What is the name of memory for factual information?

Consolidating Declarative Memories

Declarative memory concerns the ability to bring back to mind factual and episodic information. Each of us maintains a colossal but changing record of facts and events to access when needed. This information can potentially stay with us for so many years that one might say that declarative memories can last a lifetime. One general principle of memory storage is that cortical networks specialized for processing specific types of information are the very same networks involved in storing that information as fragments of declarative memories. Those fragments must be linked together in order for any particular declarative memory to exist.

Although we have learned much about the brain mechanisms responsible for declarative memory, and about ways to assess this type of memory using recall and recognition tests, pinpointing the exact neural substrates of any one specific autobiographical event or fact is beyond current technology. Indeed, a declarative memory does not reside in a single location, but rather, it depends on a dynamic network of neurons. Lively controversy surrounds questions about how consolidation operates on such a network, the precise length of time consolidation requires, and whether these memories assume a labile form under special circumstances.

Empirical evidence that can be brought to bear on theories of consolidation comes from multiple sources. Neuropsychological studies of patients with amnesia, in particular, suggest that declarative memories can change to become resistant to disruption and that this change is a by-product of consolidation. Critical brain damage in amnesia tends to include midline diencephalic or medial temporal structures, including the hippocampus and adjacent cortical regions, though the distinct memory functions presumably mediated by these different regions are currently unclear. Studies of animal models have also been designed to identify the neuroanatomical basis of this critical contribution to memory.

Declarative memory

Declarative memory refers to the ability to store and retrieve both personal information (i.e., episodic memory) and general knowledge (i.e., semantic memory) (Baddeley, 1995). This type of memory is assessed using tasks such as the Rey Auditory Verbal Learning Test (Schmidt, 1996) and the Californian Verbal Learning Test (CVLT) (Delis et al., 1987). Both are list-learning tests that evaluate verbal inhibition, retention, encoding, and retrieval abilities. Impairments on the Rey Auditory Verbal Learning Test and CVLT are frequent after severe TBI. Recently, poor performance in declarative memory by patients with severe and diffuse TBI has been associated with reduced cortical thickness and decreased anisotropy in the parietal lobe. Interestingly, in this study, damage to the temporal lobe regions did not contribute to declarative memory dysfunctions, suggesting that other regions can compensate after temporal lobe damage (Palacios et al., 2013).

Declarative learning

Declarative memories are those that most people think about when they use the term ‘memory’. These memories can be accessed for conscious recollection, such as being able to quote pi to the umpteenth decimal place or reel off the date of the gunpowder plot. Declarative memories are generally easily formed but are also unfortunately all too easily forgotten. Declarative learning requires cognitive processes to create the memory. To illustrate, if an addict is being taught harm-minimisation techniques, such as safer injecting procedures, the interaction involves cognitive processing and memorisation of the information, and so falls into the category of declarative memory. The multitude of counselling techniques start to do their work at this level of learning; by enhancing the underlying mechanisms it is hoped that cognitive changes can be used to alter subsequent behaviour. Unfortunately, however, declarative memories are often easily forgotten. Consider the earlier analogy of memory footprints. These memories are like footprints in the sand and can be washed away (Fig. 4.1). For example, can you remember all the facts you learned at school, or have they been washed away?

There are multiple types of memory. Some memories are stored in short-term memory and are selectively transferred to long-term memory, usually by the process of repetition. Repetition causes glutamate to keep being released until enough has been released to result in the aforementioned calcium influx thus triggering LTP.

16.2.3 Declarative or Explicit Memory

Declarative or explicit memory is devoted to processing of names, dates, places, facts, events, and so forth. These are entities that are thought of as being encoded symbolically and that thus can be described with language. In terms of function, declarative memory is specialized for fast processing and learning. New information can be entered into the declarative memory system on the basis of a single trial or experience. In terms of rules of operation, declarative is fallible: one forgets names, dates, places, and so forth. Although there are compelling demonstrations of long-term remembering of lessons learned in high school and college (e.g., foreign language vocabulary: Bahrick, 2000), a great deal of forgetting from declarative memory occurs literally minutes, hours, and days after an experience. Declarative memory also has a specific neural substrate. Current conceptualizations suggest that the formation, maintenance, and subsequent retrieval of declarative or explicit memories depend on a multicomponent network involving cortical structures (including posterior–parietal, anterior–prefrontal, and limbic–temporal association areas) as well as medial temporal structures (including the hippocampus and entorhinal, perirhinal, and parahippocampal cortices: e.g., Eichenbaum and Cohen, 2001; Murray and Mishkin, 1998; Zola and Squire, 2000). The medial temporal structures may be considered ‘primary’ in the sense that without them, whether measured by recall or recognition, declarative memory is impaired (Moscovitch, 2000).

Declarative memory is itself subdivided into the categories of semantic and episodic memory (e.g., Schacter and Tulving, 1994), with a finer distinction between episodic and autobiographical memory. Semantic memory supports general knowledge about the world (Tulving, 1972, 1983). People are consulting semantic memory when they retrieve the facts that the capital of the United States is Washington, DC, that the United States has 50 states, and that with over 660 000 square miles, Alaska is the largest state in terms of land mass. For practical purposes, both the capacity of semantic memory and the longevity of the information stored in it seem infinite. Semantic memory also is not tied to a particular time or place. That is, people know facts and figures, names and dates, yet in most cases, they do not know when and where they learned this information. People might be able to reconstruct how old they were or what grade they were in when they learned some tidbits of information, but unless there was something unique about the experience surrounding the acquisition of this information, they carry it around without address or reference to a specific episode.

