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Title: Effects of Electrolytic Lesions of the Reuniens and Rhomboid Nuclei on cognitive behaviors using the Intradimensional Extradimensional (IED) task in Rats.
Creator: Ellis, Randy, Pinedo, Patricia, Vertes, Robert P.
Abstract/Description: Reuniens and rhomboid nuclei (RE/RH) of the ventral midline thalamus compose a relay between the medial prefrontal cortex (mPFC) and the hippocampus (HPC). Recent behavioral studies have shown that RE/RH is critical in cognitive tasks that involve both the HPC and mPFC. Lesion and inactivation studies of the RE/RH, however, do not affect hippocampal dependent spatial behaviors. Here, we examined the effects of electrolytic lesions of RE/RH on an odor-texture discrimination task sensitive to...
Show moreReuniens and rhomboid nuclei (RE/RH) of the ventral midline thalamus compose a relay between the medial prefrontal cortex (mPFC) and the hippocampus (HPC). Recent behavioral studies have shown that RE/RH is critical in cognitive tasks that involve both the HPC and mPFC. Lesion and inactivation studies of the RE/RH, however, do not affect hippocampal dependent spatial behaviors. Here, we examined the effects of electrolytic lesions of RE/RH on an odor-texture discrimination task sensitive to faculties of orbitomedial prefrontal cortices. Rats with RE/RH lesions exhibited small deficits in reversal stages compared to controls. Reversal learning has been found to be anatomically and chemically dependent on normal functioning of the prefrontal cortex. Excitatory input from reuniens to the prefrontal cortex may be involved in mediating behavioral flexibility, the lack of which is a symptom of behavioral disorders such as Alzheimer’s and Parkinson’s diseases.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA0005013
Subject Headings: College students --Research --United States.
Format: Document (PDF)

Title: NR2C in the Thalamic Reticular Nucleus; Effects of the NR2C Knockout.
Creator: Zhang, Yuchun, Buonanno, Andres, Vertes, Robert P., Hoover, Walter B., Lisman, John E., Zhang, Zhe
Abstract/Description: NMDAR antagonists can evoke delta frequency bursting in the nucleus reticularis of the thalamus (nRT). The mechanism of this oscillation was determined; antagonist blocks an NR2C-like conductance that has low Mg block at resting potential and thus can contribute a resting inward current in response to ambient glutamate. Block of this current hyperpolarizes the cell, deinactivating T-type Ca channels and thus triggering delta frequency bursting. The basis for assuming a NR2C-like conductance...
Show moreNMDAR antagonists can evoke delta frequency bursting in the nucleus reticularis of the thalamus (nRT). The mechanism of this oscillation was determined; antagonist blocks an NR2C-like conductance that has low Mg block at resting potential and thus can contribute a resting inward current in response to ambient glutamate. Block of this current hyperpolarizes the cell, deinactivating T-type Ca channels and thus triggering delta frequency bursting. The basis for assuming a NR2C-like conductance was that (1) transcripts for NR2C are abundant in the thalamus and (2) the current-voltage curve of the synaptically evoked NMDAR current has the low rectification characteristic of NR2C. In the current study, we have sought to determine whether the channels that generate the NMDAR current are NR2C-like or are actually comprised of receptors containing NR2C. We studied the current-voltage curve of synaptically evoked NMDAR current in the nRT of NR2C knockout mice. In wild-type mice, the current was weakly voltage dependent, as previously observed in rats. This weak rectification was absent in NR2C KO mice. In contrast, NR2C KO had no effect on the strongly rectifying NMDAR current in pyramidal cells of the prefrontal cortex. These results demonstrate that the low rectification normally observed in the nRT is due to NR2C.
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Date Issued: 2012-07-25
PURL: http://purl.flvc.org/fau/fd/FAUIR000089
Format: Citation

