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Title: Unveiling the involvement of the rodent dorsal hippocampus in object recognition memory & investigating the role of context.
Creator: Cohen, Sarah J., Munchow, Alcira H., Asgeirsdottir, Herborg Nanna, Stackman, Robert W., Graduate College
Date Issued: 2013-04-12
PURL: http://purl.flvc.org/fcla/dt/3361918
Subject Headings: Hippocampus (Brain), Rodents, Memory
Format: Document (PDF)

Title: Hippocampal involvement in object recognition memory.
Creator: Velez, Elisa M., Cohen, Sarah J., Stackman, Robert W.
Date Issued: 2013-04-05
PURL: http://purl.flvc.org/fcla/dt/3361221
Subject Headings: Hippocampus (Brain), Spatial ability
Format: Document (PDF)

Title: Hippocampal place cell activity influenced by variations of the novel object recognition task in C57BL/6J mice.
Creator: Asgeirsdottir, Herborg Nanna, Cohen, Sarah J., Zhang, Gongliang, Munchow, Alcira H., Stackman, Robert W., Graduate College
Date Issued: 2013-04-12
PURL: http://purl.flvc.org/fcla/dt/3361265
Subject Headings: Hippocampus (Brain), Neurons, Mice
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: Analysis of nucleus reuniens cell behavior during hippocampal theta rhythm.
Creator: Morales, George J., Florida Atlantic University, Morgera, Salvatore D., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description: Coherence estimates have been used to determine the presence of functional coupling between two signals. While direct projections from the nucleus reuniens (RE) to the hippocampus formation in the rat have been discovered, little is known about the possible functional influence of the RE on the hippocampus. This investigation makes use of MATLAB to create a set of specialized algorithms to investigate coherence function estimates between RE cell activity and hippocampal EEG. In addition,...
Show moreCoherence estimates have been used to determine the presence of functional coupling between two signals. While direct projections from the nucleus reuniens (RE) to the hippocampus formation in the rat have been discovered, little is known about the possible functional influence of the RE on the hippocampus. This investigation makes use of MATLAB to create a set of specialized algorithms to investigate coherence function estimates between RE cell activity and hippocampal EEG. In addition, error prevention considerations as well as shortcomings in current data acquisition software that ultimately lead to the necessity for additional software analysis tools are also discussed. An investigation into RE cell behavior requires the calculation of cell activity spike rates as well as the identification of action potential bursting phenomena. Isolation of individual cell activity, from a population recording channel, is needed in order to prevent erroneous effects associated with using unresolved multi-neuron recordings. Changes in spike rate activity and frequency of bursting occurrences are calculated as a means of gauging RE unit response to the presence of a stimulus (e.g., tail pinch). The relationship of RE units on hippocampal EEG by analysis of coherence function estimates between RE units and hippocampal EEG, as well as evaluated RE unit behavior in terms of changes in unit spike rate and bursting activity are established.
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Date Issued: 2006
PURL: http://purl.flvc.org/fcla/dt/13383
Subject Headings: Hippocampus (Brain), Electroencephalography, Neurosciences, Theta rhythm, Memory
Format: Document (PDF)

Title: DORSAL HIPPOCAMPAL LESIONS AND REWARD MAGNITUDE SHIFTS IN RATS.
Creator: NUNEZ, ANTONIO ALBERTO., Florida Atlantic University
Abstract/Description: Rats with bilateral, electrolytic, dorsal-hippocampal lesions were compared with operated controls in a straight runway to assess the effects of the lesion on the animals' reactions to food-incentive shifts. Within each surgical group, half the animals received 40 preshift trials with low reward while the other half received the same number of trials with high reward, following this all Ss were shifted to the opposite reward magnitude and received 40 additional trials. At this point, the Ss...
Show moreRats with bilateral, electrolytic, dorsal-hippocampal lesions were compared with operated controls in a straight runway to assess the effects of the lesion on the animals' reactions to food-incentive shifts. Within each surgical group, half the animals received 40 preshift trials with low reward while the other half received the same number of trials with high reward, following this all Ss were shifted to the opposite reward magnitude and received 40 additional trials. At this point, the Ss were shifted back to original reward magnitudes for another 40 trials. Finally, all Ss underwent experimental extinction. The data failed to support the hypothesis that dorsal hippocampal rats "overreact" to incentive shifts. Lesion animals, as compared to controls, were less sensitive to the reward shifts and showed more resistance to extinction. The results suggest that the lesion produces a deficit in the Ss ability to vary behavior specially on tasks that require response decrements. However, the lesion-produced hyperactivity introduced confounding aspects to this interpretation.
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Date Issued: 1973
PURL: http://purl.flvc.org/fcla/dt/13539
Subject Headings: Hippocampus (Brain), Extinction (Psychology), Reward (Psychology)
Format: Document (PDF)

