Class Notes (839,394)
Canada (511,324)
Psychology (3,528)
PSY100H1 (1,637)

Memory and Cognition- ch2.docx

12 Pages

Course Code
Pare, Dwayne

This preview shows pages 1,2 and half of page 3. Sign up to view the full 12 pages of the document.
Memory and Cognition Chapter 2 – The Neural Basis of Cognition Capgras Syndrome: An Initial Example - Damaging virtually anywhere in the brain will produce specific – and sometimes disruptive- symptoms - Capgras syndrome – this disorder is rare on its own, but accompanied with Alzheimer’s syndrome – result from various injuries to the brain - Are able to recognize the people in her world but if convinced that they are not who they appear to be o the real person has been kidnapped and the person on the scene is a well trained imposter - insist that there are slight differences between the real person and the imposter such as tiny changes in appearance - can lead them to desperate steps - have murdered the imposter in an attempt to end the charade and reloacate the real character - facial recognition requires two separate systems in the brain, one of them leads to cognitive appraisal (you closely resemble my father) and an emotional appraisal (you trigger a warm response in me) - in capgras the latter emotional processing is disrupted leading to the intellectual identification without the familiar response o you resemble my father but trigger no sense of familiarity, so you must be someone else The Neural Basis for Capgras Syndrome - neuroimaging techniques – allow researchers to take high quality, three dimensional pictures of living brains - these scans suggest a link between Capgras syndrome and abnormalities in several brain areas - one site of damage is the temperol lobe particularly on the right side of the head - disrupts circuits involving the amygdala, serves to be the emotional evaluator – detect stimuli associated with threat and danger - also important for detecting positive stimuli – indicators of safety and rewards - therefore people with capgras don’t feel the warm sense of feeling when looking at a loved ones face - also have brain abnormalities in the frontal lobe, specifically in the prefrontal cortex - Fmri – allows us to track moment to moment activity levels in different sites of the brain - The prefrontal cortex is active when a person is engaged in tasks that require planning or careful analysis o Is less active when someone is dreaming- this is why dreams are not logical and bizarre - With damage to the frontal lobe, capgras patients may be less able to keep track of what is real and what is not, what is sensible and what is not o Weird beliefs can emerge unchecked, including delusions What do we Learn from Capgras syndrome? - Some evidence comes from psychology labs and confirms the suggestions that recognition of all stimuli does involve two separate mechanisms - The damage to the amygdala Is probably the reason Capgras patients experience no sense of familiarity when they look at faces they know o In turn helps us understand the crazy hypothesis about their skewed perceptions - Our understanding of Capgras comes from both the cognitive psychology and the cognitive neuroscience – use both to test the hypotheses – can illuminate broader issues about the nature of the brain and the mind - The amygdala plays a role in decision making, especially decisions that rest on emotional evaluations of ones options – tells us that our theorizing needs to incluse a broadly useful “emotional evaluator” o Capgras tells us that this emotional evaluator works in a fashion separate from the evalution of factual information, providing us a way to think about the occasions in which someone’s evaluation of the facts point toward a conclusion, while the emotional evalution points toward a different conclusion - Capgras also tells us that the parts of the brain have to work together for the simplest achievement o To recognize your father:  Store memory on what he looks like  Another part responsible for the visual input you receive when looking at his face  Emotional evaluation of the input  Another site assembles all the data from the other sites, registers the fact that the face being suspected does match thte factual recollection of your fathers face and produces a sense of familiarity The Study of the Brain - Human brain weighs between 3-4 pounds, the size of a melon - Trillion nerve cells – roughly 10 million billion connections - Different parts of the brain perform different jobs – know this because the symptoms produced by brain damage depend heavily on the location of the damage ex. Phineus Gage Hindbrain, Midbrain, Forebrain - The hindbrain sits directly atop spinal cord and includes several structures crucial for life functioning - The hindbrain also plays an essential role in maintaining the bodys overall tone, the posture and balance, and it helps control the brains level of alertness - The largest area of the hindbrain is the cerebellum – damage to it can cause problems in spatial reasoning, in discriminating sounds and integrating the input from various sensory systems - The