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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 connection between the barrel and piriform cortices is established after associative learning. The structural connection was traced by injecting 1,1′dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate into the barrel cortex and seeing its presence in the piriform cortex. The functional connection was examined by recording LFP in the piriform cortex and electrically stimulating the barrel cortex in vivo, or turned around. In in vivo recordings, bipolar tungsten electrodes were placed in barrel cortex, and glass recording electrodes (10 MΩ) were positioned into the piriform cortex (0.34–0.58 mm posterior to the bregma, 3.25–3.5 mm lateral to midline, and 4.75–5.0 mm in depth). (A) Shows neural tracing from the barrel cortex to the piriform cortex in CR-formation mouse. An arrow points fluorescent labeling in the piriform cortex. Left panel shows an enlarged image from the piriform cortex which includes DiI-labeled neuron (yellow arrow) and DiI-labeled axons (green arrow). (B) Shows the neural tracing from the barrel cortex to the piriform cortex in a NCG mouse. An arrows indicates no fluorescent labeling in the piriform cortex. (C) Shows the comparison of neural tracing in the piriform cortex from CR-formation mice (n = 9, gray bar) and NCG mice (n = 9, white), based on relative fluorescent intensity. (D) Shows LFP recording in the piriform cortex by a glass pipette of including DiI and the electrical stimulation in the barrel cortex in vivo. (E) Top trace shows LFP in the piriform cortex recorded from a CR-formation mouse and bottom trace shows no LFP recorded in the piriform cortex from a NCG mouse. (F) Illustrates the comparison of LFPs recorded in the piriform cortex from CR-formation group (n = 5 recordings from three mice, gray bar) and NCG (n = 6 recordings from three mice, white bar). (G) Shows LFP recording in the barrel cortex and electrical stimuli in the piriform cortex in the brain slices. (H) Top trace shows LFP in the barrel cortex recorded from a CR-formation mouse, and bottom trace shows no LFP recorded in the barrel cortex from a NCG mouse. (I) Illustrates the comparisons of electrical signals recorded in the barrel cortex from CR-formation mice (n = 23 recordings from five mice, gray bar) and NCG mice (from five mice, white). **p < 0.01; ***p < 0.001.
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Figure 3: The connection between the barrel and piriform cortices is established after associative learning. The structural connection was traced by injecting 1,1′dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate into the barrel cortex and seeing its presence in the piriform cortex. The functional connection was examined by recording LFP in the piriform cortex and electrically stimulating the barrel cortex in vivo, or turned around. In in vivo recordings, bipolar tungsten electrodes were placed in barrel cortex, and glass recording electrodes (10 MΩ) were positioned into the piriform cortex (0.34–0.58 mm posterior to the bregma, 3.25–3.5 mm lateral to midline, and 4.75–5.0 mm in depth). (A) Shows neural tracing from the barrel cortex to the piriform cortex in CR-formation mouse. An arrow points fluorescent labeling in the piriform cortex. Left panel shows an enlarged image from the piriform cortex which includes DiI-labeled neuron (yellow arrow) and DiI-labeled axons (green arrow). (B) Shows the neural tracing from the barrel cortex to the piriform cortex in a NCG mouse. An arrows indicates no fluorescent labeling in the piriform cortex. (C) Shows the comparison of neural tracing in the piriform cortex from CR-formation mice (n = 9, gray bar) and NCG mice (n = 9, white), based on relative fluorescent intensity. (D) Shows LFP recording in the piriform cortex by a glass pipette of including DiI and the electrical stimulation in the barrel cortex in vivo. (E) Top trace shows LFP in the piriform cortex recorded from a CR-formation mouse and bottom trace shows no LFP recorded in the piriform cortex from a NCG mouse. (F) Illustrates the comparison of LFPs recorded in the piriform cortex from CR-formation group (n = 5 recordings from three mice, gray bar) and NCG (n = 6 recordings from three mice, white bar). (G) Shows LFP recording in the barrel cortex and electrical stimuli in the piriform cortex in the brain slices. (H) Top trace shows LFP in the barrel cortex recorded from a CR-formation mouse, and bottom trace shows no LFP recorded in the barrel cortex from a NCG mouse. (I) Illustrates the comparisons of electrical signals recorded in the barrel cortex from CR-formation mice (n = 23 recordings from five mice, gray bar) and NCG mice (from five mice, white). **p < 0.01; ***p < 0.001.

Mentions: Odorant-induced whisker motion may be based on the formation of axon connections between the barrel and piriform cortices, as the wiring is detected in cross-modal plasticity (Ye et al., 2012). The structural connections between the barrel and piriform cortices were traced by injecting 1,1′dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate (DiI) in the barrel cortices. Compared to neural tracing in controls (Figures 3B,C, n = 9), DiI is detected in the piriform cortex and layer-VI white matter in CR-formation mice (Figures 3A–C, p < 0.001, n = 9; One-Way ANOVA). As DiI is detected in axonal terminals and cell bodies of the piriform cortex (enlarged images in Figures 3A,B), the mutual innervation between the barrel and piriform cortices forms after associative memory. It is noteworthy that the connection may not form through the intermediate brain areas since DiI is not trans-synaptic dye and digital spikes do not cross over chemical synapses.