Title: THE EFFECT OF DORSAL HIPPOCAMPAL LESIONS ON THE SEXUAL BEHAVIOR OF THE MALE RAT.
Creator: MILLS, JEANNE THERESA, Florida Atlantic University
Abstract/Description: Performance on three preoperative and three postoperative copulation tests was compared for male rats given dorsal hippocampal, dorsal hippocampal plus cortical, other lesion, and sham lesions. Dorsal hippocampal lesions produced statistically significant changes in the temporal pacing of some components of sexual behavior, i.e. the post-ejaculatory interval, intercopulatory interval, and total test time decreased. Hippocampal plus cortical lesions had no effect on sexual behavior. The...
Show morePerformance on three preoperative and three postoperative copulation tests was compared for male rats given dorsal hippocampal, dorsal hippocampal plus cortical, other lesion, and sham lesions. Dorsal hippocampal lesions produced statistically significant changes in the temporal pacing of some components of sexual behavior, i.e. the post-ejaculatory interval, intercopulatory interval, and total test time decreased. Hippocampal plus cortical lesions had no effect on sexual behavior. The results are interpreted as supporting a model of inhibition in which a sexual inhibitory process is built up concomitantly with the sexual arousal process.
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Date Issued: 1975
PURL: http://purl.flvc.org/fcla/dt/13700
Subject Headings: Hippocampus (Brain), Sexual behavior in animals
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: In vivo administration of a subtype selective activator of small conductance Ca2+ - activated K+ channels influences hippocampal-dependent spatial memory.
Creator: Beck, Robert, Kuchera, Claire Rice, Munchow, Alcira H., Stackman, Robert W., Graduate College
Date Issued: 2013-04-12
PURL: http://purl.flvc.org/fcla/dt/3361271
Subject Headings: Calcium-dependent potassium channels, Hippocampus (Brain), Mice, Memory
Format: Document (PDF)

Title: Hippocampal neurogenesis in the SERT ALA56 mouse model to autism.
Creator: Di Mase, Julieta Maria, Guthrie, Kathleen, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The causes of autism spectrum disorder (ASD) are not all known, but it is suspected that the serotonin transporter (SERT) plays an important role for some subjects with ASD. Mutations in the SLC6A4 gene, that encodes SERT, including the Ala56 mutation (Gly56Ala), have been found in some autism patients. This mutation makes the transporter more active and reduces the probability of serotonergic neurotransmission in the brain, which is linked to behavioral changes that are associated with core...
Show moreThe causes of autism spectrum disorder (ASD) are not all known, but it is suspected that the serotonin transporter (SERT) plays an important role for some subjects with ASD. Mutations in the SLC6A4 gene, that encodes SERT, including the Ala56 mutation (Gly56Ala), have been found in some autism patients. This mutation makes the transporter more active and reduces the probability of serotonergic neurotransmission in the brain, which is linked to behavioral changes that are associated with core domain deficits of ASD 1. Depression also has been linked to decreases in the availability of serotonin (5-hydroxytryptamine; 5-HT) in the central nervous system (CNS), and is associated with reduced hippocampal neurogenesis. Selective serotonin reuptake inhibitors (SSRIs), drugs used to block SERTs, are used to treat depression and/or anxiety by inhibiting SERT to increase synaptic 5-HT levels.
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Date Issued: 2019
PURL: http://purl.flvc.org/fau/fd/FA00013297
Subject Headings: Autism Spectrum Disorder, Hippocampus, Neurogenesis, Serotonin Plasma Membrane Transport Proteins
Format: Document (PDF)

