Frontal theta event-related synchronization: comparison of directed attention and working memory load effects
First Online: 11 April 2006 Received: 11 July 2005 Accepted: 08 December 2005 DOI:
10.1007/s00702-005-0443-9 Cite this article as: Missonnier, P., Deiber, M., Gold, G. et al. J Neural Transm (2006) 113: 1477. doi:10.1007/s00702-005-0443-9 Summary.
Early studies showed that long-term encoding and retrieval of new information is associated with modulation of the theta rhythm. More recently, changes in theta power amplitude over frontal electrode sites were reported during working memory, yet their relative significance in regard to attentional and memory processes remains unclear. Event-related synchronisation responses in the 4–7.5 Hz theta EEG frequency band was studied in 12 normal subjects performing four different tasks: two working memory tasks in which load varied from one (1-back task) to two (2-back task) items, an oddball detection (attention) task and a passive fixation task. A phasic theta increase was observed following stimulus apparition on all electrode sites within each task, with longer culmination peak and maximal amplitude over frontal electrodes. Frontal theta event-related synchronization (ERS) was of higher amplitude in the 1-back, 2-back and detection tasks as compared to the passive fixation task. Additionally, the detection task elicited a larger frontal and central theta ERS than the 2-back task. By analyzing theta ERS characteristics in various experimental conditions, the present study reveals that early phasic theta response over frontal regions primarily reflects the activation of neural networks involved in allocation of attention related to target stimuli rather than working memory processes.
Keywords: Working memory, EEG, event-related synchronisation, theta oscillations, attention. References Baddeley, A 1981 The concept of working memory: a view of its current state and probable future development Cognition 10 17 23 PubMed CrossRef Baddeley, A 1992 Working memory Science 255 556 559 PubMed Baleydier, C, Mauguiere, F 1985 Anatomical evidence for medial pulvinar connections with the posterior cingulate cortex, the retrosplenial area, and the posterior parahippocampal gyrus in monkeys J Comp Neurol 232 219 228 PubMed CrossRef Baleydier, C, Mauguiere, F 1987 Network organization of the connectivity between parietal area 7, posterior cingulate cortex and medial pulvinar nucleus: a double fluorescent tracer study in monkey Exp Brain Res 66 385 393 PubMed CrossRef Basar-Eroglu, C, Basar, E, Demiralp, T, Schurmann, M 1992 P300-response: possible psychophysiological correlates in delta and theta frequency channels. A review Int J Psychophysiol 13 161 179 PubMed CrossRef Bastiaansen, M, Hagoort, P 2003 Event-induced theta responses as a window on the dynamics of memory Cortex 39 967 992 PubMed Bastiaansen, MC, van Berkum, JJ, Hagoort, P 2002 Event-related theta power increases in the human EEG during online sentence processing Neurosci Lett 323 13 16 PubMed CrossRef Caplan, JB, Madsen, JR, Raghavachari, S, Kahana, MJ 2001 Distinct patterns of brain oscillations underlie two basic parameters of human maze learning J Neurophysiol 86 368 380 PubMed Demiralp, T, Basar-Eroglu, C, Rahn, E, Basar, E 1994 Event-related theta rhythms in cat hippocampus and prefrontal cortex during an omitted stimulus paradigm Int J Psychophysiol 18 35 48 PubMed CrossRef Doppelmayr, M, Klimesch, W, Schwaiger, J, Stadler, W, Rohm, D 2000 The time locked theta response reflects interindividual differences in human memory performance Neurosci Lett 278 141 144 PubMed CrossRef Gevins, A, Smith, ME, McEvoy, L, Yu, D 1997 High-resolution EEG mapping