Title: The Effect of Inactivation of the Nucleus Reuniens on Spatial Working Memory.
Creator: Martinez Rey, Macarena, Minnerly, Christopher, Vertes, Robert P., Office of Undergraduate Research and Inquiry
Abstract/Description: The Nucleus Reuniens (RE) of the ventral midline thalamus has been shown to have extensive reciprocal innervations with the medial prefrontal cortex (mPFC) and the hippocampus (HF) in the brain of the rat. Both structures are essential for encoding, retrieval, and delayed spatial working memory. The (RE) is believed to play a vital role in facilitating cognitive function and affective behavior and has been shown to be critical for a variety of working memory tasks. In this study we tested...
Show moreThe Nucleus Reuniens (RE) of the ventral midline thalamus has been shown to have extensive reciprocal innervations with the medial prefrontal cortex (mPFC) and the hippocampus (HF) in the brain of the rat. Both structures are essential for encoding, retrieval, and delayed spatial working memory. The (RE) is believed to play a vital role in facilitating cognitive function and affective behavior and has been shown to be critical for a variety of working memory tasks. In this study we tested Long Evan rats using a T-maze. For each trial the rats were required to alternate between the left and right goal arms with a delay period in between randomized intervals of 30s, 60s, or 120s. After two consecutive testing days of 80% the rats were infused with muscimol procaine, and saline. We expect that the effect of reversible inactivation of RE will demonstrate a significant decline in performance of the task.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00005588
Subject Headings: College students --Research --United States.
Format: Document (PDF)

Title: Afferent projections to rhomboid nucleus of thalamus.
Creator: Owens, Michelle Ann, Florida Atlantic University, Vertes, Robert P.
Abstract/Description: The midline thalamus of rats is anatomically and functionally part of the "limbic" thalamus. The midline thalamic rhomboid nucleus (RH) has not been well characterized. The rhomboid nucleus is located just dorsal to the reuniens nucleus (RE), and just ventral to the central medial nucleus (CeM) of the thalamus. Using the retrograde tracer fluorogold (FG) and anti-FG antibody, we examined afferent projections to RH in the rat. Control injections were also made in CeM and the submedial nucleus...
Show moreThe midline thalamus of rats is anatomically and functionally part of the "limbic" thalamus. The midline thalamic rhomboid nucleus (RH) has not been well characterized. The rhomboid nucleus is located just dorsal to the reuniens nucleus (RE), and just ventral to the central medial nucleus (CeM) of the thalamus. Using the retrograde tracer fluorogold (FG) and anti-FG antibody, we examined afferent projections to RH in the rat. Control injections were also made in CeM and the submedial nucleus of thalamus (SMT). The main sources of input to RH were from the anterior cingulate, agranular insular, orbital, and somatosensory cortices; the claustrum; the reticular nucleus of the thalamus; the posterior hypothalamus; and various brainstem structures. Based on patterns of the afferent projections, the role of RH in arousal, attention, and mnemonic functions is discussed.
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Date Issued: 2005
PURL: http://purl.flvc.org/fcla/dt/13220
Subject Headings: Rats as laboratory animals, Rats--Nervous system, Thalamus--Research, Rats--Embryology, Afferent pathways, Perceptual-motor processes, Sensorimotor integration
Format: Document (PDF)

Title: A PHA-L analysis of projections from the nucleus reticularis pontis oralis, the pedunculopontine tegmental nucleus and the median raphe nucleus in the rat: Implications for the modulation of the hippocampal EEG.
Creator: Fortin, William J., Florida Atlantic University, Vertes, Robert P.
Abstract/Description: Projections of the nucleus reticularis pontis oralis (RPO), the pedunculopontine tegmental nucleus (PPT) and the median raphe nucleus (MR) were examined using the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). The RPO projected strongly throughout the reticular core, to the PPT and to the intralaminar thalamic nuclei. Light projections were observed in the posterior hypothalamus but not the supramammillary nucleus. The pattern of labeling suggests that the RPO is arranged...
Show moreProjections of the nucleus reticularis pontis oralis (RPO), the pedunculopontine tegmental nucleus (PPT) and the median raphe nucleus (MR) were examined using the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). The RPO projected strongly throughout the reticular core, to the PPT and to the intralaminar thalamic nuclei. Light projections were observed in the posterior hypothalamus but not the supramammillary nucleus. The pattern of labeling suggests that the RPO is arranged topographically in longitudinal columns. The PPT projected to the RPO, MR, medial thalamic and intralaminar nuclei, the supramammillary nucleus and septum. The MR was found to project heavily to the supramammillary nucleus, intralaminar thalamic nuclei, the septum, the hippocampus and several cortical areas. The results are discussed in terms of the modulation of hippocampal EEG and a model is introduced emphasizing interactions among ascending hippocampal EEG synchronizing and desynchronizing systems.
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Date Issued: 1995
PURL: http://purl.flvc.org/fcla/dt/15185
Subject Headings: Hippocampus (Brain), Electroencephalography, Rats as laboratory animals
Format: Document (PDF)