Title: Behavioral and Electrophysiological Evidence for Hippocampal Involvement in Object Motion Processing in C57BL/6J Mice.
Creator: Asgeirsdottir, Herborg Nanna, Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Considerable research has been carried out to establish a rodent model for the study of human memory, yet functional similarities between the species remain up for debate. The hippocampus, a region deep within the medial temporal lobe of the mammalian CNS, is critical for long-term episodic memory. Projections from the medial entorhinal cortex convey spatial/contextual information, while projections from the lateral entorhinal cortex convey item/object information to the hippocampus. The...
Show moreConsiderable research has been carried out to establish a rodent model for the study of human memory, yet functional similarities between the species remain up for debate. The hippocampus, a region deep within the medial temporal lobe of the mammalian CNS, is critical for long-term episodic memory. Projections from the medial entorhinal cortex convey spatial/contextual information, while projections from the lateral entorhinal cortex convey item/object information to the hippocampus. The functional significance of these parallel projections to the rodent hippocampus has been suggested to support spatial processing, while the same projections to the human hippocampus support spatial and non-spatial memory. Discharging in a location-specific manner, hippocampal place cells contribute to spatial memory; however, evidence for neuronal correlates of non-spatial object memory has not been fully defined. The current experiments were designed to address the following questions, while utilizing electrophysiology, functional inactivation during a novel behavioral task, and immunohistochemistry. Is the memory for objects hippocampal-dependent, solely due to the location of the object, or are objects represented within hippocampal activity independent of location? To tease apart spatial and non-spatial processing by the hippocampus, the spatial aspects of 3D objects were enhanced by utilizing movement. A novel discriminatory avoidance task, Knowing Your Enemy, was adapted from an Enemy Avoidance task to test true object memory in mice. Current findings support the notion that object-associations acquisition depends upon a specific context. Retrieval of such object-associations is not context-dependent, yet remains sensitive to temporary inactivation of the CA1 region of the dorsal hippocampus. The avoidance impairments observed following hippocampal inactivation were shown to not be a result of reduced anxiety. Immunohistochemical marker expression suggests that the CA1 region was highly active during object exposures, yet the hippocampal system responded differentially to moving and to stationary objects. Recordings of CA1 neurons yielded non-bursting object-related activity during object exploration, and place cell activity remained unaffected in the presence of moving objects; supporting independent, yet simultaneous processing of spatial and non-spatial information within the hippocampus. Together, the current findings support the notion that the CA1 region of the rodent hippocampus processes object-related information, independent of spatial information.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004981
Subject Headings: Dissertations, Academic -- Florida Atlantic University, Hippocampus (Brain), Declarative memory, Explicit memory.
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: Chronic variable stress affects hippocampal neurotrophic factor gene expression in the novelty-seeking phenotype: epigenetic regulation.
Creator: Oztan, Ozge., Charles E. Schmidt College of Medicine
Abstract/Description: Experimentally naive rats exhibit varying degrees of novelty exploration. Some rats display high rates of locomotor reactivity to novelty (high responders; HR), and others display low rates (low responders; LR). The novelty-seeking phenotype (LRHR) is introduced as a model of stress responsiveness. In this thesis I examined effects of chronic variable physical and social stress or control handling on the levels of various neurotrophins in the hippocampus, and changes in mossy fibre terminal...
Show moreExperimentally naive rats exhibit varying degrees of novelty exploration. Some rats display high rates of locomotor reactivity to novelty (high responders; HR), and others display low rates (low responders; LR). The novelty-seeking phenotype (LRHR) is introduced as a model of stress responsiveness. In this thesis I examined effects of chronic variable physical and social stress or control handling on the levels of various neurotrophins in the hippocampus, and changes in mossy fibre terminal fields in LRHR rats. A positive correlation is seen between histone deacetylase 2 and brain-derived neurotrophic factor (BDNF) levels both of which are oppositely regulated in LRHR CA3 fields in response to chronic social stress. Increase in BDNF levels in CA3 field accompanied increase in supra-pyramidal mossy fibre terminal field size (SP-MF) in HRs, and decrease in BDNF levels accompanied decrease in SP-MF volume in LRs. Epigenetic regulation of neurotrophic support underlying these structural changes is discussed.
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Date Issued: 2009
PURL: http://purl.flvc.org/FAU/215290
Subject Headings: Rats as laboratory animals, Cellular signal transduction, Gene expression, Hippocampus (Brain), Physiology, Neural transmission, Genetic regulation
Format: Document (PDF)

