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Pellicer-Morata V, Wang L, Curry ADJ, Tsao JW, Waters RS. Lower jaw-to-forepaw rapid and delayed reorganization in the rat forepaw barrel subfield in primary somatosensory cortex. J Comp Neurol 2023; 531:1651-1668. [PMID: 37496376 PMCID: PMC10530121 DOI: 10.1002/cne.25523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 05/24/2023] [Accepted: 06/26/2023] [Indexed: 07/28/2023]
Abstract
We used the forepaw barrel subfield (FBS), that normally receives input from the forepaw skin surface, in rat primary somatosensory cortex as a model system to study rapid and delayed lower jaw-to-forepaw cortical reorganization. Single and multi-unit recording from FBS neurons was used to examine the FBS for the presence of "new" lower jaw input following deafferentations that include forelimb amputation, brachial plexus nerve cut, and brachial plexus anesthesia. The major findings are as follows: (1) immediately following forelimb deafferentations, new input from the lower jaw becomes expressed in the anterior FBS; (2) 7-27 weeks after forelimb amputation, new input from the lower jaw is expressed in both anterior and posterior FBS; (3) evoked response latencies recorded in the deafferented FBS following electrical stimulation of the lower jaw skin surface are significantly longer in both rapid and delayed deafferents compared to control latencies for input from the forepaw to reach the FBS or for input from lower jaw to reach the LJBSF; (4) the longer latencies suggest that an additional relay site is imposed along the somatosensory pathway for lower jaw input to access the deafferented FBS. We conclude that different sources of input and different mechanisms underlie rapid and delayed reorganization in the FBS and suggest that these findings are relevant, as an initial step, for developing a rodent animal model to investigate phantom limb phenomena.
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Affiliation(s)
- Violeta Pellicer-Morata
- Department of Physiology, University of Tennessee Health
Science Center, College of Medicine, 956 Court Avenue, Memphis, TN 38163, USA
| | - Lie Wang
- Department of Anatomy and Neurobiology, University of
Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Suite,
Memphis, TN 38163, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of
Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152,
USA
| | - Jack W. Tsao
- Department of Neurology, New York University, Langone
School of Medicine, 550 1 Avenue, New York, NY 10016, USA
| | - Robert S. Waters
- Department of Anatomy and Neurobiology, University of
Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Suite,
Memphis, TN 38163, USA
- Department of Biomedical Engineering, University of
Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152,
USA
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Pellicer-Morata V, Wang L, de Jongh Curry A, Tsao JW, Waters RS. Structural and functional organization of the lower jaw barrel subfield in rat primary somatosensory cortex. J Comp Neurol 2020; 529:1895-1910. [PMID: 33135168 DOI: 10.1002/cne.25063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 11/08/2022]
Abstract
Barrel subfields in rodent primary somatosensory cortex (SI) are important model systems for studying cortical organization and reorganization. During cortical reorganization that follows limb deafferentation, neurons in deafferented forelimb SI become responsive to previously unexpressed inputs from the lower jaw. Although the lower jaw barrel subfield (LJBSF) is a likely source of the input, this subfield has received little attention. Our aim was to describe the structural and functional organization of the normal LJBSF. To investigate LJBSF organization, a nomenclature for lower jaw skin surface was developed, cytochrome oxidase (CO) was used to label flattened-cut LJBSF sections, microelectrodes were used to map the lower jaw skin surface representation in SI, and electrolytic lesions, recovered from electrode penetrations, were used to align the physiological map to the underlying barrel map. LJBSF is a tear-shaped subfield containing approximately 24 barrels, arranged in eight mediolateral rows and a barrel-free zone capping the anterior border. The representation of the lower jaw skin consisting of chin vibrissae and microvibrissae embedded in common fur is somatotopically organized in a single map in the contralateral SI. This physiological map shows that the activity from the vibrissae aligns with the CO-staining of the underlying LJBSF. LJBSF barrels receive topographically ordered barrel-specific input from individual vibrissa and microvibrissae in the lower jaw but not from trident whiskers. The barrel-free zone receives topographically ordered input from the lower lip. These data demonstrating that the LJBSF is a highly organized subfield are essential for understanding its possible role in cortical reorganization.
