularly pantomime of tool use) might put differential demands on semantic memory and working memory.

Visual memory and visual perception: when memory improves visual search

This study examined the relationship between memory and perception in order to identify the influence of a memory dimension in perceptual processing. Our aim was to determine whether the variation of typical size between items (i.e., the size in real life) affects visual search. In two experiments, the congruency between typical size difference and perceptual size difference was manipulated in a visual search task. We observed that congruency between the typical and perceptual size differences decreased reaction times in the visual search (Exp. 1), and noncongruency between these two differences increased reaction times in the visual search (Exp. 2). We argue that these results highlight that memory and perception share some resources and reveal the intervention of typical size difference on the computation of the perceptual size difference.

The sensory nature of knowledge: Sensory priming effects in semantic categorization

The aim of the present study was to show the perceptual nature of conceptual knowledge by using a priming paradigm that excluded an interpretation exclusively in terms of amodal representation. This paradigm was divided into two phases. The first phase consisted in learning a systematic association between a geometrical shape and a white noise. The second phase consisted of a short-term priming paradigm in which a primed shape (either associated or not with a sound in the first phase) preceded a picture of an object, which the participants had to categorize as representing a large or a small object. The objects were chosen in such a way that their principal function either was associated with the production of noise (“noisy” target) or was not typically associated the production of noise (“silent” target). The stimulus onset asynchrony (SOA) between the prime and the target was 100 ms or 500 ms. The results revealed an interference effect with a 100-ms SOA and a facilitatory effect with a 500-ms SOA for the noisy targets only. We interpreted the interference effect obtained at the 100-ms SOA as the result of an overlap between the components reactivated by the sound prime and those activated by the processing of the noisy target. At an SOA of 500 ms, there was no temporal overlap. The observed facilitatory effect was explained by the preactivation of auditory areas by the sound prime, thus facilitating the categorization of the noisy targets only.

Mechanical problem-solving strategies in Alzheimer's disease and semantic dementia.

OBJECTIVE The goal of this study was to explore whether the tool-use disorders observed in Alzheimers disease (AD) and semantic dementia (SD) are of the same nature as those observed in left brain-damaged (LBD) patients. Recent evidence indicates that LBD patients with apraxia of tool use encounter difficulties in solving mechanical problems, characterized by the absence of specific strategies. This pattern may show the presence of impaired mechanical knowledge, critical for both familiar and novel tool use. So, we explored the strategies followed by AD and SD patients in mechanical problem-solving tasks in order to determine whether mechanical knowledge is also impaired in these patients. METHOD We used a mechanical problem-solving task in both choice (i.e., several tools were proposed) and no-choice (i.e., only 1 tool was proposed) conditions. We analyzed quantitative data and strategy profiles. RESULTS AD patients but not SD patients met difficulties in solving mechanical problem-solving tasks. However, the key finding is that AD patients, despite their difficulties, showed strategy profiles that are similar to that of SD patients or controls. Moreover, AD patients exhibited a strategy profile distinct from the one previously observed in LBD patients. CONCLUSIONS Those observations lead us to consider that difficulties met by AD patients to solve mechanical problems or even to use familiar tools may not be caused by mechanical knowledge impairment per se. In broad terms, what we call apraxia of tool use in AD is certainly not the same as apraxia of tool use observed in LBD patients. (PsycINFO Database Record

Involvement of the Left Supramarginal Gyrus in Manipulation Judgment Tasks: Contributions to Theories of Tool Use

OBJECTIVES Two theories of tool use, namely the gesture engram and the technical reasoning theories, make distinct predictions about the involvement of the left inferior parietal lobe (IPL) in manipulation judgement tasks. The objective here is to test these alternative predictions based on previous studies on manipulation judgment tasks using transcranial magnetic stimulations (TMS) targeting the left supramarginal gyrus (SMG). METHODS We review recent TMS studies on manipulation judgement tasks and confront these data with predictions made by both tool use theories. RESULTS The left SMG is a highly intertwined region, organized following several functionally distinct areas and TMS may have disrupted a cortical network involved in the ability to use tools rather than only one functional area supporting manipulation knowledge. Moreover, manipulation judgement tasks may be impaired following virtual lesions outside the IPL. CONCLUSIONS These data are more in line with the technical reasoning hypothesis, which assumes that the left IPL does not store manipulation knowledge per se. (JINS, 2017, 23, 685-691).

A cognitive-based model of tool use in normal aging

ABSTRACT While several cognitive domains have been widely investigated in the field of aging, the age-related effects on tool use are still an open issue and hardly any studies on tool use and aging is available. A significant body of literature has indicated that tool use skills might be supported by at least two different types of knowledge, namely, mechanical knowledge and semantic knowledge. However, neither the contribution of these kinds of knowledge to familiar tool use, nor the effects of aging on mechanical and semantic knowledge have been explored in normal aging. The aim of the present study was to fill this gap. To do so, 98 healthy elderly adults were presented with three tasks: a classical, familiar tool use task, a novel tool use task assessing mechanical knowledge, and a picture matching task assessing semantic knowledge. The results showed that aging has a negative impact on tool use tasks and on knowledge supporting tool use skills. We also found that aging did not impact mechanical and semantic knowledge in the same way, confirming the distinct nature of those forms of knowledge. Finally, our results stressed that mechanical and semantic knowledge are both involved in the ability to use familiar tools.