Hello,

I am writing an essay in cog neuroscience words to answer: Critically evaluate the hypothesis that the hippocampus has a time-limited role in episodic memory.

I have found a study in which I would like to incorporate titles :

Hippocampus-Dependent Retrieval and HippocampusIndependent Extinction of Place Avoidance Navigation, and Stress-Induced Out-of-Context Activation of a Memory Revealed by Reversible Lesion Experiments in Rats K. JEEK1 , M. WESIERSKA2 , A. A. FENTON1, please if you can assist me in formatting a template in summarising the study and it findings in relation to answering the question I would appreciate it greatly as I have tried for over 1 and half hours to articulate myself and found myself confused. I would like points on critically evaluating points to include in the theme of my essay.

Thank you greatly in advance any further feedback or assistance would be appreciated on essay so far :)

So far ..

Episodic memory (EM), a declarative neurocognitive system, encapsulates the essence of experiences through conceptual-affective-sensory-perceptual processing (Conway, 2009). This unique human ability allows conscious recollection of past events, navigating both spatial and temporal dimensions (Tulving, 2005). While attributed as a distinctive human talent, challenges arise when applying criteria rooted in human consciousness to non-verbal species, leading to difficulties in differentiating EM from other memory capacities. Extensive research across cognitive and neuropsychological disciplines underscores the homologous nature of the hippocampal formation across species, emphasizing its pivotal role in EM acquisition (Meichenbaum, 2014). Paradoxically, instances of EM impairments, not contingent on scene-specificity, are spared from damage to the hippocampus or fornix (McAvan et al., 2022). This contradiction prompts an exploration of whether the time-limited role of the hippocampus in EM a consequence of the involvement of other cortical areas or pertains to different facets of EM. Examining the purported time-limited role of the hippocampus in EM necessitates a comprehensive exploration of the processes involved in its formation and maintenance. Neural circuitry and regions both within and outside hippocampal cortical areas likely collaborate in storing, encoding, and retrieving information (Ross et al., 2022). Employing diverse methodologies, such as functional imaging, cognitive testing, and lesion studies, aims to distinguish between hippocampal-independent and hippocampal-dependent episodic memory.

Encoding is the initial stage of long-term memory; responsible of receiving and registration of sensory information a current event represent (Madan,2020).Indisputably, the unique architectural feature of the hippocampus comprises of subfields whereby autoassociative networks rapidly provide support to encode events in a single trial(Rolls, 2013).In rodents, behavioural testing paradigms - namely Novel Object Recognition (NOR), Morris water maze (MWM) and Contextual Fear Conditioning (CFC) are tasks commonly used to evaluate the nature of encoding EM in relation to hippocampal dependence; it gives rise to the distinction between remote and recently acquired memories (Hernndez-Mercado et al, 2022).

Ocampo et al. (2017) conducted a study utilizing the Morris Water Maze (MWM) task to assess the impact of hippocampal lesions on recent (subjects lesioned 1-3 days post-training) and remote (subjects lesioned 31-33 days post-training) memory in rats. Male rats with substantial lesion of hippocampal subfield CA1 (average 80.2%) were later examined for recall and acquisition of EM; reflected in escape behaviour from water to the platform. The findings revealed that hippocampal lesions led to significant impairments in both recent and remote memory performance across the MWM task. This is highlighted as hippocampal lesioned rats performed no better than chance F (1, 60) = 0.04, p > 0.1 compared to sham subjects F (1, 60) = 0.1, p > 0.05 indicative of a clear deficit in spatial memory (Ocampo et al, 2017). These results suggest a crucial and ongoing roleof the hippocampus in encoding and the consolidation of bothrecent and remote spatial information. Considering, hippocampal CA1 exclusively provides output pathway to the neocortex (Drieskens et al, 2017), supports why findings are not consistent with standard model of system consolidation (SMSC). This posits during acquisition learning of EM, information is encoded and concurrently stored in both the hippocampus and the neocortex, over a period of time, upon reactivation the hippocampal formation gradually integrates and consolidates EM trace in neocortical structures whereby upon retrieval recourse to the hippocampus is no longer required (Gilboa et al, 2021). This is in direct opposition tothe notion proposed by the Multiple Trace Theory (MTT) which aligns with the findings, emphasizing the continuous engagement of hippocampal-neocortical interactions in the retrieval and storage of EM, regardless of their maturity (Moscovitch et al, 2021).

