Biology subjects

Morozova, M. V.

Publications and source records attributed to Morozova, M. V..

3 recordsLinked to original sources

bioRxiv2026

Top-down attention modulates auditory sustained responses but not the neural processing advantage for vowels

Temporal and spectral regularities characteristic of vowels are preferentially encoded by the auditory system, giving rise to a prolonged enhancement of a negative electromagnetic response in the auditory cortex - sustained negativity (SN). However, it remains unclear how sustained attention to the auditory stream interacts with this intrinsically enhanced processing. Here, we used MEG to examine SN and its differential response to vowel-like acoustic patterns versus spectrally complex noise, while modulating subjects attention to the auditory stimulation. Four stimulus types (600 ms duration; vowel-like sounds with and without pitch, periodic non-vowel sounds, and aperiodic noise) were presented to 30 adults during passive listening and an active gap-detection task. In 16% of randomly selected trials, a 50-ms silent gap was inserted into the stimuli, which served as a target. The number of non-target trials between successive targets ranged from 1 to 10, with the highest probability corresponding to an interval of six trials. Only non-target trials were analyzed. Analysis of reaction times and omission errors indicated that target expectancy increased with the number of trials since the previous target. Task-related attention enhanced an early orienting-related negativity ([~]50-150 ms) across all stimulus types, irrespective of target expectancy. It also accelerated the processing of periodicity in non-vocal sounds but did not affect the processing of vowels. In contrast, the later segment of the SN (150-600 ms) was strongly modulated by proximity to the previous target, decreasing immediately after target events and increasing as the likelihood of target occurrence rose. Despite these attentional and expectancy-related modulations, the enhanced neural processing of periodic vowels relative to noise remained stable. These findings indicate that sustained attention modulates both early and late SN responses and accelerates the extraction of periodicity in non-vocal sounds, yet does not alter the neural advantage conferred by vowel-related regularities.

neuroscience↗

bioRxiv2025

Modulatory Effects of the Motor Imagery and Jendrassik Maneuver upon the Forearm H-Reflex and Electroencephalographic Activity

While the Jendrassik maneuver (JM) is commonly used in neurology to enhance monosynaptic reflexes such as the knee-jerk reflex, its interaction with cognitive processes like motor imagery (MI) remains unclear. In this study, we examined the effects of JM, MI, and their combination on the left flexor carpi radialis (FCR) H-reflex and cortical electroencephalographic (EEG) activity. Twenty healthy participants completed four tasks: resting, MI (imagining squeezing a tennis ball with the left hand), JM (squeezing a tennis ball with the right hand), and JM combined with MI (JM&MI). The FCR H-reflex was elicited with median nerve stimulation, and EEG changes were analyzed through event-related potentials and modulations of the mu rhythm. Surprisingly, JM performed with the right hand did not affect the contralateral H-reflex. MI of the left hand decreased the H-reflex in the right FCR. JM and MI significantly modulated cortical activity. Event-related desynchronization (ERD) of the mu-rhythm occurred during both JM and MI, and it was contralateral to the physical contraction or imagery. Bilateral ERD was observed during JM&MI. Cortical responses to nerve stimulation (P100, N100 and P300 components) varied by task, and during JM the P100 and P300 components correlated with strength of mu-rhythm ERD.

neuroscience↗

bioRxiv2023

Investigating social communication in mice: a Two-intruders test approach

Understanding the complex dynamics of social communication behaviors, such as exploration, communication, courtship, mating, and aggression in animal models is crucial to reveal key neural and hormonal mechanisms underlying these behaviors. The Two-intruders test is designed to investigate residents behavior toward a male and female intruders. During this test imitating natural conditions, several aspects of social interaction were investigated: exploration, courtship, mating, and aggressive behavior. As mating and aggression involve overlapping neural circuits, the behavioral setup testing both behaviors is best at reflecting their competitive nature. Our findings demonstrate that male mice exhibit strong preference to communicate with a female intruder, which correlates with baseline testosterone levels of test males. Relevant female preference in the Two-intruder test was also found in BALB/c males. Behavioral breakdown revealed the anogenital sniffing as a key behavioral feature that discriminates test male behavior toward intruders of different genders. At the same time, female preference was accompanied by neuronal activation in the ventromedial hypothalamus. We demonstrate that odor recognition underlies preference toward females in male residents, as experimental anosmia reduced communication with a female intruder. However, there was no correlation between female animal preference in the contact Two-intruder test and smell preference in the social odor preference test. We assume the Two-intruders test setup to be a useful tool to study the neurological basis of social communication in animal models. Combined with odor preference tests, this experimental paradigm can help to decipher neural circuits involved in social deficiency phenotypes in animal models of human diseases. Significance StatementThe Two-intruders test proves to be a highly reproducible and robust approach to assess social communication in mice. We demonstrate that the results obtained in this experimental setting replicate in different mouse groups and strains. This test is indispensable in studies assessing the competitive nature of male- and female-driven behaviors and the underlying neural mechanisms. Residents social interactions in the described here set up reflects odor processing and circulating testosterone - the key physiological drivers of animal communication with conspecifics. While easy to perform, this test provides a broad spectrum of behavioral patterns to study in the models of complex neurological diseases. Largely overseen in the literature as compared to the resident-intruder setup, the Two-intruders test can provide superior performance when used to understand the neural mechanisms of mating, aggression and social communication.

neuroscience↗