151
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Knowlton BJ, Thompson RF. Conditioning using a cerebral cortical conditioned stimulus is dependent on the cerebellum and brain stem circuitry. Behav Neurosci 1992. [PMID: 1616617 DOI: 10.1037//0735-7044.106.3.509] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Electrical stimulation of the auditory cortex (AC) was used as a conditioned stimulus (CS) in the rabbit conditioned eyeblink preparation to trace the functional anatomical connections between the AC and the circuitry underlying this conditioned response. Conditioning was shown to be dependent on the cerebellar interpositus nucleus and the pontine nuclei (PN), structures that are essential for conditioning using a peripheral CS. The results suggest that the cerebellum and associated brain stem circuitry are a necessary part of the memory trace circuit for the conditioned eyeblink response, even when the cerebral cortex is artifically engaged as a CS by electrical stimulation. The results also suggest that the PN are a site of convergence between the CS circuit subserving classical conditioning for peripheral stimuli and the AC, and may therefore be a site where the AC can modulate more elaborate forms of conditioning.
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152
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Dugich-Djordjevic MM, Tocco G, Willoughby DA, Najm I, Pasinetti G, Thompson RF, Baudry M, Lapchak PA, Hefti F. BDNF mRNA expression in the developing rat brain following kainic acid-induced seizure activity. Neuron 1992; 8:1127-38. [PMID: 1610567 DOI: 10.1016/0896-6273(92)90133-x] [Citation(s) in RCA: 155] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) mRNA expression was studied in the hippocampus at various developmental stages in normal rats and following kainic acid (KA)-induced seizure activity. Systemic administration of KA strongly elevated BDNF mRNA levels in all hippocampal subregions after postnatal day 21. In contrast, even though KA induced intense behavioral seizure activity at postnatal day 8, the seizures were not associated with elevations of BDNF mRNA levels, indicating a clear dissociation between behavioral seizures and increases in BDNF mRNA levels and contradicting the view that BDNF mRNA expression is principally regulated by neuronal activity. In the dentate gyrus at postnatal day 13, intense BDNF mRNA expression was limited to a defined area at the border between granule cell and molecular layers, suggesting the possibility that segregation of BDNF mRNA into defined subcellular compartments may play a role in establishing the well-delineated patterns of innervation in the hippocampus.
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153
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Tocco G, Massicotte G, Standley S, Thompson RF, Baudry M. Phospholipase A2-induced changes in AMPA receptor: an autoradiographic study. Neuroreport 1992; 3:515-8. [PMID: 1382660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The expression of long-term potentiation and learning of a classical conditioning task increase [3H]-AMPA binding in hippocampus. Phospholipase A2 (PLA2) has been proposed to underly these changes, as PLA2 treatment of membrane preparations increases the affinity of AMPA receptors for agonists. We demonstrate here that preincubation of thin (10 microns) frozen rat brain sections with exogenous PLA2 and calcium at physiological temperature changes the binding properties of AMPA receptors. Quantitative autoradiography reveals that PLA2-treatment produces a differential increase in [3H]-AMPA binding across brain regions. The same treatment also decreases the binding of an antagonist ([3H]-CNQX) throughout the brain. We propose that PLA2 treatment results in a modification of the AMPA receptors which is regionally specific, probably due to different AMPA receptor subunit compositions.
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154
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Abstract
The key interrelated issues in the neurobiology of memory are to identify the neural circuitries essential for memory formation, localize sites of memory storage and analyze mechanisms of memory formation, storage and retrieval. Several circuits have now been identified in vertebrates and researchers are investigating their properties, in particular the role of glutamate receptors and long-term potentiation, in memory formation. Invertebrate preparations continue to be of value and recent studies suggest that changes in gene expression and protein synthesis may be important in long-term sensitization.
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155
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Thompson RF. Memory. Curr Biol 1992. [DOI: 10.1016/0960-9822(92)90526-g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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156
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Weiss C, Thompson RF. Delayed acquisition of eyeblink conditioning in aged F1 hybrid (Fischer-344 x Brown Norway) rats. Neurobiol Aging 1992; 13:319-23. [PMID: 1522946 DOI: 10.1016/0197-4580(92)90045-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We previously reported that the freely moving male Fischer-344 rat provides a useful model to demonstrate the progressive impairment of eyeblink conditioning associated with aging. However, because the youngest F-344 rats only performed at 60% of maximum, we ran the same experiment with hybrid rats and discovered most (i.e., those age 9-24 months) learned rapidly and exhibited conditioned responses on greater than 80% of trials by the end of two training sessions. In contrast, the aged rats (36 months) exhibited significantly fewer CRs on all four training days. However, unlike all ages of F-344 rats (3-30 months) which were run in our last study, these aged hybrid rats exhibited considerable improvement with extra training. These data indicate clear differences in the rate of learning between the two strains and suggest that even young F-344 rats may have deficits in the neural circuits which mediate eyeblink conditioning. Other anecdotal findings on differences between the two strains are noted.
