Brenda Shook - Academia.edu (original) (raw)
Papers by Brenda Shook
Psychology, 2024
Evidence-based studies utilizing body-oriented techniques with traumatized populations are virtua... more Evidence-based studies utilizing body-oriented techniques with traumatized populations are virtually absent in the literature. In this study, we report the effects of Tension and Trauma Releasing Exercises (TRE) on trauma-related symptoms in a community sample of East African refugees resettled in the United States. The Harvard Trauma Questionnaire (HTQ) was used to assess symptom severity prior to and after eight weeks of performing the TRE. Results showed a reduction in symptom severity for 36 out of 40 HTQ items, and a significant reduction in overall average symptom severity for the treatment group relative to a delayed treatment control. Statistical analyses of these items showed that for the treatment group, but not the controls, there was a significant reduction in symptom severity as well as the number of symptoms. It was concluded that TRE is an effective means of improving the trauma-related symptoms in East African refugees.
Action-Oriented Approaches to Visuo-Spatial Brain Functions
Brain Mechanisms and Spatial Vision, 1985
Modes of perception of spatial relationships are evaluated for frogs and for a mammalian species,... more Modes of perception of spatial relationships are evaluated for frogs and for a mammalian species, the Mongolian gerbil. Hypotheses as to the special role of visual cortex are derived from some of these comparisons. Finally, the results of testing gerbils for spatial abilities after visual cortex ablations are found to support some hypotheses.
This study examined student perceptions of online teaching effectiveness in undergraduate courses... more This study examined student perceptions of online teaching effectiveness in undergraduate courses. End-of course evaluation data were collected from a sample of 2,750 online multisection courses taught within a 12 month period and comparisons were made between highly rated courses (at 4.5 or higher on a 5 point scale) and low rated courses (at 3.0 or lower). There was a significant difference in course evaluations as a function of academic rank, with slightly lower ratings for faculty at lower ranks relative to those at higher ranks. In general, online teaching experience and experience teaching the same course were both weak predictors of course evaluation outcomes. Overall, in highly rated courses instructors were: receptive to questions, responded promptly to emails, provided timely feedback, posted grades in a timely manner, and were perceived as active participants in the online class. Further findings and recommendations to assist faculty in understanding online teaching evaluations are discussed.
Psychology, 2016
Fifty-six full-time graduate Marriage and Family Therapy (MFT) counseling students responded to c... more Fifty-six full-time graduate Marriage and Family Therapy (MFT) counseling students responded to case scenarios involving a client's expression of feelings of love and sexual attraction toward the therapist. The scenarios differed by diagnosis of the client (adjustment disorder versus histrionic personality disorder) and students were asked about their comfort level in discussing how to manage this situation with either their supervisor, personal therapist or trusted colleague when the feelings of sexual attraction in therapy were mutual versus non-mutual. They also indicated their comfort level in discussing their client's feelings in the treatment, and continuing to treat the client versus referring the client out under these varying conditions. Overall students felt comfortable discussing a case with their supervisor, however students' comfort level was significantly higher when feelings of attraction were non-mutual. Students felt most comfortable talking with their own therapist relative to either their supervisor or a colleague about these cases. When feelings of sexual attraction were mutual, students were much less comfortable referring out the client diagnosed with a histrionic personality disorder compared to the client diagnosed with an adjustment disorder. Students reported feeling comfortable discussing a client's feelings of sexual attraction with the client regardless of type of diagnosis and whether those feelings were mutual or non-mutual. Students were more comfortable continuing therapy when feelings of sexual attraction were non-mutual than mutual. Implications for training regarding management of these issues are discussed.
Millon Adolescent Substance-Abuse Proneness Scale: Identifying Clients in a Forensic Setting
PsycEXTRA Dataset, 2000
This study examined student perceptions of online teaching effectiveness in undergraduate courses... more This study examined student perceptions of online teaching effectiveness in undergraduate courses. End-of course evaluation data were collected from a sample of 2,750 online multisection courses taught within a 12 month period and comparisons were made between highly rated courses (at 4.5 or higher on a 5 point scale) and low rated courses (at 3.0 or lower). There was a significant difference in course evaluations as a function of academic rank, with slightly lower ratings for faculty at lower ranks relative to those at higher ranks. In general, online teaching experience and experience teaching the same course were both weak predictors of course evaluation outcomes. Overall, in highly rated courses instructors were: receptive to questions, responded promptly to emails, provided timely feedback, posted grades in a timely manner, and were perceived as active participants in the online class. Further findings and recommendations to assist faculty in understanding online teaching evalu...