However, the temporal dynamics of EM formation warrants further scrutiny asSMSC is a relatively slow dynamic process, that occurs over a timeframe of over months or even years (Dudai, 2004). For instance, Ocampo et al.'s (2017) study introduced a temporal dimension by conducting surgeries at varying intervals post-training. Subjects in the remote condition received surgery 31-33 days post-training. This temporal discrepancy prompts a critical question: Is the duration between training and surgery sufficient for consolidation and transfer to the neocortex, allowing an accurate assessment of the time-limited role of the hippocampus?" Findings from Ramos (2009) emphasises this, as the expression of spared remote spatial memory is partly compensated for by the employment of long acquisition-surgery interval. Rats with dorsal hippocampal lesioning after 70 days display more spared remote EM for spatial performance during the radial maze task than those lesioned after 1 day (Ramos, 2009).

Moreover, memory for spatial location comprises of two distinct navigation strategies: egocentricandallocentric. The former accounts for encoding spatial information relative to using the body as point of reference (Wang et al 2020) and is mediated by the posterior parietal cortex which is lessis less reliant on EM intactness(Miniaci et al, 2018). Whereas FMRI recordings of hippocampal CA1placecells correlate to encodingspecific spatial locations to generate a cognitive map depending onrecognition and remembering environmental stimuli(allocentric representations).

Visual cues, although controlled and salient were placed around the test room instead of the arena wall in theMWM task in Ocampo et al. (2017). Considering rodents have weak visual behaviour (Reinagel,2015), it is likely that hippocampus-independent egocentric-based navigation was used to perform escape strategy to the platform. Therefore, the extent to which learning, and EM acquisition is supported by the hippocampus for this task should be further examined due to the inadequate application ofallocentric strategies subjects may use to perform spatial task. This limitation underscores the challenges in definitively establishing the time-limited role of the hippocampus in episodic memory. These limitations call for a nuanced interpretation of results and a cautious extension of conclusions to broader memory functions. This is emphasised by Rogerset al. (2006) findings where rats with selective lesions to the parietal cortex were diminished in the acquisition of egocentric version of the water maze task, whereas lesions of the dorsal hippocampus impairedallocentric maze acquisition (Rogers et al, 2006).

Additionally, the immersion into water with no clear escape route inducesignificant amount of stress on subjects, which is factor that may becounterproductive toperformance and is correlated to negatively disrupting EM retrieval (Van Gerven et al 2016). It is important that this factor is accounted and controlled for during an experiment which explores hippocampal function asstresscommonly impairs diversehippocampal-dependent memory tasks (Kim et al, 2015). A deeper examination of stress-related variables and their implications on hippocampal involvement could enhance the overall understanding of the time-limited role hypothesis."

The impact of stress on EM retrieval poses an intriguing dimension to our exploration. Studies like that of Diamond and Rose (2021) suggest that stress, particularly in tasks like the Morris Water Maze, may introduce confounding variables affecting memory recall. Analysing stress-related factors, such as corticosterone levels or behavioural indicators, can provide insights into the intricate interplay between stress and hippocampal-dependent memory retrieval.Jezek et al. (2002) investigated...(I was stuck and began drafting point)

REMAINING THEMES TO TOUCH ON

Cross-Species Comparisons:

• Extend discussion on the challenges of applying human-centric criteria to non-verbal species. Consider cross-species comparative studies that highlight similarities and differences in hippocampal involvement in episodic memory.

Clinical Relevance:

• Consider the clinical relevance of understanding the time-limited role of the hippocampus. How might these insights inform therapeutic interventions for memory-related disorders, and what are the potential implications for neurorehabilitation?

Is there a chance I may be able to link the K. JEEK1 study to these areas to be explored

Thank you in advance for your response and efforts. Hello,

I am writing an essay in cog neuroscience words to answer: Critically evaluate the hypothesis that the hippocampus has a time-limited role in episodic memory.

