Neurological Psychology, Memory and Cognition PDF

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Edwald Neumann: MEMORY AND COGNITION: Modal model of the mind: (diagram in book) - Atkinson and Shiffrin’s model is sometimes called the multi- store of memory, each store and process represent not a different part of the mind, but a different job that the mind performs in its overall task of acquir...

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Edwald Neumann: MEMORY AND COGNITION: Modal model of the mind: (diagram in book) - Atkinson and Shiffrin’s model is sometimes called the multistore of memory, each store and process represent not a different part of the mind, but a different job that the mind performs in its overall task of acquiring and using information. 1. Sensory Memory:  Function: take in information until it can be processed  Capacity: large amount of information (we don’t know yet what is important)  Duration: brief (2.5-3 seconds for visual, 2-3 seconds for auditory)  Type of code: Raw copy (literal, accurate)  Forgetting: result of decay 2. Working Memory (Short-term):  Function: seat of conscious thought where perceiving, comparing, feeling and reasoning take place  Capacity: small, 7 chunks of information give or take 2  Duration: stays while it is being processed (rehearsed) if attention is diverted, approximately 20 seconds  Type of code: acoustic-articulatory code  Forgetting: mostly interference but also decay 3. Long-Term Memory:  Function: store information relatively permanently  Capacity: limitless  Duration: relatively permanent  Type of code: semantic (by meaning)  Forgetting: not forgotten, we just lose access - Control Processes:  Attention: if we attend to information in sensory store, it moves to Working Memory  Rehearsal: Maintenance vs. elaborative rehearsal  Encoding: Controls movement of information from Working Memory to Long Term Memory  Retrieval: Access information from Long Term Memory and place in Working Memory SENSORY MEMORY: - The iconic store was originally proposed by Sperling (1960). It is the visual sensory store and suggests that our visual system is able to hold a great deal of information, but if we don’t attend to this information it will be rapidly lost. - Sperling conducted a task which presented people with a visual array containing up to 3 rows of 4 letters each for a duration of 5 seconds. When asked to recall all the letters, participants could only recall 4-5 of the 12 letters.

Sperling’s research also indicated that information in iconic storage usually decays within less than half a second of exposure to the stimulus. - Sperling’s experiments indicate the existence of a brief visual sensory memory known as the iconic memory, where information decays rapidly unless attention transfers items to Working Memory. - Analogous auditory sensory memory: Echoic Memory. MEMORY AND ATTENTION: - Attention must allow individuals to focus solely on challenging tasks, ignoring irrelevant stimuli that might serve as a distraction. - Attention must be distractible, indivuduals must be able to monitor their environments for other important or potentially dangerous stimuli. - Mechanisms of attention seem to meet two competing human needs: 1. To focus mental resources on the task at hand and not be distracted by other relevant stimuli 2. To monitor stimuli that are irrelevant to the task at hand and to shift attention immediately to anything that signals some danger or benefit that outweighs the task (opposing need) -

In this model all sensory input enters the sensory memory store, where it is processed preattentively. Then some of it is selected to pass thru the gate into conscious, working memory. The arrow from working memory to the gate indicates top-down control of the selection criteria. The model can accommodate many results from selective listening research. DICHOTIC LISTENING: Attention Facilitates encoding: Dichotic listening task illustrates the effect of selective auditory attention. -

Two competing speech inputs are presented simultaneously to the 2 ears using headphones (dichotic listening). People are asked to attend and verbally shadow (immediately repeat each word) a train of speech coming into one ear, while simultaneously ignoring a different stream of speech coming

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into the other ear. Subjects are unable to report any of the details of the speech in the unattended (ignored) ear, even if it was played backwards or in a foreign language. Cherry et al, 1953. This was coined the cocktail effect. Similarly, Moray (1959) found participants could not repeat words in the unattended message even if one of them was repeated 35 times.

What gets in from an unattended message? -

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Not much, we seem to remember low-level information, eg. human voices or not, changes in gender. However, if a person’s own name is said in the unattended message, they notice it roughly a third of the time (Moray, 1959) This suggests that all words spoken in the unattended voice entered the sensory memory and were to some extent processed preattentively for meaning. Since your own name has special meaning, preattentive processes alerted the attention mechanism and the person could then ‘hear’ their own name as it was still stored in sensory memory. The gate between Sensory and Working Memory is necessary so the limited capacity Working Memory System is not overloaded, but there is also monitoring of all sensory stimuli for their potential significance.