Proceedings of the National Academy of Sciences, 1985
The functional consequences of interrupting in utero binocular interactions were studied by recor... more The functional consequences of interrupting in utero binocular interactions were studied by recording from single cells in area 17 of adult cats that had one eye removed at least 2 wk before birth. In these animals all cortical neurons could be driven by the remaining eye, and in tangential microelectrode penetrations, sequences of neurons containing a full 180-degree cycle of preferred orientations were en- countered. Other response properties of cortical neurons in the prenatally enucleated animals were also normal with the notable exception that the dimensions of receptive fields were significantly smaller when compared with those of control animals. Our results indicate that orientation columns in the visual cortex can develop independently of ocular dominance columns, and they suggest that interruption of binocular interactions during prenatal development of the visual path- ways may enhance the resolving power of the remaining eye.
Journal of Police and Criminal Psychology, 2007
Screening applicants for the position of peace officer is a very uncertain process. Concomitantly... more Screening applicants for the position of peace officer is a very uncertain process. Concomitantly, trying to select applicants who will be successful throughout their careers adds another, important dimension. Unfortunately, the selection process has primarily been one of screening-out those who are for one reason or another unfit. This article used the Thurstone Scale as the methodological basis to identify those traits that experts agreed are the ones that are meaningful in predicting police officer career success.
An analysis of the transport of WGA-HRP in the cat's visual system
Journal of Neuroscience Methods, 1984
The increasing use of WGA-HRP as a neuroanatomical tracer has led us to examine two aspects of it... more The increasing use of WGA-HRP as a neuroanatomical tracer has led us to examine two aspects of its uptake and transport. Microelectrophoretic deposits of WGA-HRP were centered in lamina A of the LGd to determine whether or not there is a discrepancy between the size of the deposit site and the effective uptake zone. For this purpose, the size of the deposit site was compared to the area of labeled ganglion cells in the retina. It was found that the effective uptake zone is approximately one half the size of the geniculate area containing reaction-product. Deposits of WGA-HRP in the optic tract, optic radiations and corpus callosum were made in order to determine if this tracer is incorporated and transported by intact fibers. In no case were labeled axon terminals or neuronal somata observed. However, application of the conjugated enzyme to cut fibers of the corpus callosum resulted in robust labeling.
The Journal of Comparative Neurology, 1991
The supplementary eye field (SEF) was defined electrophysiologically in behaving monkeys to study... more The supplementary eye field (SEF) was defined electrophysiologically in behaving monkeys to study its connections with the diencephalon and corpus striatum. The specificity of SEF pathways was determined with horseradish peroxidase (HRP) histochemistry to compare its connections with those of the arcuate frontal eye field (FEF), contiguous dorsocaudal area 6 (6DC), and primary motor cortex (Ml, arm/hand region). Results indicate that patterns of SEF connectivity were similar to the FEF and markedly different from areas 6DC and M1. Primary reciprocal thalamic pathways of the SEF were with the magnocellular ventral anterior (VA) nucleus, medial parvicellular VA, medial area X, and paralaminar medialis dorsalis (multiformis and parvicellularis). FEF showed similar connections but its most robust pathway was with MD rather than VA. In contrast, area 6DC showed the most extensive reciprocal connections with lateral VApc and lateral area X with only sparse connections with paralaminar MD. Area 6DC also exhibited reciprocal connections with the ventral lateral (VL) complex and the ventral posterior lateral nucleus, pars oralis (VPLo). M1 showed dense bidirectional connections with VPLo, and to a lesser extent, with VL. M 1 pathways with the medial dorsal nucleus were negligible. All areas exhibited connections with the paracentral and central lateral nuclei and only M1 lacked connections with the central superior lateral nucleus. SEF and FEF exhibited similar efferent projections to the caudate and putamen. In the caudate, terminal fields were restricted to a central longitudinal core while those from area 6DC were more widely distributed. Eye field efferents were restricted to the putamen's face region while 6DC projections were more exuberant. The armhand region of M1 projected to the armihand region of the putamen. Pathways are discussed with respect to their significance in oculomotor control.