midbrain o Coordinates movement, precise movement of your eyes as you explore the visual world o Relays auditory information from the ears to the ares in the forebrain o Helps to regulate pain - Forebrain o Surrounds the midbrain and hindbrain o The cortex is the outer surface – consists of 80% of the human brain  Very large sheet of tissue, if stretched out would be 2 feet  The crumpling that produces the brains most obvious visual feature – the wrinkles, or convolutions that cover the brains outer surface  The valleys between the wrinkles are called grooves  The deepest groove is the longitudinal fissure running from the front of the brain to the back  Seperates the left cerebral hemisphere from the right  Other fissures divide the brain into four lobes  The frontal lobe – forms the front of the brain, right behind the forehead  The central fissure divides the frontal lobes on each side from the parietal lobes, the brains topmost part  The lateral fissure is the bottom edge of the frontal and below it are the temporal lobes  At the back of the brain connected to the parietal and the temporal is the occipital lobes Subcortical Structures - Found underneath the cortex - The thalamus acts as a relay station for nearly every sensory information going to the cortex - Underneath the thalamus is the hypothalamus – controls motivating behaviors such as eating, drinking, and sexual activity - Surrounding the thalamus and the hypothalamus – together form the limbic system o The amygdala, the hippocampus – underneath the cortex in the temporal lobe o Are essentially for learning and memory - People show more complex, longer lasting memories for emotional events, compared to similarily emotionally flat events – this is lost when the amygdala is damaged Lateralization - All parts of the brain come in pairs – there are differences in function between the leftside and the rightside structures with the left hemisphere structure playing a somewhat different role from the right hemisphere - The two halves of the brain work together, the functioning of one side is closely integrated with that of the other side – done by commissures – thick bundles of fibers that carry information back and forth between the two hemispheres o The largest one is the corpus callosum - When you break the corpus callosum – the two brain halves lose communication and you find that the right hemisphere is responsible for tasks such as spatial judgement and left for language capacities - The two hemispheres work together, with each providing its own skills which contribute to overall performance o Are NOT competitiors – but pool their specialized capacities Data from Neuropsychology - The study of individuals who have suffered brain damage whether through accident, disease or birth defect is called neuropsychology: the study of brain structures and how they relate to brain function - Clinical neuropsychology seeks to understand the functioning intact, undamaged brains by careful scrutiny of cases involving brain damage - A lesion in the hippocampus produces memory problems but not language disorders, a lesion in the occipital cortext produces problems in vision but spares the other sensory modalities - The consequence of a lesion depends on which hemisphere is damaged o Left side of the frontal lobe – disruption of language use o Right side of the frontal lobe – does not have the same effect Data from Neuroimaging - Use CT scans to study the brains structure and PET scans to study the brains activity o CT relys on X-rays and PET relys on tracer substance such as glucose - For both the primary data are collected by a bank of detectors surrounding the head; a computer then compares the signals received by each of the detectors and use this information to pinpoint the source of each signal - For CT tells us the shape, size, and postion of the structures within the bain - For PET show us what regiosn active at a particular time - MRI relies on magnetic properties of atoms that make up the brains tissue - Fmri – measures the oxygen content of blood flowing in the brain – accurate reading of neural activity in any region of the brain - CT and MRI are stable, FMRI and PET are highly variable, depend on what task the person is performing Data from Electrical Recording - The brain contains a trillion nerve cells – neurons- and the neurons do the brains main work - They communicate with each other via neurotransmitters - Two types of communication o One type: between neurons – a neuron releases the transmitter substance and this activates or de-activates another neuron o Second type: within neuron – neurons have an input end and and output end o The input end is the portion of the neurons that’s most sensitive to NT – where the signal from the neurons is received o The output is the portion of the neuron that releases the NT, sends it on to the other neurons o - How do they get the signal from one end to the other end o Made possible by the flow of charged atoms in and out of the neurons o The current generated by all of the together is great enough to be detected by sensitive electrodes