Module 4 Summary Sheet - PDF

Module 4 Learning Objectives Identify and describe a variety of brain disorders Map parts of the brain affected by these disorders Describe the functions of the affected brain areas by what changes as a consequence of their damage Brain Lobes + Disorders Visual brain definitio...

Module 4 Learning Objectives Identify and describe a variety of brain disorders Map parts of the brain affected by these disorders Describe the functions of the affected brain areas by what changes as a consequence of their damage Brain Lobes + Disorders Visual brain definition - refers to areas of the brain involved in processing visual information Regions include - primary visual cortex Akinetopsia - inability to perceive motion, resulting in viewing the world as a series of static frame Cause of Akinetopsia - Damage to the V5 (Middle temporal visual area) V5 Function: specialises in perception of motion Achromatopsia - Cortical colour blindness, individuals see the world as grey, black, white even though there optic nerves are fully functional. Cause of Achromatopsia - Damage to area V4 ( Located in occipital lobe) V4 Function: Specialises in colour perception Prosopagnosia- Inability to recognise faces, despite intact vision Cause of Prosopagnosia - Damage to the FFA FFA Function - located in temporal lobe, helps us distinguish recognize faces Blindsight - a condition where someone cannot consciously see part of there visual field Cause of Blindsight - Damage to V1 (Primary visual cortex) Primary visual cortex - Located in occipital lobe - Processes visual information from the opposite side of the visual field. Frontal Lobe Clinical conditions Fronto-temporal Dementia (FTD) What is Fronto-temporal Dementia? - Degeneration loss of neurons in the frontal and temporal lobes Symptoms - Loss of empathy - Apathy - Disinhibition - Deficits in executive functioning Parietal Lobe damage Spatial neglect (cause damage to parietal or frontal cortex) - Caused by damage to one of the hemispheres frontal or parietal cortex - Individual is unaware of there visual field (side contralateral to brain damage) e.g if your right hemisphere was damaged, your left side of space would likely be neglected - Individual ignores stimuli on side opposite to brain lesion Simultagnosia (Parietal lobe damage) - Can't perceive multiple objects simultaneously  Lateralisation of brain functions What are Lateralized functions? - some brains rely more on one side of the brain than the other Left hemisphere - primarily responsible for language and speech Right hemisphere - Tone of voice and prosody (Rhythm and pitch of speech) Perceptual grouping - the brains ability to organise visual elements into groups What hemisphere does perceptual grouping? - The right hemisphere Contralateral crossed functions? What is it? - Means each hemisphere controls and processes information from the opposite side of the body Explain the contralateral nature of parietal lobe functions - Contralateral means the opposite, each hemisphere of the parietal cortex controls attention, and sensory processing on the opposite side of the body. Therefore damage in one hemisphere affects the opposite side. Attention and Memory Bottom-up and Top-down attention involve which regions of the brain? - - Parietal lobes - - Frontal lobes Define Bottom-down attention  - Attention captured involuntarily by things that 'stand out' or 'pop out' Define Top-Down attention - it is an attention process guided by our goals, intentions, and expectations. This type of attention involves conscious control over what we focus on. Memory - H.M Patient Types of Long term memory 1. Declarative - conscious recollection (Things you can declare) 2. Episodic - memory of past events or episodes of things you've seen or done 3. Semantic - facts and basic knowledge you can declare What is Procedural memory - Procedural memory is for skills and tasks you’ve learned, like riding a bike or signing your name, and is not consciously recalled. What role does the hippocampus play in memory? - The hippocampus is crucial for encoding new long-term memories If you had damage to your hippocampus both in your left and right hemisphere, what would you most likely expect to happen? You could not encode new episodic long-term memories You could not recall anything of your life from after the time of the damage The Corpus callosum - Thick band of nerve fibres connecting left and right hemisphere Function of corpus callosum? - Connects the left and the right hemisphere by allowing axons to cross and transfer information between two hemispheres Damage to corpus callosum Split Brain - Refers to a condition where the corpus callosum has been surgically severed. With the corpus callosum cut the hemispheres operate more independently. How each hemisphere functions independently after corpus callosum is cut - Left Hemisphere (right visual field): Can see objects on the right side and verbally describe them. - Right Hemisphere (left visual field): Can see objects on the left side but cannot verbally describe them; instead, it may communicate through actions like pointing or using the left hand. Module 2 Learning Objectives Recognise and label the major regions of the brain (lobes, primary areas, and limbic system) Map function(s) to the different brain regions Identify the major parts of the neuron and describe how it functions Describe the mechanisms of neural communication along axons and across synapses Outline methods used to measure brain function Explain neurplasticity: How the brain changes with learning and experience Module 2 Lobes of The Brain 1. Frontal lobe Functions: Decision making, problem solving, planning, voluntary movement, speech production (Broca's area) 2. Parietal Lobe Functions: Sensory perception, spatial orientation, processing touch information 3. Occipital lobe Functions: Visual processing 4. Temporal lobe Functions: Hearing, memory, speech, comprehension (wernicke's area) Primary areas  1. Primary motor cortex Function: Voluntary movement control 2. Primary somatosensory