Biology subjects

Koslov, S. R.

Publications and source records attributed to Koslov, S. R..

3 recordsLinked to original sources

bioRxiv2026

Electrophysiological dissociation of human posterior cingulate cortex contributions to value- and memory-based decision-making

The human posterior cingulate cortex (PCC) is routinely implicated in cognition and disease, yet its specific functional contributions remain unclear. Historically, human neuroimaging has linked the region to episodic memory and the default mode network, while a distinct non-human primate electrophysiology literature has focused on economic decision-making. Integrating anatomical evidence with these literatures, it has recently been proposed that this divergence reflects subregional organization, with dorsal PCC as a potential convergence site for value-based and memory-based decisions. Here, we recorded local field potentials (LFPs) and single units from human PCC while the same participants performed matched value- and memory-based decision tasks. LFPs in dorsal but not ventral PCC showed sustained engagement across both tasks, with risk sensitivity emerging only after the decision. In contrast, single-unit activity was more temporally circumscribed and could be grouped into response profiles active before or after the decision. Dorsal but not ventral PCC engagement further extended to memory encoding, recognition, and confidence judgments. Together, these findings reveal a consistent functional dissociation, identifying dorsal PCC as a domain-general interface between evaluative and mnemonic systems. In doing so, they align human and non-human primate accounts of PCC function and help orient future targeted studies of its role in cognition and disease.

neuroscience↗

bioRxiv2023

Dissociable contributions of the medial parietal cortex to recognition memory

Human neuroimaging studies of episodic memory retrieval routinely observe the engagement of specific cortical regions beyond the medial temporal lobe. Of these, medial parietal cortex (MPC) is of particular interest given its ubiquitous, and yet distinct, functional characteristics during different types of retrieval tasks. Specifically, while recognition memory and autobiographical recall tasks are both used to probe episodic retrieval, these paradigms consistently drive distinct patterns of response within MPC. This dissociation adds to growing evidence suggesting a common principle of functional organization across memory related brain structures, specifically regarding the control or content demands of memory-based decisions. To carefully examine this putative organization, we used a high-resolution fMRI dataset collected at ultra-high field (7T) while subjects performed thousands of recognition-memory trials to identify MPC regions responsive to recognition-decisions or semantic content of stimuli within and across individuals. We observed interleaving, though distinct, functional subregions of MPC where responses were sensitive to either recognition decisions or the semantic representation of stimuli, but rarely both. In addition, this functional dissociation within MPC was further accentuated by distinct profiles of connectivity bias with the hippocampus during task and rest. Finally, we show that recent observations of person and place selectivity within MPC reflect category specific responses from within identified semantic regions that are sensitive to mnemonic demands. Together, these data better account for how distinct patterns of MPC responses can occur as a result of task demands during episodic retrieval and may reflect a common principle of organization throughout hippocampal-neocortical memory systems. Significance statementMedial parietal cortex (MPC) plays a growing role in contemporary theories of episodic memory, as it is reliably observed in human neuroimaging to be engaged during tasks of recognition and retrieval. However, the spatial pattern of MPC engagement consistently differs across these putatively similar episodic memory tasks. Despite a large literature indicating that the MPC is important for episodic memory, there is little consensus about its specific role. Here, we employed precision-neuroimaging to identify dissociable interleaving MPC subregions, where activity reflected either memory-based decision-making or stimulus content. This dissociation within MPC provides a better understanding for how retrieval demands shape response patterns and speaks to growing evidence for a common principle of organization across memory structures of the human brain.

neuroscience↗

bioRxiv2022

Distinct population and single-neuron selectivity for executive and episodic processing in human dorsal posterior cingulate

Posterior cingulate cortex (PCC) is an enigmatic region implicated in psychiatric and neurological disease, yet its role in cognition remains unclear. Human studies link PCC to episodic memory and default mode network (DMN), while findings from the non-human primate emphasize executive processes more associated with the cognitive control network (CCN) in humans. We hypothesized this difference reflects an important functional division between dorsal (executive) and ventral (episodic) PCC. To test this, we utilized human intracranial recordings of population and single unit activity targeting dorsal PCC during an alternated executive/episodic processing task. Dorsal PCC population responses were significantly enhanced for executive, compared to episodic, task conditions, consistent with the CCN. Single unit recordings, however, revealed four distinct functional types with unique executive (CCN) or episodic (DMN) response profiles. Our findings provide critical electrophysiological data from human PCC, bridging incongruent views within and across species, furthering our understanding of PCC function.

neuroscience↗