Title: The supramammillary nucleus: Does it play a role in the mediation of hippocampal theta rhythm?.
Creator: Thinschmidt, Jeffrey Scott., Florida Atlantic University, Vertes, Robert P.
Abstract/Description: Recent evidence suggests that the supramammillary nucleus (SUM) is an important link from the pontine reticular formation (PRF) to the septum-hippocampus in the generation of hippocampal theta rhythm. I proposed: (1) injections of WGA-HRP into the SUM would produce retrograde labeling in PRF cells; (2) lesions of the SUM would produce a reduction in the frequency and amplitude of hippocampal theta rhythm; (3) injections of procaine into the SUM would attenuate the amplitude and reduce the...
Show moreRecent evidence suggests that the supramammillary nucleus (SUM) is an important link from the pontine reticular formation (PRF) to the septum-hippocampus in the generation of hippocampal theta rhythm. I proposed: (1) injections of WGA-HRP into the SUM would produce retrograde labeling in PRF cells; (2) lesions of the SUM would produce a reduction in the frequency and amplitude of hippocampal theta rhythm; (3) injections of procaine into the SUM would attenuate the amplitude and reduce the frequency of reticular elicited theta rhythm. Although WGA-HRP injections in the SUM produced minimal labeling in the PRF, there were labeled cells in the central gray of the pons, and in the dorsal raphe and surrounding regions. I found that lesions of the SUM produced minimal changes in the frequency and amplitude of theta in the behaving animal but that injections of procaine attenuated both of these measures in the urethane anesthetized rat.
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Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14919
Subject Headings: Theta rhythm, Hippocampus (Brain), Memory
Format: Document (PDF)

