Learning and Memory 2: Beyond Hippocampus Flashcards
describe the temporal categories of memory (3)
1) Short-term memory _ aka working and immediate memory
- ability to hold information across an undistracted delay
2) Long-term memory (new memories) _ memory of thing not lost by distraction
3) Remote memory _ memory of events many months to years ago
what are four kinds of nondeclarative memory?
Nonassociative learning
Classical/Operant/Emotional Conditioning
Procedural learning
Priming
what is working memory and how much can it hold?
Mental manipulation and online holding of information over relatively short periods of time.
7 +/- 2 pieces of information, although chunking is possible
what are the two divions of working memory and where do lesions affect them?
1) phonologic information (e.g., the ability to keep a phone number in your head)
- lesions in left hemisphere
2) spatial information (e.g., the ability to mentally follow a route that is described to you)
-lesions in right hemisphere
what parts of the brain does working memory use?
dorsolateral prefrontal cortex (DLPFC) is implicated in almost all WM tasks
also subcortical and posterior cortical areas
the idea that working memory relies primarily on DLPFC with input from subcortical and posterior cortical regions was on the summary slide of the lecture so might be important
what are characteristics of working memory impairment?
Difficulty following multistep commands
Trouble multitasking
Easy loss of task set (forgetting the rules)
Inefficient learning
Reduced contextual memory
Impaired verbal fluency
Impaired comprehension of complex sentences
what are conditions that lead to working memory impairment?
Conditions that affect the frontal lobes or their relevant connections:
Examples:
Focal: Infarcts, tumors
Multifocal: e.g., multiple sclerosis
Neurodegenerative: AD, PD, HD, LBD, etc.
Psychiatric: ADHD, OCD, schizophrenia, depression
what is consolidation?
the process by which memories are solidified into long-term stores
Consolidation involves gradual transfer of information from hippocampal circuits to neocortical ones
what is some evidence that supports that long term storage of memories does not require the hippocampus?
patients who have undergone electroconvulsive therapy (ECT) to treat psychiatric disorders develop a temporally graded retrograde amnesia associated with therapy, such that events leading up to their ECT session are recalled poorly compared to more remote past events. This implies that some process occurs that differentiates remote memories from recently formed ones in a way that makes them more resistant to disruption, and that this process of transferring memories to long-term storage is gradual.
Also Patient H.M. had very clear recall of remote experiences prior to his life-altering surgery and graded memory deficits for the events leading up to the surgery.
What might consolidation and long-term storage entail at the neural level?
One well-supported theory is that consolidation strengthens associations between multiple stimulus inputs and activations of previously stores information. The hippocampus is thought to coordinate this strengthening of associations, but the effects are believed to take place in the neocortex.
what is interesting about the anatomical representation of long-term memories in the neocortex?
often related to the modality of information being stored.
Calling up representations of visual stimuli activates visual cortical areas, calling up memories of a familiar song activates neuronal assemblies in the auditory cortex, and so forth
what is nonassociative learning? Two kinds?
Nonassociative learning results when an animal or person is exposed once or repeatedly to a single type of stimulus
1) Habituation: decrease in response to a benign stimulus when that stimulus is presented repeatedly
2) Sensitization: increased response to various stimuli after a noxious stimulus
what is the habituation example with the aplysia?
Habituation of the gill siphon reflex occurs when repeated stimulation of the siphon results in a diminished gill withdrawal reflex.
In a series of investigations it has been shown that the siphon-gill reflex is mediated by a monosynaptic connection between a sensory neuron and a motor effector.
what is the sensitization example with the aplysia? What is the underlying mechanism? (more detail next lecture!)
the tail of the animal is stimulated just before the siphon is, then the withdrawal of the gill is quicker and more forceful.
The underlying mechanism appears to involve serotonergic, axoaxonal synapses.
in mammals where does nonassociative learning take place?
spinal reflexes
does nonassociative learning require conscious awareness?
no
what are the three forms of conditioning and how are they different?
classical, operant, and emotional conditioning
Classical conditioning entails learning a relationship between two stimuli.
Operant conditioning involves learning a relationship between an organism_s behavior and the consequences of that behavior.
Emotional conditioning involves the learned association between a stimulus and an emotional response.
who introduced classical conditioning?
Pavlov and the dogs!
what is an area of the brain implicated in classical conditioning?
cerebellelum
studied with eyeblink reflexes in rabbits
The importance of the cerebellum in classical conditioning is indicated more directly by the fact that electrical stimulation of the two major inputs to the cerebellum can substitute for the conditioned stimulus and unconditioned stimulus
how are emotional responses to stimuli developed?
largely implicit
what part of the brain plays a large role in emotional conditioning?
amygdala
amygdala is connected to areas of the nervous system that mediate physiologic effects of fear and other emotional states
what can lesions of the amygdala result in ?
Klu_ver-Bucy syndrome
Blunted emotionality
Lack of fear response
Altered sexual behavior
Hyperorality
Visual agnosia
describe Operant conditioning
Formation of predictive relationships between actions and consequences
- Law of effect –>behaviors that produce favorable changes in the environment are repeated, while behaviors that are followed by aversive consequences are avoided.
- A critical component of decision-making and planning
what parts of the brain are involved in operant conditioning?
Dorsomedial frontal cortex implicated in reward-related behavior
Dopaminergic projections from the ventral tegmental area are involved in reward learning
Nucleus Accumbens
what is Procedural learning?
Includes many skills –> Description is typically inadequate to transfer ability
can H.M do procedural learning?
yes! Writing in mirror
Procedural learning is unconscious
what parts of the brain are involved in procedural learning?
Supplementary motor area
Basal ganglia
Cerebellum
what causes procedural learning deficits?
Parkinson_s disease
Other movement disorders
Focal lesions - Tumors or Strokes
Depression
what is priming?
A benefit in the ability to detect or identify words or objects after recent experience with them
Ability to be primed to stimuli is unrelated to explicit recall of stimuli.
Occurs robustly in patients with anterograde amnesia.
Many kinds of stimuli can be primed, including concepts –> nurse example in slides
what does priming improve?
Improves perception for specific stimuli
Affects information available to explicit memory systems
it is modality-specific
