Repetition Suppression in Monkey Inferotemporal Cortex: Relation to Behavioral Priming

2007 ◽  
Vol 97 (5) ◽  
pp. 3532-3543 ◽  
Author(s):  
David B. T. McMahon ◽  
Carl R. Olson

In tasks requiring judgments about visual stimuli, humans exhibit repetition priming, responding with increased speed when a stimulus is repeated. Repetition priming might depend on repetition suppression, a phenomenon first observed in monkey inferotemporal cortex (IT) whereby, when a stimulus is repeated, the strength of the neuronal visual response is reduced. If the reduction resulted in sharpening of the cortical representation of the stimulus, and did not just scale it down, then speeded processing might result. To explore the relation between repetition priming and repetition suppression, we monitored neuronal activity in IT while monkeys performed a symmetry decision task. We found 1) that monkeys exhibit repetition priming, 2) that IT neurons simultaneously exhibit repetition suppression, 3) that repetition priming and repetition suppression do not vary in a significantly correlated fashion across trials, and 4) that repetition suppression scales down the representation of the stimulus without sharpening it. We conclude that repetition suppression accompanies repetition priming but is unlikely to be its cause.

2006 ◽  
Vol 20 (3) ◽  
pp. 195-211 ◽  
Author(s):  
Michael Wagner ◽  
Lioba Baving ◽  
Patrick Berg ◽  
Rudolf Cohen ◽  
Brigitte Rockstroh

The processing of attended and nonattended stimuli in schizophrenic patients was examined with event-related potentials (ERPs) in a lexical decision task. In positive semantic and repetition priming the N400 amplitude did not differ between a group of 17 medicated schizophrenic patients and a group of 20 matched healthy controls. However, negative priming affected the N400 only in controls. Reaction time effects were dissociated from these ERP effects, with patients showing stronger positive priming than controls but identical negative priming. The semantic processes related to the N400 appear to be intact in schizophrenic patients, but patients seem to incorporate less context information (about the nonattended prime) in their episodic memory traces. A stronger increase of the posterior late positive complex in parallel to the stronger positive priming in schizophrenic patients may reflect relatively stronger automatic memory retrieval processes in patients.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefano Rozzi ◽  
Marco Bimbi ◽  
Alfonso Gravante ◽  
Luciano Simone ◽  
Leonardo Fogassi

AbstractThe ventral part of lateral prefrontal cortex (VLPF) of the monkey receives strong visual input, mainly from inferotemporal cortex. It has been shown that VLPF neurons can show visual responses during paradigms requiring to associate arbitrary visual cues to behavioral reactions. Further studies showed that there are also VLPF neurons responding to the presentation of specific visual stimuli, such as objects and faces. However, it is largely unknown whether VLPF neurons respond and differentiate between stimuli belonging to different categories, also in absence of a specific requirement to actively categorize or to exploit these stimuli for choosing a given behavior. The first aim of the present study is to evaluate and map the responses of neurons of a large sector of VLPF to a wide set of visual stimuli when monkeys simply observe them. Recent studies showed that visual responses to objects are also present in VLPF neurons coding action execution, when they are the target of the action. Thus, the second aim of the present study is to compare the visual responses of VLPF neurons when the same objects are simply observed or when they become the target of a grasping action. Our results indicate that: (1) part of VLPF visually responsive neurons respond specifically to one stimulus or to a small set of stimuli, but there is no indication of a “passive” categorical coding; (2) VLPF neuronal visual responses to objects are often modulated by the task conditions in which the object is observed, with the strongest response when the object is target of an action. These data indicate that VLPF performs an early passive description of several types of visual stimuli, that can then be used for organizing and planning behavior. This could explain the modulation of visual response both in associative learning and in natural behavior.


2014 ◽  
Vol 111 (12) ◽  
pp. 2589-2602 ◽  
Author(s):  
Hiroshi Tamura ◽  
Yoshiya Mori ◽  
Hidekazu Kaneko

Detailed knowledge of neuronal circuitry is necessary for understanding the mechanisms underlying information processing in the brain. We investigated the organization of horizontal functional interactions in the inferior temporal cortex of macaque monkeys, which plays important roles in visual object recognition. Neuronal activity was recorded from the inferior temporal cortex using an array of eight tetrodes, with spatial separation between paired neurons up to 1.4 mm. We evaluated functional interactions on a time scale of milliseconds using cross-correlation analysis of neuronal activity of the paired neurons. Visual response properties of neurons were evaluated using responses to a set of 100 visual stimuli. Adjacent neuron pairs tended to show strong functional interactions compared with more distant neuron pairs, and neurons with similar stimulus preferences tended to show stronger functional interactions than neurons with different stimulus preferences. Thus horizontal functional interactions in the inferior temporal cortex appear to be organized according to both cortical distances and similarity in stimulus preference between neurons. Furthermore, the relationship between strength of functional interactions and similarity in stimulus preference observed in distant neuron pairs was more prominent than in adjacent pairs. The results suggest that functional circuitry is specifically organized, depending on the horizontal distances between neurons. Such specificity endows each circuit with unique functions.