placed on the surface of the scalp o Electroencephalography – a recording of voltage channels occurring at the scalp that reflect activity in the brain underneath o Electroencephalogram – EEG  Sometimes we want to measure the changes in EEG in the brief period just before, during and after the event – these are referred to as event-related potential The Power of Combining Techniques - Each of these research tools have there own strengths and weaknesses - Researchers deal with these limitations by means of strategy commonly used in science – seek data from multiple sources so that we can use the strength of one to make up for the shortcomings of the other o Ex. EEG tells us when the certain event took place and the Fmri tells us where the activity took place - These also only provide correlational data - Ex. Brain area called the fusiform face area seems to be active whenever a face is perceived o A different possibility may be just that the activation is a by-product of face perception and does not play a crucial role o Ex. Car speedometer becomes more activated when the car goes faster but this doesn’t mean that it caused the speed or is necessary for the speed o Its correlated with the car’s speed by in no sense causes the speed - We need other data to ask whether the brain site plays a role in causing that function … comes from studies in brain lesions … if it disrupts a function its an indication that it does play some role in its function - Transcranial magnetic stimulation - creates a series of strong magnetic pulses at a specific location on the scalp causing temp. disruption of brain region Localizaiton of a Function - Localization of function – the function of specific brain structures - Ex. Capgras – people with this had a damaged amygdala o Need to know the function of the amygdala – rely on data telling us that the amygdala is involved in many tasks involving emotional appraisal - “mental pictures” – how much do they have in common with ordinary seeing? o Localization data allows us to reveal overlap between the brain structures needed for the two activities – tells us that they have a great deal in command The Cerebral Cortex - Region where enormous amounts of information processing take place - Divided into the motor areas, sensory areas and association areas Motor Areas - Specific areas of the cerebral cortex – signals leave the cortex and control muscle movement - Other areas are arrival points coming from the eyes, ears, and other sense organs - Both together called the primary projection areas, departure points called the primary motor projection area and the arrival points the primary sensory projection area - Evidence for motor o Put mild electric current to this area in animals – caused specific movements o Show a pattern of contralateral control – stimulation of the left hemisphere produced movements in the right - Known as “projection areas” because they form maps of the external world o Particular postions of the cortex correspond to particular parts of the bosy or locations in space o Areas of the body that we can move with great precision such as the fingers or the lips have a lot more cortical area devoted to them Sensory Areas - Info form the skin sense is projected to a region in the parietal lobe, just behind the motor projection area; known as the somatosensory area - If stimulated report a tingling sensation in a specific part of the body - Ex. The “auditory area” – will hear clicks, buzz or hums - Each of these sensory areas provide a map of the sensory environment – each of the body’s surface is represented by cortical region on the cortex o Areas that are near to each other are similarly nearby in the brain o Ex. In the auditory projection are, different frequencies of sounds have their own cortical sites and adjacent brain sites are responsive to adjacent frequencies - The assignment of space is governed by function not anatomical proportions o Ex. Part of the body that are not discriminating with regard to touch get little area o Sensitive areas like that lips, tongue, fingers get more space o In occipital – more area given to the fovea – part of the eye that is sensitive to detail - Contralateral connections o The sensory areas in the left hemisphere receive main input from the right side of the body vice versa o Visual projection  Not contralateral with regard to body parts, contralateral with regard to physical space  The visual projection area in the right receives info from both the left and right eye but the info it receives corresponds to the left half of visual space – the same holds true for the left Association Areas - The motor and sensory make up only small part of the cerebral cortex – about 25% o The remaining area is referred to as the association cortex – associate simple ideas and sensations in order to form more complex thoughts and behaviors - The large volume of brain tissue can be subdivided into both functional and anatomical grounds - Some lesions in th
More Less
Unlock Document

Only pages 1,2 and half of page 3 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.