Neuropsychology and Attention Disorders

Perception

• Perception is the interpretation of information from the sensory system.
• All senses contribute to perception: vision, audition, smell, taste, and touch.

What is Perception?

• Perception involves interpreting raw sensory data.
• The brain processes sensory information to create our perceptions of the world.

"Outside World" Diagram

• Sensory information (light, sound, etc.) from the external world reaches receptors.
• The sensory organs (eyes, ears, nose, skin, tongue) process stimuli and convert it into raw data.
• The brain interprets this raw data to create perception.

Sensation and Sensory Organs

• Sensation involves receiving, transmitting, and converting information from the environment.
• Sensory organs transmit this information to the brain.
• Perception occurs in the brain.

Top-Down and Bottom-Up

• Direct perception theories involve bottom-up processing.
• Bottom-up processing starts with the sensory input and moves to higher brain levels.
• Constructive perception theories involve top-down processing, where expectations and previous experiences influence perception.
• Top-down processing is from higher brain levels to lower sensory input.

Stimuli

• Light, pattern, motion, color, and shape are examples of stimuli that provide information.
• Sensory stimuli from the environment lead to perception.
• Recognition processes, such as selection, organization, and interpretation, convert incoming data into meaningful perceptions.

Errors with Perception

• Perceptual experiences can be in error.
• Visual illusions are visual stimuli that are misinterpreted.
• Form information into patterns, and then understand the patterns.
• Organization forms information into patterns.
• Interpretation understands the pattern.

Perceptual Constancy

• Environment is perceived as remaining the same even with changes in sensory input.
• This includes size constancy, shape constancy, and color constancy.
• Also includes brightness constancy.

Interpreting Perception

• Perception depends on factors:
• Perceptual adaptation
• Perceptual set
• Motivation
• Frame of reference

Absolute Thresholds of the Senses

• Vision: Candle flame viewed from 30 miles away on a clear, dark night
• Hearing: A watch ticking 20 feet away in a quiet room
• Taste: 1 teaspoon of sugar dissolved in 2 gallons of water
• Smell: One drop of perfume diffused throughout a small house
• Touch: The pressure of a fly's wing falling on a cheek from a distance of 0.4 inches

Visual Perception

• Visual perception involves understanding 'what' an object is and 'where' it is.
• This includes aspects like color, texture, shape, and size.
• Separated into two neural systems: Ventral stream and Dorsal stream.

Visual Perception - Neural Systems

• Ventral stream supports 'what' perception.
• Dorsal stream supports 'where' perception.
• Both streams project to the frontal cortex for actions to be taken.

Visual Cortex (V1,V2) (Primary Visual Cortex)

• Sensory areas of the visual cortex process different aspects of stimuli in the visual field, like orientation, size, and color.
• The visual cortex processes stimuli and categorizes these to other regions for further analysis and recognition.
• Damage causes total or partial blindness.

Object Recognition (Ellis and Young, 1996)

• Stages of object recognition include a primal sketch, 2-dimensional image, 3-dimensional image, viewer-centered representation, object-centered representation, recognition unit, and semantic system.
• This conceptual model details the stages in object recognition.

Form Perception (Gestalt principles)

• People organize visual elements into unified wholes based on Gestalt principles.
• Principles include proximity, similarity, symmetry, closure, and common fate.

Law of Proximity

• Objects close together are perceived as a group.

Law of Similarity

• Similar objects are perceived as a group

Law of Common Fate

• Objects moving in the same direction.

Law of Closure

• Unfinished objects are seen as complete.

Law of Figure Ground

• An object is distinguished from its background, perceived as a figure and a surface/ground.

Blindsight

• Subjects are blind to visual information due to damage to area V1 in the visual cortex.
• They can still sometimes "guess" the direction of moving objects or their color.
• Suggests that visual information might still be reaching other parts of the brain.
• An unconscious processing of visual information is likely involved.

Visual Information and Cortex Damage

• Visual information reaches other levels of the cortex, even if V1 is damaged

Trichromatic and Opponent-Process Theories of Color

• Trichromatic theory: Three types of cones for color perception.
• Opponent-process theory: Three types of color pairs (red-green, blue-yellow, light-dark).

