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Lombardi WJ, Andreason PJ, Sirocco KY, Rio DE, Gross RE, Umhau JC, Hommer DW. Wisconsin Card Sorting Test performance following head injury: dorsolateral fronto-striatal circuit activity predicts perseveration. J Clin Exp Neuropsychol 1999; 21:2-16. [PMID: 10420997 DOI: 10.1076/jcen.21.1.2.940] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The Wisconsin Card Sorting Test (WCST) has been argued to be a sensitive indicator of frontal lobe function. However, several recent studies have failed to find a consistent relationship between structural damage to this cortical area and perseveration on the test. In the present study, positron emission tomography (PET) imaging with 18F-fluorodeoxyglucose was used to examine the relationship of regional brain metabolism to perseverative responding on the WCST in patients with a history of closed-head injury. An inverse relationship was found between perseverative responses and metabolism in the right, but not the left, dorsolateral prefrontal cortex and caudate nucleus. Perseverative responding was not related to metabolism in several other regions of the frontal lobes and basal ganglia, including the putamen and the frontal poles bilaterally. These data suggest that the functional integrity of the right dorsolateral frontal-subcortical circuit is critical for WCST performance.
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Hommer DW. Functional imaging of craving. ALCOHOL RESEARCH & HEALTH : THE JOURNAL OF THE NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM 1999; 23:187-96. [PMID: 10890814 PMCID: PMC6760372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
To visualize brain activity associated with mental states, such as craving for alcohol and other drugs (AODs), researchers have begun to use functional imaging techniques. Three commonly used techniques are single photon emission computed tomography (SPECT), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI). Studies using these three approaches have been reviewed in order to evaluate the validity of a proposed model of the brain regions involved in alcoholism and the craving for alcohol. This model suggests a central role for a connected group of brain regions that include the basal ganglia, thalamus, and orbital cortex. A study using SPECT technology in alcoholics, however, found altered brain activity in only some of those regions during craving. Additional studies in alcoholics, as well as cocaine users, identified several other brain regions whose activities appeared to change in response to craving. These studies have led to the development of a revised model of brain regions involved in craving for AODs. Numerous questions remain, however, that must be answered before the brain areas involved in craving can be identified conclusively.
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Ruttimann UE, Unser M, Rawlings RR, Rio D, Ramsey NF, Mattay VS, Hommer DW, Frank JA, Weinberger DR. Statistical analysis of functional MRI data in the wavelet domain. IEEE TRANSACTIONS ON MEDICAL IMAGING 1998; 17:142-154. [PMID: 9688147 DOI: 10.1109/42.700727] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The use of the wavelet transform is explored for the detection of differences between brain functional magnetic resonance images (fMRI's) acquired under two different experimental conditions. The method benefits from the fact that a smooth and spatially localized signal can be represented by a small set of localized wavelet coefficients, while the power of white noise is uniformly spread throughout the wavelet space. Hence, a statistical procedure is developed that uses the imposed decomposition orthogonality to locate wavelet-space partitions with large signal-to-noise ratio (SNR), and subsequently restricts the testing for significant wavelet coefficients to these partitions. This results in a higher SNR and a smaller number of statistical tests, yielding a lower detection threshold compared to spatial-domain testing and, thus, a higher detection sensitivity without increasing type I errors. The multiresolution approach of the wavelet method is particularly suited to applications where the signal bandwidth and/or the characteristics of an imaging modality cannot be well specified. The proposed method was applied to compare two different fMRI acquisition modalities. Differences of the respective useful signal bandwidths could be clearly demonstrated; the estimated signal, due to the smoothness of the wavelet representation, yielded more compact regions of neuroactivity than standard spatial-domain testing.
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Litman RE, Torrey EF, Hommer DW, Radant AR, Pickar D, Weinberger DR. A quantitative analysis of smooth pursuit eye tracking in monozygotic twins discordant for schizophrenia. ARCHIVES OF GENERAL PSYCHIATRY 1997; 54:417-26. [PMID: 9152095 DOI: 10.1001/archpsyc.1997.01830170035006] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Previous studies of discordant monozygotic (MZ) twins have suggested that abnormal smooth pursuit eye tracking is an indicator of genetic liability for schizophrenia. We attempted to replicate this in a different sample of twins. METHODS Probands from 12 sets of MZ twins discordant for schizophrenia who met DSM-III-R criteria for schizophrenia or schizoaffective disorder and their co-twins without psychiatric diagnosis (except 2 with a history of substance abuse) and 12 sets of normal control MZ twins. Psychiatric diagnosis was based on Structured Clinical Interview; monozygosity was based on analysis of 19 red blood cell antigens. Smooth pursuit eye movement gain (equal to the ratio of eye-target velocity) and numbers, amplitudes, and subtypes of saccadic eye movements were compared. Measures were derived from computer analysis of digitized infrared oculographic recordings of constant velocity (16.67 degrees per second) smooth pursuit eye tracking. RESULTS Quantitative measures of eye tracking for the affected twin were inferior to those of the unaffected co-twin, with affected twins showing significant decreases in gain and significant increases in numbers and amplitudes of total and intrusive saccades. Moreover, whereas means for the group of affected twins differed significantly from those of normal controls on measures of gain and total saccades, means for the group of unaffected co-twins were well within the normal range. CONCLUSIONS These data are consistent with the hypothesis that abnormal eye tracking is associated with the expression of illness, or phenotype, in schizophrenia, at least in this twin sample. The data raise questions regarding the use of eye tracking measurement for identifying putative gene carriers among at-risk relatives in genetic linkage studies of schizophrenia.
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Jacobsen LK, Hommer DW, Hong WL, Castellanos FX, Frazier JA, Giedd JN, Rapoport JL. Blink rate in childhood-onset schizophrenia: comparison with normal and attention-deficit hyperactivity disorder controls. Biol Psychiatry 1996; 40:1222-9. [PMID: 8959287 DOI: 10.1016/0006-3223(95)00625-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Several lines of evidence have implicated central dopaminergic pathways in the modulation of blink rate. In the present study, blink rate during smooth pursuit was examined in 17 children with childhood-onset schizophrenia, on and off of clozapine, and compared to that of age-matched normal children and unmedicated children with attention-deficit hyperactivity disorder (ADHD). As has been observed in adolescent and adult schizophrenics, blink rate was significantly higher in schizophrenic children relative to normal and ADHD controls. Within the schizophrenic group, blink rate did not significantly change with the introduction of clozapine and was not related to clinical variables. Blink rate was positively correlated with deterioration in smooth pursuit in normal subjects.
