Neuronal generators of the visual evoked potentials: intracerebral recording in awake humans

Ducati, Alessandro; Fava, Enrica; Motti, Enrico

doi:10.1016/0168-5597(88)90010-x

Cited by 162 publications

(47 citation statements)

References 22 publications

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“…To compare the fMRI-determined onset differences with the true absolute neural firing delay between V1 and M1, two factors need be considered. First, the onset of electrical activity in V1 is delayed by about 30 ms relative to visual stimulus onset (6,7). Similarly, a latency of about 120 ms between M1 firing and movement onset has been reported (20,22).…”

Section: Discussionmentioning

confidence: 99%

“…The traditional RT approach in studies of cognitive processing could be complemented by a measure of stimulus processing that is independent of explicit motor responses (2) and (ideally) spatially resolved within the brain. One such method is the evoked potential (EP) (3), but despite modern filtering and inversion algorithms, scalp EPs can give a somewhat distorted perspective of timing and origin of the evoked activity (4,5), with surprisingly long latencies (Ͼ50 ms) relative to direct extracellular recordings in the human cortex (6,7). Nonetheless, EPs remain the best available, noninvasive method for determining the sequence of activity in cognitive brain function.…”

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confidence: 99%

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Mental chronometry using latency-resolved functional MRI

Menon

Luknowsky

Gati

1998

Proc. Natl. Acad. Sci. U.S.A.

240

194

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Vascular responses to neural activity are exploited as the basis of a number of brain imaging techniques. The vascular response is thought to be too slow to resolve the temporal sequence of events involved in cognitive tasks, and hence, imaging studies of mental chronometry have relied on techniques such as the evoked potential. Using rapid functional MRI (fMRI) of single trials of two simple behavioral tasks, we demonstrate that while the microvascular response to the onset of neural activity is delayed consistently by several seconds, the relative timing between the onset of the fMRI responses in different brain areas appears preserved. We examined a number of parameters that characterize the fMRI response and determined that its onset time is best defined by the inf lection point from the resting baseline. We have found that fMRI onset latencies determined in this manner correlate well with independently measurable parameters of the tasks such as reaction time or stimulus presentation time and can be used to determine the origin of processing delays during cognitive or perceptual tasks with a temporal accuracy of tens of milliseconds and spatial resolution of millimeters.A large body of research in human perception͞cognition has been concerned with the analysis of mental events into their hierarchical processing stages, the temporal aspect of such processing being termed mental chronometry (1). Mental chronometric tasks have been used extensively in cognitive science to elucidate mechanisms underlying cognitive processing, often using reaction time (RT) as a variable for correlation. The traditional RT approach in studies of cognitive processing could be complemented by a measure of stimulus processing that is independent of explicit motor responses (2) and (ideally) spatially resolved within the brain. One such method is the evoked potential (EP) (3), but despite modern filtering and inversion algorithms, scalp EPs can give a somewhat distorted perspective of timing and origin of the evoked activity (4, 5), with surprisingly long latencies (Ͼ50 ms) relative to direct extracellular recordings in the human cortex (6, 7). Nonetheless, EPs remain the best available, noninvasive method for determining the sequence of activity in cognitive brain function.On the other hand, functional brain mapping techniques that give precise spatial information about the activity of neural substrates rely on changes in the relatively slowly responding cerebral hemodynamic properties such as blood flow (8-11). Maps made with positron-emission tomography (PET) (9) and, more recently, with functional MRI (fMRI) (10, 11) indicate (directly or indirectly) local blood flow changes in response to neural activity modulation. However, they do not contain information about the relative onset of activity in different brain regions. Recent advances in averaged single-trial fMRI (12, 13) have made it possible to map brain activity by using paradigms similar to those used in the EP literature, which, in principle, allows the possibilit...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Mental chronometry using latency-resolved functional MRI

Menon

Luknowsky

Gati

1998

Proc. Natl. Acad. Sci. U.S.A.

240

194

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“…Several studies of pattern reversal potentials (N70, P100) show prolonged latencies with aging (Celesia and Daly, 1977;Wright et al, 1985) but further increment in Alzheimer's disease patients does not occur (Philpot et al, 1990;Wright et al, 1986). Human studies have shown that the P100 component from the primary visual cortex (Ducati et al, 1988) was not affected by cholinergic manipulations (e.g., scopolamine) (Bajalan et al, 1986;Sloan et al, 1992).…”