The Journal of Comparative Neurology, 1990
WGA-HRP was used to examine projections to the brainstem from the supplementary eye field (SEF). ... more WGA-HRP was used to examine projections to the brainstem from the supplementary eye field (SEF). The SEF was defined electrophysiologically in awake, behaving monkeys and connections were compared to those of the arcuate frontal eye field (FEF), area 6DC, and primary motor cortex. The SEF was found to have either direct or indirect connections with almost every known pre-and paraoculomotor structure of the brainstem. The SEF was found to project bilaterally to layers I and IV of a tangentially widespread region of the superior colliculus. Terminal label was evident in the pretectal olivary nucleus, nucleus of the optic tract, nucleus raphe interpositus (omnipause region), nucleus prepositus hypoglossi, the perioculomotor cap of the central gray, dorsal central gray, nucleus reticularis tegmenti pontis, nucleus reticularis pontis oralis, and to multiple nuclei of the basis pontis (most densely to the dorsomedial nucleus). Bilateral projections were found in the parvicellular red nucleus. Reciprocal connections were present in the nucleus limitans, the mesencephalic reticular formation, locus coeruleus, and the serotonergic nuclei of the raphe complex (dorsalis and central superior). Overall patterns of connectivity were similar to those of the FEF and markedly different from those of the contiguous dorsocaudal area 6 or primary motor cortex. It was concluded that observed patterns of SEF-brainstem connectivity further justifies viewing this region as a distinct eye field that is likely to serve preparatory and trigger functions in the generation of saccadic eye movements.
Experimental Neurology, 1991
Experimental Brain Research, 1988
Using WGA-HRP we have demonstrated that a direct projection links the supplementary eye field, bu... more Using WGA-HRP we have demonstrated that a direct projection links the supplementary eye field, but not the more caudal aspect of the supplementary motor area, to the brain stem omnipause region. Findings are discussed in relation to oculomotor control.
Experimental Brain Research, 1989
Schlag, John, Alexandre Pouget, Safa Sadeghpour, and Madenow can be systematically modified. It i... more Schlag, John, Alexandre Pouget, Safa Sadeghpour, and Madenow can be systematically modified. It is deviated in the leine Schlag-Rey. Interactions between natural and electrically direction opposite to the movement just accomplished, thus evoked saccades. III. Is the nonstationarity the result of an integraappearing to correct (or compensate for) at least part of the tor not instantaneously reset? J Neurophysiol. 79: 903-910, 1998. preceding displacement. For instance, if the initial saccade In the monkey, fixed-vector saccades evoked by superior colliculus is directed upward and rightward, the electrically evoked (SC) stimulation when the animal fixates can be dramatically modsaccade will be less upward and less rightward than the ified if the stimulation is applied during or immediately after an control elicited from a steady position (see Fig. ). Stimulatinitial natural saccade. The vector is then deviated in the direction ing the superior colliculus (SC), Robinson (1972) first noopposite to the displacement just accomplished as if it were comticed this deviation and ascribed it to refractoriness, without pensating for part of the preceding trajectory. Recently, it was suggested that the amplitude of the compensatory deviation is re-implying any specific physiological mechanism. Initially, we lated to the amplitude of the initial saccade linearly, and that the called the observed change of trajectory ''compensatory'' ratio between the two decreases exponentially as stimulation is , following Sparks and Mays applied later. These two findings (spatial linearity and temporal (1983) who studied the effect of collicular stimulation on nonstationarity) were invoked as evidence for the noninstantaneous natural saccades (i.e., the same paradigm in reverse order) resetting of a feedback integrator. Such an integrator is included and reported practically the same type of change. The term in most models of saccade generation for the specific purpose of compensation immediately evokes the direction in which terminating a saccade when it has reached its intended goal. Howthe course correction is made (i.e., opposite to the initial ever, the hypothesis of a feedback integrator in the process of movement). Compensation is reliable and, eventually, can being reset implies that the exponential decay of the compensatory result in an inversion of the fixed-vector. This effect has deviation is temporally linked to the end of the initial saccade. We been proposed as the basis of a test to probe mechanisms analyzed the time course of this decay in stimulation experiments performed at 24 SC sites in two monkeys. The results show that of saccade elicitation in various brain structures (Schlag and if the start of the exponential decay of compensation is assumed Schlag-Rey 1990).
