Journal of Neurophysiology, Vol 74, Issue 1 162-178, Copyright © 1995 by APS

ARTICLES

Mnemonic firing of neurons in the monkey temporal pole during a visual recognition memory task

K. Nakamura and K. Kubota
Department of Behavioral and Brain Sciences, Kyoto University, Aichi, Japan.

1. We examined single-neuronal activity in the temporal pole of monkeys, including the anterior ventromedial temporal (VMT) cortex (the temporopolar cortex, area 36, area 35, and the entorhinal cortex) and the anterior inferotemporal (IT) cortex, during a visual recognition memory task. In the task, a trial began when the monkey pressed a lever. After a waiting period, a visual sample stimulus (S) was presented one to four times on a monitor with an interstimulus delay. Thereafter, a new stimulus (R) was presented. The monkeys were trained to remember S during the delay period and to release the lever in response to R. Colored photographs of natural objects were used as visual stimuli. 2. About 70% of the recorded neurons (225 of 311) responded to at least one of the Ss tested. Thirty percent of these neurons (68 of 225) continued to fire during the subsequent delay periods. In 75% of these neurons (51 of 68), the firing during the delay period strongly correlated with the response to S. 3. The discharge rate during the delay period did not correlate with the monkey's eye movements, pressing or releasing of the lever, or the reaction time. 4. If the monkey erroneously released the lever in response to S or during the delay period, the firing disappeared after the erroneous lever release. If the monkey failed to release the lever in response to R, the firing persisted even after R was withdrawn. The discharge rate in incorrect trials was comparable with that in correct trials. The neurons were considered to fire for as long as the memory of S was necessary. 5. Firing persisted even when an achromatic version or half (even a portion) of S was presented, indicating that the color, a particular portion, or the entire shape of S was not always necessary to elicit firing. 6. An S that elicited firing during the delay period invariably elicited a visual response. Neurons that fired during the delay period showed a higher stimulus selectivity than other visually responsive neurons in the anterior VMT cortex. Thus neurons that fire during the delay period represent a subgroup of visually responsive neurons that are selectively tuned to a certain stimulus. 7. More neurons fired during the delay period in the anterior VMT cortex than in the anterior IT cortex. 8. We conclude that firing during the delay period by neurons in the temporal pole reflects the short-term storage of visual information regarding a particular S.

This article has been cited by other articles:

				V. Yakovlev, D. J. Amit, S. Romani, and S. Hochstein Universal Memory Mechanism for Familiarity Recognition and Identification J. Neurosci., January 2, 2008; 28(1): 239 - 248. [Abstract] [Full Text] [PDF]

				H. BARBAS Specialized Elements of Orbitofrontal Cortex in Primates Ann. N.Y. Acad. Sci., December 1, 2007; 1121(1): 10 - 32. [Abstract] [Full Text] [PDF]

				K. K. Sreenivasan, J. Katz, and A. P. Jha Temporal Characteristics of Top-Down Modulations during Working Memory Maintenance: An Event-related Potential Study of the N170 Component. J. Cogn. Neurosci., November 1, 2007; 19(11): 1836 - 1844. [Abstract] [Full Text] [PDF]

				O. J. Hulme and S Zeki The Sightless View: Neural Correlates of Occluded Objects Cereb Cortex, May 1, 2007; 17(5): 1197 - 1205. [Abstract] [Full Text] [PDF]

				S. R. Lehky and K. Tanaka Enhancement of Object Representations in Primate Perirhinal Cortex During a Visual Working-Memory Task J Neurophysiol, February 1, 2007; 97(2): 1298 - 1310. [Abstract] [Full Text] [PDF]

				C. Ranganath, M. X. Cohen, and C. J. Brozinsky Working Memory Maintenance Contributes to Long-term Memory Formation: Neural and Behavioral Evidence J. Cogn. Neurosci., July 1, 2005; 17(7): 994 - 1010. [Abstract] [Full Text] [PDF]

				P. E. Latham and S. Nirenberg Computing and Stability in Cortical Networks Neural Comput., July 1, 2004; 16(7): 1385 - 1412. [Abstract] [Full Text] [PDF]

				C. Ranganath, M. X. Cohen, C. Dam, and M. D'Esposito Inferior Temporal, Prefrontal, and Hippocampal Contributions to Visual Working Memory Maintenance and Associative Memory Retrieval J. Neurosci., April 21, 2004; 24(16): 3917 - 3925. [Abstract] [Full Text] [PDF]

				R. J. Zatorre, M. Bouffard, and P. Belin Sensitivity to Auditory Object Features in Human Temporal Neocortex J. Neurosci., April 7, 2004; 24(14): 3637 - 3642. [Abstract] [Full Text] [PDF]

				R. E. Hampson, T. P. Pons, T. R. Stanford, and S. A. Deadwyler Categorization in the monkey hippocampus: A possible mechanism for encoding information into memory PNAS, March 2, 2004; 101(9): 3184 - 3189. [Abstract] [Full Text] [PDF]

				N. Brunel Dynamics and Plasticity of Stimulus-selective Persistent Activity in Cortical Network Models Cereb Cortex, November 1, 2003; 13(11): 1151 - 1161. [Abstract] [Full Text] [PDF]

				T. J. Druzgal and M. D'Esposito Dissecting Contributions of Prefrontal Cortex and Fusiform Face Area to Face Working Memory J. Cogn. Neurosci., August 1, 2003; 15(6): 771 - 784. [Abstract] [Full Text] [PDF]

				Y. Tanaka, Y. Miyazawa, R. Hashimoto, I. Nakano, and T. Obayashi Postencephalitic focal retrograde amnesia after bilateral anterior temporal lobe damage Neurology, July 1, 1999; 53(2): 344 - 344. [Abstract] [Full Text] [PDF]

				R. Hasegawa, T. Sawaguchi, and K. Kubota Monkey Prefrontal Neuronal Activity Coding the Forthcoming Saccade in an Oculomotor Delayed Matching-to-Sample Task J Neurophysiol, January 1, 1998; 79(1): 322 - 333. [Abstract] [Full Text] [PDF]

				W. A. Suzuki, E. K. Miller, and R. Desimone Object and Place Memory in the Macaque Entorhinal Cortex J Neurophysiol, August 1, 1997; 78(2): 1062 - 1081. [Abstract] [Full Text] [PDF]

				R. Desimone Neural mechanisms for visual memory and their role in attention PNAS, November 26, 1996; 93(24): 13494 - 13499. [Abstract] [Full Text] [PDF]

				E. K. Miller, C. A. Erickson, and R. Desimone Neural Mechanisms of Visual Working Memory in Prefrontal Cortex of the Macaque J. Neurosci., August 15, 1996; 16(16): 5154 - 5167. [Abstract] [Full Text] [PDF]