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Wu GY, Liu SL, Yao J, Li X, Wu B, Ye JN, Sui JF. Optogenetic Inhibition of Medial Prefrontal Cortex-Pontine Nuclei Projections During the Stimulus-free Trace Interval Impairs Temporal Associative Motor Learning. Cereb Cortex 2019; 28:3753-3763. [PMID: 28968654 DOI: 10.1093/cercor/bhx238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Indexed: 11/13/2022] Open
Abstract
The medial prefrontal cortex (mPFC) is closely involved in many higher-order cognitive functions, including learning to associate temporally discontiguous events (called temporal associative learning). However, direct evidence for the role of mPFC and the neural pathway underlying modulation of temporal associative motor learning is sparse. Here, we show that optogenetic inhibition of the mPFC or its axon terminals at the pontine nuclei (PN) during trace intervals or whole trial period significantly impaired the trace eyeblink conditioning (TEC), but had no significant effects on TEC during the conditioned stimulus or intertrial interval period. Our results suggest that activities associated with the mPFC-PN projection during trace intervals is crucial for trace associative motor learning. This finding is of great importance in understanding the mechanisms and the relevant neural pathways underlying mPFC modulation of temporal associative motor learning.
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Affiliation(s)
- Guang-Yan Wu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Shu-Lei Liu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
| | - Jian-Ning Ye
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Jian-Feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
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Wu GY, Liu SL, Yao J, Sun L, Wu B, Yang Y, Li X, Sun QQ, Feng H, Sui JF. Medial Prefrontal Cortex-Pontine Nuclei Projections Modulate Suboptimal Cue-Induced Associative Motor Learning. Cereb Cortex 2019; 28:880-893. [PMID: 28077515 DOI: 10.1093/cercor/bhw410] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Indexed: 11/14/2022] Open
Abstract
Diverse and powerful mechanisms have evolved to enable organisms to modulate learning and memory under a variety of survival conditions. Cumulative evidence has shown that the prefrontal cortex (PFC) is closely involved in many higher-order cognitive functions. However, when and how the medial PFC (mPFC) modulates associative motor learning remains largely unknown. Here, we show that delay eyeblink conditioning (DEC) with the weak conditioned stimulus (wCS) but not the strong CS (sCS) elicited a significant increase in the levels of c-Fos expression in caudal mPFC. Both optogenetic inhibition and activation of the bilateral caudal mPFC, or its axon terminals at the pontine nucleus (PN) contralateral to the training eye, significantly impaired the acquisition, recent and remote retrieval of DEC with the wCS but not the sCS. However, direct optogenetic activation of the contralateral PN had no significant effect on the acquisition, recent and remote retrieval of DEC. These results are of great importance in understanding the elusive role of the mPFC and its projection to PN in subserving the associative motor learning under suboptimal learning cue.
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Affiliation(s)
- Guang-Yan Wu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Shu-Lei Liu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Lin Sun
- Institute of Physical Education, Southwest University, Chongqing400715, China
| | - Bing Wu
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Yi Yang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Xuan Li
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Hua Feng
- Department of Neurosurgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
| | - Jian-Feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.,Experimental Center of Basic Medicine, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
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Reevaluating the ability of cerebellum in associative motor learning. Sci Rep 2019; 9:6029. [PMID: 30988338 PMCID: PMC6465343 DOI: 10.1038/s41598-019-42413-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 03/29/2019] [Indexed: 11/08/2022] Open
Abstract
It has been well established that the cerebellum and its associated circuitry constitute the essential neuronal system for both delay and trace classical eyeblink conditioning (DEC and TEC). However, whether the cerebellum is sufficient to independently modulate the DEC, and TEC with a shorter trace interval remained controversial. Here, we used direct optogenetic stimulation of mossy fibers in the middle cerebellar peduncle (MCP) as a conditioned stimulus (CS) replacement for the peripheral CS (eg, a tone CS or a light CS) paired with a periorbital shock unconditioned stimulus (US) to examine the ability of the cerebellum to learn the DEC and the TEC with various trace intervals. Moreover, neural inputs to the pontine nucleus (PN) were pharmacological blocked to limit the associative motor learning inside the cerebellum. We show that all rats quickly acquired the DEC, indicating that direct optogenetic stimulation of mossy fibers in the left MCP is a very effective and sufficient CS to establish DEC and to limit the motor learning process inside the cerebellum. However, only five out of seven rats acquired the TEC with a 150-ms trace interval, three out of nine rats acquired the TEC with a 350-ms trace interval, and none of the rats acquired the TEC with a 500-ms trace interval. Moreover, pharmacological blocking glutamatergic and GABAergic inputs to the PN from the extra-cerebellar and cerebellar regions has no significant effect on the DEC and TEC learning with the optogenetic CS. These results indicate that the cerebellum has the ability to independently support both the simple DEC, and the TEC with a trace interval of 150 or 350 ms, but not the TEC with a trace interval of 500 ms. The present results are of great importance in our understanding of the mechanisms and ability of the cerebellum in associative motor learning and memory.
