TY - JOUR

T1 - Brain activation during word identification and word recognition

AU - Jernigan, T L

AU - Ostergaard, A L

AU - Law, I

AU - Svarer, C

AU - Gerlach, C

AU - Paulson, O B

PY - 1998/7

Y1 - 1998/7

N2 - Previous memory research has suggested that the effects of prior study observed in priming tasks are functionally, and neurobiologically, distinct phenomena from the kind of memory expressed in conventional (explicit) memory tests. Evidence for this position comes from observed dissociations between memory scores obtained with the two kinds of tasks. However, there is continuing controversy about the meaning of these dissociations. In recent studies, Ostergaard (1998a, Memory Cognit, 26:40-60; 1998b, J. Int. Neuropsychol. Soc., in press) showed that simply degrading visual word stimuli can dramatically alter the degree to which word priming shows a dissociation from word recognition; i.e., effects of a number of factors on priming paralleled their effects on recognition memory tests when the words were degraded at test. In the present study, cerebral blood flow changes were measured while subjects performed the word identification (reading) and recognition memory tasks used previously by Ostergaard. The results are the direct comparisons of the two tasks and the effects of stimulus degradation on blood flow patterns during the tasks. Clear differences between word identification and word recognition were observed: the latter task evoked considerably more prefrontal activity and stronger cerebellar activation. Stimulus degradation was associated with focal increases in bilateral fusiform regions within the occipital lobe. No task, degradation, or item repetition effects were demonstrated in mesial temporal regions, no repetition effects were observed in any region, and there was no evidence for different effects of stimulus degradation in the priming and recognition memory conditions. Power limitations may have contributed to the null effects.

AB - Previous memory research has suggested that the effects of prior study observed in priming tasks are functionally, and neurobiologically, distinct phenomena from the kind of memory expressed in conventional (explicit) memory tests. Evidence for this position comes from observed dissociations between memory scores obtained with the two kinds of tasks. However, there is continuing controversy about the meaning of these dissociations. In recent studies, Ostergaard (1998a, Memory Cognit, 26:40-60; 1998b, J. Int. Neuropsychol. Soc., in press) showed that simply degrading visual word stimuli can dramatically alter the degree to which word priming shows a dissociation from word recognition; i.e., effects of a number of factors on priming paralleled their effects on recognition memory tests when the words were degraded at test. In the present study, cerebral blood flow changes were measured while subjects performed the word identification (reading) and recognition memory tasks used previously by Ostergaard. The results are the direct comparisons of the two tasks and the effects of stimulus degradation on blood flow patterns during the tasks. Clear differences between word identification and word recognition were observed: the latter task evoked considerably more prefrontal activity and stronger cerebellar activation. Stimulus degradation was associated with focal increases in bilateral fusiform regions within the occipital lobe. No task, degradation, or item repetition effects were demonstrated in mesial temporal regions, no repetition effects were observed in any region, and there was no evidence for different effects of stimulus degradation in the priming and recognition memory conditions. Power limitations may have contributed to the null effects.

KW - Adult

KW - Brain Mapping

KW - Cerebral Cortex/physiology

KW - Discrimination Learning/physiology

KW - Dominance, Cerebral/physiology

KW - Female

KW - Humans

KW - Male

KW - Mental Recall/physiology

KW - Occipital Lobe/physiology

KW - Prefrontal Cortex/physiology

KW - Problem Solving/physiology

KW - Reading

KW - Tomography, Emission-Computed

KW - Verbal Learning/physiology

U2 - 10.1006/nimg.1998.0350

DO - 10.1006/nimg.1998.0350

M3 - Journal article

C2 - 9698579

VL - 8

SP - 93

EP - 105

JO - NeuroImage

JF - NeuroImage

SN - 1053-8119

IS - 1

ER -