Transplantation of Fetal Frontal Cortex onto Degenerating Thalamus of Cats and Kittens
Developmental Neuroscience, 1990
Tissue from fetal frontal cortex survived after transplantation onto the surface of the left thal... more Tissue from fetal frontal cortex survived after transplantation onto the surface of the left thalamus in 2 kittens and 2 adult cats which 7 days previously had sustained a left cerebral hemispherectomy. There were nerve fiber connections with host tissue (WGA-HRP, Loyez myelin stain) only in the neonatal animals. The grafts contained surviving neurons in all but in one adult cat which survived 301 days. The grafts had little effects on the retrograde ventral thalamic degeneration typically seen following hemispherectomy. However, the dorsal lateral geniculate nucleus adjacent to the transplants showed reduced neuronal loss and gliosis compared to controls. Magnetic resonance imaging was successfully used to visualize the grafts in vivo and suggested a decrease in size as well as changes in composition for a graft systematically followed for 120 days posttransplantation. Cytochrome oxidase histochemistry indicated sustained metabolic activity in transplants containing surviving neurons. This study introduces the cat as a useful model for brain tissue transplantation in a classical, myelinated sensorimotor system.
Developmental Brain Research, 1986
The organization of geniculostriate connections in normal cats was compared with that of adult an... more The organization of geniculostriate connections in normal cats was compared with that of adult animals that were uniocularly enucleated before birth. In normal animals microelectrophoretic deposits of horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) into the A-lamina of the dorsal lateral geniculate body (LGd) resulted in anterograde label in layers IV and VI and labeled cells in layer VI of areas 17 and 18. The labeling pattern within both of these cortical areas consisted of alternating patches separated by zones of equivalent size that were relatively free of label. In the normal animals no reaction product was evident in any other cortical area. In the prenatally enucleated cats, the LGd both contralateral and ipsilateral to the remaining eye is comprised of only two distinct cell layers. The dorsal layer appears to be a composite of the normal A/Al-laminae, while the ventral layer appears to correspond to the C-laminae. Deposits of WGA-HRP into the superficial aspect of the A/A1 layer yielded a dense continuous band of label within layers IV and V! of areas 17 and 18. Additionally, such deposits in the prenatally enucleated cats also revealed an anomalous reciprocal connection with area 19. Punctate deposits of WGA-HRP into cortical area 19 of the fetal enucleates resulted in the labeling of two distinct populations of cells within the A/A1 layer of the LGd. No cells were labeled within the A-laminae following such deposits into area 19 of normal animals. The geniculocortical connections of the prenatally enucleated cats, including that to area 19, were found to be retinotopically organized. These results indicate that in utero interruption of binocular interactions prevents the formation of ocular dominance domains within areas 17 and 18 of the cat's visual cortex. This could reflect the maintenance of exuberant geniculocortical projections present at the time of prenatal eye removal as originally suggested by Rakic (Science, 214 (1981) 928-931). The anomalous connection with area 19, on the other hand, could be due to the disruption of LGd cell migration resulting from the early eye removal.
Traumatic brain injury produces impairments in long-term and recent memory
Brain Research, 1993
Traumatic brain injury (TBI) in humans typically produces neurological suppression and a longer l... more Traumatic brain injury (TBI) in humans typically produces neurological suppression and a longer lasting impairment of memory clinically defined as post-traumatic amnesia. An animal model that reliably reproduces the physiological changes associated with TBI was used to assess the memory deficits following brain injury. Prior to TBI, rats were trained to perform one of four tasks that assessed either motor performance, long-term or recent memory. Rats were randomly assigned to one of three groups (anesthesia only, sham operation or fluid percussion). Following fluid percussion, used to produce TBI, rats were tested for 6 test sessions. The first session occurred 1-2 min after the experimental manipulation. The next 5 sessions followed the training schedule maintained prior to experimental manipulation. Differences in long-term memory occurred only in the first post-operative test session. Differences in recent memory performance were found across all 6 test sessions. The memory deficits were clearly dissociated from motor deficits. The similar memory deficits observed following human head injury and the experimentally produced TBI injury demonstrate that fluid percussion is a useful approach to examine underlying neurobiological mechanisms involved in head injury and possible clinical interventions.
Functional Organization of the Gerbil's Visual system: A move to revise traditional working hypotheses of Brain Organization
ABSTRACT Thesis (Ph. D.)--Brandeis University, 1982. "UMI: 8318248." Includes b... more ABSTRACT Thesis (Ph. D.)--Brandeis University, 1982. "UMI: 8318248." Includes bibliographical references (p. 180-221). Photocopy.
