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Activities of visual cortical and hippocampal neurons co-fluctuate in freely moving rats during spatial behavior.

Haggerty DC, Ji D - Elife (2015)

Bottom Line: The precise activities of individual V1 neurons fluctuate every time the animal travels through the track, in a correlated fashion with those of hippocampal place cells firing at overlapping locations.The results suggest the existence of visual cortical neurons that are functionally coupled with hippocampal place cells for spatial processing during natural behavior.These visual neurons may also participate in the formation and storage of hippocampal-dependent memories.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States.

ABSTRACT
Visual cues exert a powerful control over hippocampal place cell activities that encode external spaces. The functional interaction of visual cortical neurons and hippocampal place cells during spatial navigation behavior has yet to be elucidated. Here we show that, like hippocampal place cells, many neurons in the primary visual cortex (V1) of freely moving rats selectively fire at specific locations as animals run repeatedly on a track. The V1 location-specific activity leads hippocampal place cell activity both spatially and temporally. The precise activities of individual V1 neurons fluctuate every time the animal travels through the track, in a correlated fashion with those of hippocampal place cells firing at overlapping locations. The results suggest the existence of visual cortical neurons that are functionally coupled with hippocampal place cells for spatial processing during natural behavior. These visual neurons may also participate in the formation and storage of hippocampal-dependent memories.

No MeSH data available.


Related in: MedlinePlus

Behavioral task and recording sites.(A) A C-shaped track where rats ran back and forth for food rewards. Bottom: two linearized trajectories, each 300 cm long. Vertical white lines: corners of the track. F: food wells. (B, C) The mean number of laps per minute (B) and mean running speed (C) on each day of track running, averaged over all trajectories and all animals. The number for Day 7 + included those days ≥ Day 7. Arrows: the day when the mean number of lap and speed were stabilized. Number of trajectories: N = 30, 26, 22, 22, 18, 16, 26 for Day 1 to Day 7+, respectively. (D) Nissl- (top 2 sections) and AChE-stained (bottom 2 sections) coronal brain sections to show recording sites (arrows) in the hippocampal CA1, and those in different layers of V1 (L2/3, L4 and L5/6). V2: the secondary visual cortex.DOI:http://dx.doi.org/10.7554/eLife.08902.003
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fig1: Behavioral task and recording sites.(A) A C-shaped track where rats ran back and forth for food rewards. Bottom: two linearized trajectories, each 300 cm long. Vertical white lines: corners of the track. F: food wells. (B, C) The mean number of laps per minute (B) and mean running speed (C) on each day of track running, averaged over all trajectories and all animals. The number for Day 7 + included those days ≥ Day 7. Arrows: the day when the mean number of lap and speed were stabilized. Number of trajectories: N = 30, 26, 22, 22, 18, 16, 26 for Day 1 to Day 7+, respectively. (D) Nissl- (top 2 sections) and AChE-stained (bottom 2 sections) coronal brain sections to show recording sites (arrows) in the hippocampal CA1, and those in different layers of V1 (L2/3, L4 and L5/6). V2: the secondary visual cortex.DOI:http://dx.doi.org/10.7554/eLife.08902.003

Mentions: We used tetrodes to simultaneously record firing activities of V1 cells and CA1 place cells in 15 freely moving rats, while they were performing a track running task for food rewards. During the task, the food-deprived rats were free to run along a novel C-shaped track (Figure 1A). Each end of the track (food well) was baited with a milk reward which, if consumed, was not refilled until the rat had run to the opposite end of the track to consume the other reward. Over time rats became habituated to the task and repeatedly travelled back and forth along the two overlapping trajectories in order to maximize the number of rewards. The recording started on the very first day (Day 1) and continued for 2–14 days, with 20–60 min each day. Eight animals reached at least Day 7. We quantified the task performance of all the rats from Day 1 to Day 6, and a Day 7+, which included those days ≥ Day 7. Behavioral performance was measured by the running speed and the number of times (laps) per minute an animal traveled through each of the 2 trajectories. Both parameters increased rapidly during the early few days of running and reached a stable level on Day 3 (Figure 1B,C), indicating that much of the behavioral changes occurred during the first few days.10.7554/eLife.08902.003Figure 1.Behavioral task and recording sites.


