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Neuroimaging - Basic neurophysiology
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GUIDED POSTER SESSIONS
IPs-o4.osI
Neuroimaging Basic neurophysiology -
The effect of Diazepam on EEG-AEPinterrelations in rats. M . , I ~ ~, C.M. Van Rijn ~,2,J. Van Egmond ~, W.J. Van Sehaijk 2 and A.M.L. Coenen 2. lSTl4qDepartmentof Anesthesiology, NICll2Departmentof
Comparative and Physiological Psychology, University of Nijmegen, The Netherlands. Increases in [3-activity ( 12-40 Hz) in the ongoing electroencephalogram (EEG) have been associated with increases in arousal. Paradoxically, although a sedative, diazepam is known to increase I~-activity. We investigated if diazepam effects on the rat Auditory Evoked Potential (AEP) could be ascribed to its [3-increasing effect in the EEG. Rats received vehicle or diazepam (4 mg.kg-1). AEPs were elicited by tone-pip stimuli (90dB, 10.2kHz, ISI 2 s). Trials were ranked in 10 categories according to the [~-activity in 1 second pre-stimulus EEG (3% bins). AEPs were computed for each category. Cross-correlation coefficients (CCCs) between all AEPs were determined. In the vehicle condition AEP components increased with increased 13-aetivity and CCCs changed, in the diazepam condition AEP components and CCCs remained unchanged with increased t3-activity. Diazepam affected the rat AEP, such that it resembled the AEP obtained during the lowest [~-categories in the vehicle condition. We concluded that diazepam effects on AEPs could not be ascribed to its [3-enhancing effects on the EEG. Diazepam disrupted the normal AEP-EEG interrelation such that diazepam effects on the rat AEPs seemed to reflect the behaviouraUy sedative effects of diazepam and not its physiologically 13-increasing effects. Therefore, measuring drug effects on AEPs adds information to measuring only drug effects on the ongoing EEG.
The dry eye syndrome is common in clinical diagnosis. The pathogenesis of xerophthalmia could be the degeneration of either the lacrimal gland itself or an innervated nerve. However, the present treatment of this disease is only symptom relief by medication and artificial tears. In order to cure patients of dry eye and improve their life quality, autologous lacrimal gland transplantation might be a useful means of managing xerophthalmia. However transplantation efficacy could depend on both tissue rejection and nerve reinnervation in the gland. However, it remains unknown whether reinnervation results in any morphological change of the transplanted gland. The lachrymal glands of rats were removed under surgical microscope and the autologous submandibular glands were transplanted to the lachrymal basin. After 30 days, horseradish peroxidase(HRP) was injected into the transplanted gland. The neurons that innervated the transplanted gland were demonstrated by HRP. Immunohistoehemical studies of protein gene product 9.5(PGP 9.5) were used to investigate the reinnervated nerve fibers in glands. In our study, the injected HRP could label the neurons in the superior cervical ganglion (SCG), trigeminal ganglion(TG) and pterygopalatine ganglion(PG). Abundant nerve fibers with PGP 9.5 immunoreactivity existed mainly around the survived acinar in the gland. We hypothesized that the transplanted submandibular gland could survive in the lachrymal basin and be reinnervated by sympathetic, parasympathetic and sensory nerves. The surviving of the transplanted submandibular gland was significantly dependent on its reinnervation as reflected by PGP 9.5 immunoreactivity in the transplanted glands.
Epilepsy partialis continuans: a clinical and radioiogical correlation. M.D. Christensen, E. Grant, A. J. Cole, G. R. Cosgrove. Massachusetts
The electrophysiologieal research of amygdala-visual system interactions. E. Panakhova. Institute of Physiology, Baku, Azerbaijan. Results obtained on the nature of the relationship of the amygdala with the visual system structures suggest that disturbances of biologically programmed and useful interrelations may underlie the development of such pathological agnostic syndromes as the Kluver-Bucy Syndrome and Alzheimer's Disease. Research on the mechanisms of intersystem integration between the visual system and the amygdala is very important for understanding the basic principles of the formation of a functional system which ensures the development of adequate visually controlled behaviour. The amygdala has a role in these mechanisms. Results suggest that the amygdala establishes functional relations with visual system structures, and that these relationships in turn could be components of the functional system providing a basis for goal-directed motor activity. The creating of a locus of increased excitability in the amygdala (by means of a Strychnine solution injection) causes a pronounced enhancement of Evoked Potentials formed in reaction to a light flash. Our experiments demonstrate that secondary components of these occur primarily in the visual cortex, in response to a previously ineffective stimulus (a light flash). This demonstrates the development of visual signals and increases their biological significance.
