Cholinergic and GABAergic modulation of medial septal area: Effect on working memory.

Givens, Bennet; Olton, David S.

doi:10.1037/0735-7044.104.6.849

Cited by 276 publications

(159 citation statements)

References 24 publications

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“…After A␤-injection, oscillations during these time periods became progressively weaker with no decrease in sensorimotor activity, indicating a progressive reduction in the LFP response to exposure to novelty. The parallel decrease in power and preferential visits to novel items after A␤-injection is consistent with the extensive literature regarding the concomitant reduction of the hippocampal rhythm and spatial memory performance (Chrobak et al, 1989;Brioni et al, 1990;Givens and Olton, 1990;Chrobak and Napier, 1992;Nagahara and McGaugh, 1992). The absence of a shift in the peak frequency of , recently associated with novelty detection (Jeewajee et al, 2008) in A␤-treated rats, indicates that hippocampal A␤ treatment disrupts the recruitment and modulation of oscillations in response to an increased cognitive load.…”

Section: Discussionsupporting

confidence: 87%

Decreased Rhythmic GABAergic Septal Activity and Memory-Associated θ Oscillations after Hippocampal Amyloid-β Pathology in the Rat

Villette¹,

Poindessous‐Jazat²,

Simon³

et al. 2010

J. Neurosci.

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The memory deficits associated with Alzheimer's disease result to a great extent from hippocampal network dysfunction. The coordination of this network relies on theta () oscillations generated in the medial septum. Here, we investigated in rats the impact of hippocampal amyloid ␤ (A␤) injections on the physiological and cognitive functions that depend on the septohippocampal system. Hippocampal A␤ injections progressively impaired behavioral performances, the associated hippocampal power, and frequency response in a visuospatial recognition test. These alterations were associated with a specific reduction in the firing of the identified rhythmic bursting GABAergic neurons responsible for the propagation of the rhythm to the hippocampus, but without loss of medial septal neurons. Such results indicate that hippocampal A␤ treatment leads to a specific functional depression of inhibitory projection neurons of the medial septum, resulting in the functional impairment of the temporal network.

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Section: Discussionsupporting

confidence: 87%

Decreased Rhythmic GABAergic Septal Activity and Memory-Associated θ Oscillations after Hippocampal Amyloid-β Pathology in the Rat

Villette¹,

Poindessous‐Jazat²,

Simon³

et al. 2010

J. Neurosci.

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“…Lesions that reduce theta rhythm cause behavioral impairments in tasks that require memory for specific prior episodes (Olton et al 1979;Aggleton and Brown 1999), such as delayed spatial alternation. The amplitude of hippocampal theta oscillations correlates with memory-guided performance (Winson 1978;Givens and Olton 1990;Seager et al 2002;Griffin et al 2004), and theta rhythm enhances the synaptic modification that would be necessary to link spatial and context-dependent inputs (Holscher et al 1997;Hyman et al 2003). The oscillatory interference model presented here indicates a potential mechanism for the role of hippocampal theta rhythm in memory function.…”

Section: Discussionmentioning

confidence: 72%

Arc length coding by interference of theta frequency oscillations may underlie context-dependent hippocampal unit data and episodic memory function

Hasselmo

2007

Learning & Memory

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Many memory models focus on encoding of sequences by excitatory recurrent synapses in region CA3 of the hippocampus. However, data and modeling suggest an alternate mechanism for encoding of sequences in which interference between theta frequency oscillations encodes the position within a sequence based on spatial arc length or time. Arc length can be coded by an oscillatory interference model that accounts for many features of the context-dependent firing properties of hippocampal neurons observed during performance of spatial memory tasks. In continuous spatial alternation, many neurons fire selectively depending on the direction of prior or future response (left or right). In contrast, in delayed non-match to position, most neurons fire selectively for task phase (sample vs. choice), with less selectivity for left versus right. These seemingly disparate results are effectively simulated by the same model, based on mechanisms similar to a model of grid cell firing in entorhinal cortex. The model also simulates forward shifting of firing over trials. Adding effects of persistent firing with reset at reward locations addresses changes in context-dependent firing with different task designs. Arc length coding could contribute to episodic encoding of trajectories as sequences of states and actions.Many models of the hippocampus focus on strengthening of synaptic connections between neurons to encode associations between sequential patterns of neural activity representing items or locations (McNaughton and