In contrast to semantic memory, episodic memory supports retention of information about unique events (Tulving, 1972, 1983), such as a specific visit to Washington, DC, or the fact that Alaska was one of the states on a list of state names studied in a memory experiment. Some episodic memories, such as whether a specific state was included in a word list, may not stay with one for very long and are not especially personally relevant or significant. Yet other episodic memories are personally significant and even self-defining. These so-called autobiographical memories are episodic memories that are infused with a sense of personal involvement or ownership (Bauer, 2007). They are the episodes on which people reflect when they consider who they are and how their previous experiences have shaped them.

1.15.1.1.1 Episodic Memory, Semantic Memory, and Declarative Memory

Declarative memory, also called explicit memory, refers to the memory for facts and events that can be brought into consciousness and expressed overtly (Cohen and Squire, 1980; Cohen, 1984; Squire and Cohen, 1984; Cohen and Eichenbaum, 1993; Tulving and Markowitsch, 1998). The stored information is propositional in nature (i.e., can be “declared”), such that one could describe it symbolically and infer relationships among memories. The system is large, complex, and highly structured with a presumed unlimited capacity, which allows information from all modalities to be stored, often after a single exposure to a fact or an event. A critical feature of the declarative memory representation is its flexibility of access and expression, which allows memories to be retrieved from various logical associations and expressed through a variety of behaviors. Declarative memory can be divided into episodic memory, commonly defined as the memory for personal events or experiences, and semantic memory, the memory for facts, or general knowledge about the world (Squire, 2004). Although these two forms of declarative memory have many characteristics in common, they are distinguishable by a number of features (Tulving, 1972, 1993; Tulving and Markowitsch, 1998). In his earlier work, Tulving (1972) suggested that they differed in their relationship to the context in which the information was acquired, such that episodic memories were intrinsically tied to the context, whereas semantic memories were essentially context-free. These contextual genres are colloquially referred to as the “what,” “where,” and “when” of the event (see section Episodic Memories Include Information About Specific Events Along With the Spatial, Temporal, and Situational Contexts in Which They Occurred).

1.1 Declarative Memory: Episodic and Semantic Memory

Declarative memory, also known as explicit memory, is distinct from other memory types as it is concerned with the intentional recollection of factual information, previous experiences and concepts (explicit memories). Nondeclarative memory, also known as implicit memory, is concerned with recall of information and events without requiring a conscious effort to retrieve and remember these information and events. It is accessed implicitly through performance rather than recollection (Roediger, 1990). Declarative memory can be divided into two types: episodic and semantic (Tulving, 1972). Episodic refers to contextual memory, i.e., memory of specific events or stimuli related to their temporal and spatial context. It includes sensory information, allowing one to reexperience an event. Semantic memory, on the other hand, refers to noncontextual memory, i.e., general knowledge about the world around us. It refers to general concepts and their relations, categories, facts, people, events or word meanings: items that are not particularly grounded in the experience of a temporal or spatial context (Tulving, 1986). It is still not entirely clear what is the role of the MTL and related brain structures in processing episodic and semantic memory traces and the extent to which these rely on separable memory systems.

Declarative memory – role of the hippocampus

Declarative memory is thought to depend on the integrity of the hippocampus, whereas procedural memory is probably hippocampus independent (Eichenbaum et al., 1992; Squire, 1992; Eichenbaum, 2000; but see Poldrack and Rodriguez, 2003). According to the declarative memory theory, the hippocampus is regarded as a more general learning system important for encoding relationships between environmental stimuli and creating episodic memories. Examples of such associative learning are trace eyeblink conditioning, object recognition memory, and cued (e.g., tone or light) fear conditioning (e.g., Clark et al., 2000, 2002; Prickaerts et al., 2002; Moita et al., 2003; Ahi et al., 2004) (see Table 1).

Besides different types of memory, there are different processes of memory, i.e., acquisition, consolidation, and retrieval of information (D’Mello and Steckler, 1996; Abel and Lattal, 2001). In general, the hippocampus is assumed to be necessary for the acquisition and consolidation of new information (e.g., Baddeley, 1995). However, recent evidence is accumulating that the hippocampus is also involved in (certain aspects) of retrieval of information (Moser and Moser, 1998; Izquierdo et al., 2000; Maren and Holt, 2000; Roozendaal et al., 2001b; Steffenach et al., 2002).

1.02.2.5 Declarative and Nondeclarative Memory

Declarative memory and nondeclarative memory (the latter sometimes referred to as procedural memory) are terms that have gained prominence following their use by Squire (1982), although the original distinction was proposed by Ryle (1949). Ryle distinguished between declarative knowledge (knowing that) and procedural knowledge (knowing how). For example, we know that Washington, DC, is the capital of the United States, but we know how to tie our shoes.

Squire has proposed declarative memory as an overarching category that includes episodic memory (remembering specific events of the past) as well as semantic memory (general knowledge). Declarative memory processes rely on the hippocampus and related structures in the medial-temporal lobe including the perirhinal, entorhinal, and parahippocampal cortices. As it has been extended, the term declarative memory has become a bit of a misnomer, because the concept is often applied to infrahuman species that are not prone to making declarations. (Ryle tied his distinction specifically to linguistic usage so that people would know that such and such occurred.)

What is factual memory called?

What type of memory is remembering a fact?

What are the 4 types of memories?