Experimental Neurology, 1991
Psychology, 2024
Evidence-based studies utilizing body-oriented techniques with traumatized populations are virtua... more Evidence-based studies utilizing body-oriented techniques with traumatized populations are virtually absent in the literature. In this study, we report the effects of Tension and Trauma Releasing Exercises (TRE) on trauma-related symptoms in a community sample of East African refugees resettled in the United States. The Harvard Trauma Questionnaire (HTQ) was used to assess symptom severity prior to and after eight weeks of performing the TRE. Results showed a reduction in symptom severity for 36 out of 40 HTQ items, and a significant reduction in overall average symptom severity for the treatment group relative to a delayed treatment control. Statistical analyses of these items showed that for the treatment group, but not the controls, there was a significant reduction in symptom severity as well as the number of symptoms. It was concluded that TRE is an effective means of improving the trauma-related symptoms in East African refugees.
Action-Oriented Approaches to Visuo-Spatial Brain Functions
Brain Mechanisms and Spatial Vision, 1985
Modes of perception of spatial relationships are evaluated for frogs and for a mammalian species,... more Modes of perception of spatial relationships are evaluated for frogs and for a mammalian species, the Mongolian gerbil. Hypotheses as to the special role of visual cortex are derived from some of these comparisons. Finally, the results of testing gerbils for spatial abilities after visual cortex ablations are found to support some hypotheses.
This study examined student perceptions of online teaching effectiveness in undergraduate courses... more This study examined student perceptions of online teaching effectiveness in undergraduate courses. End-of course evaluation data were collected from a sample of 2,750 online multisection courses taught within a 12 month period and comparisons were made between highly rated courses (at 4.5 or higher on a 5 point scale) and low rated courses (at 3.0 or lower). There was a significant difference in course evaluations as a function of academic rank, with slightly lower ratings for faculty at lower ranks relative to those at higher ranks. In general, online teaching experience and experience teaching the same course were both weak predictors of course evaluation outcomes. Overall, in highly rated courses instructors were: receptive to questions, responded promptly to emails, provided timely feedback, posted grades in a timely manner, and were perceived as active participants in the online class. Further findings and recommendations to assist faculty in understanding online teaching evaluations are discussed.
Psychology, 2016
Fifty-six full-time graduate Marriage and Family Therapy (MFT) counseling students responded to c... more Fifty-six full-time graduate Marriage and Family Therapy (MFT) counseling students responded to case scenarios involving a client's expression of feelings of love and sexual attraction toward the therapist. The scenarios differed by diagnosis of the client (adjustment disorder versus histrionic personality disorder) and students were asked about their comfort level in discussing how to manage this situation with either their supervisor, personal therapist or trusted colleague when the feelings of sexual attraction in therapy were mutual versus non-mutual. They also indicated their comfort level in discussing their client's feelings in the treatment, and continuing to treat the client versus referring the client out under these varying conditions. Overall students felt comfortable discussing a case with their supervisor, however students' comfort level was significantly higher when feelings of attraction were non-mutual. Students felt most comfortable talking with their own therapist relative to either their supervisor or a colleague about these cases. When feelings of sexual attraction were mutual, students were much less comfortable referring out the client diagnosed with a histrionic personality disorder compared to the client diagnosed with an adjustment disorder. Students reported feeling comfortable discussing a client's feelings of sexual attraction with the client regardless of type of diagnosis and whether those feelings were mutual or non-mutual. Students were more comfortable continuing therapy when feelings of sexual attraction were non-mutual than mutual. Implications for training regarding management of these issues are discussed.
Millon Adolescent Substance-Abuse Proneness Scale: Identifying Clients in a Forensic Setting
PsycEXTRA Dataset, 2000
This study examined student perceptions of online teaching effectiveness in undergraduate courses... more This study examined student perceptions of online teaching effectiveness in undergraduate courses. End-of course evaluation data were collected from a sample of 2,750 online multisection courses taught within a 12 month period and comparisons were made between highly rated courses (at 4.5 or higher on a 5 point scale) and low rated courses (at 3.0 or lower). There was a significant difference in course evaluations as a function of academic rank, with slightly lower ratings for faculty at lower ranks relative to those at higher ranks. In general, online teaching experience and experience teaching the same course were both weak predictors of course evaluation outcomes. Overall, in highly rated courses instructors were: receptive to questions, responded promptly to emails, provided timely feedback, posted grades in a timely manner, and were perceived as active participants in the online class. Further findings and recommendations to assist faculty in understanding online teaching evalu...