Title: Rhythmicity, synchrony and resonance within the circuit of Papez.
Creator: Albo Angelus, Zimbul, Florida Atlantic University, Vertes, Robert P.
Abstract/Description: Single unit activity from the anterior thalamus (AT) was recorded in order to investigate discharge profiles during desynchronized (large amplitude irregular activity (LIA)), and synchronized (theta rhythm) patterns of the hippocampal EEG. Units were recorded in urethane-anesthetized rats in the anteroventral (AV, n = 96), the anterodorsal (AD, n = 44) and the anteromedial (AM, n = 48) thalamic nuclei. The majority of the units (n = 164, 87%) were theta-on and a small group (n = 24, 13%) was...
Show moreSingle unit activity from the anterior thalamus (AT) was recorded in order to investigate discharge profiles during desynchronized (large amplitude irregular activity (LIA)), and synchronized (theta rhythm) patterns of the hippocampal EEG. Units were recorded in urethane-anesthetized rats in the anteroventral (AV, n = 96), the anterodorsal (AD, n = 44) and the anteromedial (AM, n = 48) thalamic nuclei. The majority of the units (n = 164, 87%) were theta-on and a small group (n = 24, 13%) was theta-off. Theta-off cells were found in AD and AM nuclei but not in AV. Theta-on cells increased their discharge in presence of hippocampal theta. Mean discharge rate was 6.0 +/- 0.52 Hz and 14.48 +/- 0.96 Hz for AV theta-on cells during control and theta states, 4.43 +/- 0.52 Hz and 10.05 +/- 1.28 Hz for AD theta-on cells, and 2.60 +/- 0.3 Hz and 6.42 +/- 0.9 Hz for AM theta-on cells, respectively. We found that 40% of AV cells showed a rhythmic pattern that peaked significantly at 250--270 ms during theta, 21.9% of AD units and only 5.7% for AM units showed a rhythmic pattern. The majority of AT cells showed unit-theta phase-locked EEG oscillations in the crosscorrelogram, indicating that in spite of low rhythmicity most units firing were modulated at theta frequency. The coherence measured by spectral analysis between unit firing and hippocampal theta was statistically significant in 75% of cases. The anatomical distribution of the cells shows that coherence values were widely distributed across the anterior thalamus. In addition, the particular contribution of this diencephalic structure during theta was determined by applying measures of information flow in the neural circuit of Papez. Partial coherence (PC) analysis together with the computation of causality measures (DTF and DC) was used to study such interaction among AV, retrosplenial cortex and hippocampus. PC analysis revealed hippocampus as the synchronizing structure for rhythmic AV cells and retrosplenial cortex. A link between hippocampus and retrosplenial cortex was found for the non-rhythmic AV group. The DTF analysis showed flow of propagation from AV to hippocampus, hippocampus to retrosplenial cortex and AV to retrosplenial cortex for both groups. The strength of connection changed depending on the state of the animal. Behaviors that have been particularly related to the hippocampal theta activity refer mainly to learning and memory. Activation of large numbers of septo-hippocampal neurons during the generation of the theta rhythm has been proposed as a 'natural tetanizer'. Numerous cellular studies have linked long-term potentiation (LTP) and the hippocampal theta rhythm. The role of theta in memory has been evidenced through lesion studies in animals. Some observations in humans have proposed the anterior thalamus as pivotal for spatial memory. Perhaps the cellular theta activity found in AV plays an important role in the generation and control of the hippocampal theta rhythm and hence in memory and learning.
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Date Issued: 2002
PURL: http://purl.flvc.org/fcla/dt/11976
Subject Headings: Neural circuitry, Electroencephalography, Hippocampus (Brain)
Format: Document (PDF)

Title: Behavioral and Electrophysiological Properties of Nucleus Reuniens: Role in Arousal, Spatial Navigation and Cognitive Processes.
Creator: Viena, Tatiana Danela, Vertes, Robert P., Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: The hippocampal-medial prefrontal circuit has been shown to serve a critical role in decision making and goal directed actions. While the hippocampus (HF) exerts a direct influence on the medial prefrontal cortex (mPFC), there are no direct return projections from the mPFC to the HF. The nucleus reuniens (RE) of the midline thalamus is strongly reciprocally connected with the HF and mPFC and represents the major link between these structures. We investigated the role of RE in functions...
Show moreThe hippocampal-medial prefrontal circuit has been shown to serve a critical role in decision making and goal directed actions. While the hippocampus (HF) exerts a direct influence on the medial prefrontal cortex (mPFC), there are no direct return projections from the mPFC to the HF. The nucleus reuniens (RE) of the midline thalamus is strongly reciprocally connected with the HF and mPFC and represents the major link between these structures. We investigated the role of RE in functions associated with the hippocampus and the mPFC -- or their interactions. Using two different inactivation techniques (pharmacological and chemogenetic), we sought to further define the role of RE in spatial working memory (SWM) and behavioral flexibility using a modified delayed non-match to sample (DNMS) working memory task. We found that the reversible inactivation of RE with muscimol critically impaired SWM performance, abolished well-established spatial strategies and produced a profound inability to correct non-rewarded, incorrect choices on the T-maze (perseverative responding). We observed similar impairments in SWM following the chemogenetic (DREADDs) inactivation of RE or selective RE projections to the ventral HF. In addition, we showed that the inhibition of RE terminals to the dorsal or ventral HF altered task related behaviors by increasing or decreasing the time to initiate the task or reach the reward, respectively. Finally, we examined discharge properties of RE cells across sleep-wake states in behaving rats. We found that the majority of RE cells discharge at high rates of activity in waking and REM and at significantly reduced rates in SWS, with a subpopulation firing rhythmically in bursts during SWS. We identified five distinct subtypes of RE cells that discharged differently across vigilant states; those firing at highest rates in waking (W1, W2), in REM sleep (R1, R2) and SWS (S1). Given the differential patterns of activity of these cells, we proposed they may serve distinct functions in waking – and possibly in SWS/REM sleep. In sum, our findings indicate that RE is critically involved in mnemonic and executive functions and the heterogeneous activity of these cells support a role for RE in arousal/attention, spatial working memory and cognition.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013139
Subject Headings: Midline Thalamic Nuclei, Hippocampus, Prefrontal cortex, Neural pathways, Arousal (Physiology), Space Perception, Cognition
Format: Document (PDF)

