What are theta sequences?

Theta sequences are ordered sequences of hippocampal place cell firing that are nested within each theta cycle and reproduce, at compressed timescales, the spatial organization of place fields in the environment.

Where are place cells found?

the hippocampus
Place cells are spatially modulated neurons found in the hippocampus that underlie spatial memory and navigation: how these neurons represent 3D space is crucial for a full understanding of spatial cognition.

Where is the Engram?

brain
An engram is a memory trace that is stored within the brain and can be extracted when the memory is requested.

Who discovered place cells?

John O’Keefe
Place cells were first discovered by John O’Keefe and Jonathan Dostrovsky in 1971 in the hippocampus of rats. They noticed that rats with impairments in their hippocampus performed poorly in spatial tasks, and thus hypothesised that this area must hold some kind of spatial representation of the environment.

Who discovered the engram?

Richard Wolfgang Semon
Semon, the overlooked hero who introduced the term “engram” Richard Wolfgang Semon (1859–1918) was an evolutionary zoologist who, despite leading a troubled life, proposed several prescient theories on memory (Fig. 1) (Schacter et al., 1978; Schacter, 2001).

What is engram cell?

“Engram cells” are a population of neurons that are activated by learning, have enduring cellular changes as a consequence of learning, and whose reactivation by a part of the original stimuli delivered during learning results in memory recall. Note that this goes beyond a correlational definition of the term.

What is a hippocampal place cell?

Place cells are hippocampal neurons, typically from regions CA1 and CA3, that fire at a high rate whenever the animal is in a specific location in the environment, called the place field.

What are border cells?

Boundary cells (also known as border cells or boundary vector cells) are neurons found in the hippocampal formation that respond to the presence of an environmental boundary at a particular distance and direction from an animal.

What is Equipotentiality law?

in learning theory, the principle that any pair of stimuli can be associated with equal ease, regardless of their nature or origin. Also called law of equipotentiality; principle of equipotentiality.

What part of the brain helps you remember?

Hippocampus. The hippocampus, located in the brain’s temporal lobe, is where episodic memories are formed and indexed for later access.

Where are engram cells located?

hippocampus
(B) During memory systems consolidation, active engram cells with high spine density are formed in the hippocampus during contextual fear conditioning and for several days, the conditioned context can evoke a conditioned response.

What are space cells?

Place cells are thought, collectively, to act as a cognitive representation of a specific location in space, known as a cognitive map. Place cells are thought to play an important role in episodic memory. They contain information about the spatial context a memory took place in.

What is theta phase precession in rats?

Theta phase precession is a phenomenon observed in the hippocampus of rats and relates to the timing of neural spikes. When rats navigate around their environment, there are certain neurons in the hippocampus that fire (spike) when the animal is near a familiar landmark.

What is phasephase precession?

Phase precession is a neurophysiological process in which the time of firing of action potentials by individual neurons occurs progressively earlier in relation to the phase of the local field potential oscillation with each successive cycle.

Does theta wave phase precession exist in other parts of the brain?

The finding that theta wave phase precession is also a property of grid cells in the entorhinal cortex demonstrated that the phenomenon exists in other parts of the brain that also mediate information about movement. Theta wave phase precession in the hippocampus also plays a role in some brain functions that are unrelated to spatial location.

Do theta-modulated cells in the ventral striatum fire phase precession?

Theta-modulated cells in ventral striatum almost invariably showed firing phase precession relative to the hippocampal theta rhythm. Across the population of ventral striatal cells, phase precession was preferentially associated with an anticipatory ramping of activity up to the reward sites.