of cortical activation related to working memory: effects of task difficulty, type of processing, and practice Cereb Cortex 7 374 385 PubMed CrossRef Jensen, O, Tesche, CD 2002 Frontal theta activity in humans increases with memory load in a working memory task Eur J Neurosci 15 1395 1399 PubMed CrossRef Kahana, MJ, Seelig, D, Madsen, JR 2001 Theta returns Curr Opin Neurobiol 11 739 744 PubMed CrossRef Klimesch, W 1999 EEG alpha and theta oscillations reflect cognitive and memory performance: a review and analysis Brain Res Brain Res Rev 29 169 195 PubMed CrossRef Klimesch, W, Doppelmayr, M, Pachinger, T, Ripper, B 1997 Brain oscillations and human memory: EEG correlates in the upper alpha and theta band Neurosci Lett 238 9 12 PubMed CrossRef Klimesch, W, Schack, B, Schabus, M, Doppelmayr, M, Gruber, W, Sauseng, P 2004 Phase-locked alpha and theta oscillations generate the P1-N1 complex and are related to memory performance Brain Res Cogn Brain Res 19 302 316 PubMed CrossRef Klimesch, W, Schimke, H, Schwaiger, J 1994 Episodic and semantic memory: an analysis in the EEG theta and alpha band Electroencephalogr Clin Neurophysiol 91 428 441 PubMed CrossRef Krause, CM, Sillanmaki, L, Koivisto, M, Saarela, C, Haggqvist, A, Laine, M, Hamalainen, H 2000 The effects of memory load on event-related EEG desynchronization and synchronization Clin Neurophysiol 111 2071 2078 PubMed CrossRef LaBar, KS, Gitelman, DR, Parrish, TB, Mesulam, M 1999 Neuroanatomic overlap of working memory and spatial attention networks: a functional MRI comparison within subjects Neuroimage 10 695 704 PubMed CrossRef McEvoy, LK, Pellouchoud, E, Smith, ME, Gevins, A 2001 Neurophysiological signals of working memory in normal aging Brain Res Cogn Brain Res 11 363 376 PubMed CrossRef Mesulam, MM 1981 A cortical network for directed attention and unilateral neglect Ann Neurol 10 309 325 PubMed CrossRef Milliken, GA, Johnson, DE 1984Designed experiments Van Nostrand Reinhold New York O’Keefe, J 1993 Hippocampus, theta, and spatial memory Curr Opin Neurobiol 3 917 924 PubMed CrossRef Pfurtscheller, G 1992 Event-related synchronization (ERS): an electrophysiological correlate of cortical areas at rest Electroencephalogr Clin Neurophysiol 83 62 69 PubMed CrossRef Pfurtscheller, G 2001 Functional brain imaging based on ERD/ERS Vision Res 41 1257 1260 PubMed CrossRef Pfurtscheller, G, Aranibar, A 1977 Event-related cortical desynchronization detected by power measurements of scalp EEG Electroencephalogr Clin Neurophysiol 42 817 826 PubMed CrossRef Raghavachari, S, Kahana, MJ, Rizzuto, DS, Caplan, JB, Kirschen, MP, Bourgeois, B, Madsen, JR, Lisman, JE 2001 Gating of human theta oscillations by a working memory task J Neurosci 21 3175 3183 PubMed Sederberg, PB, Kahana, MJ, Howard, MW, Donner, EJ, Madsen, JR 2003 Theta and gamma oscillations during encoding predict subsequent recall J Neurosci 23 10809 10814 PubMed Tallon-Baudry, C, Bertrand, O 1999 Oscillatory gamma activity in humans and its role in object representation Trends Cogn Sci 3 151 162 PubMed CrossRef Van Hoesen, G, Pandya, DN 1975 Some connections of the entorhinal (area 28) and perirhinal (area 35) cortices of the rhesus monkey. I. Temporal lobe afferents Brain Res 95 1 24 PubMed CrossRef Van Hoesen, GW, Rosene, DL, Mesulam, MM 1979 Subicular input from temporal cortex in the rhesus monkey Science 205 608 610 PubMed Wetzel, W, Ott, TA, Matthies, H 1977 Post-training hippocampal rhythmic slow activity (“theta”) elicited by septal stimulation improves memory consolidation in rats Behav Biol 21 32 40 PubMed CrossRef Winson, J 1978 Loss of hippocampal theta rhythm results in spatial memory deficit in the rat Science 201 160 163 PubMed