Ch 5.doc

Ch 5 5.1: Behavioral Processes Transient memories = short lasting and temporary (sometimes only lasting a few seconds) Sensory memory = brief, transient sensations of what you have just perceived when you have seen, heard, or tasted something Information buffer = temporary storage system for information that may subsequently undergo additional processing Visual sensory memory = the temporary storage for information perceived by your visual system People have a visual memory that persists for a very short time (less than a second) but includes all the items recently seen Iconic memory = rapidly decaying visual sensory memory Most likely there is sensory memory for each modality (smell, hearing, etc.) Short-term memory = a temporary memory that is maintained through active rehearsal Limited to 5-9 items Limited to what you can pay attention to Where new information stops for a while before being stored in long term memory Transferring info from short-term memory to long-term memory Depth of processing = the level of activity devoted to processing new information The more active you go about processing new info, by applying it in meaningful ways, the more likely you are to remember it Passive rehearsal through repetition doesn't really affect if it's stored Craik & Tulving Shallow, intermediate, and deep level processing Direct relationship between the depth of processing and the proportion of words recalled Deep processing might create a richer web of connections among stored memories Working memory = temporary holding station for maintaining information for a brief period before it is manipulated or otherwise utilized to affect behavior Executive control of working memory = the maintenance and manipulation of working memory Baddeley's working memory model: two independent short term memory buffers Visuo-spatial sketchpad = holds visual and spatial images for manipulation Can test on animals Show monkeys where the food is, then cover it Delayed nonmatch-to-sample Novel object has a treat, old object doesn't Remember which they saw before and which is novel Phonological loop = holds auditory memories for manipulation, maintaining them by means of internal (subvocal) speech rehearsal) A person's internal speech proceeds at about the same rate as the person's spoken speech Word-length effect = as the length of the word increases, the number of words you can remember declines because longer words take longer to rehearse Central executive = monitors and manipulates both of these (above) working memory buffers, providing executive control of working memory controlled updating of short-term memory buffers Adding to and deleting from the items in the suffers Selecting among the items in order to guide behavior Retrieving into from long-term memory Transferring info from the visuo-spatial sketchpad and phonological loop into longterm memory N-back test Say what number was N-back from a certain number Have to keep track of the last two numbers that were read Online storage of recent info selective attention remember task demands updating and reorganizing stored items Self-ordered tasks Have a bunch of items in different orders in each trial Point to one that you haven't pointed to before Can be used in humans and animals setting goals and planning Tower of Hanoi Decreasing sizes of disks stacked on top of each other Have to move from one peg to another Have to keep track of what subgoals have been accomplished what subgoals remain what is the next subgoal task switching Wisconsin Card Sort Task Shown cards with graphics that differ in three characteristics: color, shape, number Have to sort by category. Category they're supposed to be sorting switches without warning stimulus selection and response inhibition Inhibiting currently inappropriate reflexive responses Stroop task assess stimulus selection and response inhibition behavior Saying the color of the word that's printed 5.2: Brain substrates Prefrontal Cortex (PFC) = critical for working memory and executive control Frontal lobes are 1/3 of the cerebral cortex in humans Behavior consequences of frontal lobe damage Ways frontal lobes can be damaged Strokes Tumors Surgery Blunt trauma to the head Frontal lobe damage can affect all working-memory and executive-control tasks described in 5.1 Dysexecutive syndrome = a disrupted ability to think and plan Impulsive Not responsible Not guided by long-term goals or task-specific constraints Preservation = fail to learn a new rule but instead persist in using an old rule Functional neuroanatomy of the PFC Orbital PFC Medial PFC Lateral PFC More involved with working memory Dorsolateral PFC Remembering stimulus location Ventrolateral PFC Frontal brain activity during working memory tasks PFC holds in mind information that is needed to make a later response Temporal bridge between stimulus cues and a contingent response Links events across time Spatial delayed-response eye-gaze task Different neurons fire during cue, delay, and response 1. fixation on cross 2. cue, still fixated on cross 3. delay (cue disappears, still looking at cross) Delay neurons fire differently when monkeys look different ways Neurons of the dorsolateral PFC that fire during the delay are encoding a combination of sensory- and movement-response info Primary and secondary sensory and motor regions are also activated Dorsolateral PFC remained robust, even with distractions 4. response (look at cue) Could predict when the monkeys were going to make an error because the wrong neurons fired in the dorsolateral PFC Mapping Baddeley's Model onto PFC anatomy Maintenance vs. manipulation Ventrolateral PFC Encoding and retrieval of information Performs the roles of the visuo-spatial sketchpad and phonological rehearsal loops Mneumonics Activated by simple internal rehearsal Dorsolateral PFC Higher-order executive control functions (monitoring and manipulating stored info) Central executive Control of temporal ordering, but but mnemonics Right: monitoring Left: verbal Premotor cortex Rehearsal of visuo-spatial information Posterior parietal & occipital temporary maintenance of spatial working memory NOT rehearsal Visuo-spatial and phonological-verbal buffers Verbal working memory retains items in a phonological code based on the sounds of the words These items are retained through a rehearsal process similar to internally rehearsed speech Left PFC Spatial WM task Random circles on a screen They disappear One reappears Have to say if it's in the same location Right DLPFC