Dynamic perceptual feature selectivity in primary somatosensory cortex upon reversal learning

ABSTRACTNeurons in primary sensory cortex encode a variety of stimulus features upon perceptual learning. However, it is unclear whether the acquired stimulus selectivity remains stable when the same input is perceived in a different context. Here, we monitored the activity of individual neurons in the mouse primary somatosensory cortex in a reward-based texture discrimination task. We tracked their stimulus selectivity before and after changing reward contingencies, which allowed us to identify various classes of neurons. We found neurons that stably represented a texture or the upcoming behavioral choice, but the majority was dynamic. Among those, a subpopulation of neurons regained selectivity contingent on stimulus-value. These value-sensitive neurons forecasted the onset of learning by displaying a distinct and transient increase in activity, depending on past behavioral experience. Thus, stimulus selectivity of excitatory neurons during perceptual learning is dynamic and largely relies on behavioral contingencies, even in primary sensory cortex.

Download Full-text

Associative learning changes cross-modal representations in the gustatory cortex

eLife ◽

10.7554/elife.16420 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 33

Author(s):

Roberto Vincis ◽

Alfredo Fontanini

Keyword(s):

Associative Learning ◽

Neural Representation ◽

Sensory Cortex ◽

Gustatory Cortex ◽

Primary Sensory Cortex ◽

Sensory Modalities ◽

Before And After ◽

Olfactory Stimuli ◽

Sensory Cortices ◽

Single Modality

A growing body of literature has demonstrated that primary sensory cortices are not exclusively unimodal, but can respond to stimuli of different sensory modalities. However, several questions concerning the neural representation of cross-modal stimuli remain open. Indeed, it is poorly understood if cross-modal stimuli evoke unique or overlapping representations in a primary sensory cortex and whether learning can modulate these representations. Here we recorded single unit responses to auditory, visual, somatosensory, and olfactory stimuli in the gustatory cortex (GC) of alert rats before and after associative learning. We found that, in untrained rats, the majority of GC neurons were modulated by a single modality. Upon learning, both prevalence of cross-modal responsive neurons and their breadth of tuning increased, leading to a greater overlap of representations. Altogether, our results show that the gustatory cortex represents cross-modal stimuli according to their sensory identity, and that learning changes the overlap of cross-modal representations.

Download Full-text

Sensory cortical dynamics during optical microstimulation training

10.1101/2021.12.17.473191 ◽

2021 ◽

Author(s):

Ravi Pancholi ◽

Lauren Ryan ◽

Simon P Peron

Keyword(s):

Somatosensory Cortex ◽

Calcium Imaging ◽

Pyramidal Neurons ◽

Cortical Activity ◽

Sensory Cortex ◽

Cortical Processing ◽

Cortical Dynamics ◽

Two Photon ◽

Primary Sensory Cortex ◽

Impact Perception

Primary sensory cortex is a key locus of plasticity during learning. Exposure to novel stimuli often alters cortical activity, but isolating cortex-specific dynamics is challenging due to extensive pre-cortical processing. Here, we employ optical microstimulation of pyramidal neurons in layer (L) 2/3 of mouse primary vibrissal somatosensory cortex (vS1) to study cortical dynamics as mice learn to discriminate microstimulation intensity. Tracking activity over weeks using two-photon calcium imaging, we observe a rapid sparsification of the photoresponsive population, with the most responsive neurons exhibiting the largest declines in responsiveness. Following sparsification, the photoresponsive population attains a stable rate of neuronal turnover. At the same time, the photoresponsive population increasingly overlaps with populations encoding whisker movement and touch. Finally, we find that mice with larger declines in responsiveness learn the task more slowly than mice with smaller declines. Our results reveal that microstimulation-evoked cortical activity undergoes extensive reorganization during task learning and that the dynamics of this reorganization impact perception.

Download Full-text