Chapter 12 - Cog. Control.docx

*Mario Andretti* Cognitive Control ================= - What are the computational requirements that enable organisms to plan and execute complex behaviors? - What are the neural mechanisms that support working memory, and how is task-relevant information selected? - How does the br...

*Mario Andretti* Cognitive Control ================= - What are the computational requirements that enable organisms to plan and execute complex behaviors? - What are the neural mechanisms that support working memory, and how is task-relevant information selected? - How does the brain represent the value associated with different sensory events and experiences, and how does it use this information to make decisions when faced with multiple options for taking action? - How do we monitor ongoing performance to help ensure the success of complex behaviors? **515** ### The Anatomy Behind Cognitive Control  TAKE-HOME MESSAGES - Cognitive control is the collection of mental abilities that involve planning, controlling, and regulating the flow of information processing. - Cognitive control gives us the flexibility required for goal- oriented behavior. - The prefrontal cortex includes four major components: lateral prefrontal cortex, frontal pole, orbitofrontal cortex, and medial frontal cortex. These parts of the brain have become very prominent in mammals, and especially ### Cognitive Control Deficits TAKE-HOME MESSAGES - Patients with frontal lobe lesions have difficulty executing a plan and may exhibit stimulus-driven behavior. - Deficits in cognitive control are found in numerous psychi- atric disorders, as well as when mental health is compro- mised by situational factors such as stress or loneliness. 3. ### Goal-Oriented Behavior Cognitive Control Requires Working Memory Prefrontal Cortex Is Necessary for Working Memory but Not Associative Memory Physiological Correlates of Working Memory  10 s  0.8 0.6 0.4 0.2 0 LPFC 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 Time (s) Time (s) \ Organizational Principles of Prefrontal Cortex 1. A ventral--dorsal gradient organized in terms of maintenance and manipulation, as well as in a manner that reflects general organizational prin- ciples observed in more posterior cortex, such as the ventral and dorsal visual pathways for "what" versus "how." 2. An anterior--posterior gradient that varies in abstraction, where the more abstract representa- tions engage the more anterior regions (e.g., frontal pole), and the less abstract engage more posterior regions of the frontal lobes. In the extreme, we might think of the most posterior part of the frontal lobe, the primary motor cortex, as the point where abstract intentions are translated into concrete movement. 3. A lateral--medial gradient related to the degree to which working memory is influenced by information in the environment (more lateral) or information re- lated to personal history and emotional states (more medial). In this view, lateral regions of the PFC integrate external information that is relevant for current goal-oriented behavior, whereas more medial regions allow information related to motivation and potential reward to influence goal-oriented behavior. Rest \ TAKE-HOME MESSAGES - Working memory can be conceptualized as the informa- tion formed by the combination of a task goal and the perceptual and long-term knowledge relevant for achieving that goal. This form of dynamic memory emerges from the interactions of prefrontal cortex and the rest of the brain. - Neurons in the PFC of monkeys show sustained activity throughout the delay period in delayed-response tasks. These cells provide a neural correlate for keeping a represen- tation active after the triggering stimulus is no longer visible. - Various frameworks have been proposed to uncover functional specialization within the prefrontal cortex. Three gradients have been described to account for PFC processing differences: ventral--dorsal, anterior-- posterior, and lateral--medial. 4. ### Decision Making Is It Worth It? Value and Decision Making 50 45 40 35 30 25 20 15 10 5 Probabillity Payoff Cost Non-FC a. The participant must choose either to receive an immediate reward of modest value or to wait for a specified delay period in order to receive a larger reward. **(b)** The locations of orbitofrontal lesions in **c** 1.5 1.0 0.5 0 --0.5 --0.1 **d** More Than One Type of Decision System? 