Biology subjects

Satish, A.

Publications and source records attributed to Satish, A..

4 recordsLinked to original sources

bioRxiv2026

Amnesia Induced by Suppressing the Focus of Internal Attention

Our thoughts can recede as we direct attention to the external world. This experience may reflect the suppression of thoughts about past events, future worries, or stray ideas that could otherwise disrupt focus. Such thoughts may arise spontaneously from replay mechanisms supported by the episodic memory system; hence, sustaining external focus may require suppressing these systems to stop internal distraction. Here, periods of high external focus disrupted diverse episodic content activated near in time, inducing an 'amnesic shadow'. This shadow occurred for both novel content and already formed memories and exhibited key markers of active suppression: forgetting beyond expectations from time alone, which generalised to an alternative reminder. External attention therefore automatically engages an active suppression mechanism that appears to broadly inhibit cognitive systems supporting the emergence of distracting thoughts. The findings raise the possibility that people may naturally gravitate toward activities demanding external attention, unwittingly, to regulate unwanted thoughts.

neuroscience↗

bioRxiv2025

Effects of forest cover, temperature and flower abundance on cashew pollinators in the northern Western Ghats, India

Global declines in pollinators pose serious risks for biodiversity, ecosystem functioning, and human well-being. Understanding how landscape structure and climate shape pollinator communities is critical, yet studies that jointly assess these factors in human-dominated tropical landscapes remain scarce. Here, we investigate how forest cover, distance to forest patches, flower abundance, and temperature influence pollinator communities in monoculture cashew plantations that are rapidly expanding in the northern Western Ghats, part of the Western Ghats-Sri Lanka global biodiversity hotspot. We conducted 210 half-hour observation sessions across 30 cashew orchards in Dodamarg, India. At the community level, flower abundance and forest cover positively influenced pollinator richness, number of pollinators, and number of visits. The number of visits showed a unimodal response to temperature, with peaks occurring within narrow, taxon-specific ranges, lower temperatures for birds and higher for insects, likely reflecting physiological constraints. At the species level, flower abundance and temperature emerged as key predictors of occurrence, while three butterfly species occurred more frequently near forest patches. Contrary to expectations, proximity to forest did not reduce ambient orchard temperatures, suggesting limited forest-mediated thermal buffering in our site. Together, these findings highlight the vulnerability of pollination services to both land-use change and rising temperatures. Ongoing conversion of natural forests to cashew monocultures, coupled with climate warming, may erode pollinator communities and jeopardize crop yields in tropical agroecosystems. More broadly, our results underscore the importance of conserving remnant forests and accounting for thermal sensitivity of pollinators to sustain ecosystem services in changing landscapes worldwide.

ecology↗

bioRxiv2023

Theta and alpha oscillations in human hippocampus and medial parietal cortex support the formation of location-based representations

Our ability to navigate in a new environment depends on learning new locations. Mental representations of locations are quickly accessible during navigation and allow us to know where we are regardless of our current viewpoint. Recent fMRI research using pattern classification has shown that these location-based representations emerge in the retrosplenial cortex and parahippocampal gyrus, regions theorised to be critically involved in spatial navigation. However, little is currently known about the oscillatory dynamics that support the formation of location-based representations. We used MEG to investigate region-specific oscillatory activity in a task where participants could form location-based representations. Participants viewed videos showing that two perceptually distinct scenes (180{degrees} apart) belonged to the same location. This "overlap" video allowed participants to bind the two distinct scenes together into a more coherent location-based representation. Participants also viewed control "non-overlap" videos where two distinct scenes from two different locations were shown, where no location-based representation could be formed. In a post-video behavioural task, participants successfully matched the two viewpoints shown in the overlap videos, but not the non-overlap videos, indicating they successfully learned the locations in the overlap condition. Comparing oscillatory activity between the overlap and non-overlap videos, we found greater theta and alpha/beta power during the overlap relative to non-overlap videos, specifically at time-points when we expected scene integration to occur. These oscillations localised to regions in the medial parietal cortex (precuneus and retrosplenial cortex) and the medial temporal lobe, including the hippocampus. Therefore, we find that theta and alpha/beta oscillations in the hippocampus and medial parietal cortex are likely involved in the formation of location-based representations.

neuroscience↗

bioRxiv2022

EEG evidence that morally relevant autobiographical memories can be suppressed

Remembering unpleasant events can trigger negative feelings. Fortunately, research indicates that unwanted memories can be suppressed to prevent them from intruding into awareness, improving our mental state. The current scientific understanding of memory suppression is, however, based mostly on simpler memories such as associations between words or pictures, which may not reflect how people control unpleasant memory intrusions in everyday life. Here, we investigated the neural and behavioural dynamics of suppressing personal and emotional autobiographical memories using a modified version of the Think/No-Think task. We asked participants to suppress memories of their own past immoral actions, which were hypothesised to be both highly intrusive and motivating to suppress. We report novel evidence from behavioural, ERP and EEG oscillation measures that autobiographical memory retrieval can be suppressed and suggest that autobiographical suppression recruits similar neurocognitive mechanisms as suppression of simple laboratory associations. Suppression did fail sometimes, and EEG oscillations indicated that such memory intrusions occurred from lapses in sustained control. Importantly however, participants improved at limiting intrusions with repeated practice. Furthermore, both behavioural and EEG evidence indicated that intentional suppression may be more difficult for memories of our morally wrong actions than memories of our morally right actions. The findings elucidate the neurocognitive correlates of autobiographical retrieval suppression and have implications for theories of morally motivated memory control.

neuroscience↗