Studies on clinical samples have shown that performance on Serial Digit Learning Test (SDLT) is dependent on mesial temporal lobe and hippocampus, both of which are responsible of learning and its consolidation [1,2]. However, an effective SDLT performance also requires such processes as utilisation of various cognitive strategies, temporal ordering of events and control of interfering effects [3]; all of these processes are among the functions of the frontal lobes [4-6].Previous studies where various electrophysiological mapping techniques were utilised could not prove the hypothesis. This...

SUBJECTS.4 normal male volunteers of ages between24 and 35 years. All subjects had explicit right hand dominance. They were matched regarding education and socioeconomic level.SCANNER HARDWARE. 1.5 T (+/-33 mT/m) EPI scanner (EchoSpeed, General Electric, Milwaukee, USA), and a standard quadrature head coil. CONTRAST MECHANISM. Blood oxygen level dependent (BOLD) contrast method [8-10].PSYCHOMETRIC PARADIGM (MOTOR SDLT). Displacements caused by head movements may be responsible of almost all of the fMRI signal in extreme situations [11]. SDLT requires the oral interaction of the subjects and therefore...

SDLT caused mesial temporal activations as expected. These activations were consistent with the consolidation and learning phase of the task. SDLT correlated activations were also encountered in all subjects in frontal lobes, especially distinct at right; these activations were mapped to Brodmanns area 10 and its neighbourings (BA 9-11-32). Stereotactically activations were dispersed on toright superior frontal gyrus, cingulate gyri and right gyrus rectus and they were specifically affecting slightly dlifferent areas in learning and recall phases od the task.

It is currently known that performance on the SDLT is closely related to the functioning of the mesial temporal lobes, that the SDLT score is sensitive to disturbance in this area, and can differentiate patients with such disturbances from normal controls [1-2]. Hovewer according to contemporary theories and the latest findings, memory is a distributed function of the brain [13-15]. Since SDLT performance is closely related to memory, it too should engage a distributed system in the brain. In SDLT, the participant should further learn...

[1] Drachman DA, Arbit J (1966) Memory and the hippocampal complex: Is memory a multiple process. Archives of Neurology, 15: 52-61.[2] Lezak MD (1995) Neuropsychological Assessment, 3 rd ed., New York, Oxford University Press.[3] Karakas HM (2001) Mapping of cognitive functions. Turkish Journal of Neurology, (in press).[4] Schachter DL (1987) Memory, amnesia and frontal lobe dysfunction. Psychobiology, 15: 21-36.[5] Fuster JM (1989) The Prefrontal Cortex: Anatomy, Physiology, and Neuropsychology of the Frontal Lobe, 2.nd ed., New York, Raven Press.[6] Tsukiura T, Fujii T, Takahashi T,...

Nuri Tasali, MD [email protected], Department of Radiology, PTT Research and Education Hospital, Istanbul - TurkeyHakki M.Karakas, MD [email protected] Professor of Radiology, Department of Radiodiagnostics, TrakyaUniversity Medical Faculty, Edirne- Turkey;Brain Dynamics Research Network, The Scientific and Technical Research Council of Turkey, Ankara - Turkey Alper M. Arman, MD [email protected], Department of Radiology, Haydarpasa Numune Research and Education Hospital, Istanbul - TurkeyLevent Celik, MD [email protected] Professor of Radiology, Department of Radiology, Dr. Siyami Ersek Thoracic and Cardiovascular Surgery Hospital, Istanbul TurkeySirel Karakas, Ph.D. [email protected] of Experimental Psychology,Cognitive...