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56
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Jacobsen LK, Hong WL, Hommer DW, Hamburger SD, Castellanos FX, Frazier JA, Giedd JN, Gordon CT, Karp BI, McKenna K, Rapoport JL. Smooth pursuit eye movements in childhood-onset schizophrenia: comparison with attention-deficit hyperactivity disorder and normal controls. Biol Psychiatry 1996; 40:1144-54. [PMID: 8931918 DOI: 10.1016/s0006-3223(95)00630-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Abnormalities of the smooth pursuit eye movements of adults with schizophrenia have been well described. We examined smooth pursuit eye movements in schizophrenic children, contrasting them with normal and attention-deficit hyperactivity disorder (ADHD) subjects, to determine whether there is continuity of eye movement dysfunction between childhood- and adult-onset forms of schizophrenia. Seventeen schizophrenic children with onset of illness by age 12, 18 ADHD children, and 22 normal children were studied while engaged in a smooth pursuit eye tracking task. Eye tracking variables were compared across the three groups. Schizophrenic children exhibited significantly greater smooth pursuit impairments than either normal or ADHD subjects. Within the schizophrenic group, there were no significant relationships between eye tracking variables and clinical variables, or ventricular/brain ratio. Childhood-onset schizophrenia is associated with a similar pattern of smooth pursuit abnormalities to that seen in later-onset schizophrenia.
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Weingartner HJ, Andreason PJ, Hommer DW, Sirocco KY, Rio DE, Ruttimann UE, Rawlings RR, Eckardt MJ. Monitoring the source of memory in detoxified alcoholics. Biol Psychiatry 1996; 40:43-53. [PMID: 8780854 DOI: 10.1016/0006-3223(95)00290-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The ability to monitor the source of remembered information and related reflective cognitive processes was examined in normal volunteers and detoxified alcoholics. Normal volunteers were very accurate judges of whether remembered events were presented as stimuli or were self-generated, even when memory was tested 2 days later. In contrast, a subgroup of otherwise cognitively unimpaired alcoholics demonstrated impairments in the ability to track the source of remembered knowledge and were also less able to inhibit intrusion errors in recalling information from memory. These findings provide preliminary evidence of an impairment in cognitive control functions in certain alcoholics. This conclusion is supported by associated findings indicating that, among alcoholics, performance on explicit memory tasks that required reflective cognitive operations were positively correlated with glucose utilization rates in left prefrontal, temporal, and posterior orbital frontal cortical regions.
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58
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Cowley DS, Roy-Byrne PP, Radant A, Ritchie JC, Greenblatt DJ, Nemeroff CB, Hommer DW. Benzodiazepine sensitivity in panic disorder: effects of chronic alprazolam treatment. Neuropsychopharmacology 1995; 12:147-57. [PMID: 7779243 DOI: 10.1016/0893-133x(94)00074-a] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The aim of the current study was to determine the degree to which patients with panic disorder develop tolerance to subjective and physiological effects of benzodiazepine after chronic treatment with alprazolam. Response to acute administration of diazepam was assessed in 19 panic disorder patients receiving chronic treatment with alprazolam and 23 untreated panic disorder patients. At baseline in the laboratory, the two groups did not differ in peak saccadic eye movement velocity, saccade latency, short-term memory, plasma cortisol and growth hormone concentrations, heart rate, and self-rated levels of sedation and anxiety. Compared with untreated patients, alprazolam-treated patients displayed significantly less diazepam-induced change in peak saccadic velocity, saccade latency, growth hormone secretion, memory, and self-rated levels of sedation. There was no difference between groups in diazepam effects on plasma cortisol concentrations or self-rated anxiety. Within alprazolam-treated patients, diazepam-induced slowing of peak saccade velocity was significantly inversely correlated with illness severity, as measured by reported panic attacks per week and severity of phobic avoidance, but not with alprazolam dose, blood level, or duration of treatment. Because the alprazolam-treated group reported more panic attacks per week than the untreated panic patients, treated patients were divided into those who were asymptomatic versus those with continuing panic attacks. The subgroup of nine alprazolam-treated subjects who were asymptomatic also showed significantly less diazepam effects than the group of untreated panic disorder patients, suggesting that overall group differences were at least partially attributable to the development of tolerance to selected benzodiazepine effects with chronic alprazolam treatment.
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Ross RG, Radant AD, Young DA, Hommer DW. Saccadic eye movements in normal children from 8 to 15 years of age: a developmental study of visuospatial attention. J Autism Dev Disord 1994; 24:413-31. [PMID: 7961328 DOI: 10.1007/bf02172126] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This cross-sectional study used saccadic eye movements, as measured by infrared occulography, to assess several aspects of visuospatial attention in normal children ages 8-15 years. Saccadic latency (a global measure of the ability to shift visuospatial attention), the ability to suppress extraneous saccades during fixation, and the ability to inhibit task-provoked anticipatory saccades all improve with age. However, the pattern of development differs for different tasks; saccadic latency shortens at a linear rate across the age range 8-15 years, while the capacity to inhibit anticipatory saccades matures by 12-13 years of age, and the ability to suppress saccades matures by 10 years of age. Analyses of age-related changes in oculomotor measures of attention may provide a novel approach in the study of children with attentional difficulties.