Title: INVESTIGATING THE NEURAL CIRCUITRY SUPPORTING OBJECT RECOGNITION MEMORY IN C57BL/6J MICE.
Creator: Cinalli Jr., David A, Stackman, Jr., Robert W., Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
Abstract/Description: The hippocampus, a brain region that is part of the limbic system in the medial temporal lobe, is critical to episodic memory, or the memory of autobiographical events. The hippocampus plays an important role in the consolidation of information from short-term memory into more permanent long-term memory and spatial memory which enables navigation. Hippocampal damage in humans has been linked to memory loss, such as in Alzheimer’s disease and other dementias, as well as in amnesia such as in...
Show moreThe hippocampus, a brain region that is part of the limbic system in the medial temporal lobe, is critical to episodic memory, or the memory of autobiographical events. The hippocampus plays an important role in the consolidation of information from short-term memory into more permanent long-term memory and spatial memory which enables navigation. Hippocampal damage in humans has been linked to memory loss, such as in Alzheimer’s disease and other dementias, as well as in amnesia such as in the case of patient H.M. The role of the hippocampus has been well characterized in humans but is less understood in rodents due to contradictory findings. While rodents have served well as model organisms in developing our understanding of the cognitive map that is critical for spatial navigation, there has been substantial contention over the degree to which the rodent hippocampus supports non-spatial memory, specifically the memory for items or objects previously encountered. The overall objective of this research is to gain a better understanding of how neuronal circuits involving the hippocampus and perirhinal cortex function to support object memory in the brain. Chemogenetic technologies such as DREADDs (designer receptor exclusively activated by designer drugs) have proven to be effective tools in remote manipulation of neuronal activity. First, a series of behavioral tasks was used to validate the effects of DREADD inactivation in the CA1 region of dorsal hippocampus in C57BL/6J male mice. DREADD inhibition resulted in significant impairment in the spontaneous object recognition (SOR) task and of spatial memory in the Morris water maze. In conjunction, mice were implanted with bilateral perirhinal cortex guide cannulae to allow for temporary muscimol inactivation during distinct time points in the SOR task to further investigate the nature of its relationship with the hippocampus. The results reveal an unexpected role for the perirhinal cortex in the retrieval of strong object memory. Finally, Arc mRNA expression was quantified in CA1 of dorsal hippocampus and perirhinal cortex following both weak and strong object memory formation. The results indicate that the perirhinal cortex and hippocampus have distinct, yet complementary roles in object recognition memory and that distinction is gated by memory strength. Understanding the neural mechanisms supporting the weak-strong object memory distinction in mice is an important step not only in validating mice as a suitable model system to study episodic memory in humans, but also in developing treatments and understanding the underlying causes of diseases affecting long-term memory such as Alzheimer’s disease.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013571
Subject Headings: Neural circuitry, Hippocampus, Perirhinal Cortex, Memory, Mice, Inbred C57BL
Format: Document (PDF)