Modal Model of Memory: -

Working Memory is a limited capacity store for information – place to rehearse new information from sensory memory. Items need to be rehearsed in Working Memory before entering long term memory Probability of encoding in Long Term Memory is directly related to maintenance rehearsal time in Working Memory

Problems with Working Memory in the Modal Model: -

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The multi-store model posits that the ling-term storage of information depends on rehearsal, with a direct relationship between the amount of rehearsal in the short-term store and the strength of memory in the Long Term Store.

VARIETIES OF MEMORY: - Squire (1987) also describes how neuropsychological research suggests each of these types of memory may be associated with discrete cerebral structures and processes. Implicit Memory: - Knowledge that we cannot consciously recall but that nonetheless manifests itself in our improved performance on some task. Past experiences influence perceptions, thoughts and actions without awareness that any information from the past is accessed. - Word Fragment Completion: Implocit memory task. Fragments are often completed with words previously studied in the absence of an explicit instruction to remember the word. - Amnesiacs often show spared implicit memory coupled with impaired explicit memory. Dissociations like this suggest different systems for implicit and explicit memory.

Dissociations are situations in which different tests of memory show different results and are important in arguing for different memory systems. - Elaborate processing: Facilitates explicit memories but not implicit memories. - Priming: An enhancement of the processing of a stimulus as a function of prior exposure. - Non-Declarative Memory: Implicit memory system that includes procedural skills, priming, conditioning, habituation, and sensitization. - Explicit Memory: - Knowledge that we can consciously recall. Conscious access to info from the past - Declarative Memory: Explicit memory system that is supported by the hippocampus and includes episodic and semantic memory. SPREADING ACTIVATION: Collins and Loftus (1975) Spreading Activation Model Collins and Loftus proposed a model of conceptual knowledge that represented semantic information as an elaborate network of conceptual nodes and connections between them. It is called a ‘Spreading Activation Model’ as it proposes that the activation of any one concept initiates a spread of activity to nearby concepts in the network, which primes those concepts so that they become temporarily more retrievable than before. The spreading activity declines with distance, so concepts closely linked with the active concept receive more priming than those further away. - When a concept is accessed the node for that concept is activated - Activation is the arousal level of a node - Nodes connected to the accessed node are also activated, and nodes connected to these nodes are then activated. As the activation spreads out from the accessed node it grows weaker (activation requires longer to spread to more remote nodes) - Spreading activation is used to retrieve information from the network - Strength of the connections between concepts is determined by frequency of experience - Lifelong co-occurrence frequency determines the strength of association between concepts - Therefore, the network structure is based on a persons experience with concepts, eg. the link between vegetable and carrot will be stronger for most people than the link between vegetable and rutabaga, unless you are a lifelong rutabaga farmer. - The concept of spreading activation is appealing because it can explain all sorts of associative priming and unconscious priming effects

Elizabeth Loftus: - Expert researcher on the malleability and reliability of memories. Has created studies with over 20,000 subjects to show false memories can be triggered by suggesting or giving incorrect post-event information. This is called the Misinformation Effect. - Studies have proven memory is malleable and subject to distortion through combinations of source confusion and a subtle form of social pressure. Both of these factors can influence the constructive process of memory. - False memory experiments have shown sometimes confidence is high while accuracy is low. - It is important to know which kinds of information in memory are most vulnerable to modification and the extent of modification. Encoding Specificity Principle: - The idea that a retrieval cue can serve as an effective reminder when it helps recreate the specific way in which information was initially encoded. - Successful retrieval depends on the degree to which the retrieval environment reinstates the encoding environment. State Dependent Retrieval: - The tendency for information to be better recalled when the person is in the same state during encoding and retrieval - A whole environment can serve as a retrieval cue - Increasing the similarity between the context in which an item is encoded and the retrieval context can serve as a beneficial cue Processing Information Outside of Conscious Awareness: Marcel – Unconscious Priming Experiment: Phase 1: Critical duration set so that each subject is at chance detecting presence of the words Phase 2: Used a lexical decision task (is it a real word in English? ‘Yes’ or ‘No’ to word 2, but with 2 masking conditions (1) no mask; or (2) ‘central’ pattern mask. Serial Position Effect: - The enhanced memory for events presented at the beginning and end of a learning episode - Serial position curve: example of recall for a list of words demonstrating the primacy and recency effects of better recall for words at the beginning and end of the learning period (Glanzer and Cunitz 1966) - Retroactive Interference: Situations in which later learning impairs memory for information acquired earlier - Proactive Interference: Situations in which earlier learning impairs memory for information acquired later NEUROBIOLOGICAL BASES OF BEHAVIOR: - The Brain: One of the main frontiers in science and one of its fastest growing areas: the center of what we are.