cortex Function: processing sensory information from the body 3. Primary Visual Cortex Function: Processing visual information 4. Primary auditory cortex Function: processing auditory information Sodium Potassium Pumps What is it - A key mechanism that maintains the resting membrane potential of a neuron How it works? ➔ Pumps 3 Na+ out and 2 k+ in to maintain negative charge inside neuron ➔ Uses ATP (energy) to keep cell at - 70 mv resting potential ➔ Prepares neuron for next action potential by keeping it stable at rest Key points - Maintains resting membrane potential of neuron - Stabilies neuron at readiness - Pumps na+ out and K+ In maintaining negative charge inside neuron Action Potentials What is an Action potential? - An action potential is an electrical signal that travels along the axon of a neuron Events the occur during action potential (IN ORDER) The membrane potential passes the threshold level ion channels open to allow sodium ions to flow into the cell (depolarisation Ion channels open to allow potassium to flow out of the cell (repolarisation) Key Characteristics of an Action potential - Always same size (All-or-Nothing Principle) - Travel only in one direction Hebbian Principle - When pre synaptic, postsynaptic neurons fire at the same time connection between synapses strengthen Long term potentiation - Simultaneous firing leads to LTP increasing synaptic connections Excitatory and Inhibitory postsynaptic potentials Excitatory post synaptic potential (EPSP) - Occur when neurotransmitter bind to receptors causing depolarization - Depolarisation brings neuron closer to threshold for action potential Inhibitory Postsynaptic potential - Occur when neurotransmitters cause hyperpolarization - Hyperpolarization moves neuron further from action potential threshold Combination for triggering Action potential - Weak IPSP, Strong Epsp, Strong Epsp, Weak IPSP, Important Concepts for Visual System Retinotopic Organization: ○ Neurons in the visual cortex that respond to adjacent visual field locations are located adjacent to each other in the brain. ○ Essential for processing visual information with spatial accuracy. _______________________________________________________________ Neuroplasticity: Definition: Neuroplasticity is the brain's ability to reorganize itself by forming new connections between neurons.  After an injury, undamaged neurons can take over some of the functions that were once handled by damaged neurons. This process is essential for recovery, as it allows the brain to adapt and restore some lost abilities. Long-Term Potential (LTP): Part of neuroplasticity where repeated activation of new connections strengthens these pathways, making them more effective at performing the tasks of the damaged areas over time. Medical conditions Multiple sclerosis - An autoimmune disorder where the immune system mistakenly attacks the myelin sheath, disrupting communication between nerve cells. Methods used to measure Brain function Esp Fmri  Module 3 Explain the concept of the visual brain Map and describe the functions of the primary visual cortex Explain concepts of functional modularity and selective visual deficits Explain concepts of transduction, the blind spot, and filling-in Differentiate between attention and awareness Explain how the concept “blindsight” operates What is the visual brain - The visual brain refers to areas of the brain which process visual information What regions does the visual brain include - Multiple regions such as primary visual cortex (v1), and higher order visual areas Primary Visual Cortex Location: Occipital lobe Function: Primary visual cortex (V1) Processes visual information from the opposite sides of the visual field What is the Primary Visual cortex responsible for? - Initial processing of visual information - Basic visual processes like edge detection, motion - Reintopically organised Damage to Primary Visual cortex causes what? - Blindsight What is Blindsight - Blindsight is a condition where individuals with damage to the primary visual cortex (V1) are able to respond to visual stimuli without having any conscious awareness of seeing them.  Functional Modularity - is the idea that the brain is organised into specialised regions, or “modules,” each dedicated to handling specific types of information or function Specialised Brain Areas: Each module or brain region is specialised for particular functions, allowing efficient processing. For example: ○ Broca's area (in the left frontal lobe): Responsible for speech production. ○ Wernicke's area (in the left temporal lobe): Responsible for language comprehension. ○ V4 (in the occipital lobe): Specialised for colour perception. ○ FFA (Fusiform Face Area): Specialised for recognizing faces. ○ Key Questions How does colour constancy affect perception? Colour constancy allows us to perceive colours consistently under different lighting conditions by factoring in the light source. Lacking short cones causes? blue/yellow colour blindness Lacking long/medium cones causes? red/green colour blindness If someone has trouble seeing in the right visual field, Damage is likely in the left hemisphere of the brain, where is the likely damage? as visual fields are processed contralaterally. Key definitions Transduction (* necessary for sensory perception)  - The process by which sensory receptors convert external stimuli (like light, sound or touch) into electrical signals which are then interpreted by the brain What is Signal Detection Theory? measure how we make decisions under conditions of uncertainty. It assesses our ability to distinguish between a "signal" (an actual stimulus) and "noise" (background or irrelevant information), taking into account both sensitivity to the signal and bias in response. Mcgurk effect A phenomenon where visual information (lip movements) alters auditory perception, showing that our brain combines sensory information to create a "best guess." cortical scotoma A cortical scotoma is a partial loss of vision (blind spot) in the visual field due to damage in the visual cortex.