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David G Lavond - One of the best experts on this subject based on the ideXlab platform.

  • The Importance of Cerebellar Cortex and Facial Nucleus in Acquisition and Retention of Eyeblink/NM Conditioning: Evidence for Critical Unilateral Regulation of the Conditioned Response
    Neurobiology of learning and memory, 1997
    Co-Authors: Robert E. Clark, Andrew A. Zhang, David G Lavond
    Abstract:

    Experiment 1 examined acquisition of the classically Conditioned eyeblink Response in rabbits (Oryctolagus cuniculus) during reversible cooling lesions of the cerebellar cortex (CX), facial nucleus (FN), or lateral parvocellular reticular formation (RF). Retention was then evaluated during periods of training during reversible cooling lesions and without cooling in rabbits that had acquired the Conditioned Response. We found that cooling the CX did not prevent acquisition, but did retard the acquisition rate. Cooling the FN during acquisition prevented the expression of the unConditioned and Conditioned Response, but did not prevent the acquisition when assessed during subsequent training without cooling. Cooling the RF had no effect on the acquisition or expression of the Conditioned Response. During subsequent retention testing, in well-trained animals, cooling the CX did not abolish the learned Response. Cooling the FN abolished both the Conditioned and the unConditioned Response. The results from Experiment 1 indicate that the CX is more important for acquisition than retention of the Conditioned Response. The FN is not important for the acquisition of the Conditioned Response, but is essential for the expression of the Conditioned and unConditioned Response. Experiment 2 examined bilateral recordings from the cerebellum in well-trained rabbits, before and during interpositus or FN cooling. We found that cooling the interpositus abolished all learning related activity in the ipsilateral or contralateral cerebellum, but did not affect the stimulus evoked Responses. Cooling the FN did not abolish stimulus evoked activity or learning related activity in the cerebellum. The results emphasize the critical importance of the ipsilateral cerebellum in classical eyeblink conditioning and suggest that the memory trace for this type of learning is mediated by unilateral circuitry.

  • neural unit activity in the trigeminal complex with interpositus or red nucleus inactivation during classical eyeblink conditioning
    Behavioral Neuroscience, 1996
    Co-Authors: Robert E. Clark, David G Lavond
    Abstract:

    During classical conditioning, many neurons in the trigeminal complex of rabbits exhibit activity that is related to the Conditioned stimulus (tone), the unConditioned stimulus (airpuff), or to the Conditioned Response (eyeblink). For these reasons the trigeminal complex has been hypothesized to be a brainstem locus for the neuronal plasticity associated with conditioning. In this experiment, the learning-related activity (unit activity associated with the Conditioned Response) in the trigeminal is abolished when either the red nucleus or interpositus nucleus of the cerebellum is temporarily inactivated by cooling, but the stimulus-evoked activity is unaffected by cooling. This study and previous results support the suggestion that the learning-related activity seen in the trigeminal is driven by the interpositus by way of the red nucleus.

J E Steinmetz - One of the best experts on this subject based on the ideXlab platform.

  • The role of the cerebellum in classical conditioning of discrete behavioral Responses
    Neuroscience, 2009
    Co-Authors: Richard F. Thompson, J E Steinmetz
    Abstract:

