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Neurons in the barrel cortex turn into processing whisker and odor signals: a cellular mechanism for the storage and retrieval of associative signals.

Wang D, Zhao J, Gao Z, Chen N, Wen B, Lu W, Lei Z, Chen C, Liu Y, Feng J, Wang JH - Front Cell Neurosci (2015)

Bottom Line: How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear.After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory).Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals.

View Article: PubMed Central - PubMed

Affiliation: State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China.

ABSTRACT
Associative learning and memory are essential to logical thinking and cognition. How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear. We studied this issue in the barrel cortex by in vivo two-photon calcium imaging, electrophysiology, and neural tracing in our mouse model that the simultaneous whisker and olfaction stimulations led to odorant-induced whisker motion. After this cross-modal reflex arose, the barrel and piriform cortices connected. More than 40% of barrel cortical neurons became to encode odor signal alongside whisker signal. Some of these neurons expressed distinct activity patterns in response to acquired odor signal and innate whisker signal, and others encoded similar pattern in response to these signals. In the meantime, certain barrel cortical astrocytes encoded odorant and whisker signals. After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory). Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals.

No MeSH data available.


Related in: MedlinePlus

The neurons in the barrel cortex are reorganized after associative learning. (Left) Shows a mouse brain including reflex arcs for whisker-induced whisker motion (unconditioned reflex; blue arrow) and odorant-induced whisker motion (cross-modal reflex; red arrow) after WS/OS-pairing. Associative learning induces the connection between the barrel and piriform cortices, which allows the formation of cross-modal reflex. Afferent pathways (blue dot lines) and efferent pathway (red dash-dot) in the reflex arc are showed under the cerebral cortex. The connections from the barrel cortex (BC) to piriform cortex (PC) and from BC to the motor cortex (M) in the center of the reflex arc are presented as solid blue lines. (Right) Shows barrel cortical neurons that are recruited and refined as WS/OS-responsive neurons (three neurons in the middle), receive the axonal innervations from the thalamus and piriform cortex, and encode WS and OS, i.e., associative memory neurons. Left-middle neuron receives the thalamic input and responds to WS dominantly. Right-middle neuron receives the piriform cortical input and responds to OS dominantly. Middle neuron receives the thalamic and piriform inputs and responds to WS and OS equally. Moreover, some neurons receive thalamic input naturally and respond to WS only (left), whereas some neurons receive piriform cortical input after associative learning and respond to OS only (right). These OS-responsive cells for cross-modal memory fall into the category of new signal memory cells. Based on the different responses of individual neurons to WS and OS and the different organizations of responsive neurons, the barrel cortex becomes able to fulfill the associative storages and distinguishable retrievals of the newly acquired odor signal and the innate whisker signal.
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Figure 11: The neurons in the barrel cortex are reorganized after associative learning. (Left) Shows a mouse brain including reflex arcs for whisker-induced whisker motion (unconditioned reflex; blue arrow) and odorant-induced whisker motion (cross-modal reflex; red arrow) after WS/OS-pairing. Associative learning induces the connection between the barrel and piriform cortices, which allows the formation of cross-modal reflex. Afferent pathways (blue dot lines) and efferent pathway (red dash-dot) in the reflex arc are showed under the cerebral cortex. The connections from the barrel cortex (BC) to piriform cortex (PC) and from BC to the motor cortex (M) in the center of the reflex arc are presented as solid blue lines. (Right) Shows barrel cortical neurons that are recruited and refined as WS/OS-responsive neurons (three neurons in the middle), receive the axonal innervations from the thalamus and piriform cortex, and encode WS and OS, i.e., associative memory neurons. Left-middle neuron receives the thalamic input and responds to WS dominantly. Right-middle neuron receives the piriform cortical input and responds to OS dominantly. Middle neuron receives the thalamic and piriform inputs and responds to WS and OS equally. Moreover, some neurons receive thalamic input naturally and respond to WS only (left), whereas some neurons receive piriform cortical input after associative learning and respond to OS only (right). These OS-responsive cells for cross-modal memory fall into the category of new signal memory cells. Based on the different responses of individual neurons to WS and OS and the different organizations of responsive neurons, the barrel cortex becomes able to fulfill the associative storages and distinguishable retrievals of the newly acquired odor signal and the innate whisker signal.

Mentions: We study the recruitment of the cortical neurons and astrocytes for the storage and retrieval of the associated signals in a new mouse model of conditioned reflex. A simultaneous pairing of whisker and odor stimuli leads to odorant-induced whisker signal recall and whisker motion (Figure 1). An associative activation of the barrel and piriform cortices induces their synaptic connections (Figure 3). The afferent pathways are convergent into the sensory cortices and share the common efferent pathway in their reflex arcs (Figure 11) for co-expressing native reflex (whisker-induced whisker motion) and conditioned reflex (odorant-induced whisker motion). With the convergence of sensory pathways into the barrel cortex, a substantial amount of the neurons, and astrocytes are recruited to encode new odor signal and innate whisker signal for their associative storages (Figures 5–7). The union of these associated signals through their respective pathways (Figure 11) synaptically onto individual cells recruits associative memory cells, such that the associated signals retrieve each other. Moreover, the associative memory cells express different or similar patterns in response to the associated signals (Figures 6–10). Some cells by computing the different codes distinguish the differences of the associated signals, and others by identical patterns signify the historical association of these signals. This working principle for associative memory is granted by the observation that the cross-modal reflex and associative memory cells are present for multiple signals.


