Carl Zimmer; Cerebrum 2008 - Emerging Ideas in Brain Science
Book	Page		Topic
Frank; Learning and the Basal Ganglia	149		Learning and the Basal Ganglia.
Frank; Learning and the Basal Ganglia	151		Many human behaviors are reflexes programmed into our brains when we are rewarded or punished for taking a particular action.  [Stereotyped motor programs]  [FAPs]		2
Frank; Learning and the Basal Ganglia	151		Basal ganglia are important in learning from feedback in the formation of good and bad habits.		0
Frank; Learning and the Basal Ganglia	151		Brain is programmed to reinforce actions that are immediately followed by rewards. This is especially true when the reward is unexpected.		0
Frank; Learning and the Basal Ganglia	151		Many of our actions can be explained by principles of learning that are embedded in our neural machinery.  [Stereotyped motor programs]  [FAPs]		0
Frank; Learning and the Basal Ganglia	151		Neurosciences is shedding light on how circuits linking two parts of the brain, the basal ganglia and the frontal cortex, contribute to learning both productive and counterproductive behaviors.		0
Frank; Learning and the Basal Ganglia	152		Basal ganglia receive information from the frontal cortex about behavior that is being planned for a particular situation.		1
Frank; Learning and the Basal Ganglia	152		Basal ganglia affect activity in the frontal cortex through a series of neural projections that ultimately go back to the same cortical areas from which they received the initial input.		0
Frank; Learning and the Basal Ganglia	152		The circuit to the frontal cortex enables the basal ganglia to transform and amplify the pattern of neural firing in the frontal cortex that is associated with adaptive, or appropriate behaviors, while suppressing those that are less adaptive.		0
Frank; Learning and the Basal Ganglia	152		Neurotransmitter dopamine plays a critical role in the basal ganglia in determining, as a result of experience, which plans are adaptive and which are not.		0
Frank; Learning and the Basal Ganglia	152		Dopamine bursts and dips are thought to drive changes in the strength of synaptic connections in the basal ganglia so that actions are reinforced (in the case of dopamine bursts) or punished (in the case of dopamine dips).		0
Frank; Learning and the Basal Ganglia	153		Patterns of dopamine firing bear a striking resemblance to learning signals.		1
Frank; Learning and the Basal Ganglia	153		Humans activated reward areas of the basal ganglia, which are heavily enriched with dopamine, when receiving unexpected rewards.		0
Frank; Learning and the Basal Ganglia	153		People with Parkinson's disease, whose basal ganglia dopamine levels are severely depleted as a result of cell death, show deficits in trial and error learning from feedback.		0
Frank; Learning and the Basal Ganglia	153		Humans recruit their "primitive" reinforcement learning system in the basal ganglia to support behavior in more complex cognitive tasks.  [Stereotyped motor programs]  [FAPs]		0
Frank; Learning and the Basal Ganglia	154		Circuitry linking various neural subregions that collectively form the basal ganglia are so complex and convoluted that computer models are required to gain insight.		1
Frank; Learning and the Basal Ganglia	154		Many attempts have been made to a model basal ganglia function.		0
Frank; Learning and the Basal Ganglia	154		A number of computer models of the basal ganglia have converged on the same core idea: the architecture of the basal ganglia are particularly well  suited to support  "action selection" -- that is, to implicitly weigh all available options for what to do next and to choose the best one.		0
Frank; Learning and the Basal Ganglia	154		Actions that can be selected by the basal ganglia range from simple motor behaviors, to manipulation of information in memory, such as multiplying numbers in your head.		0
Frank; Learning and the Basal Ganglia	155		It seems that our ability to think, reason, and manipulate memories, evolved from similar mechanisms that allow an animal to perform impressive sequences of motor actions, like when a bird swoops down to catch a fish.		1
Frank; Learning and the Basal Ganglia	155		Difference between cognitive and motor functions performed by the basal ganglia may lie in the specializations of the different regions of the frontal cortex and actions that each encodes.		0
Frank; Learning and the Basal Ganglia	155		Circuits that link parts of the basal ganglia to motor cortical areas are structurally identical to those linking other parts of the basal ganglia to the regions of the prefrontal cortex that are used for cognitive processes.		0
Frank; Learning and the Basal Ganglia	155		Basal ganglia can play a similar role in selecting among both motor and cognitive actions, by interacting with different parts of the frontal cortex.		0
Frank; Learning and the Basal Ganglia	155		Computational models that explore the role of the basal ganglia when people select motor and cognitive actions.		0
