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Picture naming tests are widely used to evaluate language impairments in neurodegenerative diseases, especially in Primary Progressive Aphasia (PPA). The available tests differ for many factors affecting the performance, e.g. format of stimuli and their psycholinguistic properties. We aim to identify the most appropriate naming test to be used on PPA according to the clinical and research demands. We investigated the behavioural characteristics, i.e. proportion of correct responses and error type, and their neural correlates in two Italian naming tests, CaGi naming (CaGi) and naming subtest of the Screening for Aphasia in NeuroDegeneration battery (SAND), administered to 52 PPA patients who underwent an FDG-PET scan. We analysed the effectiveness of the tests in distinguishing PPA versus controls and among PPA variants, considering the psycholinguistic variables affecting performance. We explored the brain metabolic correlates of behavioural performance in the tests. SAND, differently from CaGi, has time limits for the response and its items are less frequent and acquired later. SAND and CaGi differed in terms of number of correct responses and error profile, suggesting a higher difficulty to name SAND items compared to CaGi. Semantic errors predominated in CaGi, while anomic and semantic errors were equally frequent in SAND. Both tests distinguished PPA from controls, but SAND outperformed CaGi in discriminating among PPA variants. FDG-PET imaging revealed a shared metabolic involvement of temporal areas associated with lexico-semantic processing, encompassing anterior fusiform, temporal pole, and extending to posterior fusiform in sv-PPA. Concluding, a picture naming test with response time limit and items which are less frequent and acquired later in life, as SAND, may be effective at highlighting subtle distinctions between PPA variants, improving the diagnosis. Conversely, a naming test without time limit for the response, as CaGi, may be useful for a better characterization of the nature of the naming impairment at the behavioural level, eliciting more naming errors than anomia, possibly helping in the development of rehabilitation protocols., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Previous brain functional specialization evidence has shown that both aware and unaware visual processing of manipulable objects activate left premotor, parietal, and posterior temporal cortices, which are thought to constitute object-directed action and object-function processing streams. An open question is whether, both under supraliminal and subliminal processing conditions, there is directional spread of activation along these functional streams, leading to causal inter-regional connectivity effects. In this study, we used Dynamic Causal Modelling to estimate the effective connectivity influences within the premotor-parieto-temporal network, as a function of factorial contrasts for Manipulability (manipulable vs non-manipulable objects) and Perceptual Awareness (above vs below perceptual threshold). We modeled forward and backward connections originating from visual area V4, as a region underlying object texture segregation, and spreading through the left premotor-parieto-temporal network. Both above and below perceptual threshold, the visual processing of manipulable objects was associated with a specific increase of reciprocal effective connectivity coupling among left premotor-parieto-temporal regions. Aware and unaware manipulable object processing differed from each other for their distinct patterns of top-down activation enhancement exerted, in the former case, by left premotor-parieto-temporal regions on area V4 and, in the latter case, by left premotor on temporal regions. Although it is only under aware processing conditions that effective connectivity in the action representation system may promote object visual contour segregation in area V4, our results suggest that the encoding of object-action and object-function information can occur through left-hemispheric premotor, parietal, and temporal causal interdependencies, even when the object is not consciously perceived., Competing Interests: Declaration of competing interest None., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The neural representation of abstract concepts is a current matter of debate. While social concepts have been associated to superior anterior temporal lobe (sATL), the neural correlates of quantity-related concepts have seldom been investigated. The right intraparietal sulcus (IPS) is known to be involved in the processing of numerical information and of quantifiers. In the present study, we investigated the causal role of right sATL and right IPS in representing social and quantity-related concepts, using a state-dependent transcranial magnetic stimulation (TMS)-priming paradigm. We modulated the neural activation by priming to a category label (either SOCIAL or QUANTITY), before applying TMS and presenting the target (i.e., an exemplar of one of the two abstract classes). When the target word belonged to the quantity category, TMS applied over the IPS (but not sATL) abolished the expected priming effect by speeding up reaction times (RTs) in incongruent trials. For the social category, both IPS and sATL stimulation abolished the priming effect, by reducing RTs in incongruent trials. Our results suggest a specialization of distinct brain areas in processing different classes of abstract concepts. The right IPS contains neuronal representations tuned to quantity-related concepts, in line with its well-known role in numerical and magnitude representation. Social concepts, in contrast, are represented in both the right sATL and the right IPS, known to be involved in social cognition and person-related knowledge., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019 Elsevier Ltd. All rights reserved.)