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Zhang LQ, Yao J, Gao J, Sun L, Wang LT, Sui JF. Modulation of eyeblink conditioning through sensory processing of conditioned stimulus by cortical and subcortical regions. Behav Brain Res 2019; 359:149-155. [PMID: 30385367 DOI: 10.1016/j.bbr.2018.10.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/25/2018] [Accepted: 10/25/2018] [Indexed: 10/28/2022]
Abstract
Classical eyeblink conditioning (EBC) is one of the simplest forms of associative learning that depends critically on the cerebellum. Using delay EBC (dEBC), a standard paradigm in which the unconditioned stimulus (US) is delayed and co-terminates with the conditioned stimulus (CS), converging lines of evidence has been accumulated and shows that the essential neural circuit mediating EBC resides in the cerebellum and brainstem. In addition to this essential circuit, multiple cerebral cortical and subcortical structures are required to modulate dEBC with suboptimal training parameters, and trace EBC (tEBC) in which a trace-interval separates the CS and US. However, it remains largely unclear why and how so many brain regions are involved for modulation of EBC. Previous research has suggested that the forebrain regions, such as medial prefrontal cortex (mPFC) and hippocampus, may be required to process weak CSs, or to realize temporal overlap between the CS and US signal inputs when the two stimuli were separated in time (i.e. during tEBC). Here, we proposed a multi-level network model for EBC modulation which focuses on sensory processing of CS. The model explains how different neural pathways projecting to pontine nucleus (PN) are involved to amplify or extend CS through heterosynaptic facilitation mechanism or "substitution effect" under different circumstances to achieve EBC. As such, our model can serve as a general framework to explain the modulating mechanism of EBC in a variety of conditions and to help understand the interaction among cerebellum, brainstem, cortical and subcortical regions in EBC modulation.
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Affiliation(s)
- Lang-Qian Zhang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China; Department of Medical Technology, Chongqing Medical and Pharmaceutical College, 82 University City Road, Shapingba District, Chongqing 401331, PR China
| | - Juan Yao
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Jie Gao
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Army Medical University, Chongqing 400042, PR China
| | - Lin Sun
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China
| | - Li-Ting Wang
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
| | - Jian-Feng Sui
- Experimental Center of Basic Medicine, College of Basic Medical Sciences, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
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Prefrontal Single-Neuron Responses after Changes in Task Contingencies during Trace Eyeblink Conditioning in Rabbits. eNeuro 2016; 3:eN-NWR-0057-16. [PMID: 27517083 PMCID: PMC4947975 DOI: 10.1523/eneuro.0057-16.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 06/21/2016] [Accepted: 07/01/2016] [Indexed: 11/23/2022] Open
Abstract
A number of studies indicate that the medial prefrontal cortex (mPFC) plays a role in mediating the expression of behavioral responses during tasks that require flexible changes in behavior. During trace eyeblink conditioning, evidence suggests that the mPFC provides the cerebellum with a persistent input to bridge the temporal gap between conditioned and unconditioned stimuli. Therefore, the mPFC is in a position to directly mediate the expression of trace conditioned responses. However, it is unknown whether persistent neural responses are associated with the flexible expression of behavior when task contingencies are changed during trace eyeblink conditioning. To investigate this, single-unit activity was recorded in the mPFC of rabbits during extinction and reacquisition of trace eyeblink conditioning, and during training to a different conditional stimulus. Persistent responses remained unchanged after full extinction, and also did not change during reacquisition training. During training to a different tone, however, the generalization of persistent responses to the new stimulus was associated with an animal’s performance—when persistent responses generalized to the new tone, performance was high (>50% response rate). When persistent responses decreased to baseline rates, performance was poor (<50% response rate). The data suggest that persistent mPFC responses do not appear to mediate flexible changes in the expression of the original learning, but do appear to play a role in the generalization of that learning when the task is modified.