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Litman RE, Hommer DW, Radant A, Clem T, Pickar D. Quantitative effects of typical and atypical neuroleptics on smooth pursuit eye tracking in schizophrenia. Schizophr Res 1994; 12:107-20. [PMID: 8043521 DOI: 10.1016/0920-9964(94)90068-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Smooth pursuit eye movement (SPEM) gain, total saccades, and subtypes of saccades were quantified from the visual pursuit tracking of 26 fluphenazine-treated patients with schizophrenia and 42 normal controls. Tracking was repeated in 16 patients who underwent a placebo-controlled, double-blind crossover comparison of fluphenazine and clozapine. Fluphenazine-treated patients showed significant reduction in SPEM gain and significant increases in both total, intrusive, and anticipatory saccades and in saccadic amplitude, when compared to controls. Clozapine significantly reduced SPEM gain and significantly increased total and catch-up saccades, when compared to placebo or fluphenazine. High amplitude of intrusive saccades in drug-free patients predicted poor response to clozapine, suggesting that intact frontal cortical function may enable optimal clozapine response.
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61
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Cowley DS, Roy-Byrne PP, Radant A, Hommer DW, Greenblatt DJ, Vitaliano PP, Godon C. Eye movement effects of diazepam in sons of alcoholic fathers and male control subjects. Alcohol Clin Exp Res 1994; 18:324-32. [PMID: 8048734 DOI: 10.1111/j.1530-0277.1994.tb00021.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Both animal and human studies suggest that the GABA-benzodiazepine receptor complex may be involved in the acute effects of ethanol, as well as the development of tolerance and dependence with chronic ethanol use. The current study was performed to assess sensitivity to benzodiazepines, and thus the functional sensitivity of the GABA-benzodiazepine receptor system, in subjects at high risk for alcoholism. Sons of alcoholic fathers (SOAs; n = 27) were compared with male controls without a family history of alcoholism (n = 23) in response to diazepam versus placebo. SOAs and controls received four logarithmically increasing doses of intravenous diazepam or placebo in randomized order on 2 days at least 1 week apart. Effects of diazepam were assessed using two eye movement tasks, peak saccadic eye movement velocity, and average smooth pursuit eye movement gain, which provide reliable, quantitative measures of benzodiazepine effects. In addition, memory, self-rated sedation, and pleasurable drug effects were measured. In comparison with control subjects, SOAs displayed significantly less diazepam effects on peak saccade velocity, average smooth pursuit gain, memory, and self-rated sedation, but significantly greater pleasurable drug effects. Differences in response to diazepam between SOAs and male controls may reflect altered functional sensitivity of the central GABA-benzodiazepine receptor system or a more general difference between groups in the effects of CNS active or sedating drugs.
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MESH Headings
- Adult
- Alcoholism/genetics
- Alcoholism/physiopathology
- Arousal/drug effects
- Arousal/genetics
- Arousal/physiology
- Diazepam
- Dose-Response Relationship, Drug
- Humans
- Infusions, Intravenous
- Male
- Memory, Short-Term/drug effects
- Memory, Short-Term/physiology
- Motivation
- Pursuit, Smooth/drug effects
- Pursuit, Smooth/genetics
- Pursuit, Smooth/physiology
- Receptors, GABA-A/drug effects
- Receptors, GABA-A/genetics
- Receptors, GABA-A/physiology
- Risk Factors
- Saccades/drug effects
- Saccades/genetics
- Saccades/physiology
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Ross RG, Radant AD, Hommer DW. Open‐ and closed‐loop smooth‐pursuit eye movements in normal children: An analysis of a step‐ramp task. Dev Neuropsychol 1994. [DOI: 10.1080/87565649409540582] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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63
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Ross RG, Radant AD, Hommer DW. A developmental study of smooth pursuit eye movements in normal children from 7 to 15 years of age. J Am Acad Child Adolesc Psychiatry 1993; 32:783-91. [PMID: 8340299 DOI: 10.1097/00004583-199307000-00012] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To examine age-related changes in smooth pursuit tracking. METHOD Using infrared occulography, smooth pursuit eye movements are examined in 53 normal 7- to 15-year-old children during 6 degrees and 12 degrees/second visual pursuit. In addition to smooth pursuit gain and saccadic frequency, measures of mean amplitude per second are introduced to facilitate comparison across age and target speed. RESULTS The 6 degrees/second task is found to be easier than the 12 degrees/second task. Age is correlated with smooth pursuit system performance but not saccadic system performance during 12 degrees/second pursuit. No measure correlates with age during 6 degrees/second pursuit. CONCLUSIONS Eye movements improve as children age. The future use of smooth pursuit eye movements to study children and adolescents with and at risk for schizophrenia must control for developmental changes.
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64
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Cowley DS, Roy-Byrne PP, Greenblatt DJ, Hommer DW. Personality and benzodiazepine sensitivity in anxious patients and control subjects. Psychiatry Res 1993; 47:151-62. [PMID: 8341768 DOI: 10.1016/0165-1781(93)90045-i] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cloninger has recently proposed a model of personality variability that is based on three independent heritable traits of harm avoidance, novelty seeking, and reward dependence, each of which is thought to be mediated by a separate neurochemical and neuroanatomic mechanism. The current study tested hypotheses generated on the basis of this theory in anxious patients and control subjects. Eighteen patients with panic disorder, 12 patients with generalized anxiety disorder, and 21 control subjects underwent both personality testing and assessment of their sensitivity to diazepam, as measured by slowing of saccadic eye movement velocity. As expected, anxious patients displayed higher harm avoidance scores than controls. Although an inverse correlation between harm avoidance and benzodiazepine sensitivity was predicted, no relationship between these variables was found in any diagnostic group. However, a significant correlation was found between novelty-seeking scores and sensitivity to diazepam. This finding, although not predicted by Cloninger's theory, is consistent with prior preclinical and human studies.
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65
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Cowley DS, Roy-Byrne PP, Godon C, Greenblatt DJ, Ries R, Walker RD, Samson HH, Hommer DW. Response to diazepam in sons of alcoholics. Alcohol Clin Exp Res 1992; 16:1057-63. [PMID: 1335221 DOI: 10.1111/j.1530-0277.1992.tb00699.x] [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: 12/26/2022]
Abstract
Alcohol exerts several of its actions via the chloride channel associated with the central GABA-benzodiazepine receptor complex. To explore a possible role for this receptor complex in risk for alcoholism, and to determine whether risk for alcoholism is associated with risk for benzodiazepine abuse, the authors administered intravenous diazepam to 18 sons of male alcoholics (SOAs) and 18 control subjects. Four logarithmically increasing doses of diazepam and matched volumes of placebo were given in randomized order on separate days about 1 week apart. SOAs were significantly more likely than controls to report euphoric responses to diazepam. At some diazepam doses, SOAs were more likely to report feeling "high" and "intoxicated." SOAs and controls did not differ in feeling "drugged." SOAs and controls may differ in expectations regarding the subjective effects of drugs and/or in the function of the central GABA-benzodiazepine receptor complex. These findings also add further evidence for increased pleasurable effects, and thus possibly increased risk for benzodiazepine abuse, in a subgroup of SOAs.