Title: Uncovering the role of the rodent dorsal hippocampus in spatial and object memory retrieval.
Creator: Rios, Lisa, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Male C7BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae. After confirming that intrahippocampal microinfusion of muscimol impaired hippocampal function, demonstrated by impaired performance in the Morris water maze, the influence of intrahippocampal muscimol was tested in the Novel Object Recognition paradigm. During a test session 24 h after the last habituation/sample session, mice were presented with one familiar object and one novel object. Successful retention of object...
Show moreMale C7BL/6J mice were implanted with bilateral dorsal CA1 guide cannulae. After confirming that intrahippocampal microinfusion of muscimol impaired hippocampal function, demonstrated by impaired performance in the Morris water maze, the influence of intrahippocampal muscimol was tested in the Novel Object Recognition paradigm. During a test session 24 h after the last habituation/sample session, mice were presented with one familiar object and one novel object. Successful retention of object memory was inferred if mice spent more time exploring the novel object than the familiar object. Results demonstrate that muscimol infused into dorsal CA1 region prior to the test session eliminates novel object preference, indicating that the hippocampus is necessary for the retrieval of this non-spatial memory - a topic that has garnered much debate. Understanding the similarities between rodent and human hippocampal function could enable future animal studies to effectively answer questions about diseases and disorders affecting human learning and memory.
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Date Issued: 2011
PURL: http://purl.flvc.org/FAU/3172696
Subject Headings: Rodents as laboratory animals, Memory, Research, Cellular signal transduction, Cognitive neuroscience, Hippocampus (Brain), Space perception
Format: Document (PDF)

Title: Representation of object-in-context within mouse hippocampal neuronal activity.
Creator: Asgeirsdottir, Herborg Nanna, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: The rodent hippocampus is critical for processing spatial memory but its contribution to non-spatial, specifically object memory is debated. The cognitive map theory of hippocampal function states that the hippocampus stores relationships of goal locations (places) to discrete items (objects) encountered within environments. Dorsal CA1 place cells were recorded in male C57BL/6J mice performing three variations of the novel object recognition paradigm to define "object-in-context"...
Show moreThe rodent hippocampus is critical for processing spatial memory but its contribution to non-spatial, specifically object memory is debated. The cognitive map theory of hippocampal function states that the hippocampus stores relationships of goal locations (places) to discrete items (objects) encountered within environments. Dorsal CA1 place cells were recorded in male C57BL/6J mice performing three variations of the novel object recognition paradigm to define "object-in-context" representation of hippocampal neuronal activity that may support object memory. Results indicate, (i) that place field stability is higher when polarizing environmental cues are provided during object recognition; (ii) hippocampal place fields remain stable throughout the novel object recognition testing without a polarizing cue; and (iii) time dependent effects on stability when objects were dissociated from the context. These data indirectly support that the rodent hippocampus processes object memory, and challenge the view that "object-in-context" representations are formed when mice perform novel object recognition task.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3362339
Subject Headings: Mice as laboratory animals, Hippocampus (Brain), Neurotransmitter receptors, Cellular control mechanisms, Cellular signal transduction
Format: Document (PDF)

Title: Selective Activation of the SK1 Subtype of Small Conductance Ca2+ Activated K+ Channels by GW542573X in C57BL6J Mice Impairs Hippocampal-dependent Memory.
Creator: Rice Kuchera, Claire A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: SK channels are small conductance Ca2+-activated K+ channels expressed throughout the CNS. SK channels modulate the excitability of hippocampal CA1 neurons by affecting afterhyperpolarization and shaping excitatory postsynaptic responses. Such SK-mediated effects on activity-dependent neuronal excitability and synaptic strength are thought to underlie the modulatory influence of SK channels on memory encoding. Here,the effect of a new SK1 selective activator, GW542573X, on hippocampal...
Show moreSK channels are small conductance Ca2+-activated K+ channels expressed throughout the CNS. SK channels modulate the excitability of hippocampal CA1 neurons by affecting afterhyperpolarization and shaping excitatory postsynaptic responses. Such SK-mediated effects on activity-dependent neuronal excitability and synaptic strength are thought to underlie the modulatory influence of SK channels on memory encoding. Here,the effect of a new SK1 selective activator, GW542573X, on hippocampal-dependent object memory, contextual and cued conditioning, and trace fear conditioning was examined. The results demonstrated that pre- but not post-training systemic administration of GW542573X impaired object memory and trace fear memory in mice 24 h after training. Contextual and cued fear memory were not disrupted. These current data suggest that activation of SK1 subtype-containing SK channels impairs long-term memory. These results are consistent with converging evidence that SK channel activation suppressed behaviorally triggered synaptic plasticity necessary for encoding hippocampal-dependent memory.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004541, http://purl.flvc.org/fau/fd/FA00004541
Subject Headings: Cellular control mechanisms, Cognitive neuroscience, Cognitive psychology, Hippocampus (Brain), Mice as laboratory animals, Neurotransmitter receptors
Format: Document (PDF)