I have found a study in which I would like to incorporate titles :

Hippocampus-Dependent Retrieval and HippocampusIndependent Extinction of Place Avoidance Navigation, and Stress-Induced Out-of-Context Activation of a Memory Revealed by Reversible Lesion Experiments in Rats K. JEEK1 , M. WESIERSKA2 , A. A. FENTON1, please if you can assist me in formatting a template in summarising the study and it findings in relation to answering the question I would appreciate it greatly as I have tried for over 1 and half hours to articulate myself and found myself confused. I would like points on critically evaluating points to include in the theme of my essay.

Thank you greatly in advance any further feedback or assistance would be appreciated on essay so far :)

So far ..

Episodic memory (EM), a declarative neurocognitive system, encapsulates the essence of experiences through conceptual-affective-sensory-perceptual processing (Conway, 2009). This unique human ability allows conscious recollection of past events, navigating both spatial and temporal dimensions (Tulving, 2005). While attributed as a distinctive human talent, challenges arise when applying criteria rooted in human consciousness to non-verbal species, leading to difficulties in differentiating EM from other memory capacities. Extensive research across cognitive and neuropsychological disciplines underscores the homologous nature of the hippocampal formation across species, emphasizing its pivotal role in EM acquisition (Meichenbaum, 2014). Paradoxically, instances of EM impairments, not contingent on scene-specificity, are spared from damage to the hippocampus or fornix (McAvan et al., 2022). This contradiction prompts an exploration of whether the time-limited role of the hippocampus in EM a consequence of the involvement of other cortical areas or pertains to different facets of EM. Examining the purported time-limited role of the hippocampus in EM necessitates a comprehensive exploration of the processes involved in its formation and maintenance. Neural circuitry and regions both within and outside hippocampal cortical areas likely collaborate in storing, encoding, and retrieving information (Ross et al., 2022). Employing diverse methodologies, such as functional imaging, cognitive testing, and lesion studies, aims to distinguish between hippocampal-independent and hippocampal-dependent episodic memory.

Encoding is the initial stage of long-term memory; responsible of receiving and registration of sensory information a current event represent (Madan,2020).Indisputably, the unique architectural feature of the hippocampus comprises of subfields whereby autoassociative networks rapidly provide support to encode events in a single trial(Rolls, 2013).In rodents, behavioural testing paradigms - namely Novel Object Recognition (NOR), Morris water maze (MWM) and Contextual Fear Conditioning (CFC) are tasks commonly used to evaluate the nature of encoding EM in relation to hippocampal dependence; it gives rise to the distinction between remote and recently acquired memories (Hernndez-Mercado et al, 2022).

Ocampo et al. (2017) conducted a study utilizing the Morris Water Maze (MWM) task to assess the impact of hippocampal lesions on recent (subjects lesioned 1-3 days post-training) and remote (subjects lesioned 31-33 days post-training) memory in rats. Male rats with substantial lesion of hippocampal subfield CA1 (average 80.2%) were later examined for recall and acquisition of EM; reflected in escape behaviour from water to the platform. The findings revealed that hippocampal lesions led to significant impairments in both recent and remote memory performance across the MWM task. This is highlighted as hippocampal lesioned rats performed no better than chance F (1, 60) = 0.04, p > 0.1 compared to sham subjects F (1, 60) = 0.1, p > 0.05 indicative of a clear deficit in spatial memory (Ocampo et al, 2017). These results suggest a crucial and ongoing roleof the hippocampus in encoding and the consolidation of bothrecent and remote spatial information. Considering, hippocampal CA1 exclusively provides output pathway to the neocortex (Drieskens et al, 2017), supports why findings are not consistent with standard model of system consolidation (SMSC). This posits during acquisition learning of EM, information is encoded and concurrently stored in both the hippocampus and the neocortex, over a period of time, upon reactivation the hippocampal formation gradually integrates and consolidates EM trace in neocortical structures whereby upon retrieval recourse to the hippocampus is no longer required (Gilboa et al, 2021). This is in direct opposition tothe notion proposed by the Multiple Trace Theory (MTT) which aligns with the findings, emphasizing the continuous engagement of hippocampal-neocortical interactions in the retrieval and storage of EM, regardless of their maturity (Moscovitch et al, 2021).