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157
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Tocco G, Maren S, Shors TJ, Baudry M, Thompson RF. Long-term potentiation is associated with increased [3H]AMPA binding in rat hippocampus. Brain Res 1992; 573:228-34. [PMID: 1380390 DOI: 10.1016/0006-8993(92)90767-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The location and nature of the changes underlying long-term potentiation (LTP) remain controversial issues. In this study, we tested the possibility that changes in binding properties of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA/quisqualate and N-methyl-D-aspartate (NMDA) subtype of glutamate receptors are associated with LTP. LTP was elicited in vivo by stimulation of the perforant pathway in anesthetized rats. One hour following stimulation the animals were sacrificed. We performed quantitative ligand binding autoradiography on frozen brain sections using [3H]AMPA and [3H]N-(1-(2-thienyl)cyclohexyl)-3,4-piperidine ([3H]TCP) to label the AMPA/quisqualate and the NMDA receptors, respectively. No changes in [3H]TCP binding were detected in any of the treatment groups. However, increases in [3H]AMPA binding were observed only in animals that exhibited LTP. These increases were bilateral and present in several subfields of the hippocampus and cortical areas. Administration of the NMDA receptor antagonist, ketamine, prior to tetanic stimulation prevented both the increase in binding and the induction of LTP. These results suggest that changes in the characteristics of AMPA/quisqualate receptors are a biochemical correlate of LTP.
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158
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Knowlton BJ, Thompson RF. Conditioning using a cerebral cortical conditioned stimulus is dependent on the cerebellum and brain stem circuitry. Behav Neurosci 1992; 106:509-17. [PMID: 1616617 DOI: 10.1037/0735-7044.106.3.509] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electrical stimulation of the auditory cortex (AC) was used as a conditioned stimulus (CS) in the rabbit conditioned eyeblink preparation to trace the functional anatomical connections between the AC and the circuitry underlying this conditioned response. Conditioning was shown to be dependent on the cerebellar interpositus nucleus and the pontine nuclei (PN), structures that are essential for conditioning using a peripheral CS. The results suggest that the cerebellum and associated brain stem circuitry are a necessary part of the memory trace circuit for the conditioned eyeblink response, even when the cerebral cortex is artifically engaged as a CS by electrical stimulation. The results also suggest that the PN are a site of convergence between the CS circuit subserving classical conditioning for peripheral stimuli and the AC, and may therefore be a site where the AC can modulate more elaborate forms of conditioning.
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159
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Swain RA, Shinkman PG, Nordholm AF, Thompson RF. Cerebellar stimulation as an unconditioned stimulus in classical conditioning. Behav Neurosci 1992; 106:739-50. [PMID: 1445654 DOI: 10.1037/0735-7044.106.5.739] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Rabbits were implanted with chronic stimulating electrodes in white matter underlying lobule HVI of the cerebellar cortex. Stimulation elicited movements of the face or neck and, when paired with a tone conditioned stimulus (CS), produced learning comparable to that seen with peripheral unconditioned stimuli (USs). CS-alone trials produced extinction. Reinstatement of paired trials produced reacquisition with savings. Additional groups received either explicitly or randomly unpaired CS-US trials before paired conditioning. Low-frequency responding during these sessions indicated that the paired training results were associative and not due to pseudoconditioning or sensitization. Explicitly unpaired sessions retarded learning on subsequent paired trials compared with groups that received either randomly unpaired or no CS-US preexposure. These results are interpreted in terms of the role of the cerebellum and associated pathways in classical conditioning of motor responses.
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160
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Uenishi N, Shors TJ, Finch CE, Nichols NR, Thompson RF. Increased synthesis of two polypeptides in area CA1 of the hippocampus in response to repetitive electrical stimulation. Brain Res 1991; 567:248-52. [PMID: 1687806 DOI: 10.1016/0006-8993(91)90802-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Changes in the pattern of newly synthesized polypeptides were investigated in the in vitro hippocampal slice following exposure to repetitive stimulation with and without the induction of long-term potentiation. Using [35S]methionine labeling of polypeptides and two-dimensional gel electrophoresis, we detected an increase in the rate of synthesis of two polypeptides (48 kDa and 89 kDa) in CA1 in response to repetitive stimulation of the Schaffer collaterals. The synthesis of the 48 kDa polypeptide (pI approximately 6.6) increased 240% in response to high-frequency stimulation (100 Hz) relative to the same protein from unstimulated slices (n = 14), and increased 220% in response to low-frequency stimulation (1 Hz) (n = 5). Blockade of the N-methyl-D-aspartate (NMDA) receptor induced the protein 180%, with no further increase following tetanic stimulation. An 89 kDa doublet (pI approximately 6.8) increased 150% following high-frequency and 140% following low-frequency stimulation. Blockade of the NMDA receptor increased this protein as well (180% of the unstimulated control) and no further increase was observed following high-frequency stimulation. Based on physicochemical and electrophysiological properties, these proteins are not identifiable as any of those previously associated with long-term potentiation or repetitive electrical stimulation.
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161
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Tocco G, Devgan KK, Hauge SA, Weiss C, Baudry M, Thompson RF. Classical conditioning selectively increases AMPA receptor binding in rabbit hippocampus. Brain Res 1991; 559:331-6. [PMID: 1665385 DOI: 10.1016/0006-8993(91)90020-v] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The NMDA and AMPA receptors have been shown to play critical roles in various forms of synaptic plasticity (learning and memory, long-term potentiation). The present study investigated the involvement of these two receptors in a well-characterized classical conditioning paradigm. Following classical conditioning of the rabbit nictitating membrane the binding properties of these two subclasses of excitatory amino acid transmitter receptors were analyzed in dorsal hippocampi by quantitative autoradiography. [3H] TCP and [3H] AMPA were used to identify the NMDA and AMPA receptors, respectively. The binding of [3H]TCP to the NMDA receptor remained unchanged in all the experimental groups tested. Paired presentations of the conditioned and unconditioned stimuli resulted in increased [3H] AMPA binding to the AMPA receptor in several subfields of the hippocampus, while unpaired presentations had no significant effects. The increase in binding was due to an increased affinity of the low-affinity component of the AMPA receptor. The results support the hypothesis that changes in glutamate receptors participate in the synaptic plasticity involved in certain forms of learning.