Transplantation of the autologous submandibular gland to the lachrymal basin in rats: the effect of nerve reinnervation of the autografted gland. C. H. Chen z, W. C. Liu ~, W. M. Hsu and J. C. Liu 2 1Department of
Ophthalmology, Taipei VeteransGeneralHospital, Taipei, Taiwan;ZDepartment of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan.
General Hospital' Boston, MA, USA. PURPOSE: To correlate preoperative functional and anatomic neuroimaging studies with intraoperative findings in a patient with Epilepsia Partialis Continuans (EPC). METHOD: Preoperative MRI, MRA, and PET scans were correlated and compared clinical seizures, noninvasive ictal EEG and intraoperative gross cortical pathology. RESULTS: Preoperative EEG, PET scan, MRI, and MRA revealed abnormalities consistent with an epileptogenic focus located in the right eentrolateral rolandic cortex. Intraoperative ECoG confirmed the preoperative findings. At craniotomy, the cortex demonstrated focal hyperemia and vascular shunting, which correlated closely with all pre and intraoperative studies. CONCLUSIONS: This case demonstrates an increase in intraoperative focal cortical blood flow to the region predicted by preoperative neuroimaging studies. This is the fwst demonstration correlating intraoperafive cortical hyperemia with EEG f'mdings and neuroimaging. This observation may provide insights into the physiological basis ofneuroimaging changes during EPC.
Functional MRI in language areas in Wada tested epilepsy patients: a preliminary study. F. Santos, V.H. Machado, A. Dalacorte, C.M. Neves, M. Portuguez, J.C. da Costa. Servi¢ode Neurologia, Programa de Cirurgia de Epilepsia do Hospital
Sdo Lucas da Pont(ficia Universidade Catdlica Do Rio Grande Do Sul±Porto Alegre RS, Brazil The use of Functional MRI (fMRI) in the study of language areas is a very interesting tool in some areas of neurology. In this study we submit a group of Wada-tested patients to fMRI in language areas. The patients belong to Neurology Service at Epilepsy Surgery Program in Hospital Sgo Lucas da
S58
Neuroimaging - Basic neurophysiology
Pontificia Universidade Cat61ica do Rio Grande do Sul (HSL PUC RS) at Porto Alegre, Brazil. OBJECTIVE: To compare the results o f fMR1 in language areas with the results of the Wada test in this particular group of patients. METHOD: The group consisted o f seven epilepsy patients who met following selection criteria, and who were undergoing comprehensive evaluation for surgical treatment of epilepsy. The Wada tested epilepsy patients at HSL PUC RS were submitted to fMRI in language areas. The scans were acquired on Siemens 1.5 T MRI system. The fMRI used a gradient echo, echo-planar sequence. Functional slices were acquired in the axial plane during a silent speech task, alternating with two periods of control task. SUMMARY: All patients in this group presented language area in the same side as shown in the two methods. CONCLUSION: This preliminary result in our institution suggests the usefulness of this new method. A great number of patients will be needed to show more clearly the limitations of this new tool in the study o f epilepsy patients. 7.REFERENCES: 1) BRAIN (1999), 122,2033-2045.2) NEUROLOGY (1999), 52,798-809.3) THE JOURNAL OF NEUROSCi ENCE (1997), 17(t ), 353-362.
Brain activation during hand-fingers mov~ .... hand writing in patients with writer's cramp: a functional magnetic resonance imaging study. F. Pauri~, C. Del Gratta -~, A. Ferretti~-, E. Cassetta ~ ,G.L. Romani 2, P.M. Rossini ~,3.l : AfaR, Ospedale Fatebenefratelli lsola 77berina, Roma, 2 :ITAB. Universitd di Chieti. 3: Universitd Campus Biomedico, Roma - ltal): Several disturbances have been found and used to explain the pathogenesis of writer's cramp: inability to efficiently control the force output during manipulative activities, wrong setting o f the sensitivity of sensory input channels from the hand, combined abnormalities in the central motor command and central processing of sensory input, maladaptive plasticity. In order to better understand the patophysiology of this focal dystonia, fMRi was performed in three ( two males and 1 female) patients affected by writer's cramp during two different motor tasks: a self-paced finger tapping task consisting of the sequential opposition of the thumb to the other fingers at a frequency of about 1 see, and a handwriting exercise consisting in holding a pen and writing consecutively the letter '7 "without interruption and without visual feed-back. The examined subject was lying supine on the bed of the MR1 scanner, inside the magnet bore, with his head firmly held inside the receiver coil. Results were similar in the three patients. A smaller activation in the primary motor and sensorimotor areas during writing- in comparison with finger movements - was found when the subjects used their right hand. Activation of supplementary motor area was found only during finger tapping. No differences were found when the left hand was performing the two tasks in the activation of primary motor area, but the supplementary motor area was activated only during finger tapping.