Color Blindness

• Trichromat: Normal color vision.
• Monochromat: Totally color blind.
• Dichromat: Partial color blindness (distinguish between two colors).
• Color blindness occurs more often in males.

Spatial Function

• Localisation and perception of objects in space as well as perception of movement.
• Depth perception, spatial memory, and topographical orientation are related.
• The left and right hemispheres of the brain are involved in spatial function.

Auditory Perception

• Sounds are processed by sensory receptors that transmit information to the brain through auditory nerves.
• The outer, middle, and inner ear play a role in this.

Absolute Thresholds – Auditory

• A watch ticking.
• Range of hearing – Decibels

Absolute Thresholds

• Decibels and levels of sound.

What vs. Where Systems (Auditory)

• Auditory pathways to different parts of the brain help in localization.
• Ventral and dorsal pathways can be used, depending on the information being processed.
• Sound localization

Perception of Smell

• Odors trigger receptor neurons in the olfactory membrane.
• Olfactory information travels to the brain.
• Smell contributes significantly to the flavor of food.

Perception of Taste

• Taste is detected through taste cells on taste buds.
• Four primary taste qualities: sweet, sour, salty, bitter.
• Flavor depends on odor, texture, temperature, and taste.

Perception of Touch and Pressure

• Sensory receptors in the skin fire when stimulated.
• Some body areas are more sensitive due to denser nerve endings.
• More sensory cortex dedicated to these areas.

Perception of Temperature

• Temperature perception is based on thermal receptors located just beneath the skin.
• Skin temperature increases, causing warm receptors to fire.
• Skin temperature decreases, causing cold receptors to fire.

Perception of Pain

• Nociceptors in the skin mediate pain sensations.
• Nociceptors stimulate pain more acutely in areas with denser nerve endings.
• Pain can be felt throughout the body.
• Phantom limb pain is pain experienced in amputated limbs.

Body Senstation

• Touch, temperature, and pain are sensed by skin receptors and transmitted to the brain.
• Vestibular sense (body orientation in space) involves semicircular canals.
• Kinesthetic sense (body posture, movement) depends on receptors within muscles, joints, and tendons.

Agnosias

• Inability to recognize objects despite intact sensory input.
• Possible sensory or associative deficits.
• Sensory agnosia, apperceptive agnosia, and associative agnosia are types.
• Prosopagnosia: Inability to recognize faces.

Visual Agnosia

• Visual acuity normal and perception of stimuli in both visual fields may be intact
• Cannot point to named objects or match/copy/discriminate simple visual forms.
• May draw well from memory.
• Recognition may improve if objects are moved around.

Associative Agnosia

• Cannot point to names of objects, but may match/copy/discriminate simple forms.
• Unable to process meaning from vision but can recognize objects from touch.
• Indicates intact object knowledge.
• May occur accompanied with optic aphasia, suggesting a deeper loss of knowledge about objects from any modality.
• Semantics related to objects can be affected.

Prosopagnosia

• Inability to recognize familiar faces.
• Normal visual acuity.
• Likely caused by a lesion to the right inferior temporal lobe.
• Patients often use other clues.

Primary Visual Cortex

• Different cells respond differently to various stimulus aspects (orientation, size, or color).
• Categorizes rather than analyzes.
• Projects to other regions for further analysis.
• Damage results in total or partial blindness.

Form Perception

• Unified whole.
• Visual elements organized into groups or unified wholes based on certain principles.
• Proximity: close objects grouped together
• Similarity: similar objects grouped together
• Symmetry: balanced or symmetrical objects appear complete or whole
• Closure: incomplete or partially obscured objects are perceived as whole.
• Common fate: objects moving in the same direction are grouped together.

Absolute Thresholds - Summary

• Minimum amount of sensory stimulation.
• Measured across different senses.

Perception of Movement

• The brain detects continuous movement from successive positions of a moving object.
• The medial temporal cortex area (MT) plays a critical role in perceiving movement
• Difficulty in judging movement might indicate problems with the MT area.

