Abstract
Neuroimaging studies have indicated involvement of left prefrontal cortex and temporal areas in verbal memory processes. The current study used event-related functional neuroimaging to compare encoding of subsequently recalled and not recalled words in high and low memory performers. Fifteen healthy volunteers were given lists of words to learn with immediate recall and to read as a control condition. High performers reported to have visualized the words whereas low performers used a rehearsal strategy. Compared to reading, unsuccessful encoding was associated with thalamic and left premotor area (BA 6) activity. Comparing successful with unsuccessful learning yielded widespread activity of the left prefrontal and posterior temporal gyrus as well as the left superior parietal lobe in the whole group. Low performers showed activation of the left premotor area throughout learning and additionally of the left middle temporal and parahippocampal gyrus during successful encoding. High performers showed increased activation in the extrastriate cortex throughout learning and additionally in the left parietal post- and paracentral areas as well as in the right precuneus during successful encoding. The results suggest that high verbal memory performance is the result of spatiovisual activation concomitant to imagery and low performance of hippocampal and motor activation, the latter being associated with rehearsal, with a common memory circuit subserving both groups.
References
(1978). Arguments concerning representations for mental imagery. Psychological Review, 85, 249– 277
(1995). Short-term and long-term verbal memory: A positron emission tomography study. Proceedings of the National Academy of Science, U S A, 92, 5111– 5115
(2000). Short-term and working memory. In E. Tulving & F.I.M. Craik (Eds.), The Oxford handbook of memory (pp. 77-92). New York: Oxford University Press
(1970). Analysis of a mnemonic device. American Scientist, 58, 496– 510
(1972). Mental imagery and associative learning. In L.W. Gregg (Ed.), Cognition in learning and memory (pp. 51- 88). New York: Wiley
(2001). Direct comparison of prefrontal cortex regions engaged by working and long-term memory tasks. Neuroimage, 14, 48– 59
(2000). Neural bases of learning and memory: Functional neuroimaging evidence. Current Opinion in Neurology, 13, 415– 421
(2002). Neural correlates of successful and unsuccessful verbal memory encoding. Brain and Language, 80, 287– 295
(1997). Brainweb. Online interface to a 3D MRI simulated brain database. Neuroimage, 5, 425–
(1997). Dissociating prefrontal and hippocampal function in episodic memory encoding. Nature, 388, 582– 585
(2000). The neural bases of mental imagery. In M.S. Gazzaniga (Ed.), The new cognitive neurosciences (pp. 965-974). Cambridge, MA:MIT Press
(1998). Successful verbal encoding into episodic memory engages the posterior hippocampus: A parametrically analyzed functional magnetic resonance imaging study. Journal of Neuroscience, 18, 1841– 1847
(1997). Linguistic processing. International Review of Neurobiology, 41, 233– 254
(1995). The mind's eye - precuneus activation in memory-related imagery. Neuroimage, 2, 195– 200
(1998). The functional roles of prefrontal cortex in episodic memory. I. Encoding. Brain, 121, 1239– 1248
(1995a). Spatial registration and normalization of images. Human Brain Mapping, 2, 165– 189
(1995b). Statistical parametric maps in functional imaging: A general linear approach. Human Brain Mapping, 2, 189– 210
(2002). A functional magnetic resonance imaging study of overt letter verbal fluency using a clustered acquisition sequence: Greater anterior cingulate activation with increased task demand. Neuroimage, 17, 871– 879
(2001). Material-specific lateralization in the medial temporal lobe and prefrontal cortex during memory encoding. Brain, 124, 1841– 1854
(1999). Human hippocampus associates information in memory. Proceedings of the National Academy of Science, USA, 96, 5884– 5889
(2000). Recoding, storage, rehearsal, and grouping in verbal short-term memory: An fMRI study. Neuropsychologia, 38, 426– 440
(2000). Cerebellar contributions to cognition and imagery. In M.S. Gazzaniga (Ed.), The new cognitive neurosciences (pp. 999-1011). Cambridge, MA: Massachusetts Institute of Technology
(2000). Prefrontal-temporal circuitry for episodic encoding and subsequent memory. Journal of Neuroscience, 20, 6173– 6180
(1998). Hippocampal PET activations of memory encoding and retrieval: The HIPER model. Hippocampus, 8, 313– 322
(1997). Recalling routes around London: Activation of the right hippocampus in taxi drivers. Journal of Neuroscience, 17, 7103– 7110
(2003). Routes to remembering: The brains behind superior memory. Nature Neuroscience, 6, 90– 95
(1999). Automatic activation of the medial temporal lobe during encoding: Lateralized influences of meaning and novelty. Hippocampus, 9, 62– 70
(1997). Modulation of human medial temporal lobe activity by form, meaning, and experience. Hippocampus, 7, 587– 593
(1996). The effect of imagery on explicit and implicit tests of memory in young and old people: A double dissociation. Canadian Journal of Experimental Psychology, 50, 34– 41
(1996). Changes in limbic and prefrontal functional interactions in a working memory task for faces. Cerebral Cortex, 6, 571– 584
(1969). Mental imagery in associative learning and memory. Psychological Review, 76, 241– 263
(1971). Imagery and verbal processes . New York: Holt, Rinehart & Winston
(2002). Observing the transformations of experience into memory. Trends in Cognitive Sciences, 6, 93– 102
(1993). The neural correlates of the verbal component of working memory. Nature, 362, 342– 345
(2002a). Neural correlates of successful encoding identified using functional magnetic resonance imaging. Journal of Neuroscience, 22, 9541– 9548
(2002b). Encoding activity in the medial temporal lobe examined with anatomically constrained fMRI analysis. Hippocampus, 12, 363– 376
(1994). Brain regions associated with acquisition and retrieval of verbal episodic memory. Nature, 368, 633– 635
(1997). Working memory: A view from neuroimaging. Cognitive Psychology, 33, 5– 42
(1998). Components of verbal working memory: Evidence from neuroimaging. Proceedings of the National Academy of Science, USA, 95, 876– 882
(2002). Dissociable human perirhinal, hippocampal, and parahippocampal roles during verbal encoding. Journal of Neuroscience, 22, 523– 528
(1988). Coplanar stereotaxic atlas of the human brain . Stuttgart: Thieme
(2002). Superior digit memory of abacus experts: An event-related functional MRI study. Neuroreport, 13, 2187– 2191
(1999). When encoding yields remembering: Insights from event-related neuroimaging. Philosophical Transactions of the Royal Society of London B Biological Sciences, 354, 1307– 1324
(1998). Building memories: Remembering and forgetting of verbal experiences as predicted by brain activity. Science, 281, 1188– 1191
