Objective To explore the characteristics of response to joint attention(RJA)under diverse guiding behaviors for pre-schoolers with moderate to severe autism spectrum disorder(ASD). Methods From March to May,2023,21 children with moderate to severe ASD and 16 children with developmental de-lays matched the physiological ages were selected from Jiaxing Sunlight Rehabilitation Kindergarten,and 16 typ-ical developmental children matched the physiological ages were selected from the kindergartens nearby.They accepted a behavioral experiment on RJA.The number of RJA,frequence of RJA and the coefficient of variation of guiding behaviors needed to RJA were compared among the three groups. Results About half of the ASD group responded after guiding of head-turning,and the others required higher levels of guiding.The frequence of RJA after guiding of head-turning was less in the ASD group than in the typical devel-opment group(χ2>6.170,P<0.05),and the coefficient of variation of guiding behaviors was more(d=4.039,P<0.001). Conclusion Preschoolers with moderate to severe ASD are able to respond to joint attention,and this ability is poorer than typically developing children.The guiding behavior of the evaluator should be considered in assessing and intervening RJA in preschoolers with ASD.

Activation of the heart normally begins in the sinoatrial node (SAN). Electrical impulses spontaneously released by SAN pacemaker cells (SANPCs) trigger the contraction of the heart. However, the cellular nature of SANPCs remains controversial. Here, we report that SANPCs exhibit glutamatergic neuron-like properties. By comparing the single-cell transcriptome of SANPCs with that of cells from primary visual cortex in mouse, we found that SANPCs co-clustered with cortical neurons. Tissue and cellular imaging confirmed that SANPCs contained key elements of glutamatergic neurotransmitter system, expressing genes encoding glutamate synthesis pathway (Gls), ionotropic and metabotropic glutamate receptors (Grina, Gria3, Grm1 and Grm5), and glutamate transporters (Slc17a7). SANPCs highly expressed cell markers of glutamatergic neurons (Snap25 and Slc17a7), whereas Gad1, a marker of GABAergic neurons, was negative. Functional studies revealed that inhibition of glutamate receptors or transporters reduced spontaneous pacing frequency of isolated SAN tissues and spontaneous Ca