GUIDED POSTER SESSIONS
IPs-o4.osI
Neuroimaging Basic neurophysiology -
The effect of Diazepam on EEG-AEPinterrelations in rats. M . , I ~ ~, C.M. Van Rijn ~,2,J. Van Egmond ~, W.J. Van Sehaijk 2 and A.M.L. Coenen 2. lSTl4qDepartmentof Anesthesiology, NICll2Departmentof
Comparative and Physiological Psychology, University of Nijmegen, The Netherlands. Increases in [3-activity ( 12-40 Hz) in the ongoing electroencephalogram (EEG) have been associated with increases in arousal. Paradoxically, although a sedative, diazepam is known to increase I~-activity. We investigated if diazepam effects on the rat Auditory Evoked Potential (AEP) could be ascribed to its [3-increasing effect in the EEG. Rats received vehicle or diazepam (4 mg.kg-1). AEPs were elicited by tone-pip stimuli (90dB, 10.2kHz, ISI 2 s). Trials were ranked in 10 categories according to the [~-activity in 1 second pre-stimulus EEG (3% bins). AEPs were computed for each category. Cross-correlation coefficients (CCCs) between all AEPs were determined. In the vehicle condition AEP components increased with increased 13-aetivity and CCCs changed, in the diazepam condition AEP components and CCCs remained unchanged with increased t3-activity. Diazepam affected the rat AEP, such that it resembled the AEP obtained during the lowest [~-categories in the vehicle condition. We concluded that diazepam effects on AEPs could not be ascribed to its [3-enhancing effects on the EEG. Diazepam disrupted the normal AEP-EEG interrelation such that diazepam effects on the rat AEPs seemed to reflect the behaviouraUy sedative effects of diazepam and not its physiologically 13-increasing effects. Therefore, measuring drug effects on AEPs adds information to measuring only drug effects on the ongoing EEG.
The dry eye syndrome is common in clinical diagnosis. The pathogenesis of xerophthalmia could be the degeneration of either the lacrimal gland itself or an innervated nerve. However, the present treatment of this disease is only symptom relief by medication and artificial tears. In order to cure patients of dry eye and improve their life quality, autologous lacrimal gland transplantation might be a useful means of managing xerophthalmia. However transplantation efficacy could depend on both tissue rejection and nerve reinnervation in the gland. However, it remains unknown whether reinnervation results in any morphological change of the transplanted gland. The lachrymal glands of rats were removed under surgical microscope and the autologous submandibular glands were transplanted to the lachrymal basin. After 30 days, horseradish peroxidase(HRP) was injected into the transplanted gland. The neurons that innervated the transplanted gland were demonstrated by HRP. Immunohistoehemical studies of protein gene product 9.5(PGP 9.5) were used to investigate the reinnervated nerve fibers in glands. In our study, the injected HRP could label the neurons in the superior cervical ganglion (SCG), trigeminal ganglion(TG) and pterygopalatine ganglion(PG). Abundant nerve fibers with PGP 9.5 immunoreactivity existed mainly around the survived acinar in the gland. We hypothesized that the transplanted submandibular gland could survive in the lachrymal basin and be reinnervated by sympathetic, parasympathetic and sensory nerves. The surviving of the transplanted submandibular gland was significantly dependent on its reinnervation as reflected by PGP 9.5 immunoreactivity in the transplanted glands.
Epilepsy partialis continuans: a clinical and radioiogical correlation. M.D. Christensen, E. Grant, A. J. Cole, G. R. Cosgrove. Massachusetts
The electrophysiologieal research of amygdala-visual system interactions. E. Panakhova. Institute of Physiology, Baku, Azerbaijan. Results obtained on the nature of the relationship of the amygdala with the visual system structures suggest that disturbances of biologically programmed and useful interrelations may underlie the development of such pathological agnostic syndromes as the Kluver-Bucy Syndrome and Alzheimer's Disease. Research on the mechanisms of intersystem integration between the visual system and the amygdala is very important for understanding the basic principles of the formation of a functional system which ensures the development of adequate visually controlled behaviour. The amygdala has a role in these mechanisms. Results suggest that the amygdala establishes functional relations with visual system structures, and that these relationships in turn could be components of the functional system providing a basis for goal-directed motor activity. The creating of a locus of increased excitability in the amygdala (by means of a Strychnine solution injection) causes a pronounced enhancement of Evoked Potentials formed in reaction to a light flash. Our experiments demonstrate that secondary components of these occur primarily in the visual cortex, in response to a previously ineffective stimulus (a light flash). This demonstrates the development of visual signals and increases their biological significance.
