The Journal Club

Journal of Neuroscience April 9, 2025

The medial nucleus of the pulvinar complex is an evolutionary novelty of the primate thalamus and is uniquely expanded in humans. However, its functions are poorly understood, as data on its connections remain incomplete and fragmentary. Using high-resolution connection-labeling methods in marmoset monkeys, we mapped in full the thalamocortical axons arising from specific medial pulvinar domains and analyzed their branching patterns. Projection motifs reveal two main subnuclei, each targeting specific cortical networks. Moreover, we show that some pulvinar neurons simultaneously innervate distant prefrontal and parietal areas or prefrontal and temporal areas. Their connection patterns might allow medial pulvinar cells modulate, at different scales, functional connectivity in the cortical networks supporting object vision, social cognition, attention sensory-guided reaching, and working memory.

Journal of Neuroscience April 9, 2025

This study explores the effects of ketamine, a compound known for its psychotomimetic effects that mimic those of neuro-psychiatric disorders like schizophrenia, on auditory processing in common marmosets using ultra-high field functional magnetic resonance imaging. We reveal a global suppression of neural activity across auditory regions under ketamine, with varying effects depending on the sound type in certain regions. Notably, the medial dorsal thalamus showed significant susceptibility in processing socially relevant sounds. These findings suggest parallels between ketamine’s impact and auditory processing disruptions seen in schizophrenia.

Journal of Neuroscience April 9, 2025

The functional role of efferent innervation of the mammalian cochlea has remained in question. Here we show that the medial olivocochlear efferent system chronically potentiates cochlear sensitivity in response to removing the afferent signal but does not affect sensitivity in response to fluctuations in pupil-indexed brain state. While partially compensating for hearing loss, the efferent mediated chronic potentiation may also contribute to associated symptoms of hearing loss, such as tinnitus and hyperacusis.

Journal of Neuroscience April 9, 2025

This study shows that sedation with dexmedetomidine in larval zebrafish reduces spontaneous brain activity and creates a quieter, more stable brain state, while sharpening and isolating auditory responses. Using brain-wide calcium imaging, the researchers reveal how sedation alters neural dynamics, highlighting reduced variability and increased signal clarity in sensory processing.

Journal of Neuroscience April 9, 2025

By comparing brain connectivity blueprints across humans, chimpanzees, and macaques, researchers identified human-specific patterns concentrated in the temporal and parietal cortices—areas linked to language and social cognition. These findings challenge the long-held view that the prefrontal cortex is the primary source of human cognitive uniqueness.

Journal of Neuroscience April 9, 2025

This study found that higher reward incentives reduce exploratory behavior and shift decision-making toward model-based learning. Individual cognitive traits and increased connectivity between ventral and dorsal reinforcement learning networks predict how reward influences the balance between exploration and exploitation.

Journal of Neuroscience April 9, 2025

This study shows that high-frequency neural activity related to reward-based decision-making is widely distributed across the human brain. While individual computations like risk and win probability occur unevenly across regions, final choice signals are more broadly and consistently represented, highlighting a brain-wide integration process in economic choices.

Journal of Neuroscience - April 9 2025

This study reveals that distinct neural timescales derived from broadband and gamma activity vary across the cortex and are differentially modulated by sleep, suggesting that brain state and anatomy jointly shape temporal dynamics and spatiotemporal integration.

In this episode, we dive into the fascinating and controversial tale of the dire wolf—Canis dirus—once one of the most dominant predators of Pleistocene America. New genomic research published in Nature reveals that dire wolves were not close cousins of the modern gray wolf as long assumed, but instead a highly divergent species that split off more than 5.7 million years ago, likely evolving in complete isolation in the Americas​.

Despite their striking morphological similarity to gray wolves, dire wolves never interbred with them, likely due to long-term reproductive isolation​. This evolutionary backstory sets the stage for today's bioethical dilemma.

Fast forward to 2025—Colossal Biosciences announces the birth of gene-edited animals resembling dire wolves, using gray wolf DNA altered with just 20 edits to mimic the ancient beast’s appearance. The animals, named Romulus and Remus, were born from surrogate dogs. The company sparked both media buzz and scientific backlash​.

We unpack the science behind the evolutionary findings, question whether Colossal’s recreation is truly a dire wolf or just a genetic cosplay, and explore the ethical implications of de-extinction efforts. Is this science fiction creeping into real life, or are we simply rebranding selective breeding with a high-tech flair?

Yang, Z., Long, M.A. Convergent vocal representations in parrot and human forebrain motor networks. Nature 640, 427–434 (2025). https://doi-org.ccmain.ohionet.org/10.1038/s41586-025-08695-8