Proceedings of the National Academy of Sciences, 1985
The functional consequences of interrupting in utero binocular interactions were studied by recor... more The functional consequences of interrupting in utero binocular interactions were studied by recording from single cells in area 17 of adult cats that had one eye removed at least 2 wk before birth. In these animals all cortical neurons could be driven by the remaining eye, and in tangential microelectrode penetrations, sequences of neurons containing a full 180-degree cycle of preferred orientations were en- countered. Other response properties of cortical neurons in the prenatally enucleated animals were also normal with the notable exception that the dimensions of receptive fields were significantly smaller when compared with those of control animals. Our results indicate that orientation columns in the visual cortex can develop independently of ocular dominance columns, and they suggest that interruption of binocular interactions during prenatal development of the visual path- ways may enhance the resolving power of the remaining eye.
Journal of Police and Criminal Psychology, 2007
Screening applicants for the position of peace officer is a very uncertain process. Concomitantly... more Screening applicants for the position of peace officer is a very uncertain process. Concomitantly, trying to select applicants who will be successful throughout their careers adds another, important dimension. Unfortunately, the selection process has primarily been one of screening-out those who are for one reason or another unfit. This article used the Thurstone Scale as the methodological basis to identify those traits that experts agreed are the ones that are meaningful in predicting police officer career success.
An analysis of the transport of WGA-HRP in the cat's visual system
Journal of Neuroscience Methods, 1984
The increasing use of WGA-HRP as a neuroanatomical tracer has led us to examine two aspects of it... more The increasing use of WGA-HRP as a neuroanatomical tracer has led us to examine two aspects of its uptake and transport. Microelectrophoretic deposits of WGA-HRP were centered in lamina A of the LGd to determine whether or not there is a discrepancy between the size of the deposit site and the effective uptake zone. For this purpose, the size of the deposit site was compared to the area of labeled ganglion cells in the retina. It was found that the effective uptake zone is approximately one half the size of the geniculate area containing reaction-product. Deposits of WGA-HRP in the optic tract, optic radiations and corpus callosum were made in order to determine if this tracer is incorporated and transported by intact fibers. In no case were labeled axon terminals or neuronal somata observed. However, application of the conjugated enzyme to cut fibers of the corpus callosum resulted in robust labeling.
The Journal of Comparative Neurology, 1991
The supplementary eye field (SEF) was defined electrophysiologically in behaving monkeys to study... more The supplementary eye field (SEF) was defined electrophysiologically in behaving monkeys to study its connections with the diencephalon and corpus striatum. The specificity of SEF pathways was determined with horseradish peroxidase (HRP) histochemistry to compare its connections with those of the arcuate frontal eye field (FEF), contiguous dorsocaudal area 6 (6DC), and primary motor cortex (Ml, arm/hand region). Results indicate that patterns of SEF connectivity were similar to the FEF and markedly different from areas 6DC and M1. Primary reciprocal thalamic pathways of the SEF were with the magnocellular ventral anterior (VA) nucleus, medial parvicellular VA, medial area X, and paralaminar medialis dorsalis (multiformis and parvicellularis). FEF showed similar connections but its most robust pathway was with MD rather than VA. In contrast, area 6DC showed the most extensive reciprocal connections with lateral VApc and lateral area X with only sparse connections with paralaminar MD. Area 6DC also exhibited reciprocal connections with the ventral lateral (VL) complex and the ventral posterior lateral nucleus, pars oralis (VPLo). M1 showed dense bidirectional connections with VPLo, and to a lesser extent, with VL. M 1 pathways with the medial dorsal nucleus were negligible. All areas exhibited connections with the paracentral and central lateral nuclei and only M1 lacked connections with the central superior lateral nucleus. SEF and FEF exhibited similar efferent projections to the caudate and putamen. In the caudate, terminal fields were restricted to a central longitudinal core while those from area 6DC were more widely distributed. Eye field efferents were restricted to the putamen's face region while 6DC projections were more exuberant. The armhand region of M1 projected to the armihand region of the putamen. Pathways are discussed with respect to their significance in oculomotor control.
