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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 barrel cortex is essential to odorant-induced whisker motion that is an odorant specific. (A) The blockade of neural activities in the barrel cortex removes odorant-induced whisker motion. In CR-formation mice, excitatory synaptic transmission in the barrel cortex was blocked by locally injecting CNQX/DAP-5 (400/500 μM), and neuronal spikes were blocked by locally injecting TTX (20 μM). The odor-test pulse was given toward the noses, and odorant-induced whisker motion was monitored by a digital video camera. Traces from the top to bottom show whisker motion tracks induced by the odor-test (top trace) toward the noses in a CR-formation mouse before and after injecting CNQX/DAP-5 for 2, 8, and 33 min. Calibration bars show whisker motion angle and time. (B) Shows whisking frequencies in CR-formation mice (n = 5) before and after injecting these reagents (p < 0.001) as well as for 0 vs. 8 and 33 min (p < 0.01; One-Way ANOVA). (C) In CR-formation mice trained by pairing WS and OS (butyl acetate), the whisker motions are examined by giving different odorants, such as butyl acetate (10%), hydrochloric acid (5%), olive oil (100%), and ethanol (75%). Odorant-induced whisker motion is seen by giving the test of butyl acetate only. Whisking frequency is increased by giving butyl acetate test (dark-gray bar), compared with that before WS/OS-pairing (light-gray; p < 0.05, n = 5; One-Way ANOVA), but not by the tests of hydrochloric acid, olive oil and ethanol (dark-gray). (D) Illustrates frequency in odorant-induced whisker motion vs. days in pairing OS and WS in different ages of the mice (postnatal days, PND 15, 18, 21, 27, 33, and 60; n = 12 for each of groups). The optimal age of the mice who are trained to express odorant-induced whisker motion is PND 21 when a maximal level of whisking frequency is seen. **p < 0.01; ***p < 0.001.
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Figure 4: The barrel cortex is essential to odorant-induced whisker motion that is an odorant specific. (A) The blockade of neural activities in the barrel cortex removes odorant-induced whisker motion. In CR-formation mice, excitatory synaptic transmission in the barrel cortex was blocked by locally injecting CNQX/DAP-5 (400/500 μM), and neuronal spikes were blocked by locally injecting TTX (20 μM). The odor-test pulse was given toward the noses, and odorant-induced whisker motion was monitored by a digital video camera. Traces from the top to bottom show whisker motion tracks induced by the odor-test (top trace) toward the noses in a CR-formation mouse before and after injecting CNQX/DAP-5 for 2, 8, and 33 min. Calibration bars show whisker motion angle and time. (B) Shows whisking frequencies in CR-formation mice (n = 5) before and after injecting these reagents (p < 0.001) as well as for 0 vs. 8 and 33 min (p < 0.01; One-Way ANOVA). (C) In CR-formation mice trained by pairing WS and OS (butyl acetate), the whisker motions are examined by giving different odorants, such as butyl acetate (10%), hydrochloric acid (5%), olive oil (100%), and ethanol (75%). Odorant-induced whisker motion is seen by giving the test of butyl acetate only. Whisking frequency is increased by giving butyl acetate test (dark-gray bar), compared with that before WS/OS-pairing (light-gray; p < 0.05, n = 5; One-Way ANOVA), but not by the tests of hydrochloric acid, olive oil and ethanol (dark-gray). (D) Illustrates frequency in odorant-induced whisker motion vs. days in pairing OS and WS in different ages of the mice (postnatal days, PND 15, 18, 21, 27, 33, and 60; n = 12 for each of groups). The optimal age of the mice who are trained to express odorant-induced whisker motion is PND 21 when a maximal level of whisking frequency is seen. **p < 0.01; ***p < 0.001.

Mentions: In terms of cellular mechanisms underlying this associative memory, we examined how the barrel cortical neurons and astrocytes process these associative signals in CR-formation mice. The rationale for studying the role of neurons and astrocytes in associative memory is based on the reports that the neuron-astrocyte interaction may affect long-term memory (Florian et al., 2011; Suzuki et al., 2011). The rationale for studying the barrel cortex instead of the motor cortex is based on our result that the inhibition of synaptic and neuronal activities in the barrel cortices removes odorant-induced whisker motion (Figures 4A,B; p < 0.001, n = 5; One-Way ANOVA). The barrel cortex becomes the primary center of this conditioned reflex. The rationale for using butyl acetate as odor test, but not others, is based on the odorant specificity of odorant-induced whisker motion that in CR-formation mice is evoked by butyl acetate, but not olive oil, hydrochloric acid, and ethanol (Figure 4C; p < 0.01, n = 5; One-Way ANOVA). Moreover, the frequencies of odorant-induced whisker motion reach the maximal level in the mice that are trained starting at postnatal day 21 (Figure 4D) which is the rationale for us to train the mice starting at postnatal day 20.