Title: Effects of adolescent stress on depressive- and anxiety-like behaviors and hippocampal mossy fibre-CA3 remodeling in the novelty-seeking phenotype: implications for epigenetic regulation of the BDNF gene.
Creator: Oztan, Ozge., Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description: Experimentally naive rats show variance in their locomotor reactivity to novelty, some displaying higher (HR) while others displaying lower (LR) reactivity, associated with vulnerability to stress. LRHR phenotype is proposed as an antecedent to the development of stress hyper responsiveness. Results presented here show emergence of antidepressive-like behavior following peripubertal-juvenile exposure to chronic variable physical (CVP) and chronic variable social stress (CVS) in HR rats, and...
Show moreExperimentally naive rats show variance in their locomotor reactivity to novelty, some displaying higher (HR) while others displaying lower (LR) reactivity, associated with vulnerability to stress. LRHR phenotype is proposed as an antecedent to the development of stress hyper responsiveness. Results presented here show emergence of antidepressive-like behavior following peripubertal-juvenile exposure to chronic variable physical (CVP) and chronic variable social stress (CVS) in HR rats, and depressive-like behavior following CVP in the LRs. The antidepressive-like behavior in HR rats was accompanied by increased levels of acetylated Histone3 (acH3) and acetylated Histone4 (acH4) at the hippocampal brain-derived neurotrophic factor (BDNF) P2 and P4 promoters respectively. This effect may mediate increased mossy fibre (MF) terminal field size, particularly the suprapyramidal mossy fibre projection volume (SP-MF), in the HR animals following both stress regimens. These findings show that chronic variable stress during adolescence induces individual differences in molecular, neuromorphological and behavioral parameters between LRs and HRs, which provides further evidence that individual differences in stress responsiveness is an important factor in resistance or vulnerability to stress-induced depression and/or anxiety.
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Date Issued: 2013
PURL: http://purl.flvc.org/fcla/dt/3360950
Subject Headings: Rats as laboratory animals, Anxiety in adolescence, Depression in adolescence, Stress (Psychology), Cellular signal transduction, Hippocampus (Brain), Physiology, Genetic regulation, Gene expression
Format: Document (PDF)

Title: Hippocampal CA1 activation during object memory encoding in the novel object recognition task.
Creator: Cinalli, David A., Stackman, Robert W., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description: Transcription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal...
Show moreTranscription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal hippocampus in mice following two variations of the novel object recognition (NOR) task. Results suggest mice that acquired strong object memory showed significant hippocampal activation. In mice that acquired weak object memory, hippocampal activation was not significantly different from controls. Arc expression was also examined in other hippocampal sub-regions, as well as in the perirhinal cortex. These results suggest that the mice must acquire a threshold amount of object information before the hippocampal CA1 region is engaged.
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Date Issued: 2015
PURL: http://purl.flvc.org/fau/fd/FA00004436, http://purl.flvc.org/fau/fd/FA00004436
Subject Headings: Association of ideas, Cellular control mechanisms, Cellular signal transduction, Episodic memory, Hippocampus (Brain) -- Physiology, Human information processing, Mice as laboratory animals
Format: Document (PDF)

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