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162
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Tocco G, Shors TJ, Baudry M, Thompson RF. Selective increase of AMPA binding to the AMPA/quisqualate receptor in the hippocampus in response to acute stress. Brain Res 1991; 559:168-71. [PMID: 1664274 DOI: 10.1016/0006-8993(91)90302-c] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The binding properties of ligands specific for two subclasses of glutamate receptors were studied by quantitative autoradiography after one hour of acute immobilization/shock stress. [3H]N-(1-(2-thienyl)cyclohexyl)-3,4-piperidine (TCP) and [3H]alpha-amino-3-methylisoxazole-4-propionic acid (AMPA) were used to visualize the N-methyl-D-aspartate receptor and the AMPA/quisqualate receptor types, respectively. While no change was observed in the binding properties of the [3H]TCP, [3H]AMPA binding was significantly increased in several areas of the hippocampus of acutely stressed rats relative to naive controls.
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163
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Schreiber SS, Maren S, Tocco G, Shors TJ, Thompson RF. A negative correlation between the induction of long-term potentiation and activation of immediate early genes. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1991; 11:89-91. [PMID: 1662748 DOI: 10.1016/0169-328x(91)90025-s] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the present study we examined the relationship between the induction of long-term potentiation (LTP) in the dentate gyrus of anesthetized rats and activation of immediate early genes (IEGs; c-fos and zif/268) using several different high-frequency stimulation paradigms. Stimulation parameters that effectively induced LTP were not associated with IEG activation. Conversely, stimulation parameters that failed to induce LTP consistently resulted in IEG activation. These results suggest that there is a negative correlation between IEG activation and LTP, and that activation of IEGs is neither necessary nor sufficient for the induction of LTP.
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164
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Nordholm AF, Lavond DG, Thompson RF. Are eyeblink responses to tone in the decerebrate, decerebellate rabbit conditioned responses? Behav Brain Res 1991; 44:27-34. [PMID: 1910568 DOI: 10.1016/s0166-4328(05)80236-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bloedel and associates recently claimed to have established conditioned eyeblink responses in the acute decerebrate, decerebellate rabbit. Their training procedure was extreme massed practice (mean intertrial interval of 9 s) and they used an idiosyncratic definition of the conditioned response (10% or more of the unconditioned response amplitude). They did not measure or control the excitability of their preparations and did not run any separate control groups for alpha responses, alpha conditioning or pseudoconditioning. Using normal animals we compared their training procedure with procedures standard in the field and analyzed the consequences of their scoring procedure. Our group trained at a 30-s intertrial interval (ITI) showed clear learning in the training session. In marked contrast, 3 groups trained at a 9-s ITI developed no conditioned responses. We also found that the method of scoring used by Bloedel and associates counts many spontaneous responses as conditioned responses (CRs) if unconditioned response (UR) amplitudes are low, excludes genuine CRs if UR amplitudes are high and does not control for the occurrence of spontaneous responses. It must therefore be concluded that the eyeblink responses to tone reported by Bloedel and associates to occur in the decerebrate, decerebellate rabbit are not associative CRs as they develop in the normal animal.
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165
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Maren S, Baudry M, Thompson RF. Differential effects of ketamine and MK-801 on the induction of long-term potentiation. Neuroreport 1991; 2:239-42. [PMID: 1832985 DOI: 10.1097/00001756-199105000-00006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Ketamine and MK-801 are phencyclidine (PCP)-like noncompetitive antagonists of the N-methyl-D-aspartate (NMDA) receptor that produce a use-dependent blockade of the NMDA receptor-coupled channel. Recent studies have suggested that the binding properties of these drugs to the NMDA receptor in-vitro are different. In the present study, the effects of ketamine and MK-801 on the induction of long-term potentiation (LTP) were compared at perforant path--granule cell synapses in anaesthetized rats. LTP was observed in animals treated with either saline or MK-801, but not in those treated with ketamine. These results reveal that ketamine and MK-801 differentially modulate the induction of LTP, and we propose that this differential modulation may be related to the different binding properties of the drugs.
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166
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Weiss C, Thompson RF. The effects of age on eyeblink conditioning in the freely moving Fischer-344 rat. Neurobiol Aging 1991; 12:249-54. [PMID: 1876231 DOI: 10.1016/0197-4580(91)90105-s] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of age were assessed on the ability of male Fischer-344 rats to acquire a classically conditioned eyeblink using the "delay" paradigm. Using a 350 ms white noise conditioning stimulus and a 100 ms coterminating periorbital shock (2 mA, 60 Hz, AC) we have demonstrated that these rats exhibit deficits as early as middle age. Middle-aged and senescent rats (18 and 30 months) exhibited significantly fewer conditioned responses than young rats (3 and 12 months). Since all of the rats responded to a test noise, and there were no differences in threshold to evoke a blink, this result is likely to be due to an associative deficit. Thus, our results indicate that eyeblink conditioning in the freely moving rat is a useful model system for behavioral and neurobiological analyses of the effects of age on associative learning and memory.
