the limbic system and memory

____ & ____can also produce anoxia of this region.

head trauma & cerebral edema

The amygdala itself also has properties suggesting

"learning" or modification with experience.

The amygdala appears to add a _____ component to memory as part of formation and recall

"sympathetic" autonomic

Limbic Subcortical components Subcortical components (nuclei) that are primary contributors to limbic system function include:

- Hippocampus - Amygdala - Septal nuclei

While the circuit appears to go in a circle, in fact there are many points at which information enters and leaves the circuit to include wide areas of cerebral cortex. ______ in particular and pathway under it, the cingulum bundle, provide a mechanism for the diffusion of information from Papez's circuit.

Cingulate cortex This area of cortex has broad two-way communication with areas including prefrontal areas, premotor areas, visual, auditory and somatosensory association cortex. -This communication forms the basis for certain types of memory

Immediate memory: working memory: long term memory:

IM : fractions of a sec Wrking M: sec-min LTM: days-yrs

_______is the ability to hold ongoing experiences in mind for fractions of a second. It is very large, and each sensory modality (visual, tactile, verbal) appears to have its own register.

Immediate memory

is a primary pathway that links together the major limbic system components.

The Circuit of Papez

In this example, tasks of identifying a face is compared with remembering where an object is in space.

The blue areas were associated with a facial identity; the red for spatial memory. The green areas were activated during both.

consolidation is

The process of converting information in working memory to long term memory It is not entirely clear if the process of consolidation may occur in sequence or in parallel with short term memory.

ability to hold information in mind for access for seconds to minutes after the present.

Working memory (aka-short term memory)

anterior nuclear group part of the thalamus then sends

broad projections (thalamic radiations) to the cingulate gyrus and other cortical areas associated with the limbic system.

The nucleus accumbens or nucleus accumbens septi contains receptors for

a variety of neurotransmitters including endogenous opioids.

pathological memory loss.

amnesia

The emotional affect and rewarding nature of behaviors that are involved in memories and remembered actions also involve some subcortical structures. Among the most important of these are the

amygdala, septal nuclei, the nucleus accumbens and the ventral tegmental area of the brainstem.

The nucleus accumbens or nucleus accumbens septi receives input from the

amygdaloid complex, the hippocampal formation, and the substantial nigra and ventral tegmental area (dopaminergic) via the medial forebrain bundle (around the hypothalamus).

The CA 1 area of the hippocampus is particularly sensitive to

anoxia

The amygdaloid complex is located in the

anterior and medial portion of temporal horn under the uncus with which part of it blends.

The inability to form new memories results in ____ whereas difficult in retrieving memories already established is ____

anterograde amnesia retrograde amnesia

Forgetting may occur at

any stage of memory formation

Memories that are "significant" usually have intense ______ responses and affect associated with them.

autonomic

Electrical stimulation of the amygdala is ____ and can produce feelings of

aversive fear or anxiousness

Diseases in which the _____ are damaged are typically accompanied by the ______

basal nuclei (Huntington's disease, Parkinson's) inability to learn motor skills (as opposed to performance) -This might include mirror drawing or tracking a spot of light

The most likely substrates for procedural memory are the

basal nuclei loops involved in the performance and integration of motor tasks.

These circuits involve the

basal nuclei, prefrontal cortex, amygdala, sensory association cortex and cerebellum (but not those of the temporal lobe or midline thalamic nuclei.)

As might be suspected by the patterns of brain activation in recall, the substrates for long term memory or its retrieval can be shown to be ______ distributed.

broadly

_____ damage can also interfere with some types of conditioned reflex learning

cerebellar (blink reflex to a tone and puff of air).

Priming is particularly noted for the

creation of associational biasing or creating false memories.

These loops have some of the same characteristics of ____ systems

declarative (loop, tonic activity, modulation with activity).

For working memory, the regions of cerebral cortex involved in the memory appear to This can be demonstrated by

depend upon the type of task. functional MRI, which can show increases in blood flow with cortical activation during a task

Only ___ or ___ will produce appreciable deficits in long term memory.

diffuse damage or overactivation (epilepsy, or using electroconvulsive therapy)

Its basic connections suggest that a primary function is involved in

feeding and defensive bxs. it receives cortical connections as well

One important mechanism to add significance to memory is

emotional affect

Circuit of Papez originally described as part of a collection of structures as involved in ____, it also describes a set structures that when damaged

emotional affect (usually bilaterally) can disrupt memory processing.

This suggests the modulation of behavior through

endogenous reward mechanisms

In declarative memory, priming is usually demonstrated by

exposing subjects to a list of words or objects (without a request to remember them) and then some time later, testing to see if memory of the list has been retained

Priming is usually demonstrated by

exposing subjects to items in their environment without an effort to remember them and then showing that this exposure affects recall.

T/F The two primary types of memory are associated with the same circuitry.

false § Declarative memory § Nondeclarative (procedural) memory These primary types of memory are associated with two different circuitries that can be distinguished by different types of damage.

The normal inability to convert memories from one form to another, loss of memory, or inability to recall is

forgetting

Anoxia related memory loss can become evident in cases where

general body oxygen levels drop as in heart attacks or cardiac surgery.

