Rat psychomotor vigilance task with fast response times using a conditioned lick behavior

Abstract

Investigations into the physiological mechanisms of sleep control require an animal psychomotor vigilance task (PVT) with fast response times (<300ms). Rats provide a good PVT model since whisker stimulation produces a rapid and robust cortical evoked response, and animals can be trained to lick following stimulation. Our prior experiments used deprivation-based approaches to maximize motivation for operant conditioned responses. However, deprivation can influence physiological and neurobehavioral effects. In order to maintain motivation without water deprivation, we conditioned rats for immobilization and head restraint, then trained them to lick for a 10% sucrose solution in response to whisker stimulation. After approximately 8 training sessions, animals produced greater than 80% correct hits to the stimulus. Over the course of training, reaction times became faster and correct hits increased. Performance in the PVT was examined after 3, 6 and 12 hours of sleep deprivation achieved by gentle handling. A significant decrease in percent correct hits occurred following 6 and 12 hours of sleep deprivation and reaction times increased significantly following 12 hours of sleep deprivation. While behaviorally the animals appeared to be awake, we observed significant increases in EEG delta power prior to misses. The rat PVT with fast response times allows investigation of sleep deprivation effects, time on task and pharmacological agents. Fast response times also allow closer parallel studies to ongoing human protocols.

Sleep deprivation and neurobehavioral dynamics

“…These characteristics and performance parameter optimizations make the new brief PVT-B a rapid assay for tracking the dynamic interaction of sleep homeostatic drive and circadian phase relative to sleep loss [30]. As importantly, rodent versions of the PVT have recently been developed and validated to be sensitive to both acute total sleep deprivation [31] and chronic partial sleep loss [32], enhancing feasibility of translational studies.…”

Precision rodent whisker stimulator with integrated servo-locked control and displacement measurement

“…To record evoked potentials from the somatosensory cortex while stimulating individual whiskers, rats were progressively accustomed to restraint conditions in custom designed wraps by a method previously described (Topchiy et al, 2009; Walker et al, 2011). All procedures were in accordance with the “Guide for the Care and Use of Laboratory Animals” and were approved by the Washington State University Animal Care and Use Committee.…”

“…Environmental features discriminated by the whisker sensory system include object localization, size and shape of objects, and texture (Ahissar and Knutsen, 2008; Arabzadeh et al, 2004; Knutsen and Ahissar, 2009; O'Connor et al, 2010; Prigg et al, 2002). Conditioned learning paradigms using whisker stimulation aid in the understanding of information processing and plasticity in the somatosensory cortex (Diamond et al, 2008; Kublik, 2004; Walker et al, 2011; Wrobel et al, 1998). When using high density electrical electrode arrays, the individual whisker barrels can be mapped in space and independently studied (Benison et al, 2006; Hollenberg et al, 2006; Yeager et al, 2008).…”

“…Since auditory cues must be minimized, we tested the effects of auditory noise (clicks) on the evoked potentials recorded over the barrel cortex by stimulating whiskers paired with and without a variety of auditory clicks of varying decibel levels (40, 45, 50, 60 dBa). These conditions were tested with and without 80 dBa white noise to determine if background noise will mask the auditory click that can accompany whisker stimulators (Galvez et al, 2007; Stuttgen et al, 2006; Walker et al, 2011). …”

Sleep and Cytokines

“…If rats are trained to lick in response to stimulation of a whisker, the error rate is higher if the cortical column of the stimulated whisker is in the sleeplike state than if it is in the wakelike state. 81,82 Localized injection of TNF onto cortical columns induces the sleeplike state in the affected columns. 78 These data suggest that sleep is a fundamental property of neuronal assemblies.…”