1990 ◽  
Vol 63 (3) ◽  
pp. 502-522 ◽  
Author(s):  
R. Lal ◽  
M. J. Friedlander

1. Extracellular recordings were made from single neurons in layer A of the left dorsal lateral geniculate nucleus (LGNd) of anesthetized and paralyzed adult cats. Responses to retinotopically identical visual stimuli (presented through the right eye) were recorded at several positions of the left eye in its orbit. Visual stimuli consisted of drifting sinusoidal gratings of optimal temporal and spatial frequencies at twice threshold contrast. Visual stimulation of the left eye was blocked by a variety of methods, including intravitreal injection of tetrodotoxin (TTX). The change in position of the left eye was achieved by passive movements in a randomized and interleaved fashion. Of 237 neurons studied, responses were obtained from 143 neurons on 20-100 trials of identical visual stimulation at each of six eye positions. Neurons were classified as X- or Y- on the basis of a standard battery of physiological tests (primarily linearity of spatial summation and response latency to electrical stimulation of the optic chiasm). 2. The effect of eye position on the visual response of the 143 neurons was analyzed with respect to the number of action potentials elicited and the peak firing rate. Fifty-seven (40%) neurons had a significant effect [by one-factor repeated-measure analysis of variance (ANOVA), P less than 0.05] of eye position on the visual response by either criterion (number of action potentials or peak firing rate). Of these 57 neurons, 47 had a significant effect (P less than 0.05) with respect to the number of action potentials and 23 had a significant effect (P less than 0.05) by both criteria. Thus the permissive measure by either criterion and the conservative measure by both criteria resulted in 40% and 16%, respectively, of all neurons' visual responses being significantly affected by eye position. 3. For the 47 neurons with a significant effect of eye position (number of action potentials criterion), a trend analysis of eye position versus visual response showed a linear trend (P less than 0.05) for 9 neurons, a quadratic trend (P less than 0.05) for 32 neurons, and no significant trend for the 6 remaining neurons. The trends were approximated with linear and nonlinear gain fields (range of eye position change over which the visual response was modulated). The gain fields of individual neurons were compared by measuring the normalized gain (change in neuronal response per degree change of eye position). The mean normalized gain for the 47 neurons was 4.3. 4. The nonlinear gain fields were generally symmetric with respect to nasal versus temporal changes in eye position.(ABSTRACT TRUNCATED AT 400 WORDS)


NeuroImage ◽  
2017 ◽  
Vol 161 ◽  
pp. 67-79 ◽  
Author(s):  
Edden M. Gerber ◽  
Tal Golan ◽  
Robert T. Knight ◽  
Leon Y. Deouell

2018 ◽  
Vol 38 (34) ◽  
pp. 7492-7504 ◽  
Author(s):  
Kasper Vinken ◽  
Hans P. Op de Beeck ◽  
Rufin Vogels

1997 ◽  
Vol 20 (4) ◽  
pp. 684-685 ◽  
Author(s):  
James M. Bower

Phillips & Singer (P&S) extend ideas derived from the observation eight years ago that the coherence (synchronization) of cortical oscillations can be modulated by the structure of visual stimuli. As described in the target article, a large part of the continued interest in this finding is related to independent theoretical work suggesting that synchronized cell firing could help solve the problem of binding together within cortex neuronal activity associated with different attributes of visual stimuli. The authors present an abstract “proof of concept” model describing how their cortical processing scheme could work, but our biologically realistic models of cortical relationships suggest that the proposal is biologically implausible. Our realistic models lead to a very different interpretation of the significance of cortical oscillations.


1990 ◽  
Vol 63 (3) ◽  
pp. 523-538 ◽  
Author(s):  
R. Lal ◽  
M. J. Friedlander

1. The nature and time window of interaction between passive phasic eye movement signals and visual stimuli were studied for dorsal lateral geniculate nucleus (LGNd) neurons in the cat. Extracellular recordings were made from single neurons in layer A of the left LGNd of anesthetized paralyzed cats in response to a normalized visual stimulus presented to the right eye at each of several times of movement of the left eye. The left eye was moved passively at a fixed amplitude and velocity while varying the movement onset time with respect to the visual stimulus onset in a randomized and interleaved fashion. Visual stimuli consisted of square-wave modulated circular spots of appropriate contrast, sign, and size to elicit an optimal excitatory response when placed in the neurons' receptive-field (RF) center. 2. Interactions were analyzed for 78 neurons (33 X-neurons, 43 Y-neurons, and 2 physiologically unclassified neurons) on 25-65 trials of identical visual stimuli for each of eight times of eye movement. 3. Sixty percent (47/78) of the neurons tested had a significant eye movement effect (ANOVA, P less than 0.05) on some aspect of their visual response. Of these 47 neurons, 42 (89%) had a significant (P less than 0.05) effect of an appropriately timed eye movement on the number of action potentials, 36 (77%) had a significant effect on the mean peak firing rate, and 31 (66%) were significantly affected as evaluated by both criteria. 4. The eye movement effect on the neurons' visual responses was primarily facilitatory. Facilitation was observed for 37 (79%) of the affected neurons. For 25 of these 37 neurons (68%), the facilitation was significant (P less than 0.05) as evaluated by both criteria (number of action potentials and mean peak firing rate). Ten (21%) of the affected neurons had their visual response significantly inhibited (P less than 0.05). 5. Sixty percent (46/78) of the neurons were tested for the effect of eye movement on both visually elicited activity (visual stimulus contrast = 2 times threshold) and spontaneous activity (contrast = 0). Eye movement significantly affected the visual response of 23 (50%) of these neurons. However, spontaneous activity was significantly affected for only nine (20%) of these neurons. The interaction of the eye movement and visual signals was nonlinear. 6. Nine of 12 neurons (75%) tested had a directionally selective effect of eye movement on the visual response, with most (8/9) preferring the temporal ward direction.(ABSTRACT TRUNCATED AT 400 WORDS)


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