    The cerebellum and its associated circuitry constitutes the entire essential neuronal system for classical conditioning of eye-blink and other discrete Responses (e.g. limb flexion) learned with an aversive unConditioned stimulus (US) using the standard delay paradigm where the Conditioned stimulus (CS) and the US coterminate. Evidence reviewed here strongly supports the following conclusions. The CS pathway involves sensory relay nuclei projections to the pontine nuclei and its mossy fiber projections to the cerebellar cortex and nuclei. The US pathway involves activation of the inferior olive (dorsal accessory olive for eye blink) and its climbing fiber projections to the cerebellar cortex and nuclei. The Conditioned Response (CR) pathway involves the cerebellar interpositus nucleus, the superior cerebellar peduncle pathway to the magnocellular red nucleus and rubral projections to premotor and motor nuclei generating the behavioral Response. Anatomical data, neuronal unit recordings, electrical stimulation, lesions and methods of reversible inactivation all strongly support the hypothesis that the essential memory trace for the learning of these discrete Conditioned Responses is formed and stored in the cerebellar interpositus nucleus. Neuronal/synaptic plasticity is also established in the cerebellar cortex in this form of learning but the role of the cortex is less clear. We argue that the cortex plays a key role in normal acquisition and adaptive timing of the Conditioned Response, under certain circumstances, but it remains unclear exactly what features of conditioning are being encoded in the cerebellar cortex in this basic form of associative learning and memory.

  • Involvement of the ventrolateral thalamic nucleus in rabbit classical eyeblink conditioning.
    Behavioural brain research, 1996
    Co-Authors: L L Sears, S F Logue, J E Steinmetz
    Abstract:

    The involvement of the ventrolateral nucleus of the thalamus in relaying learning-related activity to higher brain structures during classical conditioning of the rabbit eyelid Response was examined in two experiments. In the first study, multiple-unit ventrolateral thalamic nucleus activity was monitored before and after lesions of either the cerebellar interpositus nucleus or red nucleus were given. Before the lesions were given, Conditioned Response-related activity was observed in the ventrolateral thalamic nucleus. Lesions of the interpositus nucleus, but not the red nucleus, disrupted the conditioning-related activity in the ventrolateral thalamic nucleus, thus suggesting that an efferent copy of Conditioned Response-related activity is projected directly from the interpositus nucleus to higher brain areas by way of the ventrolateral thalamic nucleus. In the second study, multiple unit activity in the hippocampus was monitored before and after lesions were placed in the ventrolateral thalamic nucleus or red nucleus. Conditioning-related activity in the hippocampus was not affected by either lesion, thus suggesting that maintenance of training-related activity in the hippocampus is not critically dependent on cerebellar information relayed through the ventrolateral thalamic nucleus or red nucleus.

Robert E. Clark - One of the best experts on this subject based on the ideXlab platform.

  • The Importance of Cerebellar Cortex and Facial Nucleus in Acquisition and Retention of Eyeblink/NM Conditioning: Evidence for Critical Unilateral Regulation of the Conditioned Response
    Neurobiology of learning and memory, 1997
    Co-Authors: Robert E. Clark, Andrew A. Zhang, David G Lavond
    Abstract:

    Experiment 1 examined acquisition of the classically Conditioned eyeblink Response in rabbits (Oryctolagus cuniculus) during reversible cooling lesions of the cerebellar cortex (CX), facial nucleus (FN), or lateral parvocellular reticular formation (RF). Retention was then evaluated during periods of training during reversible cooling lesions and without cooling in rabbits that had acquired the Conditioned Response. We found that cooling the CX did not prevent acquisition, but did retard the acquisition rate. Cooling the FN during acquisition prevented the expression of the unConditioned and Conditioned Response, but did not prevent the acquisition when assessed during subsequent training without cooling. Cooling the RF had no effect on the acquisition or expression of the Conditioned Response. During subsequent retention testing, in well-trained animals, cooling the CX did not abolish the learned Response. Cooling the FN abolished both the Conditioned and the unConditioned Response. The results from Experiment 1 indicate that the CX is more important for acquisition than retention of the Conditioned Response. The FN is not important for the acquisition of the Conditioned Response, but is essential for the expression of the Conditioned and unConditioned Response. Experiment 2 examined bilateral recordings from the cerebellum in well-trained rabbits, before and during interpositus or FN cooling. We found that cooling the interpositus abolished all learning related activity in the ipsilateral or contralateral cerebellum, but did not affect the stimulus evoked Responses. Cooling the FN did not abolish stimulus evoked activity or learning related activity in the cerebellum. The results emphasize the critical importance of the ipsilateral cerebellum in classical eyeblink conditioning and suggest that the memory trace for this type of learning is mediated by unilateral circuitry.