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 barrel cortex is essential to odorant-induced whisker motion that is an odorant specific. (A) The blockade of neural activities in the barrel cortex removes odorant-induced whisker motion. In CR-formation mice, excitatory synaptic transmission in the barrel cortex was blocked by locally injecting CNQX/DAP-5 (400/500 μM), and neuronal spikes were blocked by locally injecting TTX (20 μM). The odor-test pulse was given toward the noses, and odorant-induced whisker motion was monitored by a digital video camera. Traces from the top to bottom show whisker motion tracks induced by the odor-test (top trace) toward the noses in a CR-formation mouse before and after injecting CNQX/DAP-5 for 2, 8, and 33 min. Calibration bars show whisker motion angle and time. (B) Shows whisking frequencies in CR-formation mice (n = 5) before and after injecting these reagents (p < 0.001) as well as for 0 vs. 8 and 33 min (p < 0.01; One-Way ANOVA). (C) In CR-formation mice trained by pairing WS and OS (butyl acetate), the whisker motions are examined by giving different odorants, such as butyl acetate (10%), hydrochloric acid (5%), olive oil (100%), and ethanol (75%). Odorant-induced whisker motion is seen by giving the test of butyl acetate only. Whisking frequency is increased by giving butyl acetate test (dark-gray bar), compared with that before WS/OS-pairing (light-gray; p < 0.05, n = 5; One-Way ANOVA), but not by the tests of hydrochloric acid, olive oil and ethanol (dark-gray). (D) Illustrates frequency in odorant-induced whisker motion vs. days in pairing OS and WS in different ages of the mice (postnatal days, PND 15, 18, 21, 27, 33, and 60; n = 12 for each of groups). The optimal age of the mice who are trained to express odorant-induced whisker motion is PND 21 when a maximal level of whisking frequency is seen. **p < 0.01; ***p < 0.001.
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Figure 4: The barrel cortex is essential to odorant-induced whisker motion that is an odorant specific. (A) The blockade of neural activities in the barrel cortex removes odorant-induced whisker motion. In CR-formation mice, excitatory synaptic transmission in the barrel cortex was blocked by locally injecting CNQX/DAP-5 (400/500 μM), and neuronal spikes were blocked by locally injecting TTX (20 μM). The odor-test pulse was given toward the noses, and odorant-induced whisker motion was monitored by a digital video camera. Traces from the top to bottom show whisker motion tracks induced by the odor-test (top trace) toward the noses in a CR-formation mouse before and after injecting CNQX/DAP-5 for 2, 8, and 33 min. Calibration bars show whisker motion angle and time. (B) Shows whisking frequencies in CR-formation mice (n = 5) before and after injecting these reagents (p < 0.001) as well as for 0 vs. 8 and 33 min (p < 0.01; One-Way ANOVA). (C) In CR-formation mice trained by pairing WS and OS (butyl acetate), the whisker motions are examined by giving different odorants, such as butyl acetate (10%), hydrochloric acid (5%), olive oil (100%), and ethanol (75%). Odorant-induced whisker motion is seen by giving the test of butyl acetate only. Whisking frequency is increased by giving butyl acetate test (dark-gray bar), compared with that before WS/OS-pairing (light-gray; p < 0.05, n = 5; One-Way ANOVA), but not by the tests of hydrochloric acid, olive oil and ethanol (dark-gray). (D) Illustrates frequency in odorant-induced whisker motion vs. days in pairing OS and WS in different ages of the mice (postnatal days, PND 15, 18, 21, 27, 33, and 60; n = 12 for each of groups). The optimal age of the mice who are trained to express odorant-induced whisker motion is PND 21 when a maximal level of whisking frequency is seen. **p < 0.01; ***p < 0.001.
Mentions: In terms of cellular mechanisms underlying this associative memory, we examined how the barrel cortical neurons and astrocytes process these associative signals in CR-formation mice. The rationale for studying the role of neurons and astrocytes in associative memory is based on the reports that the neuron-astrocyte interaction may affect long-term memory (Florian et al., 2011; Suzuki et al., 2011). The rationale for studying the barrel cortex instead of the motor cortex is based on our result that the inhibition of synaptic and neuronal activities in the barrel cortices removes odorant-induced whisker motion (Figures 4A,B; p < 0.001, n = 5; One-Way ANOVA). The barrel cortex becomes the primary center of this conditioned reflex. The rationale for using butyl acetate as odor test, but not others, is based on the odorant specificity of odorant-induced whisker motion that in CR-formation mice is evoked by butyl acetate, but not olive oil, hydrochloric acid, and ethanol (Figure 4C; p < 0.01, n = 5; One-Way ANOVA). Moreover, the frequencies of odorant-induced whisker motion reach the maximal level in the mice that are trained starting at postnatal day 21 (Figure 4D) which is the rationale for us to train the mice starting at postnatal day 20.

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