The Journal of Comparative Neurology, 1990
WGA-HRP was used to examine projections to the brainstem from the supplementary eye field (SEF). ... more WGA-HRP was used to examine projections to the brainstem from the supplementary eye field (SEF). The SEF was defined electrophysiologically in awake, behaving monkeys and connections were compared to those of the arcuate frontal eye field (FEF), area 6DC, and primary motor cortex. The SEF was found to have either direct or indirect connections with almost every known pre-and paraoculomotor structure of the brainstem. The SEF was found to project bilaterally to layers I and IV of a tangentially widespread region of the superior colliculus. Terminal label was evident in the pretectal olivary nucleus, nucleus of the optic tract, nucleus raphe interpositus (omnipause region), nucleus prepositus hypoglossi, the perioculomotor cap of the central gray, dorsal central gray, nucleus reticularis tegmenti pontis, nucleus reticularis pontis oralis, and to multiple nuclei of the basis pontis (most densely to the dorsomedial nucleus). Bilateral projections were found in the parvicellular red nucleus. Reciprocal connections were present in the nucleus limitans, the mesencephalic reticular formation, locus coeruleus, and the serotonergic nuclei of the raphe complex (dorsalis and central superior). Overall patterns of connectivity were similar to those of the FEF and markedly different from those of the contiguous dorsocaudal area 6 or primary motor cortex. It was concluded that observed patterns of SEF-brainstem connectivity further justifies viewing this region as a distinct eye field that is likely to serve preparatory and trigger functions in the generation of saccadic eye movements.
Experimental Neurology, 1991
Experimental Brain Research, 1988
Using WGA-HRP we have demonstrated that a direct projection links the supplementary eye field, bu... more Using WGA-HRP we have demonstrated that a direct projection links the supplementary eye field, but not the more caudal aspect of the supplementary motor area, to the brain stem omnipause region. Findings are discussed in relation to oculomotor control.
Experimental Brain Research, 1989
Schlag, John, Alexandre Pouget, Safa Sadeghpour, and Madenow can be systematically modified. It i... more Schlag, John, Alexandre Pouget, Safa Sadeghpour, and Madenow can be systematically modified. It is deviated in the leine Schlag-Rey. Interactions between natural and electrically direction opposite to the movement just accomplished, thus evoked saccades. III. Is the nonstationarity the result of an integraappearing to correct (or compensate for) at least part of the tor not instantaneously reset? J Neurophysiol. 79: 903-910, 1998. preceding displacement. For instance, if the initial saccade In the monkey, fixed-vector saccades evoked by superior colliculus is directed upward and rightward, the electrically evoked (SC) stimulation when the animal fixates can be dramatically modsaccade will be less upward and less rightward than the ified if the stimulation is applied during or immediately after an control elicited from a steady position (see Fig. ). Stimulatinitial natural saccade. The vector is then deviated in the direction ing the superior colliculus (SC), Robinson (1972) first noopposite to the displacement just accomplished as if it were comticed this deviation and ascribed it to refractoriness, without pensating for part of the preceding trajectory. Recently, it was suggested that the amplitude of the compensatory deviation is re-implying any specific physiological mechanism. Initially, we lated to the amplitude of the initial saccade linearly, and that the called the observed change of trajectory ''compensatory'' ratio between the two decreases exponentially as stimulation is , following Sparks and Mays applied later. These two findings (spatial linearity and temporal (1983) who studied the effect of collicular stimulation on nonstationarity) were invoked as evidence for the noninstantaneous natural saccades (i.e., the same paradigm in reverse order) resetting of a feedback integrator. Such an integrator is included and reported practically the same type of change. The term in most models of saccade generation for the specific purpose of compensation immediately evokes the direction in which terminating a saccade when it has reached its intended goal. Howthe course correction is made (i.e., opposite to the initial ever, the hypothesis of a feedback integrator in the process of movement). Compensation is reliable and, eventually, can being reset implies that the exponential decay of the compensatory result in an inversion of the fixed-vector. This effect has deviation is temporally linked to the end of the initial saccade. We been proposed as the basis of a test to probe mechanisms analyzed the time course of this decay in stimulation experiments performed at 24 SC sites in two monkeys. The results show that of saccade elicitation in various brain structures (Schlag and if the start of the exponential decay of compensation is assumed Schlag-Rey 1990).