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Chen H, Wang YJ, Yang L, Sui JF, Hu ZA, Hu B. Theta synchronization between medial prefrontal cortex and cerebellum is associated with adaptive performance of associative learning behavior. Sci Rep 2016; 6:20960. [PMID: 26879632 PMCID: PMC4754690 DOI: 10.1038/srep20960] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 01/12/2016] [Indexed: 12/11/2022] Open
Abstract
Associative learning is thought to require coordinated activities among distributed brain regions. For example, to direct behavior appropriately, the medial prefrontal cortex (mPFC) must encode and maintain sensory information and then interact with the cerebellum during trace eyeblink conditioning (TEBC), a commonly-used associative learning model. However, the mechanisms by which these two distant areas interact remain elusive. By simultaneously recording local field potential (LFP) signals from the mPFC and the cerebellum in guinea pigs undergoing TEBC, we found that theta-frequency (5.0-12.0 Hz) oscillations in the mPFC and the cerebellum became strongly synchronized following presentation of auditory conditioned stimulus. Intriguingly, the conditioned eyeblink response (CR) with adaptive timing occurred preferentially in the trials where mPFC-cerebellum theta coherence was stronger. Moreover, both the mPFC-cerebellum theta coherence and the adaptive CR performance were impaired after the disruption of endogenous orexins in the cerebellum. Finally, association of the mPFC -cerebellum theta coherence with adaptive CR performance was time-limited occurring in the early stage of associative learning. These findings suggest that the mPFC and the cerebellum may act together to contribute to the adaptive performance of associative learning behavior by means of theta synchronization.
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Affiliation(s)
- Hao Chen
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, P.R. China
| | - Yi-jie Wang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, P.R. China
| | - Li Yang
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, P.R. China
| | - Jian-feng Sui
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, P.R. China
| | - Zhi-an Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, P.R. China
| | - Bo Hu
- Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, P.R. China
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Abstract
This chapter reviews the past research toward identifying the brain circuit and its computation underlying the associative memory in eyeblink classical conditioning. In the standard delay eyeblink conditioning paradigm, the conditioned stimulus (CS) and eyeblink-eliciting unconditioned stimulus (US) converge in the cerebellar cortex and interpositus nucleus (IPN) through the pontine nuclei and inferior olivary nucleus. Repeated pairings of CS and US modify synaptic weights in the cerebellar cortex and IPN, enabling IPN neurons to activate the red nucleus and generate the conditioned response (CR). In a variant of the standard paradigm, trace eyeblink conditioning, the CS and US are separated by a brief stimulus-free trace interval. Acquisition in trace eyeblink conditioning depends on several forebrain regions, including the hippocampus and medial prefrontal cortex as well as the cerebellar-brainstem circuit. Details of computations taking place in these regions remain unclear; however, recent evidence supports a view that the forebrain encodes a temporal sequence of the CS, trace interval, and US in a specific environmental context and signals the cerebellar-brainstem circuit to execute the CR when the US is likely to occur. Together, delay eyeblink conditioning represents one of the most successful cases of understanding the neural substrates of long-term memory in mammals, while trace eyeblink conditioning demonstrates its utility for uncovering detailed computations in the whole brain network underlying long-term memory.
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Affiliation(s)
- Kaori Takehara-Nishiuchi
- Department of Psychology, Cell and Systems Biology, Neuroscience Program, University of Toronto, Toronto, M5S 3G3, Canada.
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Trace Eyeblink Conditioning in Mice Is Dependent upon the Dorsal Medial Prefrontal Cortex, Cerebellum, and Amygdala: Behavioral Characterization and Functional Circuitry. eNeuro 2015; 2:eN-NWR-0051-14. [PMID: 26464998 PMCID: PMC4596016 DOI: 10.1523/eneuro.0051-14.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 06/26/2015] [Accepted: 06/26/2015] [Indexed: 11/26/2022] Open
Abstract
Trace eyeblink conditioning is useful for studying the interaction of multiple brain areas in learning and memory. The goal of the current work was to determine whether trace eyeblink conditioning could be established in a mouse model in the absence of elicited startle responses and the brain circuitry that supports this learning. We show here that mice can acquire trace conditioned responses (tCRs) devoid of startle while head-restrained and permitted to freely run on a wheel. Most mice (75%) could learn with a trace interval of 250 ms. Because tCRs were not contaminated with startle-associated components, we were able to document the development and timing of tCRs in mice, as well as their long-term retention (at 7 and 14 d) and flexible expression (extinction and reacquisition). To identify the circuitry involved, we made restricted lesions of the medial prefrontal cortex (mPFC) and found that learning was prevented. Furthermore, inactivation of the cerebellum with muscimol completely abolished tCRs, demonstrating that learned responses were driven by the cerebellum. Finally, inactivation of the mPFC and amygdala in trained animals nearly abolished tCRs. Anatomical data from these critical regions showed that mPFC and amygdala both project to the rostral basilar pons and overlap with eyelid-associated pontocerebellar neurons. The data provide the first report of trace eyeblink conditioning in mice in which tCRs were driven by the cerebellum and required a localized region of mPFC for acquisition. The data further reveal a specific role for the amygdala as providing a conditioned stimulus-associated input to the cerebellum.
