Biology subjects

Tomasek, M.

Publications and source records attributed to Tomasek, M..

4 recordsLinked to original sources

bioRxiv2025

Experimental study of social learning in three wild shell-dwelling Tanganyikan cichlids that vary in sociality

The social intelligence hypothesis posits that animals living in more complex social groups display better cognitive performances. However, this hypothesis has mainly been investigated in primates and studies using similar paradigms across different species are scarce. We tested three species of wild Lamprologine shell-dwelling cichlids from Lake Tanganyika (Neolamprologus multifasciatus, Lamprologus ocellatus, and Lamprologus ornatipinnis) that vary in their levels of sociality, in identical colour associative learning and social learning tasks. We found species differences in engagement in the training for these tasks and only 5 out of 24 individuals learnt to feed from a neutral object (a shell). One L. ocellatus and one L. ornatipinnis learnt to choose the correct colour in the associative learning task and were further used as demonstrators in the social learning task. In this task, no species showed signs of colour stimulus enhancement as the observers choices of colours were not influenced by the demonstrators. However, we found evidence for stimulus enhancement at a larger scale as naive observers approached the novel experimental apparatus faster than the demonstrators when first exposed to this apparatus. Our results encourage further research of social learning processes in individual fishes and highlights the difficulties in using identical paradigms in comparative psychology, even across very close species.

animal behavior and cognition↗

bioRxiv2025

Decision-making strategies of two related fish species diverge under increased perceptual load

Three main mechanisms have been proposed to explain divergent decisions between species faced with the same options: differences in sensory abilities, attentional capacities, or cognitive evaluations. While these mechanisms have been well-established in controlled settings, there is limited empirical evidence regarding the ways in which different species make decisions under varying perceptual loads. Here we investigated the decision-making processes of two closely related cichlid species, Aulonocranus dewindti and Cyathopharynx furcifer, in Lake Tanganyika. Males of these species construct sand bowers from which they remove foreign objects, and we examined their preferences when presented with objects varying in three attributes: colour, size, and shape. We show that both species exhibited similar preferences under low perceptual load. Similarly, when the perceptual load was increased by increasing the number of options, both species choices were driven by attentional capture, and an oddity effect was observed. However, when the perceptual load was increased by adding more attributes (feature conjunctions), the species diverged in their decision-making. One species, A. dewindti, evaluated the options in an absolute manner, considering all available attributes, as evidenced by its insensitivity to decoy effects. The other species, C. furcifer either showed attentional capture or evaluated the options in a comparative manner. We discuss the potential reasons behind these differences and their implications for the evolution of decision-making mechanisms.

animal behavior and cognition↗

bioRxiv2021

Direct-from-specimen microbial growth inhibition spectrums under antibiotic exposure and comparison to conventional antimicrobial susceptibility testing

Increasing global travel and changes in the environment may increase the frequency of contact with a natural host carrying an infection, and therefore increase our chances of encountering microorganisms previously unknown to humans. During an emergency (man-made, natural disaster, or pandemic), the etiology of infection might be unknown at the time of patient treatment. The existing local or global Antimicrobial Stewardship Programs might not be fully prepared for emerging/re-emerging infectious disease outbreaks, especially if they are caused by an unknown organism, engineered bioterrorist attack, or rapidly evolving superbug. We demonstrate an antimicrobial efficacy profiling method that can be performed in hours directly from clinical urine specimens. The antimicrobial potency is determined by the microbial growth inhibition and compared to conventional antimicrobial susceptibility testing (AST) results. The oligonucleotide probe pairs on the sensor were designed to target gram-negative bacteria, specifically Enterobacterales and Pseudomonas aeruginosa. A total of 10 remnant clinical specimens from the CLIA labs of New York-Presbyterian Queens were tested, resulting in 100% categorical agreement with reference AST methods (Vitek and broth microdilution method). The combined categorical susceptibility reporting of 12 contrived urine specimens was 100% for ciprofloxacin, gentamicin, and meropenem over a range of microbial loads from 105 to 108 CFU/mL.

microbiology↗

bioRxiv2017

Global and Local Dynamics of High-Gamma Activity Underlying Error Processing in the Human Brain Revealed by Noninvasive and Intracranial EEG

Error detection in motor behavior is a fundamental cognitive function heavily relying on cortical information processing. Neural activity in the high-gamma frequency band (HGB) closely reflects such local cortical processing, but little is known about its role in error processing, particularly in the healthy human brain. Here we characterize the error-related response of the human brain based on data obtained with noninvasive EEG optimized for HGB mapping in 31 healthy subjects (15 females, 16 males), and additional intracranial EEG data from 9 epilepsy patients (4 females, 5 males). Our findings reveal a comprehensive picture of the global and local dynamics of error-related HGB activity in the human brain. On the global level as reflected in the noninvasive EEG, the error-related response started with an early component dominated by anterior brain regions, followed by a shift to parietal regions, and a subsequent phase characterized by sustained parietal HGB activity. This phase lasted for more than 1 s after the error onset. On the local level reflected in the intracranial EEG, a cascade of both transient and sustained error-related responses involved an even more extended network, spanning beyond frontal and parietal regions to the insula and the hippocampus. HGB mapping appeared especially well suited to investigate late, sustained components of the error response, possibly linked to downstream functional stages such as error-related learning and behavioral adaptation. Our findings establish the basic spatio-temporal properties of HGB activity as a neural correlate of error processing, complementing traditional error-related potential studies.\n\nSignificance StatementThere is great interest to understand how the human brain reacts to errors in goal-directed behavior. An important index of cortical and subcortical information processing is fast oscillatory brain activity, particularly in the high-gamma band (above 50 Hz). Here we show that it is possible to detect signatures of errors in event-related high-gamma responses with noninvasive techniques, characterize these responses comprehensively, and validate the EEG procedure for the detection of such signals. In addition, we demonstrate the added value of intracranial recordings pinpointing the fine-grained spatio-temporal patterns in error-related brain networks. We anticipate that the optimized noninvasive EEG techniques as described here will be helpful in many areas of cognitive neuroscience where fast oscillatory brain activity is of interest.

neuroscience↗