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66
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Radant AD, Hommer DW. A quantitative analysis of saccades and smooth pursuit during visual pursuit tracking. A comparison of schizophrenics with normals and substance abusing controls. Schizophr Res 1992; 6:225-35. [PMID: 1349241 DOI: 10.1016/0920-9964(92)90005-p] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The eye movements of schizophrenic patients are characterized by decreased smooth pursuit gain and an increased frequency of saccades. However, the nature of these saccades and their function during smooth pursuit has not been clearly defined. To address this issue we examined the eye movements of 22 schizophrenic patients, 20 substance abusing patients (primarily alcohol; some with concomitant cocaine and/or cannabis abuse), and 17 normal controls during a visual pursuit task using infra-red oculography. A computerized pattern recognition algorithm divided pursuit eye movements into two basic components: smooth pursuit and saccadic eye movements. The algorithm also determined eye position error and velocity error before and after each saccade. Schizophrenic patients had lower smooth pursuit gain (p less than 0.02) and made more saccades during smooth pursuit (p less than 0.02) than either comparison group. When saccades were assigned to subcategories based on direction and position error, only the frequency of 'catch-up' saccades differentiated schizophrenic patients from the comparison groups (p less than 0.05). Smooth pursuit gain was negatively correlated with saccadic frequency among all three subject groups. Eye velocity preceding saccades was significantly lower among the schizophrenic patients, but pre or post saccadic position error did not differ among the three groups. Discrete analysis of the fine structure of visual pursuit tracking may lead to a better understanding of eye movement abnormalities in schizophrenia.
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67
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Litman RE, Hommer DW, Clem T, Ornsteen ML, Ollo C, Pickar D. Correlation of Wisconsin Card Sorting Test performance with eye tracking in schizophrenia. Am J Psychiatry 1991; 148:1580-2. [PMID: 1928477 DOI: 10.1176/ajp.148.11.1580] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The authors studied the relationship between performance on the Wisconsin Card Sorting Test and on the Trailmaking-B test and measures of smooth pursuit eye movements in 12 patients with chronic schizophrenia and 12 normal volunteers. They found that performance on the Wisconsin Card Sorting Test was significantly correlated with measures of smooth pursuit eye movements in schizophrenic patients but not in normal subjects. Trailmaking-B scores, however, were unrelated to smooth pursuit eye movements in either group.
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Abstract
We compared the saccades made by 8 neuroleptic-treated and 7 drug-free schizophrenic inpatients with those made by 11 normal controls during two eye movement tasks. The first task was designed to elicit visually guided but not internally guided saccades. The second task was designed so that optimal performance required saccades be guided on the basis of an internal representation of target behavior. During the first task, schizophrenics made visually guided saccades that were as accurate as those made by control, but both drug-free and neuroleptic-treated schizophrenics made intrusive saccades at a significantly higher rate than control subjects. Most of these maladaptive saccades appeared to be premature attempts to anticipate target jump. During the second eye movement task, which for optimal performance required use of an internal representation to guide eye movements, most patients learned to anticipate target jump as well as controls. However, neuroleptic-treated patients made significantly smaller adaptive anticipatory saccades than either drug-free schizophrenic patients or normal subjects. These finding are discussed as they relate to the prefrontal cortex-basal ganglia circuits involved in the regulation of behavior by representational knowledge and the idea that the abnormal anticipatory saccades we observed represent a failure in the sensorimotor gating of information derived from internal representations.
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69
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Weingartner HJ, Eckardt MJ, Hommer DW, Mendelson W, Wolkowitz OM. Specificity of memory impairments with triazolam use. Lancet 1991; 338:883-4. [PMID: 1681231 DOI: 10.1016/0140-6736(91)91534-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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70
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Nickoloff SE, Radant AD, Reichler R, Hommer DW. Smooth pursuit and saccadic eye movements and neurological soft signs in obsessive-compulsive disorder. Psychiatry Res 1991; 38:173-85. [PMID: 1754630 DOI: 10.1016/0165-1781(91)90042-n] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Patients with obsessive-compulsive disorder (OCD) demonstrate an increased number of neurological soft signs as well as neuroanatomic abnormalities detected with modern imaging techniques. Quantitative analysis of eye movements has proved fruitful in investigations of other neuropsychiatric disorders with similar findings. Therefore, we studied the smooth pursuit and saccadic eye movements of 8 OCD patients and 12 normal controls using infrared oculography and computerized pattern recognition software. We also measured neurologic soft signs using a standardized rating instrument. Despite having an increased number of neurological soft signs, OCD patients' performance on a variety of measures of eye movement was not significantly impaired. Neither the severity of obsessions or compulsions nor the number of neurologic soft signs correlated with any of the parameters of eye movement function. We conclude that OCD patients do not have prominent oculomotor dysfunction and that eye movement dysfunction and neurologic soft signs are not inextricably linked.