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Wang YJ, Chen H, Hu C, Ke XF, Yang L, Xiong Y, Hu B. Baseline theta activities in medial prefrontal cortex and deep cerebellar nuclei are associated with the extinction of trace conditioned eyeblink responses in guinea pigs. Behav Brain Res 2014; 275:72-83. [PMID: 25200518 DOI: 10.1016/j.bbr.2014.08.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/23/2014] [Accepted: 08/30/2014] [Indexed: 12/12/2022]
Abstract
It has been shown that both the medial prefrontal cortex (mPFC) and the cerebellum are involved in the extinction of trace conditioned eyeblink responses (CR). However, the neural mechanisms underlying the extinction are still relatively unclear. Theta oscillation in either the mPFC or the cerebellum has been revealed to correlate with the performance of trace CRs during the asymptotic acquisition. Therefore, we sought to further evaluate the impacts of pre-conditioned stimulus (CS) spontaneous theta (5.0-10.0Hz) oscillations in the mPFC and the deep cerebellar nuclei (DCN) on the extinction of trace CRs. Albino guinea pigs were given acquisition training for ten daily sessions followed by seven daily sessions of extinction. Local field potential (LFP) signals in the mPFC and the DCN were recorded when the animals received the CS-alone extinction training. It was found that higher mPFC relative theta ratios [theta/(delta+beta)] during the baseline period (850-ms prior to the CS onset) were predictive of fewer CR incidences rather than more adaptive CR performance (i.e., higher CR magnitude and later CR peak/onset latencies). Likewise, the pre-CS DCN theta activity was associated with the faster CR extinction. Furthermore, it was revealed that the power of pre-CS theta activities in the mPFC and the DCN were correlated until the extinction training day 2. Collectively, these results suggest that the mPFC and the DCN may interact with each other, and the brain oscillation state in which baseline theta activities in both areas are present contributes to the subsequent extinction of trace CRs.
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Affiliation(s)
- Yi-jie Wang
- Department of Physiology, College of Basic Medical Sciences, Chongqing 400038, PR China; Battalion 5 of Cadet Brigade, Third Military Medical University, Chongqing 400038, PR China
| | - Hao Chen
- Department of Physiology, College of Basic Medical Sciences, Chongqing 400038, PR China
| | - Chen Hu
- Department of Physiology, College of Basic Medical Sciences, Chongqing 400038, PR China; Battalion 8 of Cadet Brigade, Third Military Medical University, Chongqing 400038, PR China
| | - Xian-feng Ke
- Department of Physiology, College of Basic Medical Sciences, Chongqing 400038, PR China; Battalion 8 of Cadet Brigade, Third Military Medical University, Chongqing 400038, PR China
| | - Li Yang
- Department of Physiology, College of Basic Medical Sciences, Chongqing 400038, PR China
| | - Yan Xiong
- Department of Orthopedics, Daping Hospital, Third Military Medical University, Chongqing 400042, PR China.
| | - Bo Hu
- Department of Physiology, College of Basic Medical Sciences, Chongqing 400038, PR China.
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Siegel JJ. Modification of persistent responses in medial prefrontal cortex during learning in trace eyeblink conditioning. J Neurophysiol 2014; 112:2123-37. [PMID: 25080570 DOI: 10.1152/jn.00372.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Persistent spiking in response to a discrete stimulus is considered to reflect the active maintenance of a memory for that stimulus until a behavioral response is made. This response pattern has been reported in learning paradigms that impose a temporal gap between stimulus presentation and behavioral response, including trace eyeblink conditioning. However, it is unknown whether persistent responses are acquired as a function of learning or simply represent an already existing category of response type. This fundamental question was addressed by recording single-unit activity in the medial prefrontal cortex (mPFC) of rabbits during the initial learning phase of trace eyeblink conditioning. Persistent responses to the tone conditioned stimulus were observed in the mPFC during the very first training sessions. Further analysis revealed that most cells with persistent responses showed this pattern during the very first training trial, before animals had experienced paired training. However, persistent cells showed reliable decreases in response magnitude over the first training session, which were not observed on the second day of training or for sessions in which learning criterion was met. This modification of response magnitude was specific to persistent responses and was not observed for cells showing phasic tone-evoked responses. The data suggest that persistent responses to discrete stimuli do not require learning but that the ongoing robustness of such responses over the course of training is modified as a result of experience. Putative mechanisms for this modification are discussed, including changes in cellular or network properties, neuromodulatory tone, and/or the synaptic efficacy of tone-associated inputs.
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Affiliation(s)
- Jennifer J Siegel
- Center for Learning and Memory and Institute for Neuroscience, The University of Texas at Austin, Austin, Texas
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