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167
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Bartha GT, Thompson RF, Gluck MA. Sensorimotor Learning and the Cerebellum. RESEARCH NOTES IN NEURAL COMPUTING 1991. [DOI: 10.1007/978-3-642-84545-1_25] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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168
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Abstract
Evidence supports the view that "memory traces" are formed in the hippocampus and in the cerebellum in classical conditioning of discrete behavioral responses (e.g. eyeblink conditioning). In the hippocampus, learning results in long-lasting increases in excitability of pyramidal neurons that appear to be localized to these neurons (i.e. changes in membrane properties and receptor function). However, these learning-altered pyramidal neurons are distributed widely throughout CA3 and CA1. Although it plays a key role in certain aspects of classical conditioning, the hippocampus is not necessary for learning and memory of the basic conditioned responses. The cerebellum and its associated brain stem circuitry, on the other hand, does appear to be essential (necessary and sufficient) for learning and memory of the conditioned response. Evidence to date is most consistent with a localized trace in the interpositus nucleus and multiple localized traces in cerebellar cortex, each involving relatively large ensembles of neurons. Perhaps "procedural" memory traces are relatively localized and "declarative" traces more widely distributed.
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169
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Abstract
We used in-situ hybridization to study the effect of acute stress on induction of the immediate early genes (IEGs), c-fos and zif/268, in the rat brain. After one hour of restraint plus intermittent tail shock, messenger RNA (mRNA) levels for both genes were significantly increased bilaterally in the neocortex, particularly in layers IV, V and VI, and in the CA1 region of the hippocampus. This regionally-specific response suggests that IEGs may have a role in the mediation of acute stress responses in the central nervous system.
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170
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Chapman PF, Steinmetz JE, Sears LL, Thompson RF. Effects of lidocaine injection in the interpositus nucleus and red nucleus on conditioned behavioral and neuronal responses. Brain Res 1990; 537:149-56. [PMID: 2085770 DOI: 10.1016/0006-8993(90)90351-b] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The role of the cerebellum and the red nucleus in the conditioned eyeblink response was assessed, using a combination of reversible lesions and multiple-unit extracellular recording in the awake, behaving rabbit. Lesion, recording, and stimulation experiments have indicated that both of these structures are involved in the performance of learned skeletal muscle responses. The present study sought to distinguish the relative contributions of the interpositus nucleus and the red nucleus to the expression of the learned response by recording behavior-related multiple unit activity in one structure while reversibly inactivating the other via injections of local anesthetic. Results indicate that inactivating either the interpositus or the red nucleus temporarily abolishes the learned eyeblink response. Injection of lidocaine into the interpositus also abolishes the neuronal unit model of the conditioned response in the red nucleus, while injection into the red nucleus does not affect the model in the interpositus. These results are consistent with the hypothesis that the red nucleus acts as a relay for motor commands from the cerebellum, and that the plasticity that generates conditioned responses occurs in the cerebellum or an afferent structure.
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171
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Woodruff-Pak DS, Logan CG, Thompson RF. Neurobiological substrates of classical conditioning across the life span. Ann N Y Acad Sci 1990; 608:150-73; discussion 174-8. [PMID: 2075952 DOI: 10.1111/j.1749-6632.1990.tb48896.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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172
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173
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Austrom MG, Thompson RF, Hendrie HC, Norton J, Farlow MR, Edwards MK, Dean R. Foci of increased T2 signal intensity in MR images of healthy elderly subjects. A follow-up study. J Am Geriatr Soc 1990; 38:1133-8. [PMID: 2229868 DOI: 10.1111/j.1532-5415.1990.tb01377.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An 18-month follow-up study was conducted on 26 healthy elderly subjects with and without foci of increased T2 signal intensity on MR imaging. The subjects did not differ with respect to health status or cognitive performance as measured by the Cognitive Subscale of the Cambridge Mental Disorders of the Elderly Examination and the Mini Mental State Examination at follow-up. There was a significant decline in performance on the Digit Symbol Substitution Test in subjects who had evidence of T2 foci compared to the performance of subjects without T2 foci. This may indicate that the presence of T2 foci is correlated with subtle difficulties in learning and memory.
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174
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Thompson RF. Neural mechanisms of classical conditioning in mammals. Philos Trans R Soc Lond B Biol Sci 1990; 329:161-70. [PMID: 1978361 DOI: 10.1098/rstb.1990.0161] [Citation(s) in RCA: 170] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Evidence supports the view that 'memory traces' are formed in the hippocampus and in the cerebellum in classical conditioning of discrete behavioural responses. In the hippocampus learning results in long-lasting increases in excitability of pyramidal neurons that resemble the phenomenon of long-term potentiation. Although it plays a role in certain aspects of conditioning, the hippocampus is not necessary for learning and memory of the basic conditioned responses. The cerebellum and its associated brain-stem circuitry, on the other hand, does appear to be essential (necessary and sufficient) for learning and memory of the conditioned response. Evidence to date supports the view that mossy fibre convey conditioned stimulus information and that climbing fibres conveys the critical 'reinforcement' information to the cerebellum and that 'memory traces' appear to be formed in cerebellar cortex and interpositus nucleus.
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175
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Shors TJ, Foy MR, Levine S, Thompson RF. Unpredictable and uncontrollable stress impairs neuronal plasticity in the rat hippocampus. Brain Res Bull 1990; 24:663-7. [PMID: 2192774 DOI: 10.1016/0361-9230(90)90005-k] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Almost by definition, learning and the effect of stress on learning represent modifications of existing neuronal circuitry. Under some circumstances, this modification can be measured electrophysiologically. One such measure of plasticity is long-term potentiation (LTP), a long-lasting increase in synaptic efficacy following brief exposure to tetanic stimulation. In 1987, Foy et al. reported that hippocampal LTP was impaired by exposure to inescapable shock. We have recent evidence that the impairment in LTP can be prevented by allowing the animal to learn to escape the shock (Shors et al., 1989), indicating that the stress effect is to some extent mediated by "psychological" variables. Regardless of LTP's putative role in learning and memory processes, such a stress-induced decrease in neuronal plasticity is likely to have profound effects on the behaving organism.
