Anxiety from a Phylogenetic Perspective: Is there a Qualitative Difference between Human and Animal Anxiety?

Abstract

A phylogenetic approach to anxiety is proposed. The different facets of human anxiety and their presence at different levels of the phylum are examined. All organisms, including unicellular such as protozoan, can display a specific reaction to danger. The mechanisms enabling the appraisal of harmful stimuli are fully present in insects. In higher invertebrates, fear is associated with a specific physiological response. In mammals, anxiety is accompanied by specific cognitive responses. The expression of emotions diversifies in higher vertebrates, only primates displaying facial expressions. Finally, autonoetic consciousness, a feature essential for human anxiety, appears only in great apes. This evolutive feature parallels the progress in the complexity of the logistic systems supporting it (e.g., the vegetative and central nervous systems). The ability to assess one's coping potential, the diversification of the anxiety responses, and autonoetic consciousness seem relevant markers in a phylogenetic perspective.

Translating rodent behavioral repertoire to zebrafish (Danio rerio): Relevance for stress research

“…Such behavior is also referred to as thigmotaxis. This pattern of behavior is also consistent with previous findings in rodents [7][8][9]35] thus confirming that an unfamiliar environment can robustly evoke anxiety-like behavioral responses such as thigmotaxis in zebrafish. However, pharmacological manipulations using anti-anxiety drugs remain to be performed to ascertain the anxiety-like nature of darkavoidance (in the light/dark box) and thigmotaxic (in the open field) behaviors in zebrafish.…”

“…After correcting for arena size, we also observed that stressed (but not non-stressed control) zebrafish no longer display any preference for either inner or outer zones. Traditionally, increased time and exploration of aversive zones in both light/dark box [32,33] and open field [8,9,31,35,47] tests in rodents are usually regarded as anxiolytic effects. These findings therefore suggest that acute stress may momentarily relieve anxiety in zebrafish.…”

“…Lately, the zebrafish has been quickly propelled to the forefront of modern technology for high-throughput drug screening and discovery, becoming a valuable whole organism model for preclinical research [1][2][3][4][5]. Traditionally, the search for novel neuroactive drugs (especially in the fields of neurology and psychiatry) has been achieved through rodent models [6][7][8][9]. These models have proven to be useful but have major pitfalls (i.e.…”

The Genetic Basis of Emotional Behavior: Has the Time Come for a Drosophila Model?

“…However, emotions such as fear and anger, which underlie anxiety and depression, may, indeed, be there. Interesting, the potential for fruit flies to be used to study anxiety and depression has been stated several times (Belzung & Philippot, 2007;Damasio, 2001;Kalueff et al, 2007;Moldin, 2000). To date, Drosophila has been successfully used as a model system to elucidate molecular, physiological, and behavioral mechanisms of several human neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's (Chan & Bonini, 2000).…”

Serotonin, but not dopamine, controls stress response and anxiety-like behavior in crayfish, Procambarus clarkii.

“…When stress is prolonged, it can elicit long-lasting behavioral adaptations, resulting in a sustained apprehension of the environment, which persists even in a new context and in the absence of stressor. This state of higher alertness is called anxiety (Blanchard and Blanchard, 1988;Belzung and Philippot, 2007;Steimer, 2011). Recently, it has been shown that anxiety-like behavior (ALB) is also observable in crustaceans (Fossat et al, 2014), allowing the study of primitive forms of anxiety and of their neurobiological correlates.…”