Neurons in the barrel cortex turn into processing whisker and odor signals: a cellular mechanism for the storage and retrieval of associative signals.

Wang D, Zhao J, Gao Z, Chen N, Wen B, Lu W, Lei Z, Chen C, Liu Y, Feng J, Wang JH - Front Cell Neurosci (2015)

The neurons in the barrel cortex are reorganized after associative learning. (Left) Shows a mouse brain including reflex arcs for whisker-induced whisker motion (unconditioned reflex; blue arrow) and odorant-induced whisker motion (cross-modal reflex; red arrow) after WS/OS-pairing. Associative learning induces the connection between the barrel and piriform cortices, which allows the formation of cross-modal reflex. Afferent pathways (blue dot lines) and efferent pathway (red dash-dot) in the reflex arc are showed under the cerebral cortex. The connections from the barrel cortex (BC) to piriform cortex (PC) and from BC to the motor cortex (M) in the center of the reflex arc are presented as solid blue lines. (Right) Shows barrel cortical neurons that are recruited and refined as WS/OS-responsive neurons (three neurons in the middle), receive the axonal innervations from the thalamus and piriform cortex, and encode WS and OS, i.e., associative memory neurons. Left-middle neuron receives the thalamic input and responds to WS dominantly. Right-middle neuron receives the piriform cortical input and responds to OS dominantly. Middle neuron receives the thalamic and piriform inputs and responds to WS and OS equally. Moreover, some neurons receive thalamic input naturally and respond to WS only (left), whereas some neurons receive piriform cortical input after associative learning and respond to OS only (right). These OS-responsive cells for cross-modal memory fall into the category of new signal memory cells. Based on the different responses of individual neurons to WS and OS and the different organizations of responsive neurons, the barrel cortex becomes able to fulfill the associative storages and distinguishable retrievals of the newly acquired odor signal and the innate whisker signal.
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Related In: Results  -  Collection

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Figure 11: The neurons in the barrel cortex are reorganized after associative learning. (Left) Shows a mouse brain including reflex arcs for whisker-induced whisker motion (unconditioned reflex; blue arrow) and odorant-induced whisker motion (cross-modal reflex; red arrow) after WS/OS-pairing. Associative learning induces the connection between the barrel and piriform cortices, which allows the formation of cross-modal reflex. Afferent pathways (blue dot lines) and efferent pathway (red dash-dot) in the reflex arc are showed under the cerebral cortex. The connections from the barrel cortex (BC) to piriform cortex (PC) and from BC to the motor cortex (M) in the center of the reflex arc are presented as solid blue lines. (Right) Shows barrel cortical neurons that are recruited and refined as WS/OS-responsive neurons (three neurons in the middle), receive the axonal innervations from the thalamus and piriform cortex, and encode WS and OS, i.e., associative memory neurons. Left-middle neuron receives the thalamic input and responds to WS dominantly. Right-middle neuron receives the piriform cortical input and responds to OS dominantly. Middle neuron receives the thalamic and piriform inputs and responds to WS and OS equally. Moreover, some neurons receive thalamic input naturally and respond to WS only (left), whereas some neurons receive piriform cortical input after associative learning and respond to OS only (right). These OS-responsive cells for cross-modal memory fall into the category of new signal memory cells. Based on the different responses of individual neurons to WS and OS and the different organizations of responsive neurons, the barrel cortex becomes able to fulfill the associative storages and distinguishable retrievals of the newly acquired odor signal and the innate whisker signal.
Mentions: We study the recruitment of the cortical neurons and astrocytes for the storage and retrieval of the associated signals in a new mouse model of conditioned reflex. A simultaneous pairing of whisker and odor stimuli leads to odorant-induced whisker signal recall and whisker motion (Figure 1). An associative activation of the barrel and piriform cortices induces their synaptic connections (Figure 3). The afferent pathways are convergent into the sensory cortices and share the common efferent pathway in their reflex arcs (Figure 11) for co-expressing native reflex (whisker-induced whisker motion) and conditioned reflex (odorant-induced whisker motion). With the convergence of sensory pathways into the barrel cortex, a substantial amount of the neurons, and astrocytes are recruited to encode new odor signal and innate whisker signal for their associative storages (Figures 5–7). The union of these associated signals through their respective pathways (Figure 11) synaptically onto individual cells recruits associative memory cells, such that the associated signals retrieve each other. Moreover, the associative memory cells express different or similar patterns in response to the associated signals (Figures 6–10). Some cells by computing the different codes distinguish the differences of the associated signals, and others by identical patterns signify the historical association of these signals. This working principle for associative memory is granted by the observation that the cross-modal reflex and associative memory cells are present for multiple signals.

Bottom Line: How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear.After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory).Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals.

View Article: PubMed Central - PubMed

Affiliation: State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China.

ABSTRACT
Associative learning and memory are essential to logical thinking and cognition. How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear. We studied this issue in the barrel cortex by in vivo two-photon calcium imaging, electrophysiology, and neural tracing in our mouse model that the simultaneous whisker and olfaction stimulations led to odorant-induced whisker motion. After this cross-modal reflex arose, the barrel and piriform cortices connected. More than 40% of barrel cortical neurons became to encode odor signal alongside whisker signal. Some of these neurons expressed distinct activity patterns in response to acquired odor signal and innate whisker signal, and others encoded similar pattern in response to these signals. In the meantime, certain barrel cortical astrocytes encoded odorant and whisker signals. After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory). Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals.

No MeSH data available.


Related in: MedlinePlus