Activities of visual cortical and hippocampal neurons co-fluctuate in freely moving rats during spatial behavior.

Haggerty DC, Ji D - Elife (2015)

Behavioral task and recording sites.(A) A C-shaped track where rats ran back and forth for food rewards. Bottom: two linearized trajectories, each 300 cm long. Vertical white lines: corners of the track. F: food wells. (B, C) The mean number of laps per minute (B) and mean running speed (C) on each day of track running, averaged over all trajectories and all animals. The number for Day 7 + included those days ≥ Day 7. Arrows: the day when the mean number of lap and speed were stabilized. Number of trajectories: N = 30, 26, 22, 22, 18, 16, 26 for Day 1 to Day 7+, respectively. (D) Nissl- (top 2 sections) and AChE-stained (bottom 2 sections) coronal brain sections to show recording sites (arrows) in the hippocampal CA1, and those in different layers of V1 (L2/3, L4 and L5/6). V2: the secondary visual cortex.DOI:http://dx.doi.org/10.7554/eLife.08902.003
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4595967&req=5

fig1: Behavioral task and recording sites.(A) A C-shaped track where rats ran back and forth for food rewards. Bottom: two linearized trajectories, each 300 cm long. Vertical white lines: corners of the track. F: food wells. (B, C) The mean number of laps per minute (B) and mean running speed (C) on each day of track running, averaged over all trajectories and all animals. The number for Day 7 + included those days ≥ Day 7. Arrows: the day when the mean number of lap and speed were stabilized. Number of trajectories: N = 30, 26, 22, 22, 18, 16, 26 for Day 1 to Day 7+, respectively. (D) Nissl- (top 2 sections) and AChE-stained (bottom 2 sections) coronal brain sections to show recording sites (arrows) in the hippocampal CA1, and those in different layers of V1 (L2/3, L4 and L5/6). V2: the secondary visual cortex.DOI:http://dx.doi.org/10.7554/eLife.08902.003
Mentions: We used tetrodes to simultaneously record firing activities of V1 cells and CA1 place cells in 15 freely moving rats, while they were performing a track running task for food rewards. During the task, the food-deprived rats were free to run along a novel C-shaped track (Figure 1A). Each end of the track (food well) was baited with a milk reward which, if consumed, was not refilled until the rat had run to the opposite end of the track to consume the other reward. Over time rats became habituated to the task and repeatedly travelled back and forth along the two overlapping trajectories in order to maximize the number of rewards. The recording started on the very first day (Day 1) and continued for 2–14 days, with 20–60 min each day. Eight animals reached at least Day 7. We quantified the task performance of all the rats from Day 1 to Day 6, and a Day 7+, which included those days ≥ Day 7. Behavioral performance was measured by the running speed and the number of times (laps) per minute an animal traveled through each of the 2 trajectories. Both parameters increased rapidly during the early few days of running and reached a stable level on Day 3 (Figure 1B,C), indicating that much of the behavioral changes occurred during the first few days.10.7554/eLife.08902.003Figure 1.Behavioral task and recording sites.

Bottom Line: The precise activities of individual V1 neurons fluctuate every time the animal travels through the track, in a correlated fashion with those of hippocampal place cells firing at overlapping locations.The results suggest the existence of visual cortical neurons that are functionally coupled with hippocampal place cells for spatial processing during natural behavior.These visual neurons may also participate in the formation and storage of hippocampal-dependent memories.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States.

ABSTRACT
Visual cues exert a powerful control over hippocampal place cell activities that encode external spaces. The functional interaction of visual cortical neurons and hippocampal place cells during spatial navigation behavior has yet to be elucidated. Here we show that, like hippocampal place cells, many neurons in the primary visual cortex (V1) of freely moving rats selectively fire at specific locations as animals run repeatedly on a track. The V1 location-specific activity leads hippocampal place cell activity both spatially and temporally. The precise activities of individual V1 neurons fluctuate every time the animal travels through the track, in a correlated fashion with those of hippocampal place cells firing at overlapping locations. The results suggest the existence of visual cortical neurons that are functionally coupled with hippocampal place cells for spatial processing during natural behavior. These visual neurons may also participate in the formation and storage of hippocampal-dependent memories.

No MeSH data available.


Related in: MedlinePlus