Dopamine modulation of sensory processing and adaptive behavior in flies

Abstract

Behavioral flexibility for appropriate action selection is an advantage when animals are faced with decisions that will determine their survival or death. In order to arrive at the right decision, animals evaluate information from their external environment, internal state, and past experiences. How these different signals are integrated and modulated in the brain, and how context- and state-dependent behavioral decisions are controlled are poorly understood questions. Studying the molecules that help convey and integrate such information in neural circuits is an important way to approach these questions. Many years of work in different model organisms have shown that dopamine is a critical neuromodulator for (reward based) associative learning. However, recent findings in vertebrates and invertebrates have demonstrated the complexity and heterogeneity of dopaminergic neuron populations and their functional implications in many adaptive behaviors important for survival. For example, dopaminergic neurons can integrate external sensory information, internal and behavioral states, and learned experience in the decision making circuitry. Several recent advances in methodologies and the availability of a synaptic level connectome of the whole-brain circuitry of Drosophila melanogaster make the fly an attractive system to study the roles of dopamine in decision making and state-dependent behavior. In particular, a learning and memory center—the mushroom body—is richly innervated by dopaminergic neurons that enable it to integrate multi-modal information according to state and context, and to modulate decision-making and behavior.

Tyrosine hydroxylase immunostaining in the central complex of dicondylian insects

“…In contrast to the DP2/PPM3 neurons, only a fraction of DC/PPL1 neurons targets the central body. Most of these neurons bypass the CX, but innervate various parts of the mushroom body with a prominent role in olfactory memory formation (Huetteroth et al, 2015; Siju et al, 2021). These neurons are already present in the flightless firebrat (Figure 2(d,e)), but here, none of the DC neurons innervate the central body.…”

“…Immunostaining for dopamine and/or tyrosine hydroxylase (TH), the rate limiting enzyme in dopamine biosynthesis, revealed small numbers of neurons with processes that innervate most brain areas (honeybee: Schürmann et al, 1989; Schäfer & Rehder, 1989; blowfly, vinegar fly: Nässel & Elekes, 1992; Mao & Davis, 2009; desert locust: Wendt & Homberg, 1992; American cockroach: Hamanaka et al, 2016). Corresponding to its wide distribution, different functions have been demonstrated for dopamine in the insect nervous system, including a role in learning and memory, arousal, aggressiveness, and sleep–wake regulation (reviewed in van Swinderen & Andretic, 2011; Mustard et al, 2012; Yamamoto & Seto, 2014; Verlinden, 2018; Siju et al, 2021). Studies in the fly Drosophila , the honeybee, and the field cricket show that dopaminergic neurons are involved in associative learning (Das et al, 2016; Waddell, 2013; Wright, 2011).…”

Dopamine, sleep, and neuronal excitability modulate amyloid-β–mediated forgetting in Drosophila

“…As the expression of Aβ in the MB, the main learning center does not affect learning, these defects could be due to other neurons in the nSyb driver line required for learning. One candidate would be the dopaminergic neurons (DANs), which have a well-established role in learning [ 39 , 40 ]. Therefore, we expressed Aβ 42 Arctic in the DANs using the TH-Gal4 driver comprising most of the DANs [ 41 , 42 ].…”

Phenylalanine Rich Diet (Vicia faba L.) Enhances the Expression of Dopamine Receptor D3 (DRD3) Gene in Rabbits

“…Dopamine also affects the quality of life and health for humans and animals. Low dopamine levels result in increasing the hostility of the animal and its lack of calmness, it also affects its productivity in terms of the amount of milk produced [21], [22].…”