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Affiliation(s)
- Violeta Pellicer-Morata
- Department of Physiology, University of Tennessee Health Science Center, College of Medicine, Memphis, Tennessee, USA
| | - Lie Wang
- Department of Neurology, University of Tennessee Health Science Center, College of Medicine, Memphis, Tennessee, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, Memphis, Tennessee, USA
| | - Jack W Tsao
- Department of Neurology, University of Tennessee Health Science Center, College of Medicine, Memphis, Tennessee, USA.,Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, Memphis, Tennessee, USA.,Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, Tennessee, USA
| | - Robert S Waters
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, Memphis, Tennessee, USA.,Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, Memphis, Tennessee, USA
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DeCosta-Fortune TM, Ramshur JT, Li CX, de Jongh Curry A, Pellicer-Morata V, Wang L, Waters RS. Repetitive microstimulation in rat primary somatosensory cortex (SI) strengthens the connection between homotopic sites in the opposite SI and leads to expression of previously ineffective input from the ipsilateral forelimb. Brain Res 2020; 1732:146694. [PMID: 32017899 PMCID: PMC7237062 DOI: 10.1016/j.brainres.2020.146694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 01/06/2020] [Accepted: 01/29/2020] [Indexed: 10/25/2022]
Abstract
The primary somatosensory cortex (SI) receives input from the contralateral forelimb and projects to homotopic sites in the opposite SI. Since homotopic sites in SI are linked by a callosal pathway, we proposed that repetitive intracortical microstimulation (ICMSr) of neurons in layer V of SI forelimb cortex would increase spike firing in the opposite SI cortex thereby strengthening the callosal pathway sufficiently to allow normally ineffective stimuli from the ipsilateral forelimb to excite cells in the ipsilateral SI. The forelimb representation in SI in one hemisphere was mapped using mechanical and electrical stimulation of the contralateral forelimb, a homotopic site was similarly identified in the opposite SI, the presence of ipsilateral peripheral input was tested in both homotopic sites, and ICMS was used to establish an interhemispheric connection between the two homotopic recording sites. The major findings are: (1) each homotopic forelimb site in SI initially received short latency input only from the contralateral forelimb; (2) homotopic sites in layer V in each SI were interconnected by a callosal pathway; (3) ICMSr delivered to layer V of the homotopic SI in one hemisphere generally increased evoked response spike firing in layer V in the opposite homotopic site; (4) increased spike firing was often followed by the expression of a longer latency normally ineffective input from the ipsilateral forelimb; (5) these longer latency ipsilateral responses are consistent with a delay time sufficient to account for travel across the callosal pathway; (6) increased spike firing and the resulting ipsilateral peripheral input were also corroborated using in-vivo intracellular recording; and (7) inactivation of the stimulating site in SI by lidocaine injection or local surface cooling abolished the ipsilateral response, suggesting that the ipsilateral response was very likely relayed across the callosal pathway. These results suggest that repetitive microstimulation can do more than expand receptive fields in the territory adjacent to the stimulating electrode but in addition can also alter receptive fields in homotopic sites in the opposite SI to bring about the expression of previously ineffective input from the ipsilateral forelimb.
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Affiliation(s)
- Tina M DeCosta-Fortune
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - John T Ramshur
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - Cheng X Li
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA; Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA
| | - Violeta Pellicer-Morata
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
| | - Lie Wang
- Department of Neurology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA
| | - Robert S Waters
- Department of Biomedical Engineering, University of Memphis, Herff College of Engineering, 3815 Central Avenue, Memphis, TN 38152, USA; Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, College of Medicine, 855 Monroe Avenue, Memphis, TN 38163, USA.
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Myers MH, Jolly E, Li Y, de Jongh Curry A, Parfenova H. Power Spectral Density Analysis of Electrocorticogram Recordings during Cerebral Hypothermia in Neonatal Seizures. Ann Neurosci 2017; 24:12-19. [PMID: 28596673 PMCID: PMC5460947 DOI: 10.1159/000464418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/11/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Neonatal seizures (NS) are the most common form of neurological dysfunction observed in newborns. PURPOSE The purpose of this study in newborn piglets was to determine the effect of cerebral hypothermia (CH) on neural activity during pharmacologically induced NS. We hypothesized that the neuroprotective effects of CH would preserve higher frequencies observed in electrocorticogram (ECoG) recordings. METHODS Power spectral density was employed to determine the levels of brain activity in ECoGs to quantitatively assess the power of each frequency observed in neurological brain states of delta, theta, alpha, and beta-gamma frequencies. RESULT The most significant reduction of power occurs in the lower frequency band of delta-theta-alpha of CH cohorts, while t score probabilities imply that high-frequency brain activity in the beta-gamma range is preserved in the CH population. CONCLUSION While the overall power density decreases over time in both groups, the decrease is to a lesser degree in the CH population.
