Cortical processing of chemosensory and hedonic features of taste in active licking mice

Abstract

Relatively little information is available on the neural dynamics of taste processing in the mouse gustatory cortex (GC). In this study we investigate how the GC encodes chemosensory and palatability features of a wide panel of gustatory stimuli when actively sampled through licking. Our results show that GC neurons broadly encode basic taste qualities but also process taste hedonics and licking information in a temporally dynamic manner.

Trehalose Reduces Nerve Injury Induced Nociception in Mice but Negatively Affects Alertness

“…A continuous trehalose administration over an extended period may mimic long-term nutrient deficiency for neurons, and one may speculate that neurons will try to save energy and reduce their activity. We assume that antinociceptive effects and the in vivo sedation-like behavior reflect sedation-like effects on excitatory neurons, based on previous studies using in vivo electrophysiologic recordings in behaving mice [ 61 , 62 , 63 ]. However, we did not directly study cortical activity under trehalose.…”

Cortical Hub for Flavor Sensation in Rodents

“…While it is important to highlight that taste-responsive neurons in the gustatory cortex are often multimodal (see the section 4), these studies showed that neurons in the gustatory cortex represent the identity and hedonic value of taste stimuli. Neurophysiological data obtained from extracellular recordings in anaesthetized and alert rodents highlight the presence of both narrowly-tuned neurons (those modulated by one taste quality) and broadly-tuned neurons (those modulated by multiple taste qualities) (Yamamoto et al, 1981 ; Kosar et al, 1986 ; Ogawa et al, 1992 ; Katz et al, 2001 ; Stapleton et al, 2006 ; Jezzini et al, 2013 ; Levitan et al, 2019 ; Bouaichi and Vincis, 2020 ; Dikecligil et al, 2020 ), with the latter being the majority in awake conditions (Katz et al, 2001 ; Stapleton et al, 2006 ; Samuelsen et al, 2012 , 2013 ; Jezzini et al, 2013 ; Levitan et al, 2019 ; Bouaichi and Vincis, 2020 ). Studies in alert rodents, receiving taste stimuli either via an intraoral cannula (IOC) or by licking a spout, emphasized the importance of the temporal dynamics of taste-evoked activity.…”

“…For example, the intraoral delivery of taste stimuli evokes different epochs in firing rates during the first 2.5 s. In this context, the neural activity first represents the presence (~0–250 ms), then the identity (~250–750 ms), and finally the hedonic value of taste stimuli (Katz et al, 2001 ; Fontanini and Katz, 2006 ; Jones et al, 2007 ; Grossman et al, 2008 ; Piette et al, 2012 ; Sadacca et al, 2012 ; Jezzini et al, 2013 ; Samuelsen et al, 2013 ; Levitan et al, 2019 ; Mukherjee et al, 2019 ). In addition, studies in which rodents lick a spout to receive taste stimuli revealed additional complex and rich temporal dynamics related to licking rhythmicity in the gustatory cortex (see the section 4) (Stapleton et al, 2006 ; Gutierrez et al, 2010 ; Bouaichi and Vincis, 2020 ).…”

“…Many studies, in both anesthetized and alert rodents, show that neurons in the gustatory cortex respond to somatosensory tactile stimulation of the tongue and oral cavity (Yamamoto et al, 1981 , 1988 ; Kosar et al, 1986 ; Katz et al, 2001 ; Stapleton et al, 2006 ; Gutierrez et al, 2010 ; Bouaichi and Vincis, 2020 ; Dikecligil et al, 2020 ). In awake behaving rodents, when taste stimuli are delivered directly into the mouth via IOCs, somatosensory responses emerge as fast and phasic changes in neural activity within 200ms following fluid delivery (Katz et al, 2001 ).…”

“…In awake behaving rodents, when taste stimuli are delivered directly into the mouth via IOCs, somatosensory responses emerge as fast and phasic changes in neural activity within 200ms following fluid delivery (Katz et al, 2001 ). Moreover, neurons in the gustatory cortex exhibit somatosensory-evoked activity when taste-delivery is contingent upon licking a spout (Stapleton et al, 2006 ; Gutierrez et al, 2010 ; Bouaichi and Vincis, 2020 ; Dikecligil et al, 2020 ). In this condition, the vast majority of neurons exhibit spiking activity entrained to licking at rates between 6 to 12 Hz.…”