  • neural unit activity in the trigeminal complex with interpositus or red nucleus inactivation during classical eyeblink conditioning
    Behavioral Neuroscience, 1996
    Co-Authors: Robert E. Clark, David G Lavond
    Abstract:

    During classical conditioning, many neurons in the trigeminal complex of rabbits exhibit activity that is related to the Conditioned stimulus (tone), the unConditioned stimulus (airpuff), or to the Conditioned Response (eyeblink). For these reasons the trigeminal complex has been hypothesized to be a brainstem locus for the neuronal plasticity associated with conditioning. In this experiment, the learning-related activity (unit activity associated with the Conditioned Response) in the trigeminal is abolished when either the red nucleus or interpositus nucleus of the cerebellum is temporarily inactivated by cooling, but the stimulus-evoked activity is unaffected by cooling. This study and previous results support the suggestion that the learning-related activity seen in the trigeminal is driven by the interpositus by way of the red nucleus.

R F Thompson - One of the best experts on this subject based on the ideXlab platform.

  • extinction of a classically Conditioned Response red nucleus and interpositus
    The Journal of Neuroscience, 2008
    Co-Authors: Karla Robleto, R F Thompson
    Abstract:

    It is well established that the cerebellum and its associated circuitry are essential for classical conditioning of the eyeblink Response and other discrete motor Responses (e.g., limb flexion, head turn, etc.) learned with an aversive unConditioned stimulus. However, brain mechanisms underlying extinction of these Responses are still relatively unclear. Behavioral studies have demonstrated extinction to be an active learning process distinct from acquisition. Accordingly, this current understanding of extinction has guided neural studies that have tried to identify possible brain structures that could support this new learning. However, whether extinction engages the same brain sites necessary for acquisition is not yet clear. This poses an overriding problem for understanding brain mechanisms necessary for extinction because such analysis cannot be done without first identifying brain sites and pathways involved in this phenomenon. Equally elusive is the validity of a behavioral theory of extinction that can account for the properties of extinction. In this study, we looked at the involvement of the interpositus and the red nucleus in extinction. Results show that, although inactivation of both nuclei blocks Response expression, only inactivation of the interpositus has a detrimental effect on extinction. Moreover, this detrimental effect was completely removed when inactivation of the interpositus was paired with electrical stimulation of the red nucleus. These findings speak to the important role of cerebellar structures in the extinction of discrete motor Responses and provide important insight as to the validity of a particular theory of extinction.

Roger K Pitman - One of the best experts on this subject based on the ideXlab platform.

  • effects of beta blockade ptsd diagnosis and explicit threat on the extinction and retention of an aversively Conditioned Response
    Biological Psychology, 2006
    Co-Authors: Scott P Orr, Mohammed R Milad, Linda J Metzger, Natasha B Lasko, Mark W Gilbertson, Roger K Pitman
    Abstract:

    An aversively Conditioned SC Response was assessed in 18 males meeting DSM-IV criteria for chronic posttraumatic stress disorder (PTSD) and 10 trauma-exposed males who never developed PTSD. Effects of beta blockade on acquisition and retention of a Conditioned Response (CR) were examined by administering propranolol HCl before acquisition or following extinction trials. Retention of the CR was assessed 1 week following acquisition under conditions of non-threat and threat. Conditioned stimuli were colored circles and the unConditioned stimulus (UCS) was a "highly annoying" electrical stimulus. The propranolol failed to produce any measurable effects on acquisition or retention of the CR and there was no evidence of increased conditionability in individuals diagnosed with PTSD. One week following acquisition, the differential CR to the reinforced stimulus was evident only in the threat condition. This suggests that belief in the presence of a threat is necessary and sufficient for activating a previously established CR.