Clinical Example

• Bilateral damage to area V5 in medial temporal cortex in a patient.
• The patient lacked the ability to perceive continuous motion.
• Difficulty with daily tasks requiring a perception of movement, such as crossing the street or pouring a drink.

Auditory-visual Perception

• Auditory receptors, processing in the brain
• Integration with multiple senses, including vision, results in more nuanced perceptions.

Absolute Threshold Levels (Auditory)

• Measures sound levels (decibels) in terms of a threshold.

Spatial Perception

• Relating objects in space to oneself in a three-dimensional structure.
• Ability to orient the body in space and use three-space in a comprehensive sense.

Memory

• Sensory memory: Information from the senses (very brief duration, large capacity)
• Working memory: Storing information temporarily (limited duration, limited capacity)
• Long-term memory: Storing information permanently (limitless capacity)

Memory and Brain Structures

• Hippocampus, dentate gyrus, and subcortical cortex play a role in forming memories.

Hebbian Theory

• Learning process based on a network of neurons responding to a stimulus.
• Changes in the synaptic strength in response to repeated exposure (the stimulus activation) and the development of a neural network called an engram are crucial to memory formation.
• Memory is stored in different parts of the brain, and multiple sources of sensory information may contribute to its formation.

Declarative Memory

• Declarative memory is of storing facts and events.
• The brain areas that are involved in declarative memory include: frontal cortex, parietal cortex, temporal cortex, hippocampus, thalamus, and amygdala.

Long-Term Potentiation (LTP)

• A change in synaptic strength as a result of repeated stimulation.
• A mechanism for memories to be created.

Procedural Memory

• Knowledge of how to do things (e.g., playing a piano, riding a bicycle)
• Involvement of areas, like the pre-motor cortex, basal ganglia, and cerebellum.

Forgetting

• Forgetting occurs at different stages of information processing.
• Short-term memory: inability to code information.

How to Ensure Effective and Ethical Rehabilitation

• Cognition and emotion should be considered together.
• Focus on real-life problems and understand the different terminology used by different disciplines.
• Use a broader and more inclusive theoretical base.

General Guidelines

• Provide guidelines, assistance, and support to individuals with memory problems.

Approaches to Rehabilitation

• Improving encoding
• Improving storage: Rehearsal strategies in memory.
• Improving retrieval: Contextual details as prompts
• Anatomical Reorganisation: Brain areas taking over memory functions.
• Environmental adaptations
• External aids for functional adaptations
• Self-help support groups

### Improving Encoding, Storage, and Retrieval

• Simplify information (to make encoding easier)
• Use rehearsal strategies (PQRST, for example, to improve storage)
• Use contextual cues (improve retrieval from multiple perspectives)

Remembering and Learning

• Memory aids need to be practised to be useful over time.

Memory Problems and Aids

• Using memory aids: Requires memory function to work effectively and may need additional training on use.

Better use of Residual Skills

• Mnemonic strategies may improve memory learning and retention, and repetition could be important too.

Errorless Learning

• Errorless learning is a way of teaching new information or skills without mistakes occurring.
• It emphasizes repetition from different perspectives and may be important for individuals experiencing memory dysfunction.

Implicit Learning/Memory

• Learning new skills and information through repetition or experience.
• Includes activities like Motor tracking, Typing, and piano playing.

Stem Completion

• Retelling a word/sentence from its letters or parts of an existing or known word.
• This may be used in assessment of memory.

Frequency Word

• Common words are used as part of learning.

Case Study- What Do You Observe?

• Detailed observation of a patient with a case study of a road accident.

Theory of Executive Dysfunction

• Executive function relies on a range of distributed neural networks.
• Frontal, parietal, basal ganglia, thalamus, and cerebellum are all involved.

Metacognition (Flavell)

• Metacognition refers to thinking about your thinking—your knowledge and regulation about your cognition.

Metacognitive Strategy Training

• Metacognitive strategies training involves knowing your own strengths and weaknesses, recognizing task demands, and selecting appropriate strategies to use to improve your performance.

Behavioral Assessment of the Dysexecutive Syndrome (BADS)

• Everyday problems for individuals with executive dysfunction.
• Problems with planning, organizing, problem-solving, and decision-making abilities are assessed in this method.