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71
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Stoner GR, Skirboll LR, Werkman S, Hommer DW. Preferential effects of caffeine on limbic and cortical dopamine systems. Biol Psychiatry 1988; 23:761-8. [PMID: 2835113 DOI: 10.1016/0006-3223(88)90064-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In this study, we investigated the effects of acute caffeine administration on the activity of midbrain dopamine neurons. Caffeine significantly depressed the firing rates of dopamine neurons in the ventral tegmental area (A10 group), but had no significant effect on the firing rates of dopamine neurons in the substantia nigra zona compacta (A9 group). The action of caffeine in A10 was completely blocked by pretreatment with the adenosine agonist L-phenyl-isopropyl-adenosine (L-PIA), confirming numerous lines of evidence that caffeine and other xanthines act as competitive antagonists at adenosine receptors. The dopamine antagonist haloperidol also antagonized the effects of caffeine. This finding is consistent with a mechanism of caffeine-induced depression of dopamine neuron activity involving dopamine release, similar to that observed during amphetamine administration. Finally, the benzodiazepine diazepam also antagonized the dopaminergic effects of caffeine. It appears that, in the rat, caffeine administration inhibits mesolimbic and mesocortical projecting dopamine neurons, but has no effect on dopamine neurons that project to the striatum.
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72
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Clarke PB, Hommer DW, Pert A, Skirboll LR. Innervation of substantia nigra neurons by cholinergic afferents from pedunculopontine nucleus in the rat: neuroanatomical and electrophysiological evidence. Neuroscience 1987; 23:1011-9. [PMID: 3437988 DOI: 10.1016/0306-4522(87)90176-x] [Citation(s) in RCA: 165] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Dopaminergic neurons of the substantia nigra pars compacta are excited by nicotine and acetylcholine, and possess both high-affinity nicotine binding sites and intense acetylcholinesterase activity, consistent with a cholinoceptive role. A probable source of cholinergic afferents is the pedunculopontine nucleus, which forms part of a prominent group of cholinergic perikarya located caudal to the substantia nigra in the tegmentum. Although pedunculopontine efferents, many of them cholinergic, project to the substantia nigra pars compacta, it has not been established whether they terminate in this structure. In the first experiment, which combined retrograde tracing with immunohistochemical visualization of cholinergic neurons, cholinergic cells in and around the pedunculopontine nucleus were found to send projections to the substantia nigra. This projection was almost completely ipsilateral. Subsequent experiments employed anaesthetized rats; kainate was microinfused into tegmental sites in order to stimulate local cholinergic perikarya, and concurrently, extracellular recordings were made of single dopaminergic neurons in the substantia nigra. Consistent with our anatomical findings, unilateral microinfusion of kainic acid in or near the pedunculopontine nucleus increased the firing rate of dopaminergic neurons situated remotely in the ipsilateral substantia nigra. The kainate-induced excitation of nigral dopaminergic neurons was dose-related and was prevented by intravenous administration of the centrally-acting nicotinic cholinergic antagonist mecamylamine. These results suggest that cholinergic perikarya in the vicinity of the pedunculopontine tegmental nucleus innervate dopaminergic neurons in the substantia nigra pars compacta via nicotinic receptors.
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73
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Breier A, Wolkowitz OM, Doran AR, Roy A, Boronow J, Hommer DW, Pickar D. Neuroleptic responsivity of negative and positive symptoms in schizophrenia. Am J Psychiatry 1987; 144:1549-55. [PMID: 3688278 DOI: 10.1176/ajp.144.12.1549] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The authors prospectively examined the effects of double-blind, placebo-controlled neuroleptic withdrawal and administration on ratings of negative and positive symptoms in 19 young patients with chronic schizophrenia. Negative symptoms were significantly reduced by neuroleptic treatment, and negative and positive symptoms demonstrated similar patterns of reduction and exacerbation during neuroleptic treatment and withdrawal, respectively. The changes in negative and positive symptoms induced by neuroleptic treatment and withdrawal were not significantly correlated, however. The negative and positive symptom profiles of individual patients were significantly altered by neuroleptic treatment, indicating limitations to the cross-sectional classification of patients on the basis of predominance of one or the other symptom group. The authors discuss implications for the neurobiological underpinnings of negative and positive symptoms.
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74
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Robertson BC, Hommer DW, Skirboll LR. Electrophysiological evidence for a non-opioid interaction between dynorphin and GABA in the substantia nigra of the rat. Neuroscience 1987; 23:483-90. [PMID: 2893989 DOI: 10.1016/0306-4522(87)90071-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Interactions between neuronal responses mediated by dynorphin A1-8 and GABA were investigated in the substantia nigra zona reticulata. Extracellular recordings and microiontophoresis were performed using five-barrel microelectrodes in chloral hydrate-anesthetized male rats. When iontophoresed alone, dynorphin A1-Q significantly inhibited the firing of 22% of the neurons tested. The inhibition was rapid in onset and recovery and was dose-dependent. In another 22% of the cells, iontophoretic dynorphin produced an increase in the baseline firing rate which was slow in both onset and offset; the remaining 56% were unaffected by dynorphin. When GABA and dynorphin A1-8 were applied in conjunction, the inhibitory action of GABA was attenuated in 61% of the cells; whereas, when dynorphin and GABA were ejected simultaneously onto the cells that were inhibited by dynorphin A1-8, the respective inhibitory effects of dynorphin and GABA appeared to be additive. The kappa antagonist, MR-2266, failed to block the ability of dynorphin A1-8 to attenuate the action of GABA. In addition, the non-opiate peptide des-tyr-dynorphin A2-17, produced effects similar to that of dynorphin A1-8. The role of dynorphin in the basal ganglia and its interaction with the other major transmitter in the substantia nigra zona reticulata, GABA, is discussed.
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Stoner GR, Skirboll LR, Hommer DW. Differential effects of an anxiogenic beta-carboline on single unit activity in the locus coeruleus and substantia nigra of the rat brain. Neuropharmacology 1987; 26:1185-90. [PMID: 2821442 DOI: 10.1016/0028-3908(87)90266-8] [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: 01/02/2023]
Abstract
The firing rates of single units in the substantia nigra pars reticulata, substantia nigra pars compacta and the locus coeruleus were recorded during the intravenous administration of beta-carboline-3-carboxylic acid ethyl ester (beta CCE). beta-Carboline-3-carboxylic acid produced a dose-dependent excitation in all units tested in the substantia nigra pars reticulata and a small inhibitory effect on some units in the substantia nigra pars compacta. It had no effect on the firing rates of single units in the locus coeruleus, but did prove effective in reversing inhibition induced by diazepam in this nucleus. The relevance of the findings to the anxiogenic effects of beta-carboline-carboxylic acid ethyl ester are discussed.
