Flashcards in Chapter 8 Deck (54):
Learning without awareness
Serial reaction time task
participants learn to press 1 of 4 keys as soon as a visual cue indicates which key to press. The cues come up either unpredictably ordered (random condition) or ordered in the fixed seq of about 12 cues (sequential or implicit learning condition). Even if they see a pattern, they usually show no awareness that any of the seq was repeating patterns. They learned the seq without knowing that they learned them, marking their learning implicit.
A loss of skill through non use
Memories of new skills ____ with recollection of older skills.
Finger tapping task
learned to press keys in 2 diff. sequences on the same day:
sleep-dependent enhancement was seen only for the 2nd sequence earned.
- learned the 2nd sequence one day after the 1st sequence:
- sleep enhanced performance of both.
- if on the 2nd day the students reviewed 1st day’s sequence before learning the new sequence:
- on the 3rd day sleep enhanced accuracy on only the 2nd sequence.
- reviewing a recently learned skill before beginning to practice a new one can interfere with subsequent recall of the skill that was reviewed.
The restricted applicability of some learned skills to specific situations.
Thorndike's identical elements theory
the transfer of learned abilities to novel situations depends on the number of elements in the new situation that are identical to those in the situation in which the skills were encoded.
Motor programs and rules:
- sequences of movements that an organism can perform virtually automatically.
- either inborn/learned.
- 1 way to determine: remove the stimulus & observe the results.
- cognitive skills become motor programs too.
- e.g. multiplication tables.
- skill memories: memories of the instructions/of a past episode.
- e.g. following recipe in a cookbook.
Fitt's 3 stage model of skill learning
1. Cognitive stage - using written instructions to set up tent
2. Associative stage - setting up tend in a fixed sequence without instructions
3. Autonomous stage - setting up a tend while carrying on a discussion about politics
A collection of ganglia that lie at the base of the forebrain
Most cortical areas do what to the basal ganglia?
Morris water maze
Place rats in tank, rats must swim around until they discover a platform hidden just below the water surface. Basal ganglia damage: swim to where platform used to be if it's moved.
4 basic patterns of neural activity in the basal ganglia
(1) some neutrons fired most at the start
(2) some fired most when the instructional sound was broadcast
(3) some responded strongly when the rat turned
(4) some fired at the end of a trial when food was received.
- increased neural activity seen in the beginning & end states.
Are basal ganglia active during cognitive skill learning?
Skill memories are the neural outcomes of repeated ____
Are there changes happening to cortical regions that aren't the focus for skill training?
Expansion of cortical regions results in what?
Superior performance... to a certain extent!
Musicians dystonia. Why does it happen?
Excessive practice playing an instrument can result in a loss of motor control. Too much reorganization happening in the motor cortex.
Cortical gray matter
Where the cell bodies and neurons are found
Monkey tactile discrimination task
researchers trained monkeys to perform a tactile discrimination task
The task required the monkey to release handgrip whenever the monkey felt a stimulus on its fingertip (that is different from a standard stimulus)
The monkeys felt a vibration of a fixed speed on their finger (initial tactile stimulus - the standard), which was followed by a half second break and then 1-4 additional vibrations; vibrating at either the same speed as the standard or faster
The monkey was rewarded with fruit juice if it released the handgrip if the vibrations were faster than the standard
When the monkey learned that responding to the stimulus resulted in juice, the area of the somatosensory cortex that processed the cue increased in size
This study showed that perceptual motor skill learning results in expansion of representations within the sensory cortex involving the skill
What is the criterion for an ability to be a skill?
If it can be improved with experience.
Finger touch study
Avi Karni and colleagues asked participants to touch each of their fingers to their thumb in a fixed sequence and as fast as possible
The motor cortex involved with sequential-finger-moving motor skills increases rapidly during the first training session and more gradually in the later sessions
In this specific study, after the 3rd week (out of 6) there were even more additional increases
The region of motor cortex activated during performance of the practiced sequence expanded relative to the area activated by different, untrained sequences of finger movements
The initial period of "fast learning" involves processes that select and establish the optimal plans for a performance of a certain task, whilst the slower stages of learning reflect long term structural changes of basic motor control circuits in the cortex
Most of the inputs to the cerebellum come from the...
Spinal cord, sensory systems in cerebral cortex
Most of the output signals from the cerebellum go to...
The spinal cord or the motor systems in the cerebral cortex
Cerebellar lesions result in impaired performance of motor sequences. Which helps us conclude what?