Tempora Judgment

• Estimating various complete events and their duration.

Action Program

• Analyzing practical problem-solving and planning skills based on achieving a specific result from multiple steps.

Key Search

• Subjects' abilities to use a strategy to search and solve a problem—in an analogy, like searching for a lost item within a space.

Zoo Map

• Ability to plan a route to different places based on a constructed map.

Modified Six Elements

• This task involves planning and task-scheduling skills. Subjects are asked to identify, schedule, and perform a series of tasks over a set period.

Rule Shift Cards

• Learning to change established response patterns using familiar materials is assessed.
• The ability to adapt responses and inhibit previous responses, when rules change, is measured.

Modified Six Elements Task

• This is a test of the ability to plan and sequence tasks.
• Involves specific tasks, instructions, and feedback and is done over a set period

Tower of London Test

• Assessing the individual's ability to plan, sequence, and solve problems (in a practical example).
• Tasks are complex and may involve multiple steps.
• Subjects may struggle with tasks that demand complex planning.

Benton Controlled Oral Word Association Test (COWAT)

• Assessment of fluency/verbal expression. Involves generating words starting with a particular letter within a set time limit.

Reading and Written Comprehension

• Reading and written comprehension, in these sections, involves the use of multiple brain components.

Types of Aphasia

• Fluent aphasia: Speech is fluent but comprehension is affected.
• Global aphasia: All language aspects impaired—this is the most severe form of aphasia.
• Broca's aphasia: Difficulty producing speech but comprehension is relatively well-preserved
• Wernicke's aphasia: Ability to produce speech but struggle with comprehension.
• Conduction aphasia: Relatively good speech production and comprehension, but the inability to repeat words.

Alexia & Agraphia

• Alexia is an acquired disorder characterized by the inability to read aloud or to comprehend writing.
• Agraphia: an acquired disorder in which writing deficits are evident, often occurring in association with alexia, with impairments in other areas like arithmetic and in distinguishing the left from the right.

Different Types of Language Disorders

• Spoken language deficits
• Acquired language disorders (e.g., aphasia)
• Reading (e.g., dyslexia)
• Developmental language disorders (e.g., dyslexia)

Reading Comprehension

• Processing units of information (letters, syllables, words, phrases)
• Combining units for meaning
• Context is used for understanding words and phrases.

Reading - Consistency

• Consistent and inconsistent words (spelling, phonetics) and their influence on decoding speed
• Consistency effects based on patterns in the orthographic to phonological mapping during reading processes.

Reading Comprehension - Bilinguals

• Inconsistent/consistent orthography of different languages (with a comparison between English and Welsh)
• Bilinguals may adjust their decoding strategies depending on the associated language.

Reading Comprehension - Memory, Focus, Speed

• Speed, focus, and memory related to reading.
• Using previously understood vocabulary, contexts, and patterns from previous experience are vital for reading comprehension.

Reading Comprehension - Models, Theories

• Dual route: Combination of lexical and sublexical routes for decoding.
• Orthographic depth: The effect of a language on how complex the reading process is.
• Consistency effects in decoding are dependent on consistency and the associated language.

Reading Comprehension - Problems

• Inconsistent input influences the reading process.
• People reading in languages with inconsistent orthographic depth may be slower and make more mistakes.
• Whole-word lexical phonology is more important in reading with inconsistent orthography.

Reading Comprehension - Groups of German and English Language Speakers

• Analysis of visual behaviours for cognates among German and English speakers (using various tasks and measurements)
• Sub-lexical approach to language decoding.

Reading Comprehension - Bilingual Understanding

• Alteration of the reading strategy based on the language being processed.
• Linguistic context—and the related knowledge from other experiences—may determine which strategy to use.

Reading Comprehension - Fixation and Consistency

• Comparison of eye fixations among languages that are similar lexically.
• Number of fixations to understand words with similar semantics across different languages.

This quiz explores various aspects of neuropsychology, focusing on attention disorders, apraxias, and memory issues. Test your knowledge on topographical memory, auditory agnosia, ADHD presentations, and the effectiveness of treatment methods. Answer questions to understand the complex relationship between neurological conditions and cognitive functions.