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Abstract
The photomyoclonic reflex (PMR), consisting of a one- or two-component blink reflex associated with the flash electroretinogram (ERG), is sensitive to the acute effect of intravenously administered diazepam. In the 29% (two of seven) of normal volunteers who had a PMR, diazepam reduced it to a nonobservable level. Diazepam also had a significant attenuating effect on the a- and b-waves of the ERG; the magnitude of attenuation in normal volunteers, however, probably would not alter a clinical diagnosis based on ERG. These two findings together predict that individuals known to have a marked PMR may have the diagnostic risk associated with these specious artifacts reduced by receiving diazepam before clinical ERG studies are begun.
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77
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Hommer DW, Matsuo V, Wolkowitz OM, Weingartner H, Paul SM. Pharmacodynamic approaches to benzodiazepine action in man. PSYCHOPHARMACOLOGY SERIES 1987; 3:52-61. [PMID: 3029755 DOI: 10.1007/978-3-642-71288-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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78
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van Kammen DP, Hommer DW, Malas KL. Effect of pimozide on positive and negative symptoms in schizophrenic patients: are negative symptoms state dependent? Neuropsychobiology 1987; 18:113-7. [PMID: 3453426 DOI: 10.1159/000118403] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In a double-blind, placebo-controlled trial of treatment with the neuroleptic pimozide, negative symptoms improved in schizophrenic patients who showed an antipsychotic response. Furthermore, there was a significant positive correlation between changes in positive and negative symptoms for the group as a whole, including both pimozide responders and nonresponders. In our patient sample, neuroleptic treatment did not exert a differential effect on the positive and negative symptoms of schizophrenia. It is conceivable that negative symptoms are state dependent and may become neuroleptic nonresponsive over time just as positive symptoms do in some chronic patients.
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Wolkowitz OM, Weingartner H, Thompson K, Pickar D, Paul SM, Hommer DW. Diazepam-induced amnesia: a neuropharmacological model of an "organic amnestic syndrome". Am J Psychiatry 1987; 144:25-9. [PMID: 3799835 DOI: 10.1176/ajp.144.1.25] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Diazepam has well-known amnestic properties. These effects, however, are selective for certain psychobiologically distinct memory functions. In this study, incremental doses of diazepam administered to 10 normal volunteers selectively impaired anterograde episodic memory and attention while totally sparing access to information in long-term memory (semantic or knowledge memory). This pattern of disruption mimics that seen in patients with organic amnesias and is in sharp contrast to the pattern seen in patients with dementia. These findings provide a framework for defining specific psychobiological determinants of cognitive failure.
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80
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Hommer DW, Stoner G, Crawley JN, Paul SM, Skirboll LR. Cholecystokinin-dopamine coexistence: electrophysiological actions corresponding to cholecystokinin receptor subtype. J Neurosci 1986; 6:3039-43. [PMID: 3760947 PMCID: PMC6568787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Cholecystokinin (CCK)-like peptides when administered intravenously produce 2 distinct actions on the single-unit activity of mesencephalic dopamine (DA) neurons in the rat: an excitatory action and a potentiation of the inhibitory effects of DA agonists. The ability of several CCK fragments that have been shown to bind selectively to the peripheral and/or the central CCK-binding sites were examined for their ability to induce either excitation or a potentiation of DA. Only sulfated CCK-8 was able to induce excitation of mesencephalic DA neurons, but both sulfated and unsulfated CCK-8, as well as CCK-4, potentiated the inhibitory effects of the DA agonist apomorphine (APO). CCK-3 failed to potentiate APO-induced inhibition. Both of these effects appeared to be confined to cell bodies in regions of the ventral tegmental area and substantia nigra, zona compacta that have been reported to contain both DA and CCK. Thus, CCK-like peptides that have been shown to bind to the high-affinity CCK binding site in brain potentiated the effects of DA. In contrast, the ability of CCK-like peptides to induce neuronal excitation corresponds with their affinity for the peripheral-type CCK binding site.
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81
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Hommer DW, Matsuo V, Wolkowitz O, Chrousos G, Greenblatt DJ, Weingartner H, Paul SM. Benzodiazepine sensitivity in normal human subjects. ARCHIVES OF GENERAL PSYCHIATRY 1986; 43:542-51. [PMID: 2871819 DOI: 10.1001/archpsyc.1986.01800060032005] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Increasing intravenous doses of diazepam or placebo were administered to ten healthy normal volunteers, and the changes in saccadic eye velocity, self-rated sedation and anxiety, and plasma cortisol and growth hormone concentrations were measured. Diazepam administration (4.4 to 140 micrograms/kg, cumulative dose) resulted in a dose-dependent decrease in saccadic eye velocity and plasma cortisol level as well as a dose-dependent increase in self-rated sedation and plasma growth hormone level. Self-rated anxiety was unaffected in these relatively nonanxious subjects. The diazepam-induced changes in saccadic eye velocity, sedation, and growth hormone and cortisol levels were highly correlated with each other and with increasing plasma diazepam concentration. These results are consistent with a benzodiazepine receptor-mediated action of diazepam. The highly quantifiable and dose-dependent decrease in saccadic eye velocity by benzodiazepines should make this a useful measure of benzodiazepine receptor sensitivity in humans.
