Locomotor and Hippocampal Processing Converge in the Lateral Septum

Abstract

The lateral septum (LS) has been implicated in anxiety and fear modulation and may regulate interactions between the hippocampus and regions, such as the VTA, that mediate goal-directed behavior. In this study, we simultaneously record from cells in the LS and the hippocampus during navigation and conditioning tasks. In the LS, we identify a speed and acceleration spiking code that does not map to states of anticipation or reward. Additionally, we identify an overlapping population of LS cells that change firing to cue and reward during conditioning. These cells display sharp wave ripple and theta modulation, spatial firing fields, and responses similar to the hippocampus during conditioning. These hippocampus-associated cells are not disproportionately speed or acceleration modulated, suggesting that these movement correlates are not hippocampally derived. Finally, we show that LS theta coordination is selectively enhanced in hippocampus-associated LS cells during navigation behavior that requires working memory. Taken together, these results suggest a role for the LS in transmitting spatial and contextual information, in concert with locomotor information, to downstream areas, such as the VTA, where value weighting may take place.

‘Awake delta’ and theta-rhythmic hippocampal network modes during intermittent locomotor behaviors in the rat

“…1C). As has been previously observed, a consistent peak in speed occupancy was evident at ~7 cm/s (e.g., Wirtshafter & Wilson, 2019) reflecting the prevalence of slower exploratory behaviors. Across all sessions the average distance traveled was 36.46 ± 14.45 m, with more distance covered in rewarded (40.19 ± 15.55 m) compared to non-rewarded sessions (29.38 ± 8.67m; t (52.8) = -3.31; P = 1.7x10 -3 ).…”

The Role of Gait Speed in Dementia: A Secondary Analysis from the SABE Colombia Study

“…GS and dementia can be the result of underlying processes affecting function in these shared brain regions such as neurodegeneration, chronic inflammation, impaired neuroplasticity, and micronutrient deficiencies [42]. Animal models evaluating activity in the speed cells and acceleration cells in the hippocampus and entorhinal cortex are related to motivation-related behaviors such as GS, underlying as a possible biological theory of how these variables are affected in Alzheimer disease [44, 45].…”

Conjunctive spatial and idiothetic codes are topographically organized in the GABAergic cells of the lateral septum

“…The LS consists almost exclusively of highly interconnected inhibitory GABAergic cells (Zhao et al, 2013) that are densely innervated by the principal cells of the hippocampus (Risold and Swanson, 1996; Tingley and Buzsáki, 2018). Previous research has implicated the LS in a wide variety of behaviors, including spatial and working memory (Brito and Thomas, 1981; Rawlins and Olton, 1982; Stanton et al, 1984; Thomas, 1979; Thomas and Brito, 1980), the regulation of feeding (Calderwood et al, 2020; Carus-Cadavieco et al, 2017; Sweeney and Yang, 2016; Xu et al, 2019), anxiety (Anthony et al, 2014; Besnard et al, 2019; Sparks and Ledoux, 2000; Trent and Menard, 2010), locomotion (Bender et al, 2015; Wirtshafter and Wilson, 2019), and social behaviors (Bredewold et al, 2015; Chee et al, 2015; Clemens et al, 2020; Leroy et al, 2018).…”

“…Several studies have reported place cells in the LS, but the number, information content, and stability vary widely from study to study (Kita et al, 1995; Leutgeb and Mizumori, 2002; Nishijo et al, 1997; Takamura et al, 2006; Wirtshafter and Wilson, 2019; Zhou et al, 1999), while others described a lack of canonical place cells (Tingley and Buzsáki, 2018). As previous studies often depended on variable criteria of what defines a place cell, estimates range from 5.3% (Tingley and Buzsáki, 2018) to 56.0% (Wirtshafter and Wilson, 2019) of LS cells classified as spatially-modulated. Strikingly, even estimates by the same authors on data acquired from the same subjects engaging the same task ranged between 26.5% (Wirtshafter and Wilson, 2020) to 56.0% (Wirtshafter and Wilson, 2019).…”

“…As previous studies often depended on variable criteria of what defines a place cell, estimates range from 5.3% (Tingley and Buzsáki, 2018) to 56.0% (Wirtshafter and Wilson, 2019) of LS cells classified as spatially-modulated. Strikingly, even estimates by the same authors on data acquired from the same subjects engaging the same task ranged between 26.5% (Wirtshafter and Wilson, 2020) to 56.0% (Wirtshafter and Wilson, 2019). When reported, LS place cells are typically described as of lesser quality than classic hippocampal place cells, with lower within-session stability and larger place fields (Takamura et al, 2006; Zhou et al, 1999).…”