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176
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Shors TJ, Levine S, Thompson RF. Opioid antagonist eliminates the stress-induced impairment of long-term potentiation (LTP). Brain Res 1990; 506:316-8. [PMID: 2154288 DOI: 10.1016/0006-8993(90)91270-q] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rats (n = 20) were injected with the opioid antagonist naltrexone and half were exposed to inescapable shock/restraint. Another 20 rats were injected with saline and half were exposed to shock. Neither saline nor naltrexone alone had any effect on hippocampal LTP. A large reduction in LTP was observed in saline rats exposed to shock, while normal LTP developed in the naltrexone rats exposed to shock. Thus, naltrexone eliminated the impairment, and thereby implicated endogenous opioids in the mechanism responsible for the stress-induced impairment of LTP.
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177
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Shors TJ, Levine S, Thompson RF. Effect of adrenalectomy and demedullation on the stress-induced impairment of long-term potentiation. Neuroendocrinology 1990; 51:70-5. [PMID: 2106090 DOI: 10.1159/000125318] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In these three experiments, we investigated the effect of adrenalectomy and adrenal demedullation on the stress-induced impairment of long-term potentiation (LTP) in the rat hippocampal slice. In the first, adrenalectomy alone resulted in a significant reduction in LTP, while exposure to stress resulted in a further reduction. In the second, replacing corticosterone in adrenalectomized rats did not restore LTP. In the last experiment, demedullation resulted in a reduction in LTP similar to that induced by adrenalectomy, while exposure to stress did not result in a further reduction. In combination, these studies provide evidence that the adrenal medullary system modulates hippocampal plasticity and the stress-induced impairment of LTP.
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178
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Thompson RF, Gluckman JL, Kulwin D, Savoury L. Orbital hemorrhage during ethmoid sinus surgery. Otolaryngol Head Neck Surg 1990; 102:45-50. [PMID: 2106117 DOI: 10.1177/019459989010200108] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Orbital hemorrhage is an unusual complication of ethmoid surgery. A case of intraoperative orbital hemorrhage occurring during a medial maxillectomy and one occurring during a transethmoid sphenoidotomy are presented. The pathogenesis of this potentially serious complication is discussed. A sequential treatment algorithm is presented, consisting of medial orbitotomy, lateral canthotomy and inferior cantholysis, and inferior orbital decompression, along with concomitant medical management with mannitol, acetazolamide, and dexamethasone.
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179
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Thompson RF, Crist DM, Osborn LA, Atterbom HA. Treadmill exercise electrocardiography in the elderly with physical impairments. Gerontology 1990; 36:112-8. [PMID: 2142924 DOI: 10.1159/000213184] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Treadmill testing (TMT) was performed on 76 frail but ambulatory subjects, between 64 and 84 years of age, who had common health problems contributing to physical limitations but had no clinically apparent heart disease. The subjects achieved a mean symptom-limited maximal heart rate of 140.1 +/- 2.07 (SEM) beats per minute which was 80.2 +/- 2.1% of the predicted maximum for age. By standard criteria, ischemic responses were noted in only 5 subjects (6.6%). Three responses were categorized as inconclusive (multifocal ventricular ectopy, chest pain without electrocardiographic change, and prompt ST depression upon standing). TMT was well tolerated, with no significant difficulties encountered. Even for those frail elderly with diseases and physical impairments, symptom-limited TMT may be used with low risk to quantify functional capacity and for exercise prescription. Attempts to screen more intensively for cardiac disease may be irrelevant to their immediate need for maintaining function.
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180
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Woodruff-Pak DS, Thompson RF. Classical conditioning of the eyeblink response in the delay paradigm in adults aged 18-83 years. Psychol Aging 1989; 3:219-29. [PMID: 3268262 DOI: 10.1037/0882-7974.3.3.219] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
To determine if age differences in classical conditioning of the eyelid response begin to appear in middle age in humans as they do in animals, adult subjects aged 18-83 years were trained in the delay conditioning paradigm. Large age effects occurred. Statistically significant differences first appeared in the decade of the 40s. Within-age-group variability was large. To reduce variability, subjects were classified by the magnitude of their unconditioned response (UR). Regardless of age, subjects with low amplitude URs conditioned poorly. In the normal UR amplitude group, the correlation between age and total percentage conditioned responses (CRs) was -.58. Eyeblink rate and voluntary responding did not account for age differences in conditioning, and it was unlikely that hearing acuity or corneal sensitivity caused the differences. Parallels between human and animal eyelid conditioning are considered, and it is suggested that age changes in the cerebellum may affect conditioning in aging mammals, including humans.
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181
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Rosen DJ, Steinmetz JE, Thompson RF. Classical discrimination conditioning of the rabbit's eyelid response using pontine stimulation as a conditioned stimulus. BEHAVIORAL AND NEURAL BIOLOGY 1989; 52:51-62. [PMID: 2757584 DOI: 10.1016/s0163-1047(89)90158-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Classical discrimination conditioning of the nictitating membrane/eyelid response was performed on seven rabbits using stimulation of the pontine nuclei or middle cerebellar peduncle as the conditioned stimulus (CS) and an air puff as the unconditioned stimulus (US). The rabbits learned to discriminate between a CS paired with a US and delivered to one pontine nucleus (the CS+) and a CS presented alone and delivered to the contralateral pontine nucleus (the CS-). Subsequent reversal of the discrimination was also achieved when the CS+ and CS- stimulation sites were interchanged. The results are interpreted as support for the idea that essential plasticity for classical eyelid conditioning occurs efferent to the pontine nuclei, possibly in regions of the cerebellum.