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Affiliation(s)
- Mark H. Myers
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center Memphis, Memphis, TN, USA
| | - Elliott Jolly
- Department of Biomedical Engineering, University of Memphis, Memphis, TN, USA
| | - Yaqin Li
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of Memphis, Memphis, TN, USA
| | - Helena Parfenova
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
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Harsono M, Pourcyrous M, Jolly EJ, de Jongh Curry A, Fedinec AL, Liu J, Basuroy S, Zhuang D, Leffler CW, Parfenova H. Selective head cooling during neonatal seizures prevents postictal cerebral vascular dysfunction without reducing epileptiform activity. Am J Physiol Heart Circ Physiol 2016; 311:H1202-H1213. [PMID: 27591217 DOI: 10.1152/ajpheart.00227.2016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 08/22/2016] [Indexed: 01/12/2023]
Abstract
Epileptic seizures in neonates cause cerebrovascular injury and impairment of cerebral blood flow (CBF) regulation. In the bicuculline model of seizures in newborn pigs, we tested the hypothesis that selective head cooling prevents deleterious effects of seizures on cerebral vascular functions. Preventive or therapeutic ictal head cooling was achieved by placing two head ice packs during the preictal and/or ictal states, respectively, for the ∼2-h period of seizures. Head cooling lowered the brain and core temperatures to 25.6 ± 0.3 and 33.5 ± 0.1°C, respectively. Head cooling had no anticonvulsant effects, as it did not affect the bicuculline-evoked electroencephalogram parameters, including amplitude, duration, spectral power, and spike frequency distribution. Acute and long-term cerebral vascular effects of seizures in the normothermic and head-cooled groups were tested during the immediate (2-4 h) and delayed (48 h) postictal periods. Seizure-induced cerebral vascular injury during the immediate postictal period was detected as terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive staining of cerebral arterioles and a surge of brain-derived circulating endothelial cells in peripheral blood in the normothermic group, but not in the head-cooled groups. During the delayed postictal period, endothelium-dependent cerebral vasodilator responses were greatly reduced in the normothermic group, indicating impaired CBF regulation. Preventive or therapeutic ictal head cooling mitigated the endothelial injury and greatly reduced loss of postictal cerebral vasodilator functions. Overall, head cooling during seizures is a clinically relevant approach to protecting the neonatal brain by preventing cerebrovascular injury and the loss of the endothelium-dependent control of CBF without reducing epileptiform activity.
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Affiliation(s)
- Mimily Harsono
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Massroor Pourcyrous
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Elliott J Jolly
- Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee
| | - Amy de Jongh Curry
- Department of Biomedical Engineering, University of Memphis, Memphis, Tennessee
| | - Alexander L Fedinec
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Jianxiong Liu
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Shyamali Basuroy
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Daming Zhuang
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Charles W Leffler
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Helena Parfenova
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
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Fitch DA, Soberman JE, de Jongh Curry A. Esophageal electric fields are correlated to atrial defibrillation thresholds: towards patient-specific optimization of external atrial defibrillation. Conf Proc IEEE Eng Med Biol Soc 2006; 2006:4378-4381. [PMID: 17946242 DOI: 10.1109/iembs.2006.259417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Studies have investigated the effect of defibrillator paddle position on the efficacy of external electrocardioversion of atrial fibrillation, without agreeing upon an optimal placement. We wish to investigate using esophageal electric fields (EEFs) to predict atrial defibrillation thresholds (ADFTs) on a patient-specific basis. We propose to (1) investigate the relationship between EEFs and ADFTs using computer simulations, (2) develop an esophageal probe that can accurately measure three-dimensional electric fields and (3) investigate the relationship between EEFs and ADFTs values in-vivo. Sixteen anterior-anterior and eleven anterior-posterior placements were simulated yielding a negative relationship between EEFs and ADFTs (R2=0.91 and 0.93, respectively). An esophageal probe was developed that accurately measures EEFs. Animal studies showed a negative relationship between EEFs and ADFTs. This data suggests using EEFs to predict ADFTs on a patient-specific basis is plausible.
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