bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2022.02.20.481099

Identifying the midline thalamus in humans in vivo

Reeders, P. C.·Rivera N., M. V.·Vertes, R. P.·Mattfeld, A. T.·Allen, T. A.
View original source ↗Export metadata ↓

Abstract

The midline thalamus is essential to flexible cognition, memory, and stress regulation and its dysfunction is associated with several neurological and mental health disorders including Alzheimers disease, schizophrenia, and depression. Despite the pervasive role of the midline thalamus in cognition and disease, almost nothing is known about it in humans due to the lack of a rigorous methodology for finding this brain region using noninvasive imaging technologies. Here, we introduce a new method for identifying the midline thalamus in vivo using probabilistic tractography and k-means clustering with diffusion weighted imaging data. This method clusters thalamic voxels based on data-driven cortical and subcortical connectivity profiles, and then segments midline thalamic nuclei based on connectivity profiles established in rodent and macaque tracer studies. Results from two different diffusion weighted imaging sets, including adult data (22-35yrs) from the Human Connectome Project (n=127) and adolescent data (9-14yrs) collected at Florida International University (n=34) showed that this approach reliably classifies midline thalamic clusters. As expected, these clusters were most evident along the dorsal/ventral extent of the third ventricle and primarily connected to the agranular medial prefrontal cortex (e.g., anterior cingulate cortex), nucleus accumbens, and medial temporal lobe regions. The midline thalamic clusters were then bisected based on a human brain atlas (Ding et al., 2016) into a dorsal midline thalamic cluster (paraventricular and paratenial nuclei) and a ventral midline thalamic cluster (rhomboid and reuniens nuclei). This anatomical connectivity-based identification procedure for the midline thalamus offers new opportunities to study this region in vivo in healthy populations and in those with psychiatric and neurological disorders. Significance StatementThe midline thalamus is essential for flexible cognition, decision making, and stress regulation. Abnormal development, dysfunction, and neurodegeneration of the midline thalamus is thought to be a critical pathology in several psychiatric and neurological disorders. Yet, little is known about the role of the human midline thalamus. Here we solve the problem of localization in vivo by using probabilistic tractography and data driven clustering (k-means), a method capable of capitalizing on known connectivity in non-human animal tracer studies. Localizing the midline thalamus based on its connectivity patterns provides a useful tool for future functional and structural human MRI studies to investigate clinical implications of the midline thalamus in diseases such as Alzheimers and schizophrenia.

Source connections

Explore related subjects

neurosciencePreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Reeders, P. C., Rivera N., M. V., Vertes, R. P., Mattfeld, A. T., Allen, T. A.. 2022-02-22. Identifying the midline thalamus in humans in vivo. https://doi.org/10.1101/2022.02.20.481099

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Novel Tau Interaction Partners as Potential Biomarkers and Therapeutic Targets in Neurodegenerative Diseases

Alzheimers disease is a progressive neurodegenerative disorder leading to cognitive decline and ultimately death. One of the main hallmarks of this disease is the accumulation of pathological tau protein into neurofibrillary tangles. To better understand these pathological mechanisms, it is essential to characterize the tau protein interactome in health and disease. In this study, we performed a yeast two-hybrid screening using a human brain cDNA library, from which we identified 15 novel tau-interacting proteins that bind to full-length human tau, or its fragments: the N-terminus, microtubule-binding domain, or C-terminus. We subsequently validated these novel interactions using in vitro co-immunoprecipitation and colocalization assays with both physiological and pathological tau isoforms. Furthermore, their interactions with the human tau protein were analyzed using surface plasmon resonance. Finally, an in silico interactome analysis of these newly discovered tau-binding partners revealed several additional interactors that can link them to downstream processes critical to neurodegenerative pathways Our findings offer fresh insights into tau biology and highlight novel targets for therapeutic intervention and biomarker development.

neuroscience↗
bioRxiv2026

Early visual cortex is not functionally necessary for temporal attention: A TMS study

Temporal attention enhances the selective processing of information at a specific point in time and improves perception. Previous neuroimaging studies investigating its neural mechanisms have either conflated temporal attention with temporal expectation or provided correlational evidence. Thus, whether early visual cortex is functionally necessary for temporal attention remains unknown. Here, we combined psychophysics with transcranial magnetic stimulation (TMS) to examine whether V1/V2 are functionally necessary and play a causal role in temporal attention. Observers performed an orientation-discrimination task in which two consecutive stimuli, T1 and T2, were presented in the periphery, preceded by a precue providing either valid or neutral temporal information. Double-pulse TMS was delivered under four conditions: at T1 (T1-TMS), at T2 (T2-TMS), at both T1 and T2 (both-TMS), or not at all (none-TMS), to assess its effects on temporal attention and the efficacy of the stimulation was verified by pupil size analysis. Behavioral results revealed robust temporal attention benefits on d', reaction time, and the Balanced Integration Score (BIS) across all four TMS conditions, indicating that the benefits of temporal attention were unaffected by occipital TMS. Furthermore, pupil dilation was largest in the both-TMS condition, followed by the T1-TMS and T2-TMS conditions, and smallest in the none-TMS condition, providing physiological verification of the stimulation protocol. Together, these findings reveal the first causal evidence that the early visual cortex is not functionally necessary for endogenous temporal attention.

neuroscience↗
bioRxiv2026

Disentanglement of persistent and dynamic neural substrates of working memory

Competing theories of working memory have alternatively emphasized the importance of persistent and dynamic substrates of this cognitive function. Here, we directly tested these theories by computationally isolating the contributions of persistent and dynamic activity to working memory. We analyzed neuronal population activity recordings in macaques doing match/non-match working memory tasks. We first extracted signatures of persistent and dynamic activity through cue-specific temporal means, temporal principal components, and correlations of activity patterns across task epochs. We then generated synthetic data constrained by these signatures, and decoded cue stimuli from these data, separately from persistent and non-persistent neurons. We found that high decoding performance arose from a nuanced interplay of persistent and dynamic activity. Specifically, we could decode stimuli at empirical or above-chance levels across all tasks only from persistent neurons, but only after constraining correlations of activity patterns across epochs. In this way, we showed distinct roles for persistent and dynamic neuronal activity that help to unify two competing theories of working memory. More broadly, we also advanced computational controlled experiments as a principled framework for adjudicating between competing models of neuronal population activity.

neuroscience↗