Title: The Limbic Thalamus.
Creator: Hoover, Walter Boyd III, Florida Atlantic University, Vertes, Robert P., Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
Abstract/Description: The thalamus has been traditionally viewed as a structural relay to specific cortical areas behaviorally associated with sensory or motor functions, and thalamic nuclei that function in this manner are referred to as 'relay nuclei·. However. the parts of the thalamus interconnecting limbic association cortices (functionally involved in memory. reward, emotion. and decision making) comprise the midline and intralaminar nuclei. The midline thalamus has not been examined fully at the anatomical,...
Show moreThe thalamus has been traditionally viewed as a structural relay to specific cortical areas behaviorally associated with sensory or motor functions, and thalamic nuclei that function in this manner are referred to as 'relay nuclei·. However. the parts of the thalamus interconnecting limbic association cortices (functionally involved in memory. reward, emotion. and decision making) comprise the midline and intralaminar nuclei. The midline thalamus has not been examined fully at the anatomical, physiological. or behavioral level, and may serve as an important relay between cortical and subcortical structures and the limbic system. The work incorporated into this dissertation included five axonal tract tracing projects that were conducted in the rat. to explore and test the hypothesis that the midline thalamus serves as an important interface between limbic structures including the amygdala. nucleus accumbens. medial prefrontal cortex and hippocampal formation. An important finding was the demonstration of a closed anatomical loop between the hippocampal formation, the ventral medial prefrontal cortex and the ventral midline thalamus: CA 1/subiculum > PLIIL > RE > CA 1/subiculum. Another finding was that 1) the hippocampal formation innervates the entire medial prefrontal cortex; and 2) the hippocampal formation projects more heavily to ventral as compared to dorsal cortices in the mPFC. The paraventricular, parataenial, rhomboid and reuniens nuclei of the midline thalamus were shown to distribute to limbic structures important for cognitive processing: the amygdala, nucleus accumbens, hippocampal formation, parahippocampal cortex, and the prefrontal cortex. Present results demonstrate that the ventral midline nuclei (reuniens and rhomboid) extensively innervate limbic cortical structures (the medial prefrontal cortex and hippocampal formation) whereas dorsal midline nuclei (paraventricular and parataenial) distribute more heavily to subcortical limbic structures (the amygdala and the nucleus accumbens). These midline nuclei may, therefore, relay information between these limbic areas. This connectivity suggests that the midline nuclei could further be subdivided from the intralaminar and relay groups. The midline thalamic nuclei would, therefore, comprise the limbic thalamus.
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Date Issued: 2007
PURL: http://purl.flvc.org/fau/fd/FA00000861
Subject Headings: Neuroanatomy, Limbic system--Physiology, Prefrontal cortex--Physiology, Thalamus--Physiology, Neurotransmitter receptors
Format: Document (PDF)

Title: The brain decade in debate: VII. Neurobiology of sleep and dreams.
Creator: Aloe, F., Amzica, F., Hening, W., Menna-Barreto, L., Pinto Jr., L.R., Velluti, R., Vertes, Robert P., Timo-Iaria, C.
Date Issued: 2001-12
PURL: http://purl.flvc.org/fau/fd/FAUIR000196
Format: Citation

FAU Theses and Dissertations (6)	+ -
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