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182
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Thompson RF. CPR in the nursing home: a delusion? J Am Geriatr Soc 1989; 37:487-8. [PMID: 2703647 DOI: 10.1111/j.1532-5415.1989.tb02657.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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183
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Shors TJ, Seib TB, Levine S, Thompson RF. Inescapable versus escapable shock modulates long-term potentiation in the rat hippocampus. Science 1989; 244:224-6. [PMID: 2704997 DOI: 10.1126/science.2704997] [Citation(s) in RCA: 364] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A group of rats was trained to escape low-intensity shock in a shuttle-box test, while another group of yoked controls could not escape but was exposed to the same amount and regime of shock. After 1 week of training, long-term potentiation (LTP) was measured in vitro in hippocampal slices. Exposure to uncontrollable shock massively impaired LTP relative to exposure to the same amount and regime of controllable shock. These results provide evidence that controllability modulates plasticity at the cellular-neuronal level.
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184
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Zacher LL, Teslow TW, Thompson RF. Pheochromocytoma and ischemic enterocolitis. SOUTH DAKOTA JOURNAL OF MEDICINE 1989; 42:11-4. [PMID: 2704986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In the nine year period, 1978-1987, two patients with pheochromocytoma presented to Sacred Heart Hospital, Yankton, South Dakota. Both cases were complicated pre-operatively by ischemic enterocolitis--a rarely reported, usually fatal complication of pheochromocytoma. It is thought that catecholamine-induced vasoconstriction of the mesenteric vessels resulted in the wide-spread hemorrhagic necrosis of the gut. Both patients survived not only the initial ischemic mesenteric insult, but also excision of the tumor.
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185
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Knowlton BJ, Thompson RF. Stimulation of the lateral septum is a more effective conditioned stimulus than stimulation of the medial septum during classical conditioning of the eye-blink response. Behav Neurosci 1989. [PMID: 2923674 DOI: 10.1037//0735-7044.103.1.206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Eight rabbits were trained in the classically conditioned eye-blink response procedure using stimulation of the septal nuclei as the conditioned stimulus (CS). Each rabbit was trained with both medial septal stimulation and lateral septal stimulation. Stimulation of the medial septum was a far less effective CS than stimulation of the lateral septum. This effect may be due to the different roles of these two nuclei in classical conditioning. Conditioning using lateral septal stimulation as a CS is dependent on the cerebellar interpositus nucleus as is conditioning using peripheral and other brain stimulation CSs.
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186
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Knowlton BJ, Thompson RF. Stimulation of the lateral septum is a more effective conditioned stimulus than stimulation of the medial septum during classical conditioning of the eye-blink response. Behav Neurosci 1989; 103:206-8. [PMID: 2923674 DOI: 10.1037/0735-7044.103.1.206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Eight rabbits were trained in the classically conditioned eye-blink response procedure using stimulation of the septal nuclei as the conditioned stimulus (CS). Each rabbit was trained with both medial septal stimulation and lateral septal stimulation. Stimulation of the medial septum was a far less effective CS than stimulation of the lateral septum. This effect may be due to the different roles of these two nuclei in classical conditioning. Conditioning using lateral septal stimulation as a CS is dependent on the cerebellar interpositus nucleus as is conditioning using peripheral and other brain stimulation CSs.
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187
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Towbin RB, Myer CM, Thompson RF. Percutaneous transnasal sphenoidotomy with sphenoid window. AJNR Am J Neuroradiol 1989; 10:845-7. [PMID: 2505510 PMCID: PMC8332618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ten percutaneous transnasal sphenoidotomies were performed in nine children; and in seven, a sphenoid window was also created. All procedures were performed in the special procedures laboratory, with biplane fluoroscopic guidance used in each case. Under general anesthesia, with the child in the supine position, a 14-gauge antral trocar was placed transnasally into the sphenoid sinus. The sinus was aspirated and material was obtained for culture. A Takahashi forceps was placed via the same tract into the sphenoid sinus. The cusps were centered across the anterior cortex, and under fluoroscopic visualization, opened and rotated 360 degrees, creating a sphenoid window. All procedures were completed without complication, and no child required further surgery.
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188
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Crist DM, Mackinnon LT, Thompson RF, Atterbom HA, Egan PA. Physical exercise increases natural cellular-mediated tumor cytotoxicity in elderly women. Gerontology 1989; 35:66-71. [PMID: 2792786 DOI: 10.1159/000213001] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The influence of acute treadmill exercise on natural killer (NK) cell tumor cytotoxicity in vitro was studied in elderly women after participation in a program of physical exercise training (PET) (n = 7) or after participation in a paralleling nonexercise control (NEC) condition (n = 7). The two study groups were equated (p greater than 0.05) according to age, percent total body fat, functional status as measured by multi-inventory ranking, and exercise capacity. After the experimental period, the PET subjects had a greater basal level of NK activity than the NEC subjects (PET 38.2 percent specific lysis, %SL, vs. NEC 28.8 %SL; p less than 0.05). Both groups experienced an increase in NK activity after acute treadmill exercise (PET 38.2-57.4 %SL, p less than 0.01; NEC 28.8-37.8 %SL, p less than 0.05), but the increase in the PET subjects was significantly (p less than 0.05) greater than that observed in the NEC subjects. We conclude that natural cellular-mediated tumor cytotoxicity is increased in response to acute exercise and long-term PET in elderly women.
