A neuronal ensemble encoding adaptive choice during sensory conflict in Drosophila

Feeding decisions are fundamental to survival, and decision making is often disrupted in disease. Here, we show that neural activity in a small population of neurons projecting to the fan-shaped body higher-order central brain region of Drosophila represents food choice during sensory conflict. We found that food deprived flies made tradeoffs between appetitive and aversive values of food. We identified an upstream neuropeptidergic and dopaminergic network that relays internal state and other decision-relevant information to a specific subset of fan-shaped body neurons. These neurons were strongly inhibited by the taste of the rejected food choice, suggesting that they encode behavioral food choice. Our findings reveal that fan-shaped body taste responses to food choices are determined not only by taste quality, but also by previous experience (including choice outcome) and hunger state, which are integrated in the fan-shaped body to encode the decision before relay to downstream motor circuits for behavioral implementation.

Beyond sensory conflict: The role of beliefs and perception in motion sickness

Illusory self-motion often provokes motion sickness, which is commonly explained in terms of an inter-sensory conflict that is not in accordance with previous experience. Here we address the influence of cognition in motion sickness and show that such a conflict is not provocative when the observer believes that the motion illusion is indeed actually occurring. Illusory self-motion and motion sickness were elicited in healthy human participants who were seated on a stationary rotary chair inside a rotating optokinetic drum. Participants knew that both chair and drum could rotate but were unaware of the actual motion stimulus. Results showed that motion sickness was correlated with the discrepancy between participants’ perceived self-motion and participants’ beliefs about the actual motion. Together with the general motion sickness susceptibility, this discrepancy accounted for 51% of the variance in motion sickness intensity. This finding sheds a new light on the causes of visually induced motion sickness and suggests that it is not governed by an inter-sensory conflict per se, but by beliefs concerning the actual self-motion. This cognitive influence provides a promising tool for the development of new countermeasures.

The Use of Frequency Analysis as a Complementary and Explanatory Element for Time Domain Analysis in Measurements of the Ability to Maintain Balance

Assessment of human balance is one of the most common diagnostic tests, both in medical applications and during sports training. Many new methods of measuring are introduced in these studies; however, the analysis of results is still carried out mainly based on the values determined in the time domain – the average COP speed or the ellipse field of the prediction. The aim of the current work is to present the possibilities for the practical application of frequency analyses in assessment of the ability to maintain body balance as a method supplementing standard analyses. As part of the study, measurements of the ability to maintain balance in sensory conflict conditions introduced in the form of an oscillating, three-dimensional, virtual scenery were carried out. 27 healthy volunteers (13 women and 14 men) took part in the study. The three-dimensional scenery, presented by means of the Oculus system, oscillated in the sagittal plane with frequencies equal to 0.7 Hz and 1.4 Hz. The frequency value during the measurement was constant or changed in the middle of the test. Measurements were conducted on the FDM Zebris platform. The results were analyzed using developed coefficients determined on the basis of the Short-time Fourier transform (STFT). The use of frequency-domain analyses confirmed that in the COP movement, one can observe a cyclical component corresponding to following the scenery, as well as the appearance of other cyclical components whose observation is important in terms of assessing the ability to maintain balance. It has been shown that the changes in the average COP speed that occur during the measurement can result from changes related to the movement of following the scenery as well as additional body movements indicating a greater or lesser loss of balance. It has been shown that there are differences in the COP movement provoked by the movement of the surrounding scenery, which depend on the parameters of the introduced disturbances – something that can only be observed in results obtained in the frequency domain. The conducted research shows that in measurements involving the ability to maintain one’s balance conducted in sensory conflict conditions, standard time-domain analyses should be supplemented with other types of data analysis, e.g. frequency domain analyses.

Managing the resilience of future marine specialists to sickness

В статье приводится обоснование условий тренировки устойчивости к укачиванию будущих морских специалистов, способствующих снижению объемов нагрузки в специальных упражнениях и временных затрат на цикл подготовки. Предложен способ расчета перегрузок в упражнениях, применяемых в активной, пассивной и смешанной тренировках устойчивости к укачиванию. Значение критерия определяется путем вычисления отношения полного ускорения, действующего на вестибулярный анализатор в процессе движения, к ускорению свободного падения. Установлено, что ведущей теорией для отбора средств тренировки является теория сенсорного конфликта. Дается описание и обоснование применения авторских разработок для тренировки статического и динамического равновесия на возвышенной, наклонной, качающейся и соскальзывающей опорах, моделирующих условия сохранения статокинетической устойчивости в морских условиях. Предложен необходимый и достаточный комплекс технических устройств и тренажеров для управления устойчивостью будущих морских специалистов к укачиванию. The article substantiates the conditions of resistance to motion sickness of future marine specialists, the possibilities of the system for measuring the load in special exercises and the time spent on the training cycle. A method for calculating overloads in exercises used in active, passive and mixed trainings of resistance to motion sickness is proposed. The value is determined by calculating the ratio of the total acceleration acting on the vestibular analyzer during the acceleration of gravity. It has been established that the leading theory for the selection of training means is the theory of sensory conflict. A description and justification of the use of author's developments for training static and dynamic balance on an elevated, inclined, swinging and sliding support, simulating the conditions for maintaining statokinetic stability in marine conditions, is given. The necessity and a sufficient set of technical devices and simulators for the sustainable development of marine specialists for motion sickness is proposed.

A neural signature of choice under sensory conflict in Drosophila

SummaryFeeding decisions are fundamental to survival, and decision making is often disrupted in disease, yet the neuronal and molecular mechanisms of adaptive decision making are not well understood. Here we show that neural activity in a small population of neurons projecting to the fan-shaped body higher-order central brain region of Drosophila represents final food choice during sensory conflict. We found that hungry flies made tradeoffs between appetitive and aversive values of food in a decision making task to choose bittersweet food with high sucrose concentration, but adulterated with bitter quinine, over sweet-only food with less sucrose. Using cell-specific optogenetics and receptor RNAi knockdown during the decision task, we identified an upstream neuropeptidergic and dopaminergic network that relays internal state and other decision-relevant information, such as valence and previous experience, to a specific subset of fan-shaped body neurons. Importantly, calcium imaging revealed that these neurons were strongly inhibited by the taste of the rejected food choice, suggesting that they encode final behavioral food choice. Our findings reveal that fan-shaped body taste responses to food choices are determined not only by taste quality, but also by previous experience (including choice outcome) and hunger state, which are integrated in the fan-shaped body to encode the decision before relay to downstream motor circuits for behavioral implementation. Our results uncover a novel role for the fan-shaped body in choice encoding, and reveal a neural substrate for sensory and internal state integration for decision making in a genetically tractable model organism to enable mechanistic dissection at circuit, cellular, and molecular levels.