Psychology is a major path to study the brain. Psychology is obviously the most important, because it focuses on what the brain is for: behavior and cognition - Neuroscience especially, puts psychology in a unique position at the interface between the Natural and Social Sciences. - Opportunities exist for graduate students to make significant research contributions The Nervous System: 1. Central Nervous System (CNS) 1.1 Brain (grey outer and white inner) 1.2 Spinal Cord (white outer and grey inner) 2. Pheripheral Nervous System (PNS) connects body muscles and organs with the CNS 2.1 Somatic Nervous system (motor nerves to muscles and sensory nerves from body; the cranial and spinal nerves) 2.2 Autonomic Nervous System (relatively autonomous actions of internal organs and glands) 2.2.1 Sympathetic Division (increase/arousal, for action) 2.2.2 Parasympathetic Division (dampen, rest, return) Neuroscience vs Neuropsychology: - Neuroscience covers all aspects of different nervous systems, especially their biology. - Neuropsychology focuses on the behavioral and cognitive characteristics associated with brain function, and especially dysfunction, in animals and especially humans - Our goal is to understand humans, so we learn key issues from both human and animal research and use animal models to improve experimental control to determine brain functions and to help investigate important components of and potential treatments for any given disorder. - Connecting back to general neuroscience, the basic neural properties, key neuroanatomy and basic functions are common across different animal species. - As of 2015, the NZ wide ‘Centre for Research Excellence – Brain Research NZ’ is now addressing brain health and repair in the context of the aging brain. - Roughly 20% of individuals will have a neuropsychiatric disorder Drugs and Neuroscience: - MDMA may cause loss or dysfunction of the terminals of neurons that release the neurochemical, serotonin (5-HT). - Neurotoxicity (loss of 5-HT binding) was found 1 week after even a single, relevant, small oral dose in a squirrel monkey, which has similar pharmaco-kinetics to humans. (Mueller et al 2012) Brain Repair: - How can we minimize the acute and evolving brain injury caused by trauma or a stroke? - Use progesterone? (Don Stein in Atlanta, USA) -

Use of Neural Growth Factors and their matabolites? (Jian Guan, Auckland, Andrew Clarkson, Otago) Neuroplasticity: - Even undamaged neurons are continuously remodeling their details. Even in adult brains, there is a production of new brain neurons in some regions. - These effects are stimulated by physical and cognitive activity and new cells survive better with learning and experience. MRI: - MRI creates ‘live’ images of soft tissue, such as brain, using minute signals produced by brief changes in the behavior of Hydrogen (h) nuclei (protons) in the abundant (70%) ‘water’ of brain tissue. - When you are in the MRI, its huge magnetic field (3T) makes the H protons (in water, in brain tissue) align with the field, creating a small difference between H Protons aligned up and others aligned down. - We add brief pulses of resonance frequency (radio waves) to perturb (excite) the H Protons’ direction and spin (‘precession’) - After pulses end, H Protons realign (relax), releasing detectable signals, which vary in different parts of the brain, and their exact position is determined by local field gradient coils. - Tweaking parameters produces many different kinds of images. Types of MRI: T1: Basic scan to check Grey, White Matter, CSF integrity (size, shape). A structural T1 will show brain atrophy in dementia. Dementia patients will have increased fluid filled ventricles (CSF) and loss of brain tissue. This results in a loss of independent function, impaired thoughts and decision-making. T2: Axial, white matter is dark, CSF light; bleeds/tumors T2 Flair: Homogenous, but shows lesions in white matter and cortex, eg. in multiple sclerosis. - These MRI types are created by ‘tweaking’ different parameters giving three different imaging contrasts of grey matter, white matter and cerebral spinal fluid (CSF, the butterfly-looking area in the brain) - Diffusion MRI: Tweaked to be sensitive to moving water molecules. White matter will deteriorate in Parkinson’s disease. Only when Parkinson’s disease patients also show mild cognitive impairments and show dementia, this provides an early marker of cognitive decline. Functional MRI: - Yields images of changes in neural activity (every 2-3 seconds) by using pulse and gradient tweaks sensitive to the level of oxygenated blood. Oxygenated blood is sensitive to magnetic fields. -