However, the temporal dynamics of EM formation warrants further scrutiny asSMSC is a relatively slow dynamic process, that occurs over a timeframe of over months or even years (Dudai, 2004). For instance, Ocampo et al.'s (2017) study introduced a temporal dimension by conducting surgeries at varying intervals post-training. Subjects in the remote condition received surgery 31-33 days post-training. This temporal discrepancy prompts a critical question: Is the duration between training and surgery sufficient for consolidation and transfer to the neocortex, allowing an accurate assessment of the time-limited role of the hippocampus?" Findings from Ramos (2009) emphasises this, as the expression of spared remote spatial memory is partly compensated for by the employment of long acquisition-surgery interval. Rats with dorsal hippocampal lesioning after 70 days display more spared remote EM for spatial performance during the radial maze task than those lesioned after 1 day (Ramos, 2009).

Moreover, memory for spatial location comprises of two distinct navigation strategies: egocentricandallocentric. The former accounts for encoding spatial information relative to using the body as point of reference (Wang et al 2020) and is mediated by the posterior parietal cortex which is lessis less reliant on EM intactness(Miniaci et al, 2018). Whereas FMRI recordings of hippocampal CA1placecells correlate to encodingspecific spatial locations to generate a cognitive map depending onrecognition and remembering environmental stimuli(allocentric representations).

Visual cues, although controlled and salient were placed around the test room instead of the arena wall in theMWM task in Ocampo et al. (2017). Considering rodents have weak visual behaviour (Reinagel,2015), it is likely that hippocampus-independent egocentric-based navigation was used to perform escape strategy to the platform. Therefore, the extent to which learning, and EM acquisition is supported by the hippocampus for this task should be further examined due to the inadequate application ofallocentric strategies subjects may use to perform spatial task. This limitation underscores the challenges in definitively establishing the time-limited role of the hippocampus in episodic memory. These limitations call for a nuanced interpretation of results and a cautious extension of conclusions to broader memory functions. This is emphasised by Rogerset al. (2006) findings where rats with selective lesions to the parietal cortex were diminished in the acquisition of egocentric version of the water maze task, whereas lesions of the dorsal hippocampus impairedallocentric maze acquisition (Rogers et al, 2006).

Additionally, the immersion into water with no clear escape route inducesignificant amount of stress on subjects, which is factor that may becounterproductive toperformance and is correlated to negatively disrupting EM retrieval (Van Gerven et al 2016). It is important that this factor is accounted and controlled for during an experiment which explores hippocampal function asstresscommonly impairs diversehippocampal-dependent memory tasks (Kim et al, 2015). A deeper examination of stress-related variables and their implications on hippocampal involvement could enhance the overall understanding of the time-limited role hypothesis."

The impact of stress on EM retrieval poses an intriguing dimension to our exploration. Studies like that of Diamond and Rose (2021) suggest that stress, particularly in tasks like the Morris Water Maze, may introduce confounding variables affecting memory recall. Analysing stress-related factors, such as corticosterone levels or behavioural indicators, can provide insights into the intricate interplay between stress and hippocampal-dependent memory retrieval.Jezek et al. (2002) investigated...(I was stuck and began drafting point)

REMAINING THEMES TO TOUCH ON

Cross-Species Comparisons:

• Extend discussion on the challenges of applying human-centric criteria to non-verbal species. Consider cross-species comparative studies that highlight similarities and differences in hippocampal involvement in episodic memory.

Clinical Relevance:

• Consider the clinical relevance of understanding the time-limited role of the hippocampus. How might these insights inform therapeutic interventions for memory-related disorders, and what are the potential implications for neurorehabilitation?

Is there a chance I may be able to link the K. JEEK1 study to these areas to be explored

Thank you in advance for your response and efforts.

REFERENCE

Jezek, K., Wesierska, M., & Fenton, A. A. (2002). Hippocampus-dependent retrieval and hippocampus-independent extinction of place avoidance navigation, and stress-induced out-of-context activation of a memory revealed by reversible lesion experiments in rats. Physiological research, 51, S35-S48.