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189
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Steinmetz JE, Lavond DG, Thompson RF. Classical conditioning in rabbits using pontine nucleus stimulation as a conditioned stimulus and inferior olive stimulation as an unconditioned stimulus. Synapse 1989; 3:225-33. [PMID: 2718098 DOI: 10.1002/syn.890030308] [Citation(s) in RCA: 232] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Classical conditioning of skeletal muscle responses was accomplished by pairing microstimulation of the pontine nuclei as a conditioned stimulus (CS) with microstimulation of the dorsal accessory olive as an unconditioned stimulus (US). A conditioned response identical in form to the behavioral response elicited by the olivary stimulation was established when the CS was forward paired with the US, and behavioral extinction occurred with CS-alone presentations or unpaired CS-US presentations. Conditioned responding could not be established or maintained when the CS and US were simultaneously presented or when the US preceded the CS (i.e., backward paired). Complete lesions of the interpositus nucleus abolished both conditioned and unconditioned responses. These findings support the idea that plasticity associated with classical conditioning of skeletal muscle responses occurs in regions of the cerebellum that receive convergent CS and US input.
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190
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Woodruff-Pak DS, Thompson RF. Classical conditioning of the eyeblink response in the delay paradigm in adults aged 18-83 years. Psychol Aging 1988. [PMID: 3268262 DOI: 10.1037//0882-7974.3.3.219] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To determine if age differences in classical conditioning of the eyelid response begin to appear in middle age in humans as they do in animals, adult subjects aged 18-83 years were trained in the delay conditioning paradigm. Large age effects occurred. Statistically significant differences first appeared in the decade of the 40s. Within-age-group variability was large. To reduce variability, subjects were classified by the magnitude of their unconditioned response (UR). Regardless of age, subjects with low amplitude URs conditioned poorly. In the normal UR amplitude group, the correlation between age and total percentage conditioned responses (CRs) was -.58. Eyeblink rate and voluntary responding did not account for age differences in conditioning, and it was unlikely that hearing acuity or corneal sensitivity caused the differences. Parallels between human and animal eyelid conditioning are considered, and it is suggested that age changes in the cerebellum may affect conditioning in aging mammals, including humans.
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191
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Thompson RF. Classical conditioning: the Rosetta stone for brain substrates of age-related deficits in learning and memory. Neurobiol Aging 1988; 9:547-8. [PMID: 3211260 DOI: 10.1016/s0197-4580(88)80111-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The three chapters on the use of classical conditioning paradigms to investigate neurobiological and behavioral substrates of memory impairments with aging are in close agreement on all key issues. Based on these chapters, it is argued here that classical conditioning of discrete behavioral responses in rabbit and other mammals is among the most promising animal models of the human condition in which to analyze brain mechanisms of normally occurring age-related deficits in learning and memory.
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192
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Haley DA, Thompson RF, Madden J. Pharmacological analysis of the magnocellular red nucleus during classical conditioning of the rabbit nictitating membrane response. Brain Res 1988; 454:131-9. [PMID: 3408999 DOI: 10.1016/0006-8993(88)90811-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Previous experiments have suggested that the red nucleus is an essential structure in the neural pathways subserving the conditioned responses (CRs) elicited in several simple associative learning paradigms. The present investigation confirms the involvement of the magnocellular red nucleus in production of the classically conditioned nictitating membrane response in the rabbit and suggests that gamma-aminobutyric acid (GABA) processes within this structure are involved in expression of the CR. Specifically, these studies demonstrate that microinfusion of a GABA antagonist (either picrotoxin or bicuculline methiodide) into the magnocellular red nucleus can selectively and reversibly reduce or abolish retention of the CR, without altering the unconditioned reflex response. Furthermore, these pharmacological manipulations that disrupt the CR are both anatomically and pharmacologically specific, and demonstrate a predictable dose-dependent function. These findings suggest that GABAergic processes within the magnocellular red nucleus are part of the critical circuitry subserving the CR.
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193
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Thompson RF, Bode RB, Rhodes JC, Gluckman JL. Paecilomyces variotii. An unusual cause of isolated sphenoid sinusitis. ARCHIVES OF OTOLARYNGOLOGY--HEAD & NECK SURGERY 1988; 114:567-9. [PMID: 3355698 DOI: 10.1001/archotol.1988.01860170097028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Isolated fungal sphenoid sinusitis is an unusual head and neck infection. We describe the first reported case (to our knowledge) of Paecilomyces variotii sphenoid sinusitis. In addition, it represents one of the few reported cases of isolated fungal sphenoid sinusitis. Diagnosis and management of this condition are described. Aggressive surgical management is advocated when fungal sphenoid sinusitis is suspected.
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194
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Abstract
The pediatric otolaryngologist is often asked to evaluate intubated patients in the neonatal intensive care unit (NICU) because of sudden deterioration in respiratory status unresponsive to medical management. Previously, evaluation of infants required transportation to the operating room for rigid endoscopy. At the present time, however, flexible fiberoptic bronchoscopy may be performed on such patients in the NICU as an initial diagnostic or therapeutic measure. The procedure is performed through an endotracheal tube or tracheostomy tube already in place, thereby assuring maintenance of a safe airway. Ten representative cases are presented detailing the indications, technique and potential applications in the NICU.
