Children with attention-deficit/hyperactivity disorder (ADHD) show performance deficits and excessive motor activity during extinction and in situations where no reinforcer can be identified, suggesting an extinction deficit in ADHD possibly linked to dopamine dysfunction. The present study examined extinction of responding previously maintained by intra-cranial self-stimulation (ICSS) in spontaneously hypertensive rats (SHR), an animal model of ADHD using three different extinction procedures. Delivery of electrical pulses were terminated altogether or presented independently of responding using two different current intensities. The results showed that more responses were retained in the SHR, especially during the initial transition from ICSS-maintained responding to response-independent delivery of electrical pulses with current reduced relative to that given during reinforcement. Slower extinction of previously reinforced behavior is suggested as an alternative explanation for the frequently observed increased behavioral output that has previously been interpreted as "disinhibition" of behavior in ADHD.
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http://dx.doi.org/10.1016/j.bbr.2005.02.035 | DOI Listing |
J Cogn
January 2025
General Psychology, Trier University, Germany.
Observations from multisensory body illusions indicate that the body representation can be adapted to changing task demands, e.g., it can be expanded to integrate external objects based on current sensorimotor experience (embodiment).
View Article and Find Full Text PDFJ Anat
December 2024
Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa.
During the Late Permian, saber-toothed gorgonopsian therapsids were the dominant terrestrial predators, playing crucial roles as apex predators alongside therocephalian therapsids within Permian terrestrial ecosystems. The entire gorgonopsian clade went extinct during the Permo-Triassic mass extinction, leaving other therapsids to continue into the Triassic. Gorgonopsians have not been well studied, particularly in terms of their growth patterns, with only a few genera having undergone osteohistological analysis.
View Article and Find Full Text PDFNeurosci Biobehav Rev
December 2024
Department of Psychology, University Hamburg, Hamburg, Germany.
Fear learning processes are believed to play a crucial role in the development and maintenance of anxiety and stress-related disorders. To integrate results across different studies, we conducted a systematic meta-analysis following PRISMA guidelines to examine differences in fear conditioning during fear acquisition, extinction, and extinction recall between individuals with anxiety-related or stress-related disorders and healthy participants. This analysis updates the work of Duits et al.
View Article and Find Full Text PDFJ Morphol
January 2025
Department of Biological Sciences, University of Cape Town, University Avenue Cape Town, Cape Town, Western Cape, South Africa.
Skeletochronology and growth dynamics are intensively investigated in vertebrate osteohistology. These techniques are particularly important for interpreting the life history of long-lived species, such as crocodilians. To understand the longevity, growth dynamics, sexual maturity, and sexual dimorphism of caimans we studied an almost complete ontogenetic series of captive and wild specimens of Caiman latirostris from different localities of Argentina.
View Article and Find Full Text PDFGlob Chang Biol
December 2024
Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Anthropogenic rapid warming has caused decreases in richness and body mass of birds following the metabolic theory of ecology; yet, the pervasiveness of these shifts remains controversial among different taxa. Here, by combining phylogenetic methods and fossil data, we synthesized spatial patterns of richness and body mass for 328 seabird species belonging to two groups: Procellariimorphae (PM) and non-Procellariimorphae (NPM). We found that the relationship between body mass and richness, as well as diversification rate, exhibits distinct patterns in these two groups.
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