关键词: 恐惧泛化, 无意识, 知觉, 概念, N1, N400

Abstract: This study investigated the cognitive neural mechanisms underlying perceptual and conceptual fear generalization under conscious and non-conscious conditions. Sixty-one healthy participants were recruited and randomly assigned to conscious or non-conscious groups after completing a classical fear conditioning paradigm. The experimental design incorporated three independent variables: two within-subject factors (1) conceptual generalization stimulus type (C+ vs. C-); (2) perceptual generalization stimulus type (P+ vs. P-) and one between-subjects factor ,consciousness condition (conscious vs. non-conscious). The experimental protocol consisted of three phases. Participants first underwent a habituation phase to familiarize all stimuli. During conscious acquisition phase, perceptual stimuli (navy blue and olive green colors) and conceptual stimuli (animal and furniture words) served as conditioned stimuli (CSs), with one type designated as CS+ (e.g., navy blue as P+ and animal words as C+) and the other as CS-. Electric shock was used as the unconditioned stimulus (US). During generalization phase, four types of generalization stimuli(GSs) were implemented: navy blue animal words (C+P+), olive green animal words (C+P-), olive green furniture words (C-P-), and navy blue furniture words (C-P+). Critical temporal parameters differed between groups. For the conscious condition group, GSs were presented for 30ms followed by a 200ms blank screen and 100ms mask. The unconscious condition group received 30ms GSs followed by immediate 100ms masking before the 200ms blank screen. Behavioral and electrophysiological responses were recorded throughout the experiment. Behavioral data revealed significantly higher US expectancy ratings for CS+ compared to CS- during acquisition. Electrophysiological results demonstrated two critical patterns, 1,The unconscious group exhibited more negative frontal N1 amplitudes in response to GS than the conscious group. 2, C- elicited more negative N400 amplitudes compared to C+ in the unconscious condition group, while the reverse pattern emerged in the conscious condition group. These findings suggest three main conclusions, First, perceptual stimuli demonstrate superior threat detection learning compared to conceptual stimuli. Second, unconscious GSs induce enhanced early attentional vigilance, as reflected in N1 modulation. Third, distinct neural signatures were observed in conceptual processing - conscious conditions facilitated threat recognition through N400 modulation for threat-related concepts, whereas unconscious conditions revealed fear overgeneralization to semantically safe concepts .The differential mechanisms in perceptual threat detection and conceptual fear generalization under non-conscious conditions may provide novel insights into the pathological mechanisms of anxiety disorders. The dissociation between early attentional processes (N1) and later semantic processing (N400) highlights stage-specific neural correlates of fear generalization across consciousness states.