Ginkgo biloba treatments reverse the impairment of conditioned suppression acquisition induced by GluN2B-NMDA and 5-HT1A receptor blockade: Modulatory effects of the circuitry of the dorsal hippocampal formation

2019 ◽  
Vol 209 ◽  
pp. 112534
Author(s):  
Cláudia R. Zamberlam ◽  
Myrcea A.S. Tilger ◽  
Laís Moraes ◽  
Janete M. Cerutti ◽  
Suzete M. Cerutti
Keyword(s):  
Conditioned Suppression ◽  
Ginkgo Biloba ◽  
Hippocampal Formation ◽  
Receptor Blockade ◽  
Dorsal Hippocampal

scholarly journals Target Proteins in the Dorsal Hippocampal Formation Sustain the Memory-Enhancing and Neuroprotective Effects of Ginkgo biloba

2019 ◽  
Vol 9 ◽  
Author(s):  
Renan Barretta Gaiardo ◽  
Thiago Ferreira Abreu ◽  
Alexandre Keiji Tashima ◽  
Monica Marques Telles ◽  
Suzete Maria Cerutti
Keyword(s):  
Ginkgo Biloba ◽  
Hippocampal Formation ◽  
Neuroprotective Effects ◽  
Target Proteins ◽  
Dorsal Hippocampal ◽  
Memory Enhancing

scholarly journals Noncanonical projections to the hippocampal CA3 regulate spatial learning and memory by modulating the feedforward hippocampal trisynaptic pathway

PLoS Biology ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. e3001127
Author(s):  
Xiaoxiao Lin ◽  
Michelle Amalraj ◽  
Crisylle Blanton ◽  
Brenda Avila ◽  
Todd C. Holmes ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Formation ◽  
Back Propagation ◽  
Spatial Learning And Memory ◽  
Functional Roles ◽  
Theta Wave ◽  
Dorsal Hippocampal ◽  
Hippocampal Ca3 ◽  
Mapping Techniques

The hippocampal formation (HF) is well documented as having a feedforward, unidirectional circuit organization termed the trisynaptic pathway. This circuit organization exists along the septotemporal axis of the HF, but the circuit connectivity across septal to temporal regions is less well described. The emergence of viral genetic mapping techniques enhances our ability to determine the detailed complexity of HF circuitry. In earlier work, we mapped a subiculum (SUB) back projection to CA1 prompted by the discovery of theta wave back propagation from the SUB to CA1 and CA3. We reason that this circuitry may represent multiple extended noncanonical pathways involving the subicular complex and hippocampal subregions CA1 and CA3. In the present study, multiple retrograde viral tracing approaches produced robust mapping results, which supports this prediction. We find significant noncanonical synaptic inputs to dorsal hippocampal CA3 from ventral CA1 (vCA1), perirhinal cortex (Prh), and the subicular complex. Thus, CA1 inputs to CA3 run opposite the trisynaptic pathway and in a temporal to septal direction. Our retrograde viral tracing results are confirmed by anterograde-directed viral mapping of projections from input mapped regions to hippocampal dorsal CA3 (dCA3). We find that genetic inactivation of the projection of vCA1 to dCA3 impairs object-related spatial learning and memory but does not modulate anxiety-related behaviors. Our data provide a circuit foundation to explore novel functional roles contributed by these noncanonical hippocampal circuit connections to hippocampal circuit dynamics and learning and memory behaviors.

scholarly journals Non-Canonical Projections from Ventral CA1 and Subicular Complex to CA3 Augments the Feedforward Hippocampal Trisynaptic Pathway

2021 ◽  
Author(s):  
Xiaoxiao Lin ◽  
Michelle Amalraj ◽  
Crisylle Blanton ◽  
Brenda Avila ◽  
Todd C. Holmes ◽  
...  
Keyword(s):  
Hippocampal Formation ◽  
Back Propagation ◽  
Perirhinal Cortex ◽  
Functional Roles ◽  
Theta Wave ◽  
Dorsal Hippocampal ◽  
Canonical Pathways ◽  
Hippocampal Ca3 ◽  
Mapping Techniques ◽  
And Behavior

AbstractThe hippocampal formation is well documented as having a feedforward, unidirectional circuit organization termed the trisynaptic pathway. This circuit organization exists along the septotemporal axis of the hippocampal formation, but the circuit connectivity across septal to temporal regions is less well described. The emergence of viral-genetic mapping techniques enhances our ability to determine the detailed complexity of hippocampal formation circuitry. In earlier work, we mapped a subiculum back-projection to CA1 prompted by the discovery of theta wave back-propagation from the subiculum to CA1 and CA3. We reason that this circuitry may represent multiple extended non-canonical pathways involving the subicular complex and hippocampal subregions CA1 and CA3. In the present study, multiple retrograde viral tracing approaches produced robust mapping results, which supports this prediction. We find significant non-canonical synaptic inputs to dorsal hippocampal CA3 from ventral CA1, perirhinal cortex, and the subicular complex. Thus, CA1 inputs to CA3 run opposite the trisynaptic pathway and in a temporal to septal direction. Our retrograde viral tracing results are confirmed by anterograde-directed viral mapping of projections from input mapped regions to hippocampal dorsal CA3. Together, our data provide a circuit foundation to explore novel functional roles contributed by these non-canonical hippocampal circuit connections to hippocampal dynamics and behavior.

scholarly journals Lesions of the dorsal hippocampal formation interfere with background but not foreground contextual fear conditioning.

1994 ◽  
Vol 1 (1) ◽  
pp. 34-44
Author(s):  
R G Phillips ◽  
J E LeDoux
Keyword(s):  
Fear Conditioning ◽  
Hippocampal Formation ◽  
Dorsal Hippocampus ◽  
Contextual Fear Conditioning ◽  
Contextual Conditioning ◽  
Dorsal Hippocampal ◽  
The Us ◽  
Hippocampal Lesions ◽  
Conditioned Freezing ◽  
Contextual Stimuli

The effects of hippocampal lesions on the conditioning of fear responses (freezing responses) to contextual stimuli (static, continuously present stimuli) were examined in three conditioning paradigms: forward pairing of a phasic tone conditioned stimulus (CS) with a footshock unconditioned stimulus (US), unpaired presentations of the CS and US, or presentations of the US alone. All three procedures resulted in the acquisition of conditioned freezing to contextual stimuli. Lesions of the dorsal hippocampus prevented the acquisition of contextual conditioning in the Paired procedure, as reported previously, but not in the Unpaired or US Alone procedures. In the Paired procedure, static contextual cues occur in the background, with the phasic tone CS being the primary stimulus that enters into the association with the US. However, in the other two procedures, where there is no phasic CS, the primary associations with the US involve static contextual stimuli, which are therefore in the foreground. We refer to these types of contextual conditioning as background and foreground contextual conditioning, respectively, and argue that the hippocampus is only involved in background contextual conditioning. These results have implications for understanding both fear conditioning and hippocampal function.

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