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0 Dopamine Activity 3.0 2.6 2.2 1.8 1.4 1.0 **b** **c** (No CS) a. No predictions; reward occurs  b. Reward predicted; reward occurs CS c. Reward predicted; no reward occurs  Odor A Time (s) Time (s) Alternative Views a. People were presented with one of four cues: A, B, C, or D. Over time, they learned that each cue was associated with one of two possible outcomes (or, for Cue A, the same neutral outcome). b. Prediction errors reliably predicted the BOLD response in the ventral striatum, with the center of the positive RPE response (green) slightly anterior to the center of the negative RPE response (red). a. Response profile of DA neurons that code valence. These neurons increase their firing rate as the probability of a positive outcome increases and decrease their firing rate as the probability of a negative outcome increases. **(b)** Response profile of DA neurons coding salience. These neurons increase their firing rate as reinforcement probability increases, independent of whether the reinforcement is positive or negative, signaling that the stimulus is important (or predictive). TAKE-HOME MESSAGES - A decision involves the selection of one option among several. It typically involves an evaluation of the expected outcome (reward) associated with each option. - The subjective value of an item is made up of multiple variables that include payoff amount, context, prob- ability, effort/cost, temporal discounting, novelty, and preference. - Single-cell recordings in monkeys and fMRI studies in humans have implicated frontal regions, including the orbitofrontal cortex, in value representation. - Reward prediction error (RPE) is the difference between the expected reward and what is actually obtained. The RPE is used as a learning signal to update value informa- tion as expectancies and the valence of rewards change. The activity of some DA neurons provides a neuronal code of prediction errors. - DA neurons also appear to code other variables that may be important for goal-oriented behavior and decision making, such as signaling the salience of information in the environment. ### Goal Planning: Staying on Task 1. The goal must be identified and subgoals developed. For instance, in preparing for an exam, a conscien- tious student develops an action plan like the one in **Figure 12.20**. This plan can be represented as a hier- archy of subgoals, each requiring actions to achieve the goal: Reading must be completed, lecture notes reviewed, and material integrated to identify themes and facts. 2. In choosing among goals and subgoals, consequences must be anticipated. Would the information be remembered better if the student set aside an hour 3. Requirements for achieving the subgoals must be determined. The student must find a place to study. The coffee supply must be adequately stocked. Retrieval and Selection Multitasking The Benefits and Costs of Goal-Based Selection 1.5 1 0.5 0 --0.5 --1 1.5 1 0.5 0 --0.5 --1  \ TAKE-HOME MESSAGES - Successful execution of an action plan involves three components: (1) identifying the goal and developing subgoals, (2) anticipating consequences when choosing among goals, and (3) determining what is required to achieve the goals. - Goal-oriented behavior requires the retrieval and selec- tion of task-relevant information. The prefrontal cortex can be conceptualized as a dynamic filtering mechanism through which the task-relevant information is activated and maintained in working memory. - Cognitive control is also essential when we need to maintain multiple goals at the same time, especially when those goals are unrelated. With practice, the brain develops connectivity patterns that enable people to ef- ficiently shift between different goals. - Through the selection of task-relevant information, the prefrontal cortex helps make action selection more efficient. This benefit of using experience to guide action selection may also come at a cost in terms ### Mechanisms of Parietal Left prefrontal lesions \+ 0.5 μV -- 0 Instruction Delay Remember scenes, ignore faces **Right PPA** Prefrontal Cortex and Modulation of Processing 100 90 80 70 60 50 0 2 0 --2 2 0 --2 Time (ms) Time (ms) First half Second half Actual rTMS Inhibition of Action 0.08 0.06 0.04 0.02 0 --0.02 --0.04 Failed stop **Train** AC 1,800 1,700 1,600 1,500 1,400 0 Seniors Off DBS On DBS **Patient condition** a. The participant selected one of two symbols on each trial. Feedback was provided after the response. Each symbol had a specific probability of reward (e.g., Symbol A had an 80% probability of reward, while Symbol B had only a 20% probability). During training, there were only three pairs (A and B, C and D, E and F). During the generalization test, untrained pairs were presented. The stimuli could be classified into low- and high-conflict pairs. Low-conflict pairs were defined as trials in which one member had a \>50% chance of reward and the other had a \50% chance of reward (win--win) or \