Transplantation of Fetal Frontal Cortex onto Degenerating Thalamus of Cats and Kittens
Developmental Neuroscience, 1990
Tissue from fetal frontal cortex survived after transplantation onto the surface of the left thal... more Tissue from fetal frontal cortex survived after transplantation onto the surface of the left thalamus in 2 kittens and 2 adult cats which 7 days previously had sustained a left cerebral hemispherectomy. There were nerve fiber connections with host tissue (WGA-HRP, Loyez myelin stain) only in the neonatal animals. The grafts contained surviving neurons in all but in one adult cat which survived 301 days. The grafts had little effects on the retrograde ventral thalamic degeneration typically seen following hemispherectomy. However, the dorsal lateral geniculate nucleus adjacent to the transplants showed reduced neuronal loss and gliosis compared to controls. Magnetic resonance imaging was successfully used to visualize the grafts in vivo and suggested a decrease in size as well as changes in composition for a graft systematically followed for 120 days posttransplantation. Cytochrome oxidase histochemistry indicated sustained metabolic activity in transplants containing surviving neurons. This study introduces the cat as a useful model for brain tissue transplantation in a classical, myelinated sensorimotor system.
Developmental Brain Research, 1986
The organization of geniculostriate connections in normal cats was compared with that of adult an... more The organization of geniculostriate connections in normal cats was compared with that of adult animals that were uniocularly enucleated before birth. In normal animals microelectrophoretic deposits of horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) into the A-lamina of the dorsal lateral geniculate body (LGd) resulted in anterograde label in layers IV and VI and labeled cells in layer VI of areas 17 and 18. The labeling pattern within both of these cortical areas consisted of alternating patches separated by zones of equivalent size that were relatively free of label. In the normal animals no reaction product was evident in any other cortical area. In the prenatally enucleated cats, the LGd both contralateral and ipsilateral to the remaining eye is comprised of only two distinct cell layers. The dorsal layer appears to be a composite of the normal A/Al-laminae, while the ventral layer appears to correspond to the C-laminae. Deposits of WGA-HRP into the superficial aspect of the A/A1 layer yielded a dense continuous band of label within layers IV and V! of areas 17 and 18. Additionally, such deposits in the prenatally enucleated cats also revealed an anomalous reciprocal connection with area 19. Punctate deposits of WGA-HRP into cortical area 19 of the fetal enucleates resulted in the labeling of two distinct populations of cells within the A/A1 layer of the LGd. No cells were labeled within the A-laminae following such deposits into area 19 of normal animals. The geniculocortical connections of the prenatally enucleated cats, including that to area 19, were found to be retinotopically organized. These results indicate that in utero interruption of binocular interactions prevents the formation of ocular dominance domains within areas 17 and 18 of the cat's visual cortex. This could reflect the maintenance of exuberant geniculocortical projections present at the time of prenatal eye removal as originally suggested by Rakic (Science, 214 (1981) 928-931). The anomalous connection with area 19, on the other hand, could be due to the disruption of LGd cell migration resulting from the early eye removal.
Traumatic brain injury produces impairments in long-term and recent memory
Brain Research, 1993
Traumatic brain injury (TBI) in humans typically produces neurological suppression and a longer l... more Traumatic brain injury (TBI) in humans typically produces neurological suppression and a longer lasting impairment of memory clinically defined as post-traumatic amnesia. An animal model that reliably reproduces the physiological changes associated with TBI was used to assess the memory deficits following brain injury. Prior to TBI, rats were trained to perform one of four tasks that assessed either motor performance, long-term or recent memory. Rats were randomly assigned to one of three groups (anesthesia only, sham operation or fluid percussion). Following fluid percussion, used to produce TBI, rats were tested for 6 test sessions. The first session occurred 1-2 min after the experimental manipulation. The next 5 sessions followed the training schedule maintained prior to experimental manipulation. Differences in long-term memory occurred only in the first post-operative test session. Differences in recent memory performance were found across all 6 test sessions. The memory deficits were clearly dissociated from motor deficits. The similar memory deficits observed following human head injury and the experimentally produced TBI injury demonstrate that fluid percussion is a useful approach to examine underlying neurobiological mechanisms involved in head injury and possible clinical interventions.
Functional Organization of the Gerbil's Visual system: A move to revise traditional working hypotheses of Brain Organization
ABSTRACT Thesis (Ph. D.)--Brandeis University, 1982. "UMI: 8318248." Includes b... more ABSTRACT Thesis (Ph. D.)--Brandeis University, 1982. "UMI: 8318248." Includes bibliographical references (p. 180-221). Photocopy.
Experimental Neurology, 1991