Section: Visual Potentials In Amnestic Mild Cognitive Impairment and mentioning

confidence: 99%

Cholinesterase inhibitors affect brain potentials in amnestic mild cognitive impairment

et al. 2007

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Amnestic mild cognitive impairment (MCI) is an isolated episodic memory disorder that hasa high likelihood of progressing to Alzheimer's disease. Auditory sensory cortical responses (P50, N100) have been shown to be increased in amplitude in MCI compared to older controls. We tested whether (1) cortical potentials to other sensory modalities (somatosensory and visual) were also affected in MCI and (2) cholinesterase inhibitors (ChEIs), one of the therapies used in this disorder, modulated sensory cortical potentials in MCI. Somatosensory cortical potentials to median nerve stimulation and visual cortical potentials to reversing checkerboard stimulation were recorded from 15 older controls and 15 amnestic MCI subjects (single domain). Results were analyzed as a function of diagnosis (Control, MCI) and ChEIs treatment (Treated MCI, Untreated MCI). Somatosensory and visual potentials did not differ significantly in amplitude in MCI subjects compared to controls.When ChEIs use was considered, somatosensory potentials (N20, P50) but not visual potentials (N70, P100, N150) were of larger amplitude in untreated MCI subjects compared to treated MCI subjects. Three individual MCI subjects showed increased N20 amplitude while off ChEIs compared to while on ChEIs. An enhancement of N20 somatosensory cortical activity occurs in amnestic single-domain MCI and is sensitive to modulation by ChEIs. IntroductionMild cognitive impairment (MCI) describes older individuals having cognitive impairments without accompanying functional impairments that characterize dementia (Petersen et al., 1999). Recent studies have suggested criteria for distinguishing among four subtypes of MCI based on the presence of both episodic memory impairment (amnestic or non-amnestic MCI) and other cognitive impairments (single-or multipledomain MCI) (Petersen, 2004). For example, amnestic singledomain MCI refers to patients with involvement of only memory deficit whereas amnestic multiple-domain MCI refers to patients with impairment of both memory and other cognitive domains such as language or executive function. MCI subjects have a high risk of converting to Alzheimer's disease Petersen et al., 1999) and show neuropathological features of β-amyloid plaques and neurofibrillary tangles similar to early Alzheimer's disease (Kordower et al., 2001;Mufson et al., 1999). These findings suggest that MCI can be a precursor of Alzheimer's disease. Cholinergic processes in neocortical areas are affected in Alzheimer's disease (Geula and Mesulam, 1989;Heckers et al., 1992) and are particularly apparent late in the course of

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“…On the other hand there is a growing body of evidence that visual processing occurs faster than previously thought. Several human depth studies (18,19,60,61), and microelectrode studies in humans (41) and monkeys (for review see 62) showed increased neuronal activity at 30 -50 ms in the striate and extrastriate visual cortex as well as in the temporal lobe after onset of simple visual stimuli such as flashes, pattern reversal, and moving pattern. Since evidence accumulates that visual analysis is computed in a parallel rather than in a serial fashion, there is reason to believe that recognition memory of complex visual pattern starts before 100 ms.…”

Section: The Speed Of Face Recognitionmentioning

confidence: 99%

Intracranial Neurophysiological Correlates Related to the Processing of Faces

Seeck¹,

Michel²,

Blanke³

et al. 2001

Epilepsy & Behavior

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Face perception and recognition is an intriguing ability, already present in neonates. Numerous studies in patients with brain lesions identified the temporo-occipital cortex as the crucial structure for this capacity. Analysis of electrical signals (EEG) inside the brain of patients implanted with intracranial electrodes for diagnostic purposes allows researchers to describe the temporal and spatial organization of responses to various aspects of face processing in human subjects. Several findings have emerged and appear relevant for cerebral organization in general: (1) Selective face responses were obtained from the basal temporo-occipital cortex at around 200 ms (N200); however, other structures such as the lateral temporal lobe and frontal cortex also participate in face recognition and perception tasks. (2) Each structure has a distinct "response profile"; that is, with respect to a given task certain structures respond strongly, others less or not at all. This profile might change with a different task, although the physical parameters of the stimuli remain the same. (3) The right hemispheric predominance of face processing, as suggested by patient data and studies in healthy volunteers, seemed to be restricted to its early stages (i.e., before 100 -150 ms). (4) Recognition of faces might be associated with differential intracranial responses, despite an incorrect overt response, reflecting neurophysiological correlates of implicit memory. (5) The more the stimulus resembled a complete human face, the earlier and larger the N200 response was found, in particular over the basal temporobasal cortex. Analysis of electrical signals from intracranial electrodes might help to improve our understanding of the underlying physiological and anatomical constraints of cognitive processes.

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Neuronal generators of the visual evoked potentials: intracerebral recording in awake humans

Cited by 162 publications

References 22 publications

Mental chronometry using latency-resolved functional MRI

Mental chronometry using latency-resolved functional MRI

Cholinesterase inhibitors affect brain potentials in amnestic mild cognitive impairment

Intracranial Neurophysiological Correlates Related to the Processing of Faces

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