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 connection between the barrel and piriform cortices is established after associative learning. The structural connection was traced by injecting 1,1′dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate into the barrel cortex and seeing its presence in the piriform cortex. The functional connection was examined by recording LFP in the piriform cortex and electrically stimulating the barrel cortex in vivo, or turned around. In in vivo recordings, bipolar tungsten electrodes were placed in barrel cortex, and glass recording electrodes (10 MΩ) were positioned into the piriform cortex (0.34–0.58 mm posterior to the bregma, 3.25–3.5 mm lateral to midline, and 4.75–5.0 mm in depth). (A) Shows neural tracing from the barrel cortex to the piriform cortex in CR-formation mouse. An arrow points fluorescent labeling in the piriform cortex. Left panel shows an enlarged image from the piriform cortex which includes DiI-labeled neuron (yellow arrow) and DiI-labeled axons (green arrow). (B) Shows the neural tracing from the barrel cortex to the piriform cortex in a NCG mouse. An arrows indicates no fluorescent labeling in the piriform cortex. (C) Shows the comparison of neural tracing in the piriform cortex from CR-formation mice (n = 9, gray bar) and NCG mice (n = 9, white), based on relative fluorescent intensity. (D) Shows LFP recording in the piriform cortex by a glass pipette of including DiI and the electrical stimulation in the barrel cortex in vivo. (E) Top trace shows LFP in the piriform cortex recorded from a CR-formation mouse and bottom trace shows no LFP recorded in the piriform cortex from a NCG mouse. (F) Illustrates the comparison of LFPs recorded in the piriform cortex from CR-formation group (n = 5 recordings from three mice, gray bar) and NCG (n = 6 recordings from three mice, white bar). (G) Shows LFP recording in the barrel cortex and electrical stimuli in the piriform cortex in the brain slices. (H) Top trace shows LFP in the barrel cortex recorded from a CR-formation mouse, and bottom trace shows no LFP recorded in the barrel cortex from a NCG mouse. (I) Illustrates the comparisons of electrical signals recorded in the barrel cortex from CR-formation mice (n = 23 recordings from five mice, gray bar) and NCG mice (from five mice, white). **p < 0.01; ***p < 0.001.
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Figure 3: The connection between the barrel and piriform cortices is established after associative learning. The structural connection was traced by injecting 1,1′dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate into the barrel cortex and seeing its presence in the piriform cortex. The functional connection was examined by recording LFP in the piriform cortex and electrically stimulating the barrel cortex in vivo, or turned around. In in vivo recordings, bipolar tungsten electrodes were placed in barrel cortex, and glass recording electrodes (10 MΩ) were positioned into the piriform cortex (0.34–0.58 mm posterior to the bregma, 3.25–3.5 mm lateral to midline, and 4.75–5.0 mm in depth). (A) Shows neural tracing from the barrel cortex to the piriform cortex in CR-formation mouse. An arrow points fluorescent labeling in the piriform cortex. Left panel shows an enlarged image from the piriform cortex which includes DiI-labeled neuron (yellow arrow) and DiI-labeled axons (green arrow). (B) Shows the neural tracing from the barrel cortex to the piriform cortex in a NCG mouse. An arrows indicates no fluorescent labeling in the piriform cortex. (C) Shows the comparison of neural tracing in the piriform cortex from CR-formation mice (n = 9, gray bar) and NCG mice (n = 9, white), based on relative fluorescent intensity. (D) Shows LFP recording in the piriform cortex by a glass pipette of including DiI and the electrical stimulation in the barrel cortex in vivo. (E) Top trace shows LFP in the piriform cortex recorded from a CR-formation mouse and bottom trace shows no LFP recorded in the piriform cortex from a NCG mouse. (F) Illustrates the comparison of LFPs recorded in the piriform cortex from CR-formation group (n = 5 recordings from three mice, gray bar) and NCG (n = 6 recordings from three mice, white bar). (G) Shows LFP recording in the barrel cortex and electrical stimuli in the piriform cortex in the brain slices. (H) Top trace shows LFP in the barrel cortex recorded from a CR-formation mouse, and bottom trace shows no LFP recorded in the barrel cortex from a NCG mouse. (I) Illustrates the comparisons of electrical signals recorded in the barrel cortex from CR-formation mice (n = 23 recordings from five mice, gray bar) and NCG mice (from five mice, white). **p < 0.01; ***p < 0.001.
Mentions: Odorant-induced whisker motion may be based on the formation of axon connections between the barrel and piriform cortices, as the wiring is detected in cross-modal plasticity (Ye et al., 2012). The structural connections between the barrel and piriform cortices were traced by injecting 1,1′dioctadecyl-3,3,3′,3-tetramethylindocarbocyanine perchlorate (DiI) in the barrel cortices. Compared to neural tracing in controls (Figures 3B,C, n = 9), DiI is detected in the piriform cortex and layer-VI white matter in CR-formation mice (Figures 3A–C, p < 0.001, n = 9; One-Way ANOVA). As DiI is detected in axonal terminals and cell bodies of the piriform cortex (enlarged images in Figures 3A,B), the mutual innervation between the barrel and piriform cortices forms after associative memory. It is noteworthy that the connection may not form through the intermediate brain areas since DiI is not trans-synaptic dye and digital spikes do not cross over chemical synapses.

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