Animal behavioral paradigms, such as classical conditioning and operant conditioning, are an important tool to study the neural basis of cognition and behavior. These paradigms involve manipulating sensory stimuli in a way that learning processes are induced under controlled experimental conditions. However, the majority of the commercially available equipment did not offer flexibility to manipulate stimuli. Therefore, the development of most versatile devices would allow the study of more complex cognitive functions. The purpose of this work is to present a low-cost, customized and wireless-operated chamber for animal behavior conditioning, based on the joint operation of two microcontroller modules: Arduino Due and ESP8266-12E. Our results showed that the auditory stimulation system allows setting the carrier frequency in the range of 1 Hz up to more than 100 kHz and the sound stimulus can be modulated in amplitude, also over a wide range of frequencies. Likewise, foot-shock could be precisely manipulated regarding its amplitude (from ∼200 μA to ∼1500 μA) and frequency (up to 20 pulses per second). Finally, adult rats exposed to a protocol of cued fear conditioning in our device showed consistent behavioral response and electrophysiological evoked responses in the midbrain auditory pathway. Furthermore, the device developed in the current study represents an open source alternative to develop customized protocols to study fear memory under conditions of varied sensory stimuli.

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34Animal behavioral paradigms, such as classical conditioning and operant conditioning, 35 are an important tool to study the neural basis of cognition and behavior. These paradigms 36 involve manipulating sensory stimuli in a way that learning processes are induced under 37 controlled experimental conditions. However, the majority of the commercially available 38 equipment did not offer flexibility to manipulate stimuli. Therefore, the development of 39 most versatile devices would allow the study of more complex cognitive functions. The 40 purpose of this work is to present a low-cost, customized and wireless-operated chamber 41 for animal behavior conditioning, based on the joint operation of two microcontroller 42 modules: Arduino Due and ESP8266-12E. Our results showed that the auditory 43 stimulation system allows setting the carrier frequency in the range of 1 Hz up to more 44 than 100 kHz and the sound stimulus can be modulated in amplitude, also over a wide 45 range of frequencies. Likewise, foot-shock could be precisely manipulated regarding its 46 amplitude (from ~200 μA to ~1500 μA) and frequency (up to 20 pulses per second). 47 53 54 Animal behavioral paradigms have long played an important role in understanding 55 the underlying neurobiological mechanisms of learning and memory processes; 56 ubiquitously considered one of the greatest challenges in Neuroscience (Squire, 2009). In 57 Classical or Pavlovian Conditioning, animal innate or reflex responses become evocable 58 by stimuli that are usually neutral (such as sound or visual stimuli), if previously paired 59 with an emotionally relevant stimuli, characterizing the basis of an associative learning 60 process (Kim and Jung, 2006). Using a more appropriate terminology, the conditioned 61 responses (CR) are established under an appropriate contingency of unconditioned 62 stimulus (US) presentations paired with the conditioned stimulus (CS) occurrences 63 (Baron, 1959; Holland, 1977). Proper controls undergo the exact same procedure aside 64 from the fact that CS or US can be presented alone or CS is not paired in time with the 65 US (Rescorla, 1967). Although the laboratory equipments designed to perform such 66 associative learning protocols are supposedly fairly simple, the price can be prohibitive 67 for small budget projects and they are usually quite inflexible in terms of controlling and 68 programming the stimuli. The latter may constitute a drawback for the design of 69 customized behavioral paradigms which may use amplitude modulated stimuli in order 70 to isolate neural circuitry involved in the sensory processing by means of steady state 71 evoked responses (Lockmann et al., 2017; Pinto et al., 2017). In addition, the study of 72 more complex cognitive and behavioral processes becomes impracticable, since they 73 require more sophisticated and robust means of controlling contextual parameters and 74 interacting with the animals (Cushman et al., 2013). 75 Fortunately, custom development of laboratory tools is becoming more fe...