Some of working memory is contributed by the _____, however, more recent studies suggest that _____ & _____ are associated with the more complex tasks of working memory, particularly ___ & ___ - The difference may be the inclusion of being able to use the items as well as remembering them.

hippocampus, prefrontal cortex and other neocortical areas problem solving and behavioral planning.

Outgoing connections (efferents) are to the

hypothalamus, brainstem and the globus pallidus as part access to the basal nuclei.

Patients with isolated lesions of the Declarative Memory system/Circuit of Papez have

immediate and some short term memory, but cannot consolidate information into long term memory.

1. a pathway to the hypothalamus (the part that goes 2. a major projection to the

in front of the anterior commissure (precommissural) mammillary bodies (postcommissural).

Working memory is

information held for a short period of time in order to accomplish a task.

The nucleus accumbens or nucleus accumbens septi lies at the

junction of the caudate nucleus and the putamen and next to the septal nuclei.

The cortical structures form a ring around the ____ the primary parts include:

medial aspect of the brain. the cingulate gyrus, the parahippocampal gyrus, the uncus, and small cortical areas included in hippocampal formation.

Nondeclarative (procedural) memory

memories that largely cannot be retrieved at a conscious level; how to perform tasks (e.g., riding a bicycle, gymnastic maneuvers).

The limbic system contains several cortical and subcortical structures that are interconnected for the processing of

memory and the expression of related emotions.

Amygdala's connections with the hypothalamus are believed to be the mechanism for

memory associated autonomic responses.

The neural circuitry involved in the incorporation of STM to LTM has been revealed primarily through the study of cases where lesions have produced

memory deficits

To actually confirm forgetting, it must be clear that a

memory has been formed.

A major function of limbic system circuitry is

memory processing

Association is important to enhance _____, particularly if the association is perceived as ____ for the individual

memory storage "significant" The association of random objects, words, or numbers with objects significant to the individual can dramatically increase particularly declarative memory, but also non-declarative aspects.

Long term memory is the

more permanent storage of information for periods of days, weeks, months, or years.

the _____ appears to play a role in addiction though the moderation of the rewarding nature of behavior.

nucleus accumbens

Immediate memory is required to be ___ & ____ in an environment. ___ & their connections contribute to this. It is evaluated clinically as

oriented and responsive Broad areas of cerebral cortex general orientation to environment.

Circuit of Papez Basic Pathway- extends sequentially from the ____ to the _____ to the _____ via the fornix (post commissural) to the _____ (via the mammillothalamic fasciculus) to the ______ back to the ______ via a pathway called the _____ that runs just under the cingulate gyrus.

parahippocampal gyrus (entorhinal area) hippocampus mammillary bodies anterior thalamic nuclei cingulate gyrus parahippocampal gyrus (entorhinal area) cingulum bundle

This suggests that at least image recall involves a process of the reactivation of similar brain regions to those involved in

perception

_____ is a phenomenon that demonstrates the continual transfer of information from working memory into long term memory whether or not there is an intent to remember it.

priming

In such patients, ____ memory is often intact, and intelligence testing may indicate ______ In general, _____ injury is required to produce appreciable deficits in this system (but not always).

procedural normal or even above normal. bilateral

The consolidation process is particularly sensitive to

processes which damage or interfere with the hippocampus.

patterns of brain activation involved in perception are similar to those activated in the process of

recall

Electrical stimulation of this area is

rewarding, and it may be responsible for the for addictive or compulsive behaviors by attaching a positive affect to them.

forgetting is an important process in the

selectivity of information that is incorporated

The amygdaloid complex connects directly and indirectly to the _____ It has large input from areas associated with

septal area (nuclei), the hypothalamus, the nucleus accumbens, and rostral areas of the caudate nucleus & putamen taste & olfaction

The fornix- contains two major pathways that interconnect the hippocampus to the

septal area, hypothalamus, and mammillary bodies

There is also some evidence that some disruption of ____ can be achieved by manipulation during recall.

specific long term memories

Declarative memory is

storage and retrieval that is available to consciousness and can be expressed by language (e.g., remembering a telephone number or images of events that have happened).

Non-declarative Memory Substrates The fact that patients with memory consolidation deficits can be shown to retain the ability to acquire procedures or non-declarative memory indicates that these memories have a different

substrates

Declarative memory is generally associated with

the circuit of Papez

Papez's circuit appears to be most closely associated with

the formation of new memories, primarily of the type that can be stated (declarative memory). In particular, it is associated with the transition between short term memory and long term memory.

Long term memory is the general model studied to identify

the incorporation of a piece of information (in the form of afferent action potentials) into a physical embodiment of neuronal change (engram).

The Mammillothalamic tract connects

the mammillary bodies with the thalamus (anterior nuclear group).

These forms may occur

together, but also apart and can give a clinical picture of the severity of brain trauma after brain injury. (e.g., the extent of amnesia after head trauma, memory of the accident, before and after can indicate the severity of injury).

The amygdala uses ______ sensory inputs to coordinate emotional responses to ____ stimuli

visceral and somatic pleasurable, fearful, and visceral stimuli

Clinical test is to remember a span of digits presented; 7-9 is normal. § Another is a list of several words to be recalled later in an interview. are examples for which type of memory?

working memory (STM)

Although there are many neural pathways that interconnect the structures of the limbic system, the two major ones are the

§ Fornix § Mammillothalamic tract.

temporal aspects of these two memory types:

§ Immediate memory § Working memory § Long term memory