Transplantation of the autologous submandibular gland to the lachrymal basin in rats: the effect of nerve reinnervation of the autografted gland. C. H. Chen z, W. C. Liu ~, W. M. Hsu and J. C. Liu 2 1Department of
Ophthalmology, Taipei VeteransGeneralHospital, Taipei, Taiwan;ZDepartment of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan.
General Hospital' Boston, MA, USA. PURPOSE: To correlate preoperative functional and anatomic neuroimaging studies with intraoperative findings in a patient with Epilepsia Partialis Continuans (EPC). METHOD: Preoperative MRI, MRA, and PET scans were correlated and compared clinical seizures, noninvasive ictal EEG and intraoperative gross cortical pathology. RESULTS: Preoperative EEG, PET scan, MRI, and MRA revealed abnormalities consistent with an epileptogenic focus located in the right eentrolateral rolandic cortex. Intraoperative ECoG confirmed the preoperative findings. At craniotomy, the cortex demonstrated focal hyperemia and vascular shunting, which correlated closely with all pre and intraoperative studies. CONCLUSIONS: This case demonstrates an increase in intraoperative focal cortical blood flow to the region predicted by preoperative neuroimaging studies. This is the fwst demonstration correlating intraoperafive cortical hyperemia with EEG f'mdings and neuroimaging. This observation may provide insights into the physiological basis ofneuroimaging changes during EPC.
Functional MRI in language areas in Wada tested epilepsy patients: a preliminary study. F. Santos, V.H. Machado, A. Dalacorte, C.M. Neves, M. Portuguez, J.C. da Costa. Servi¢ode Neurologia, Programa de Cirurgia de Epilepsia do Hospital
Sdo Lucas da Pont(ficia Universidade Catdlica Do Rio Grande Do Sul±Porto Alegre RS, Brazil The use of Functional MRI (fMRI) in the study of language areas is a very interesting tool in some areas of neurology. In this study we submit a group of Wada-tested patients to fMRI in language areas. The patients belong to Neurology Service at Epilepsy Surgery Program in Hospital Sgo Lucas da
S58
Neuroimaging - Basic neurophysiology
Pontificia Universidade Cat61ica do Rio Grande do Sul (HSL PUC RS) at Porto Alegre, Brazil. OBJECTIVE: To compare the results o f fMR1 in language areas with the results of the Wada test in this particular group of patients. METHOD: The group consisted o f seven epilepsy patients who met following selection criteria, and who were undergoing comprehensive evaluation for surgical treatment of epilepsy. The Wada tested epilepsy patients at HSL PUC RS were submitted to fMRI in language areas. The scans were acquired on Siemens 1.5 T MRI system. The fMRI used a gradient echo, echo-planar sequence. Functional slices were acquired in the axial plane during a silent speech task, alternating with two periods of control task. SUMMARY: All patients in this group presented language area in the same side as shown in the two methods. CONCLUSION: This preliminary result in our institution suggests the usefulness of this new method. A great number of patients will be needed to show more clearly the limitations of this new tool in the study o f epilepsy patients. 7.REFERENCES: 1) BRAIN (1999), 122,2033-2045.2) NEUROLOGY (1999), 52,798-809.3) THE JOURNAL OF NEUROSCi ENCE (1997), 17(t ), 353-362.
Brain activation during hand-fingers mov~ .... hand writing in patients with writer's cramp: a functional magnetic resonance imaging study. F. Pauri~, C. Del Gratta -~, A. Ferretti~-, E. Cassetta ~ ,G.L. Romani 2, P.M. Rossini ~,3.l : AfaR, Ospedale Fatebenefratelli lsola 77berina, Roma, 2 :ITAB. Universitd di Chieti. 3: Universitd Campus Biomedico, Roma - ltal): Several disturbances have been found and used to explain the pathogenesis of writer's cramp: inability to efficiently control the force output during manipulative activities, wrong setting o f the sensitivity of sensory input channels from the hand, combined abnormalities in the central motor command and central processing of sensory input, maladaptive plasticity. In order to better understand the patophysiology of this focal dystonia, fMRi was performed in three ( two males and 1 female) patients affected by writer's cramp during two different motor tasks: a self-paced finger tapping task consisting of the sequential opposition of the thumb to the other fingers at a frequency of about 1 see, and a handwriting exercise consisting in holding a pen and writing consecutively the letter '7 "without interruption and without visual feed-back. The examined subject was lying supine on the bed of the MR1 scanner, inside the magnet bore, with his head firmly held inside the receiver coil. Results were similar in the three patients. A smaller activation in the primary motor and sensorimotor areas during writing- in comparison with finger movements - was found when the subjects used their right hand. Activation of supplementary motor area was found only during finger tapping. No differences were found when the left hand was performing the two tasks in the activation of primary motor area, but the supplementary motor area was activated only during finger tapping.