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Crawley JN, Stivers JA, Hommer DW, Skirboll LR, Paul SM. Antagonists of central and peripheral behavioral actions of cholecystokinin octapeptide. J Pharmacol Exp Ther 1986; 236:320-30. [PMID: 3003339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Pharmacological studies on the behavioral functions of sulfated cholecystokinin (CCK) in the gut and in the brain require potent, specific antagonists to CCK. Compounds identified as competitive antagonists at the peripheral receptors for CCK were tested for their ability to block the behavioral effects of CCK administered centrally and peripherally. Behavioral effects of CCK (8.8 X 10-10 mmol) administered centrally into the nucleus accumbens, i.e., potentiation of dopamine-induced hyperlocomotion in rats, were effectively blocked by pretreatment with proglumide (6 X 10(-5) mmol of nucleus accumbens), by benzotript (3 X 10(-5) mmol of nucleus accumbens) and by rabbit antiserum raised against CCK (0.2 microliter/nucleus accumbens), but not by CCK26-33 (1.7 X 10(-7) mmol) or unsulfated CCK26-33 (1.9 X 10(-6) mmol). The behavioral effects of peripherally administered CCK, i.e. reduced food consumption and reduced exploratory behaviors in mice, were blocked effectively by pretreatment with proglumide (0.3-0.9 mmol/kg), and by benzotript (0.03 mmol/kg), but not by CCK30-33 (0.003 mmol/kg). None of the compounds administered peripherally significantly affected food consumption or exploratory behaviors when given alone. Furthermore, none of the compounds significantly affected locomotion when administered alone into the nucleus accumbens, or significantly affected dopamine-induced hyperlocomotion when given into the nucleus accumbens before dopamine. Benzotript, proglumide and a CCK antibody appear to act as specific antagonists of the behavioral effects of CCK at both the peripheral gastrointestinal site and at the central nucleus accumbens site. Neither unsulfated CCK26-33 or CCK30-33 were effective as antagonists of peripheral or central behavioral effects of CCK. However, whereas benzotript and proglumide may be useful as pharmacologically specific antagonists, the high doses required suggest that more potent CCK antagonists are required for investigating the behavioral functions of endogenous CCK.
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83
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Clarke PB, Hommer DW, Pert A, Skirboll LR. Electrophysiological actions of nicotine on substantia nigra single units. Br J Pharmacol 1985; 85:827-35. [PMID: 4041681 PMCID: PMC1916681 DOI: 10.1111/j.1476-5381.1985.tb11081.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Extracellular recordings of single unit activity were made in the substantia nigra (SN) of chloral hydrate-anaesthetized rats. Dopaminergic neurones of the pars compacta (SNC) were stimulated by (-)-nicotine bitartrate (1.0 mg kg-1) given subcutaneously (s.c.). This action was prevented by the secondary amine mecamylamine HCl (2.0 mg kg-1 i.v.) but not by a ganglion-blocking dose of the bisquaternary compound chlorisondamine Cl (0.1 mg kg-1 i.v.). Mecamylamine reduced the spontaneous activity of dopaminergic neurones. Nicotine, when administered intravenously (2-128 micrograms kg-1 cumulative dose), also stimulated dopamine cells and this action was dose-related. Nicotine, administered intravenously, (2-128 micrograms kg-1 cumulative dose) markedly excited non-dopamine cells in the pars reticulata (SNR) in a dose-related manner. In rats pretreated with chlorisondamine (0.1 mg kg-1 i.v.), nicotine induced a small excitatory or depressant action, but the marked excitation was not seen. Mecamylamine (2 mg kg-1 i.v.) completely prevented the actions of nicotine. The results are consistent with a direct excitatory action of nicotine on dopaminergic neurones of the substantia nigra pars compacta. The pronounced excitatory action of systemically administered nicotine on non-dopamine cells of the pars reticulata appears to be of peripheral origin.
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84
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Skirboll LR, Hommer DW. Electrophysiological studies of the role of cholecystokinin in the substantia nigra and its interactions with dopamine. Ann N Y Acad Sci 1985; 448:275-82. [PMID: 3861121 DOI: 10.1111/j.1749-6632.1985.tb29923.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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85
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Hommer DW, Pickar D, Crawley JN, Weingartner H, Paul SM. The effects of cholecystokinin-like peptides in schizophrenics and normal human subjects. Ann N Y Acad Sci 1985; 448:542-52. [PMID: 3896099 DOI: 10.1111/j.1749-6632.1985.tb29947.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Eight neuroleptic-resistant schizophrenic patients were treated with ceruletide, a cholecystokinin-like peptide, in a placebo-controlled, double-blind, crossover study. Ceruletide or placebo was administered intramuscularly twice a day for 4 consecutive days while patients were maintained on a constant dose of fluphenazine. There were no changes in either the positive or negative symptoms of schizophrenia between the periods of placebo and ceruletide administration. To further characterize ceruletide actions we also administered it to seven normal volunteers and evaluated its effects on cognition and mood. Volunteers were administered ceruletide (0.3 micrograms/kg or 0.6 micrograms/kg) or saline placebo intramuscularly. Ceruletide had no effects on recent or remote memory or attention, but the higher dose did cause a significant increase in fatigue. These results suggest that although CCK-like peptides lack antipsychotic or cognitive effects they do induce mild sedation. This sedation may be part of a "satiety-like" state induced by peripheral administration of CCK.
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86
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Crawley JN, Hommer DW, Skirboll LR. Topographical analysis of nucleus accumbens sites at which cholecystokinin potentiates dopamine-induced hyperlocomotion in the rat. Brain Res 1985; 335:337-41. [PMID: 4005562 DOI: 10.1016/0006-8993(85)90489-5] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sulfated cholecystokinin octapeptide (CCK) potentiates dopamine-induced hyperlocomotion in the nucleus accumbens of the rat. Immunocytochemical evidence has shown a topographical distribution of terminals containing both CCK and dopamine (DA), within the medial posterior nucleus accumbens. Seven sites within the nucleus accumbens were cannulated and tested for the ability of CCK to enhance the behavioral effects of DA. Close agreement was found between the anatomical sites of CCK-DA coexistence, and the anatomical sites at which CCK potentiated DA-induced hyperlocomotion. Behaviorally inactive sites were found primarily in the anterior nucleus accumbens, where DA-containing terminals do not contain CCK.