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“…The amplitude of hippocampal theta oscillations correlates with memory-guided performance (Givens and Olton, 1990;Seager et al, 2002;Winson, 1978). The model presented here demonstrates how this functional role of hippocampal theta rhythm could result from the oscillations in synaptic input to region CA1 during theta rhythm (Brankack et al, 1993).…”

mentioning

confidence: 70%

Hippocampal mechanisms for the context-dependent retrieval of episodes

2005

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Behaviors ranging from delivering newspapers to waiting tables depend on remembering previous episodes to avoid incorrect repetition. Physiologically, this requires mechanisms for long-term storage and selective retrieval of episodes based on time of occurrence, despite variable intervals and similarity of events in a familiar environment. Here, this process has been modeled based on physiological properties of the hippocampal formation, including mechanisms for sustained activity in entorhinal cortex and theta rhythm oscillations in hippocampal subregions. The model simulates the context-sensitive firing properties of hippocampal neurons including trial specific firing during spatial alternation and trial by trial changes in theta phase precession on a linear track. This activity is used to guide behavior, and lesions of the hippocampal network impair memory-guided behavior. The model links data at the cellular level to behavior at the systems level, describing a physiologically plausible mechanism for the brain to recall a given episode which occurred at a specific place and time.Keywords entorhinal cortex; dentate gyrus; region CA3; region CA1; spatial alternation; single unit recording; theta phase precession; current source density A waiter only takes orders once from each customer at each mealtime in a restaurant. Similarly, a foraging rat should avoid immediate return to a food cache where it just ate all the food. The ability to avoid repeating a completed behavior in a highly familiar environment depends on the ability to selectively retrieve recent episodes based on temporal context (e.g. in order to remember which customers or garbage cans were visited in a given time period).The context-sensitive properties of the spiking activity in the hippocampus may provide physiological mechanisms for this process. Some hippocampal neurons ("splitter cells" or "episodic cells") fire selectively dependent on the context of a specific recent response or future goal (Wood et al., 2000;Frank et al., 2000;Ferbinteanu and Shapiro, 2003). For example, during performance of a spatial alternation task, many hippocampal pyramidal neurons fire selectively after right turn or left turn trials, even though the rat is running in the same direction through the same location on the stem of the maze on both types of trials, as shown in Figure 1 (Wood et al., 2000). The model presented here shows how this activity may depend upon selective retrieval of prior episodes of behavior.During recordings on a linear track, other neurons show systematic changes in phase relative to theta frequency (7 Hz) oscillations in the hippocampal EEG (O'Keefe and Recce, 1993; Address correspondence to: Prof. Michael E. Hasselmo, Department of Psychology Center for Memory and Brain, Boston University, 2 Cummington St., Boston, MA 02215, (617) 353−1397, FAX: (617) Skaggs et al., 1996;Huxter et al., 2003). However, this theta phase precession does not appear on the first trial of the day, but appears on later trials of each day (Mehta ...

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Cholinergic and GABAergic modulation of medial septal area: Effect on working memory.

Cited by 276 publications

References 24 publications

Decreased Rhythmic GABAergic Septal Activity and Memory-Associated θ Oscillations after Hippocampal Amyloid-β Pathology in the Rat

Decreased Rhythmic GABAergic Septal Activity and Memory-Associated θ Oscillations after Hippocampal Amyloid-β Pathology in the Rat

Arc length coding by interference of theta frequency oscillations may underlie context-dependent hippocampal unit data and episodic memory function

Hippocampal mechanisms for the context-dependent retrieval of episodes

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