Unicellular associative conditioning: an interspecies analysis

The capacity to learn new systemic behaviour is a fundamental issue to understand the adaptive mechanisms involved in cellular evolution. We have recently observed, in a preliminary analysis, the emergence of conditioned behaviour in individual amoebae cells. In these experiments, cells were able to acquire new migratory conduct and remember it for long periods of their cellular cycle, forgetting it later on. Here, following a similar conceptual framework of Pavlov’s experiments, we have exhaustively studied the migration trajectories of more than 2000 individual cells belonging to three different species: Amoeba proteus, Metamoeba leningradensis, and Amoeba borokensis. Fundamentally, we have analysed several properties of conditioned cells, such as the intensity of the responses, the directionality persistence, the total distance traveled, the directionality ratio, the average speed, and the persistence times. We have observed that these three species can modify the systemic response to a specific stimulus by associative conditioning. Our main analysis shows that such new behaviour is very robust and presents a similar structure of migration patterns in the three species, which was characterized by the presence of conditioning for long periods, remarkable straightness in their trajectories and strong directional persistence. Our quantitative results, compared with other studies on complex cellular responses in bacteria, protozoa, fungus-like organisms and metazoans, allow us to conclude that cellular associative conditioning might be a widespread characteristic of unicellular organisms. This finding could be essential to understand some key evolutionary principles involved in increasing the cellular adaptive fitness to microenvironments.

Explaining causes

This chapter addresses the causes of cruelty. It covers a continuum of explanations from the banality of evil to automaton-like behaviour in bureaucracies, from pleasures derived from sadism to the cruelties fostered by selfishness. The banality thesis identifies widespread acceptance of cruelties if legitimized by states, their governments, their policies and/or by other powerful institutions. Analysis of conditioned behaviour refers largely to operators of state and non-state organizations who keep the wheels of cruelty turning, yet such personnel usually remain invisible, inaccessible, and non-accountable. Completing the cruelty puzzles requires accounts of sadistic behaviour, which is embedded as much in cultures of violence as in the pathology of any one person. The explanations overlap but have distinct characteristics. The chapter also considers cruelty driven by managerial demands for efficiency, a powerfully addictive notion which is not value neutral, and looks at the civil war between Colombian government forces and Revolutionary Armed Forces of Colombia (FARC) rebels in Colombia.

Documenting Aggression, Dominance and the Impacts of Visitor Interaction on Galápagos Tortoises (Chelonoidis nigra) in a Zoo Setting

Ensuring high levels of welfare is imperative for modern zoos, but such organisations must also engage visitors in order to successfully spread awareness and raise conservation funds. It is therefore important to understand the responses of animals to visitor interaction to optimise welfare. Often, the opportunity to interact with humans may be enriching for animals, but in other contexts, this interaction may have negative welfare effects. We observed captive female Galápagos giant tortoises (Chelonoidis nigra) to describe aggressive interactions, characterize hierarchy using Elo ratings and assess the impact of visitor interactions. Elo ratings indicated that one individual was dominant over two equally ranked subordinates; aggressive interactions are discussed in this context. We detected significant effects of the presence of visitors and visitor type (keepers, vets or public) within the enclosure on aggression and activity. We suggest that previous miscategorisation of a natural behaviour (the finch response) as an operantly conditioned behaviour, rather than a fixed action pattern, may have triggered aggression. We then document changes made to the management of the animals to mitigate the impacts discovered. This work highlights the importance of empirical evidence in determining optimal management strategies for zoo animals with regards to public interactions and animal welfare.

The Evolution of Mind

The evolution of the nervous system is described, with speculation on when consciousness first appears and when belief first appears. The developments of nonverbal communication and flexibility of response are traced. With humans the ability for mental simulation and inquiry by thought experiments appears, greatly extending the old method of trial by error. Humans still do most of the old things in the old ways, nonverbal communication, emotional feeling and expression, trial and error, family and kinship, in-group behaviour, aggression, conditioned behaviour, and instinct. System 2 reasoning has evolved, while old system 1 reasoning, of which belief is a part, retains its importance. The unique ability to adapt the environment to suit human needs has evolved.

Action-inhibition hierarchies: Using a simple gastropod model to investigate serotonergic and dopaminergic control of action selection and reinforcement learning

IntroductionBasal ganglia (BG) activity plays an important role in action selection and reinforcement learning. Inputs from and to other areas of the brain are modulated by a number of neurotransmitter pathways in the BG. Disturbances in the normal function of the BG may play a role in the aetiology of psychiatric disorders such as schizophrenia and bipolar disorder.AimsDevelop a simple animal model to evaluate interactions between glutamatergic, dopaminergic, serotonergic and GABAergic neurones in the modulation of action selection and reinforcement learning.ObjectivesTo characterise the effects of changing dopaminergic and serotonergic activity on action selection and reinforcement learning in an animal model.MethodsThe food seeking / consummation (FSC) activity of the gastropod Planorbis corneus was suppressed by operant conditioning using a repeated unconditioned stimulus-punishment regime. The effects of elevated serotonin or dopamine levels (administration into cerebral, pedal and buccal ganglia), on operantly-conditioned FSC activity was assessed.ResultsOperantly-conditioned behaviour was reversed by elevated ganglia serotonin levels but snails showed no food consummation motor activity in the absence of food. In contrast, elevated ganglia dopamine levels in conditioned snails elicited food consummation motor movements in the absence of food but not orientation towards a food source.ConclusionsThe modulation of FSC activity elicited by reinforcement learning is subject to hierarchical control in gastropods. Serotoninergic activity is responsible establishing the general activity level whilst dopaminergic activity appears to play a more localised and subordinate ‘command’ role.