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196
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Thompson RF. Ethical principles should be part of nursing home policy. PROVIDER (WASHINGTON, D.C.) 1988; 14:17, 24. [PMID: 10312415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Ethically influenced decisions in the long term care setting should not be guided by policy, procedure, dictum. If policies seem indicated, they should provide for the incorporation of ethical principles and the application of medical information on a case-by-case basis, to make it possible to do what is best for the individual patient. Following a long history of accepting paternalistic behavior, our society has now clearly shifted to support the autonomous conduct of the patient, even for those moments when the patient cannot reliably express a preference. This societal change will continue to influence our work in nursing homes.
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197
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Woodruff-Pak DS, Steinmetz JE, Thompson RF. Classical conditioning of rabbits 2-1/2 to 4 years old using mossy fiber stimulation as a CS. Neurobiol Aging 1988; 9:187-93. [PMID: 3374735 DOI: 10.1016/s0197-4580(88)80049-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A basic issue in age-related deterioration in memory formation concerns the locus of the age changes. Changes in peripheral portions of the auditory CS pathway could account for the observed age differences in classical conditioning in rabbits. We bypassed peripheral portions of the CS pathway and input the CS more centrally by electrical microstimulation of mossy fibers in the pons. New Zealand White rabbits aged 2-1/2-4 years were compared to six 3-month-old control rabbits with electrode implantations in comparable areas. Training consisted of 108 trials per day in which stimulation CS was paired with a corneal airpuff US. Older rabbits took almost five times as long to condition as the young animals. Thus, age differences in eyelid classical conditioning cannot be entirely attributed to changes in the peripheral CS pathway. Changes in the nervous system occurring more centrally in the cerebellum appear to affect learning and memory.
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198
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Chapman PF, Steinmetz JE, Thompson RF. Classical conditioning does not occur when direct stimulation of the red nucleus or cerebellar nuclei is the unconditioned stimulus. Brain Res 1988; 442:97-104. [PMID: 3359261 DOI: 10.1016/0006-8993(88)91436-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The involvement of the cerebellum and the red nucleus in the classically conditioned nictitating membrane/eyeblink response in the rabbit is investigated using direct stimulation of the interpositus or the red nucleus as the unconditioned stimulus. Stimulation of either of these structures produced eye closure in naive animals, and this eye closure was paired with a tone in the standard Pavlovian conditioning paradigm. The results indicate that eyelid closure due to stimulation of either the red nucleus or the interpositus nucleus is not sufficient for the development of conditioned responses to the tone. Animals which had received interpositus stimulation as the unconditioned stimulus acquired the conditioned response to tone significantly faster following the substitution of air puff for stimulation than did those animals that had received red nucleus stimulation, or controls that did not receive any stimulation. However, animals that had been trained to tone-air puff could not retain the conditioned response after being switched to tone-interpositus stimulation. Lesions of the interpositus and the red nucleus through the stimulating electrodes were effective in impairing or abolishing conditioned responses. The results are interpreted to indicate that the red nucleus and interpositus are elements of the circuit that carries out the expression of the conditioned response. In addition the interpositus, but not the red nucleus, may be critical in the formation of the memory trace for the conditioned stimulus-unconditioned stimulus association, by virtue of the greatly accelerated learning that results from its stimulation.
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199
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Thompson RF, Crist DM, Marsh M, Rosenthal M. Effects of physical exercise for elderly patients with physical impairments. J Am Geriatr Soc 1988; 36:130-5. [PMID: 3339217 DOI: 10.1111/j.1532-5415.1988.tb01782.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Exercise is known to preserve many physiological responses in the healthy elderly, yet those with physical impairments are often discouraged from exercising. The authors studied the effects of a closely supervised exercise program designed specifically for elders with health problems and functional limitations. Tests, selected for their relevance to clinical patient management, included the Self Evaluation of Life Function questionnaire, treadmill performance, and tests of autonomic nervous system and neuromotor functions. Ambulatory volunteers, aged 64 to 83 years, with noncardiac health problems, were randomly assigned to a control group (CG; n = 17) or a 16-week exercise group (EG; 3 hr/wk, n = 18). Nine of the control and 13 of the exercise subjects completed the study. All EG dropouts were due to illness. EG attendance averaged 87%, and subjects trained at a heart rate (HR) of 103 +/- 5 beats/min (SD) (98% of prescription HR). Though EG test responses showed a tendency to improve, none reached statistical significance. This result was affected by the small number completing the study and the variability inherent in such a sample. Though these impaired elderly subjects enthusiastically and safely participated with high attendance and at an exercise intensity adequate to expect benefit, measurable training effects were not demonstrated.
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200
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Knowlton BJ, Thompson RF. Microinjections of local anesthetic into the pontine nuclei reduce the amplitude of the classically conditioned eyelid response. Physiol Behav 1988; 43:855-7. [PMID: 3237801 DOI: 10.1016/0031-9384(88)90389-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Seventeen rabbits were implanted bilaterally with cannulae into the pontine nuclei, and were then trained in the classically conditioned eyeblink procedure. Nine of the rabbits were trained with a tone as a conditioned stimulus (CS), and eight were trained with both tone and a light CS. After each rabbit had learned the conditioned response (CR) well, testing began. One microliter of 5% lidocaine injected bilaterally significantly impaired the CR amplitude for both tone and light as a CS, although unconditioned response amplitude was not affected. Injection of 1 microliter of isotonic saline did not impair CR amplitude, suggesting that the impairment seen after lidocaine injection was due to the anesthetic action of lidocaine in the pons, and not to nonspecific effects distal to the site of injection. These results support and extend the lesion data which shows that the pontine nuclei and their mossy fiber projection to the cerebellum are necessary for eyeblink conditioning using a peripheral CS.
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