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Hommer DW, Palkovits M, Crawley JN, Paul SM, Skirboll LR. Cholecystokinin-induced excitation in the substantia nigra: evidence for peripheral and central components. J Neurosci 1985; 5:1387-92. [PMID: 4009236 PMCID: PMC6565261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cholecystokinin (CCK), one of the most common brain peptides, coexists with dopamine (DA) in neurons of the medial substantia nigra (SN). CCK has been shown to excite these neurons following either direct iontophoretic or systemic administration suggesting that peripherally administered CCK may cross the blood brain barrier to act directly on nigral DA cells. However, biochemical evidence suggests that CCK does not cross the blood brain barrier, and several studies have shown that the behavioral and the satiety-inducing effects of peripherally administered CCK are abolished by vagotomy. In order to test for vagal mediation of the nigral response to systemically administered CCK, we examined the effects of a series of lesions to the vagal pathways on CCK-induced excitation in the SN. Neither acute thoracic nor chronic subdiaphragmatic vagotomies had any effect on the excitatory response of nigral DA neurons to systemically administered CCK. High cervical spinal cord transections were similarly without effect. In contrast, lesions of either vagal fibers in the medulla or of the efferent pathways from the nucleus tractus solitarii, the primary sensory nucleus of the vagus, produced significant attenuations of the nigral effects of systemically administered CCK. However, neither lesion blocked effects of CCK completely. We suggest that peripherally administered CCK has two components to its excitatory action in the SN; a component probably mediated through CCK receptors in the nucleus tractus solitarii and a direct action on DA neurons.
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88
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Hommer DW, Pickar D, Roy A, Ninan P, Boronow J, Paul SM. The effects of ceruletide in schizophrenia. ARCHIVES OF GENERAL PSYCHIATRY 1984; 41:617-9. [PMID: 6329121 DOI: 10.1001/archpsyc.1984.01790170091010] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Eight neuroleptic-resistant schizophrenic patients were treated with ceruletide diethylamine, a cholecystokininlike peptide, in a placebo-controlled, double-blind, cross-over study. Ceruletide or placebo was administered intramuscularly twice a day for four consecutive days while patients received a constant dose of fluphenazine hydrochloride. Cholecystokinin octapeptide was also administered to four different schizophrenic patients in a double-blind, cross-over study. Cholecystokinin or placebo was administered as a slow intravenous infusion daily for four days. There were no changes in either the positive or negative symptoms of schizophrenia between the periods of placebo, ceruletide, or cholecystokinin administration. Furthermore, there was no tendency for the patients' conditions to either improve or worsen during the course of ceruletide or cholecystokinin treatment. In contrast to previous reports from uncontrolled studies, cholecystokininlike peptides appear to be devoid of antipsychotic properties when administered parenterally.
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89
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Hommer DW, Zahn TP, Pickar D, van Kammen DP. Prazosin, a specific alpha 1-noradrenergic receptor antagonist, has no effect on symptoms but increases autonomic arousal in schizophrenic patients. Psychiatry Res 1984; 11:193-204. [PMID: 6145176 DOI: 10.1016/0165-1781(84)90068-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The specific alpha 1-noradrenergic antagonist, prazosin, was administered to seven schizophrenic patients in a double-blind, placebo-controlled trial. Patients showed no change in any of their psychiatric symptoms as rated by nurses on global depression and psychosis scales and by physicians on the Brief Psychiatric Rating Scale. However, they did show a significant increase in autonomic arousal as measured by changes in skin conductance. The increased autonomic arousal is probably mediated by increases in plasma norepinephrine induced by chronic prazosin treatment.
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Abstract
Single unit recording and micropressure ejection techniques were used to investigate the actions of opiates on dopaminergic and non-dopaminergic neurons in the rat substantia nigra. Systemic administration of morphine, 1 to 4 mg/kg, led to a naloxone-reversible increase in firing rate of all zona compacta dopaminergic (ZC) neurons examined (n = 10). In a specifically defined subpopulation of non-dopaminergic nigral zona reticulata (ZR) neurons, systemically administered morphine led to a naloxone reversible decrease in activity (n = 9). D-Ala2-d-leu5 (DADL)-enkephalin, when applied directly onto ZC neurons by micropressure ejection techniques, had no effect on their firing rate. In contrast, micropressure ejection of DADL enkephalin onto ZR neurons produced a decrease in firing rate which was blocked by systemically administered naloxone. Morphine sulfate applied by pressure ejection onto both ZC and ZR neurons produced mixed results which were not always blocked by naloxone. These results suggest that one of the mechanisms by which opiates increase dopaminergic neurotransmission is through disinhibition of dopaminergic neurons in the substantia nigra.
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91
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Hommer DW, Skirboll LR. Cholecystokinin-like peptides potentiate apomorphine-induced inhibition of dopamine neurons. Eur J Pharmacol 1983; 91:151-2. [PMID: 6617736 DOI: 10.1016/0014-2999(83)90380-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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92
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Skirboll LR, Grace AA, Hommer DW, Rehfeld J, Goldstein M, Hökfelt T, Bunney BS. Peptide-monoamine coexistence: studies of the actions of cholecystokinin-like peptide on the electrical activity of midbrain dopamine neurons. Neuroscience 1981; 6:2111-24. [PMID: 6120481 DOI: 10.1016/0306-4522(81)90002-6] [Citation(s) in RCA: 283] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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93
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Hommer DW, Bunney BS. Effect of sensory stimuli on the activity of dopaminergic neurons: involvement of non-dopaminergic nigral neurons and striato-nigral pathways. Life Sci 1980; 27:377-86. [PMID: 7412480 DOI: 10.1016/0024-3205(80)90185-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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94
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Bunney BS, Grace AA, Hommer DW. Changing concepts of nigral dopamine system function within the basal ganglia: relevance to extrapyramidal disorders. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 1980:17-23. [PMID: 6107330 DOI: 10.1007/978-3-7091-8582-7_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The recent discovery of new methods for tracing brain pathways and studying their function has greatly expanded our knowledge of the areas of the brain involved in extrapyramidal disorders and has begun to change our concept of how these areas function. One such change has involved our understanding of the role of the dopaminergic system within the basal ganglia. Rather than dopamine being seen primarily as a major influence on striatal output it is now perhaps best conceptualized as one link in a set of circular pathways, one of whose functions is to modulate nondopaminergic output from the substantia nigra to other brain regions. In addition, new evidence suggests that this neurotransmitter system may play a role in the way sensory inputs are handled by the basal ganglia. These new roles for the nigral dopaminergic system raise important new questions about its function in extrapyramidal motor systems as well as provide possible answers to questions concerning the mechanisms underlying some of the symptoms seen in disorders involving the basal ganglia.
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