The cerebellum contributes to the performance of perceptual motor skills
The cerebellum is important in learning ____ sequences
Rats watching other rats study
Rats that received cerebellar lesions after observing other rats navigate a maze benefited from those observations when they were later trained in the maze, whereas rats that received lesions before observing other rats traverse the maze did not benefit from their observations
Rats depend on cerebellar processing even when they learn to perform a task by simply watching other rats do it
Mirror tracing task
Mirror tracing = trace drawing by looking in a mirror to observe your hand and the figure to be traced, which is otherwise hidden from view
Although this is difficult, a person with a properly working cerebellum will eventually learn how to do it well with practice
It took participants with cerebellar damage twice as long to trace images, even after a couple training sessions
The rate of learning of the control group was comparable to the rate of learning of the cerebellar damage group, BUT the control group benefitted more from the training sessions
Groups were learning at the same rate, but were not transferring mirror-tracing skills in the same way
When individuals learn to read mirror reversed text
The cerebellum, cerebral cortex and basal ganglia are each critical to skill learning
There is no cut-and-dried division of labor between these brain regions
Cerebellum: most critical for timing
Cerebral cortex: most critical for controlling complex action sequences
Basal ganglia: most critical for linking sensory events to responses
One feature they all have in common: skill learning is associated with gradual changes in the firing of neurons in these areas during performance of the skill
Happens because of damage in the cerebral cortex which leads to problems in coordination of skilled movements
Most common causes for apraxia?
Sharp blow to head or interruption of blood supply to neurons
A patient with apraxia can usually perform individual steps but can't...
Combine the steps in a sequenced movement pattern.
Cortical damage clearly causes deficits in ____ performance.
A hypothesis for why individuals with apraxia have difficulty performing skills is that they cannot flexibly access memories of how to perform these actions
This would suggest that the patients have not simply lost the ability to generate an action but rather can no longer access memories to perform them
Studies show that cortical damage interferes with the control and execution of skills more than with the learning and recalling of skills
i.e. with practice a patient can improve at performing a skill and their rate of improve is comparable to that of a non-impaired person
BUT, the highest level of performance they can reach will likely be lower than a non-impaired person's
How well someone with apraxia can perform depends on what?
The nature of the task as well as the nature of the persons deficits
Transcranial magnetic stimulation
a procedure in which a brief magnetic pulse is applied to the scalp and produces small electrical currents in the brain that affect normal patterns of activity over an area of about 1 square centimetre
Whats one way to investigate the conditions leading up to apraxia?
we create temporary apraxia in a healthy individual by inactivating cortical circuits and then examining the effect on skill learning and recall, this is made possible by transcranial magnetic stimulation
What is the current main technique for helping apraxia patients?
Behavioral training that involves extensive repetitive practice.
An inherited disorder that causes gradual damage to neurons throughout the brain, especially in the basal ganglia and cerebral cortex. It leads to many psychological problems such as mood disorders, depression, psychosis etc
Patients with huntingtons disease show many memory deficits, some of which affect ____ memories.
People with huntingtons disease have difficulty learning tasks that require...
Planning and sequencing of action
Barbara Knowlton and colleagues found that an experimental group of 13 with HD who were tested on the weather prediction task showed NO signs of learning after 150 trials, unlike the healthy group
This can be explained by the basal ganglia damage
Patients with HD typically show large deficits in perceptual motor skill learning that seem to be related to problems with retrieval and decreased storage capacity
Difficulty with tasks like serial reaction time task, rotary pursuit task and other tasks that require tracking a target
Studies showed that both explicit and implicit components of a motor sequence task were impaired even before people with HD showed any clinical symptoms
This allows us to reach the conclusion that learning deficits are not simply a side effect of motor control problems or abnormal psychological states
A nervous system disease involving disruptions in the normal functions of the basal ganglia and progressive deterioration of motor control.
The main brain damage associated with PD is a reduction in the number of dopaminergic neurons in the substantia nigra pars compacta (SNc) that control activity in the basal ganglia. Why is this?
This is because neurons in the SNc normally determine the levels of dopamine in the basal ganglia, and when they are gone, dopamine levels are greatly reduced
Patients with parkinson's disease show ____ tremors.
Parkinson's disease symptoms usually arise at what age?
Skill learning is impaired with huntingtons disease and parkinsons. But people with parkinsons can learn skills such as mirror reading, which huntingtons cannot.
This suggests that although both diseases affect processing in the basal ganglia and cerebral cortex, the damage each causes leads to different but overlapping deficits in skill memory systems
PD selectively disrupts circuits in the basal ganglia
Main treatment for parkinson's disease?
Drug therapies that counteract the reduced level of dopamine or surgeries that counteract the disruption caused by lack of dopamine in basal ganglia.
Deep brain simulation
When an electrical current is delivered through one or more electrodes permanently implanted deep in the patients brain (effective).
Neurosurgeons place the ends of electrodes near neurons that are a part of the basal ganglia cortical loop
When electrical current from an implanted stimulator passes through these electrodes, many of the motor symptoms associated with PD (i.e. tremors) disappear within SECONDS, but eventually return
This helps because without a proper amount of dopamine, interactions between neurons in the cerebral cortex and basal ganglia become locked into fixed patterns
The stimulation from the electrode stops this fixed pattern and allows normal brain activity to resume