Frank; Learning and the Basal Ganglia	155		Cognitive models have been focusing on how dopamine signals in the basal ganglia, which occur as a result of positive and negative outcomes of decisions (that is, rewards and punishments), drive learning.		0
Frank; Learning and the Basal Ganglia	155		Basal ganglia learning is made possible by two main types of dopamine receptors, D1 and D2, which are associated with two separate neural pathways through the basal ganglia.		0
Frank; Learning and the Basal Ganglia	155		When the "Go" pathway is active, it facilitates an action directed by the frontal cortex; when the opposing "NoGo" pathway is more active, the action is suppressed.		0
Frank; Learning and the Basal Ganglia	155		These Go and NoGo pathways compete with each other when the brain selects among multiple possible actions, so that an adaptive action can be facilitated while at the same time competing actions are suppressed.		0
Frank; Learning and the Basal Ganglia	156		During unexpected rewards, dopamine bursts drive increased activity and changes in synaptic plasticity (learning) in the Go pathway.		1
Frank; Learning and the Basal Ganglia	156		When a given action is rewarded in a particular environmental context, the associated Go neurons learn to become more active the next time the same context is encountered.		0
Frank; Learning and the Basal Ganglia	156		The Go neurons learning depends on the D1 dopamine receptor, which is highly concentrated in the Go pathway.		0
Frank; Learning and the Basal Ganglia	156		When desired rewards are not received, the resulting dips in dopamine support increases synaptic plasticity in the NoGo  pathway (a process that depends on dopamine B2 receptors concentrated in that pathway).		0
Frank; Learning and the Basal Ganglia	156		A computer model of these Go/NoGo signals, (and the spread of the signals through the rest of the basal ganglia circuit) can learn to produce actions that are most likely to lead to reward in the long run.  [Bayesian inference]		0
Frank; Learning and the Basal Ganglia	156		The same dopamine reinforcement learning process can be extended to reinforce cognitive actions that are essential intermediate steps, for example, doing the arithmetic that is needed to achieve the longer-term goal of preparing your taxes.  [Stereotyped motor programs]  [FAPs]		0
Frank; Learning and the Basal Ganglia	156		Dopamine reinforcement learning process also punishes distracting thoughts ("What's for dinner?"), allowing you to stay on task.		0
Frank; Learning and the Basal Ganglia	156		Dopamine reinforcement learning process enable complex cognitive working memory operations, such as remembering figures as you multiply them, to be executed more swiftly and efficiently with practice.  [Stereotyped motor programs]  [FAPs]		0
Frank; Learning and the Basal Ganglia	159		Parkinson's disease offers one of the clearest instances of basal ganglia dysfunction, since the loss of dopamine in the basal ganglia in Parkinson's is well understood.		3
Frank; Learning and the Basal Ganglia	160		It is often assumed that Parkinson's disease affects only motor function.  Recent studies have confirmed that Parkinson's is a complex neuropsychiatric condition that clearly has cognitive effects.		1
Frank; Learning and the Basal Ganglia	161		In attention-deficit/hyperactivity disorder (ADHD), neurobiological research has consistently implicated dopamine deficiency, and stimulant medications often used to treat ADHD, act by directly increasing basal ganglia dopamine.		1
Frank; Learning and the Basal Ganglia	162		The majority of drugs of abuse act by hijacking the natural rewards system.		1
Frank; Learning and the Basal Ganglia	162		When an addict snorts cocaine or smokes a cigarette, he not only experiences a drug-induced high ("reward"), but the associated dopamine bursts act to further stamp these destructive behaviors into his brain so they are more likely to be repeated.		0
Frank; Learning and the Basal Ganglia	162		Dopamine signals are primarily associated with unexpected rewards.		0
Frank; Learning and the Basal Ganglia	162		Normally, as people come to expect a reward, an adaptive process prevents dopamine bursts from occurring when the reward is actually delivered.		0
Frank; Learning and the Basal Ganglia	162		Unfortunately, drugs of abuse bypass the circuitry that would normally enable the discounting of expected rewards, and directly elevate dopamine levels. Consequently, maladapted drug-taking behavior is continually strengthened, making it particularly difficult to override.  This enhanced stimulus-response learning also may explain the high rate of relapse in recovering addicts who encounter cues associated with taking drugs.		0
Frank; Learning and the Basal Ganglia	163		Obsessive-compulsive disorder (OCD) people tend to repeat the same behaviors again and again.		1
Frank; Learning and the Basal Ganglia	164		Higher order decisions and working memory may involve a choice between an action directed by the basal ganglia's implicit learning systems or a more elaborate conscious processing in the prefrontal areas of the brain, which can override the more primitive basal ganglia system.		1