PHYSIOLOGICAL UNDERPINNINGS OF LANGUAGE, PROBLEM SOLVING, AND REASONING

Thinking vs. Language  Is there a difference between thinking and language? In other words, do you “think” language and thinking should be studied separately or together?

Language  Arbitrary system of communication that combines symbols, such as words or gestural signs, in rule- based ways to create meaning  Allows for communication of information, as well as social and emotional functions

Features of Language  Highly practiced and automatic process  Four levels of analysis that must coordinate  Phonemes  Morphemes  Syntax  Extralinguistic information

Nonhuman Animal Communication  Animal species differ in the complexity and type of communication  Most communication is geared towards mating and aggression  Honeybees and vervet monkeys

Teaching Human Language  Many attempts to teach non-humans our language, with mixed results  Chimpanzees  Bonobos  Humans appear unique in our ability to use language in a sophisticated way

Aphasias Paved the Way  What is an aphasia?  2 important discoveries from aphasias  Left hemisphere is dominant in language  Two key cortical areas have different roles in language Broca’s Area Wernicke’s Area **arcuate fasciculus is bidirectional

Modern Framework  3 large systems interact closely in language perception and production  Language implementation system Broca and Wernicke Analyzes incoming signals and ensures articulatory control  Mediational system Temporal, parietal, occipital, and frontal association cortices  Conceptual system Remainder of higher-order association cortices

Problem Solving and Reasoning  Involves reliable planning, judgment, and decision- making  Requires monitoring of external world, attention to information, retrieval from long-term memory, manipulation/integration of information, and output of appropriate information.  Also, suppression of unnecessary information and inappropriate actions.  Altogether, this is called executive function.

Problem Solving and Reasoning  “Executive control”– mechanism or system responsible for the coordinated operation of various systems.  Prefrontal cortex is considered the important structure for executive control  Numerous studies on damage of the prefrontal cortex  Studies indicate a sensitivity, not a specificity for executive function

Prefrontal Damage  Normal IQ  Normal long-term memory  Normal perceptual and motor skills  Deficits when intellectual operations demand creation of a program of action  Difficulties when a choice needs to be made between several equally probable alternatives  Coordination of perceptual, motor, and memory processes is deficient

3 divisions of prefrontal cortex  Dorsolateral Prefrontal Cortex  Anterior Cingulate Cortex  Orbitofrontal Cortex

Dorsolateral Prefrontal Cortex  Involved with on-line processing such as integrating different dimensions of cognition and behavior  Verbal fluency, maintain and shift set, planning, response inhibition, working memory, organizational skills, reasoning, problem solving, abstract thinking.

Anterior Cingulate  Involved in emotional drives, experience, and integration  Responsible for inhibition of inappropriate responses, decision making, and motivated behavior.  Lesions related to low drive states

Orbitofrontal Cortex  Involved in impulse control, maintenance of set, monitoring ongoing behavior and socially appropriate behavior  Role in representing the value of rewards based on sensory stimuli and evaluating subjective emotional experiences  Lesions lead to impulsivity, aggressive outbursts, sexual promiscuity, antisocial behavior.

The role of working memory  Involved with temporary storage of information  Also a mechanism of for manipulating and processing stored information  This is an indication that working memory can be considered a “workspace” for information processing

3 Features of Prefrontal Mechanism 1. Represent and process any kind of new information 2. Access any kind of necessary information 3. Provide information to various neuronal systems to direct information processing **The prefrontal mechanism must have flexible and dynamic input-output relationships with various brain systems