Memory Flashcards
What 2 ways can memory be categorised
effective time over (Temporal)
types of memory (Qualitative)
Describe declarative memory
Declarative memory is the storage and retrieval of material that is available to consciousness and can be expressed by language. Examples of this type of memories are ability to remember a telephone number, a song, or the images of some past event. Declarative memory is divided into:
-episodic memory for autobiographical life experiences
-semantic memory for facts.
Describe non-declarative memory
Non-declarative memory is not available to consciousness and involve skills and associations that are acquired and retrieved at an unconscious level. Remembering how to dial the telephone, how to sing a song or how to tie shoelaces are example of this type of memory. Non-declarative memory fall into several categories:
-procedural (motor skills & habits)
-non- associate learning (habituation & sensitization)
-simple classical conditioning (associations)
-priming
What is priming?
It is defined as a change in the processing of a stimulus due to a previous encounter with the same or a related stimulus with or without conscious awareness of the original encounter
What are the temporal categories of memory?
Immediate/sensory memory is the routine ability to hold ongoing experiences in mind for fractions of a second. The capacity of immediate memory is very large and each sensory modality (visual, verbal, tactile, and so on) appears to have its own memory register.
Working memory is the ability to hold information in mind for seconds to minutes once the present moment has passed. An everyday example of working memory is searching for a lost object; working memory allows the hunt to proceed efficiently, avoiding places already inspected.
long-term memory is the ability to hold information in a more permanent form of storage for days, weeks, or even a lifetime.
Attention is very essential factor for immediate memory transfers to working memories.
If there is no rehearsal/repetition, forgetting occurs.
Describe Immediate/Sensory Memory (short term memory)
Automatic response to different types of sensory stimuli
Max 500 ms
Does not store in brain (no consolidation)
Weakly dependent on attention
Modality specific
Decreases with age
Describe Working memory and what it includes
It is a multi-component system (short term memory) allows information to store in different areas. The working memory includes:
-Central executive: Drives the whole system, deals with cognitive tasks such as problem-solving.
-Visuo-spatial sketchpad: Responsible for processing visual and spatial information. This allows people to store images of objects and their locations and is also used in navigation.
-Phonological loop: processes sound and is responsible for speech-based information. This includes sounds that are processed in one’s mind.
-Episodic buffer: a place to temporarily integrate information gathered from the phonological loop, visuo-spatial sketchpad, and long-term memory.
Describe long term potentiation and the synaptic changes steps
It is a form of activity-dependent plasticity which results in a persistent strengthening /enhancement of synaptic transmission between neurons. It is an important process in the context of synaptic plasticity and formation of long-term memory. Most research have been conducted in the hippocampus.
Synaptic changes during LTP:
The AMPA receptor is a ligand (glutamate) gated Na ion channel
The NMDA receptor channel is permeable to Ca2+ but is blocked by physiological concentrations of Mg2+ during normal resting membrane potential.
blockade of the NMDA channel by Mg2+ is voltage dependent.
During high frequency stimulation, Influx of Na+ by opening of the AMPA receptors causes change in voltage and the subsequent electrostatic repulsion of Mg2+ from the NMDA receptor.
This allows Ca2+ to enter the postsynaptic neuron.
High concertation of Ca2+ activates calcium/calmodulin-dependent (CaM) kinase.
Then, new AMPA receptors are recruited.
Therefore, equal pre-synaptic levels of stimulation result in greater postsynaptic action potential.
Describe long term depression
Long Term Depression (LTD) :
It is a process by which synaptic connections between neurons are weakened.
Synaptic changes during LTD:
-Prolonged low intensity simulations cause removal of some AMPA receptors on the post synaptic neurons and weakening of the synapses.
-The frequency of stimulation determines whether we get LTP/LTD.
-High stimulation frequency causes LTP; low rate of stimulation causes LTD.
The functions of LTD are not completely understood, but it is important to memory formation by resetting previous synaptic changes to allow for new memories to be formed via long-term potentiation (LTP).
Describe the 2 types of amnesia
Retrograde amnesia is characterized by memory loss for events prior to the trauma.
Anterograde amnesia is an inability to form new memories following brain trauma
What factors can affect short term memory
Sleep deprivation
Stress
depression
Post-traumatic stress disorder (PTSD)
Old age
Alzheimer’s Disease
Schizophrenia
Cerebral contusions (caused by head trauma)
Infarcts or ischemia of medial temporal or medial diencephalic structures
Global cerebral anoxia (e.g. cardiac arrest)
What is Korsakoff syndrome and it’s symptoms
It is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1).
Causes: commonly by alcohol misuse but other conditions such as cancers, chronic infections, poor nutrition can cause this syndrome.
Damage brain regions: thalamus, hippocampus, hypothalamus, brain stem, and cerebellum.
Symptoms:
problems with learning new information
inability to remember recent events.
long-term memory gaps.
Confusional state that can progress to coma.