Areas that increase activity show increases in the delivery of oxygenated blood, and thus increased in MRI signal. - We contrast the level of oxygenated blood from one condition (or task, eg. memory task) vs another condition (control comparison): a visual picture of specific brain regions that change activity due to the task. - Separately, large scale neural networks of activity can also be described: here, we simply look for ‘correlated’ (co-varying) increases and decreases in fMRI activity across different brain regions (the ‘new’ direction in imaging). Basic Organisation of the Mammalian (human) Brain: Terminology: - The human brain has about 170 billion cells, roughly half are neurons and half are impt support cells, called glial cells, which make up the second type of brain cell. The neurons process information and transmit it from one place to another; the glial cells keep the neurons healthy in diverse ways. Types of Brain Neurons: 1. Purkinje cell from cerebellum 2. Spiny neuron in the basal ganglia (nucleus accumbens, meaning ‘adjacent nucleus’) 3. Pyramidal neuron located in the CA1 region, a critical part of the hippocampus. Brain Cells: - Brain cells are not randomly arranged, different groupings, types and proportions of cells are aggregated in different ways, in different places. - There are also different sizes and shapes of fiber bundles. Each made up of axons from many thousands or even millions of neurons. - These features create a matrix of different shapes that make up the different brain structures. Abbreviations of Brain Parts: 1. Corp. Call.: Corpus Callosum 2. F.M.: Foramen of Monroe 3. Hypoth.: Hypothalamus 4. IV: fourth ventricle 5. Medul.: Medulla 6. Midbr.: Midbrain 7. Spet. Pell.: Septum Pellucidum 8. Thal.: Thalamus - These abbreviations are in Latin made in renaissance times. When translated into English they are basically just descriptions of shapes, which the parts of the brain look similar to. Five Main Divisions of the Brain: FOREBRAIN: 1. Telencephalon (Cerebral hemispheres): Neocortex, Basal Ganglia, Limbic system. Tel: end-brain -

2. Diencephalon: Thalamus, Hypothalamus. Di: between-brin MIDBRAIN: 3. Mesencephalon: Midbrain. HINDBRAIN: 4. Metencephalon: Cerebellum, Pons. Met: across 5. Mylenecephalon: Medulla Oblongata. Myel: spinal TELL DIANNE A MESSENGER MET MY ELEPHANT Embryonic development of the basic brain organization: (copy diagram) - Looking at how the brain develops is the key to learning where the 5 main divisions of the brain get their names. - Brain development starts as a ‘neural tube’ (left) with three parts that grow differently in size. - After the initial ‘neural tube’, three bulges are created, the fore, mid and hind brains. - Two buds then grow out from the front end, leaving the forebrain part between them - The telencephalon then grows enormously to become the left and right cerebral hemispheres - Bulges develop and grow across (met) the hind brain, leaving the spinal (myel) below. Translations: - Cortex – outer bark (neo = 6 layered) - Basal Ganglia – neural aggregate at the base of the forebrain - Limbic system – collection of structure that lie on the inner borders of the remaining cortex - Thalamus – chamber-like structure at the center of the brain - Hypothalamus – below the thalamus - Cerebellum – little brain - Pons – bridge (includes many fiber pathways, some of which connect with the cerebellum) Similarities across different brains: - Although subtle differences occur between all individuals, the basic organization is the same in all individuals, and the fundamental brain organization is the same across all mammals, even to some degree across all vertebrates. - Each human brain is unique in detail, but we usually have all the same brain structures and pathways. - The human brain weighs about 1300-1400gm and has a similar volume, but can vary in total size from 1000-2000gm, as well as in the precise number of brain cells in different parts, and in the strength and number of the neural connections in different regions. - Much of this variation is genetic, but it is also extremely dependent on the environment, including the effects of different experience/epigenetic effects. - Higher IQ individuals have relatively larger surface area, but thinner cortex than lower IQ cases at age 10. Higher IQ individual...