Biology subjects

Samii Moghaddam, A.

Publications and source records attributed to Samii Moghaddam, A..

3 recordsLinked to original sources

bioRxiv2026

Spatial working memory enhances gamma oscillations in rodent olfactory bulb and medial prefrontal cortex

Spatial working memory (SWM), a specialized form of working memory that temporarily encodes and retains spatial information, is fundamental to guide animal behaviors, yet our current knowledge of its circuit mechanisms remains far from known. Since, olfactory bulb (OB) and medial prefrontal cortex (mPFC) are critical brain structures for a wide range of cognitive behaviors, we hypothesized that the OB-mPFC circuit gamma oscillations might support rodent SWM processing. Our results show that SWM enhances regional low (30-60 Hz), but not high (60-100 Hz), gamma oscillations in both OB and mPFC, in correlation with the animals behavioral performance. Additionally, the OB-mPFC gamma band functional connectivity is strengthened by SWM. Moreover, we find that mPFC gamma oscillatory information transfer to OB supports the animals SWM performance. We also show that OB low gamma oscillations are modulated by mPFC delta phase, which further signifies the roles of mPFC feedbacks to shape OB gamma activity during SWM. These results suggest that OB-mPFC circuit gamma rhythms underlie SWM processing, and point towards possible mechanisms for cognitive disorders.

neuroscience↗

bioRxiv2026

Distinct tuning properties of human hippocampal neurons along the longitudinal axis during working memory

Working memory (WM) is among the most sophisticated and fundamental capabilities of the mammalian brain. While the roles of prefrontal and sensory areas are heavily explored, there is little knowledge on how the hippocampus (HPC) contributes to this process. Here, we studied human HPC neuronal activities during a verbal WM task and reveal that neurons in the posterior HPC (PH) show more robust rate-modulations during WM. On the other hand, anterior HPC (AH) neurons are more prominently modulated by the phase of local and frontal cortex {theta} and {beta} oscillations, a phenomenon that is accompanied by enhanced phase-synchronization between frontal cortex and HPC. Moreover, absence of correlational correspondence suggested that rate and phase are independent coding mechanisms. These results open a window to explore the functional dissociations along the primate HPC antero-posterior axis, a phenomenon long known to exist in the rodent brain. Furthermore, we suggest that combination of a variety of coding mechanisms in the human HPC neuronal population supports execution of WM.

neuroscience↗

bioRxiv2025

Olfactory bulb-medial prefrontal cortex circuit slow oscillations encode working memory representations

Working memory (WM), the ability to maintain task-related information, is fundamental to animal behaviors. Despite significance, there is limited knowledge on how it is orchestrated by the neural activity in the brain. Here, we show that the olfactory bulb (OB) and medial prefrontal cortex (mPFC) slow oscillations (1-30 Hz) are augmented during WM, and furthermore, the pattern of these activities convey task-related information. Moreover, we find that the OB-mPFC delta and beta power-based connectivity is enhanced by WM. On the other hand, theta oscillations have the most prominent roles in phase coupling in this circuit. We also show bidirectional information transfer, stronger in the mPFC-to-OB direction, between the two brain areas. Furthermore, during WM, beta activity in both regions is tuned by the phase of local and long-range delta as well as theta oscillations. Together, our results suggest that the dynamics of OB-mPFC circuit slow band activities underlies WM, with possible implications for other cognitive functions in health and disease.

neuroscience↗