The Effect of FEF Microstimulation on the Responses of Neurons in the Lateral Intraparietal Area

2014 ◽  
Vol 26 (8) ◽  
pp. 1672-1684 ◽  
Author(s):  
Elsie Premereur ◽  
Wim Vanduffel ◽  
Peter Janssen

The macaque FEFs and the lateral intraparietal area (LIP) are high-level cortical areas involved in both spatial attention and oculomotor behavior. Stimulating FEF at a level below the threshold for evoking saccades increases fMRI activity and gamma power in area LIP, but the precise effect exerted by the FEF on LIP neurons is unknown. In our study, we recorded LIP single-unit activity during a visually guided saccade task with a peripherally presented go signal during microstimulation of FEF. We found that FEF microstimulation increased the LIP spike rate immediately after the highly salient go signal inside the LIP receptive field when both target and go signal were presented inside the receptive field, and no other possible go cues were present on the screen. The effect of FEF microstimulation on the LIP response was positive until at least 800 msec after microstimulation had ceased, but reversed for longer trial durations. Therefore, FEF microstimulation can modulate the LIP spike rate only when attention is selectively directed toward the stimulated location. These results provide the first direct evidence for LIP spike rate modulations caused by FEF microstimulation, thus showing that FEF activity can be the source of top–down control of area LIP.

2009 ◽  
Vol 101 (1) ◽  
pp. 289-305 ◽  
Author(s):  
Alessandra Fanini ◽  
John A. Assad

The lateral intraparietal area (LIP) of the macaque is believed to play a role in the allocation of attention and the plan to make saccadic eye movements. Many studies have shown that LIP neurons generally encode the static spatial location demarked by the receptive field (RF). LIP neurons might also provide information about the features of visual stimuli within the RF. For example, LIP receives input from cortical areas in the dorsal visual pathway that contain many direction-selective neurons. Here we examine direction selectivity of LIP neurons. Animals were only required to fixate while motion stimuli appeared in the RF. To avoid spatial confounds, the motion stimuli were patches of randomly arrayed dots that moved with 100% coherence in eight different directions. We found that the majority (61%) of LIP neurons were direction selective. The direction tuning was fairly broad, with a median direction-tuning bandwidth of 136°. The average strength of direction selectivity was weaker in LIP than that of other areas of the dorsal visual stream but that difference may be because of the fact that LIP neurons showed a tonic offset in firing whenever a visual stimulus was in the RF, independent of direction. Direction-selective neurons do not seem to constitute a functionally distinct subdivision within LIP, because those neurons had robust, sustained delay-period activity during a memory delayed saccade task. The direction selectivity could also not be explained by asymmetries in the spatial RF, in the hypothetical case that the animals attended to slightly different locations depending on the direction of motion in the RF. Our results show that direction selectivity is a distinct attribute of LIP neurons in addition to spatial encoding.


1989 ◽  
Vol 61 (5) ◽  
pp. 1064-1084 ◽  
Author(s):  
R. A. Boch ◽  
M. E. Goldberg

1. We recorded from 257 neurons in the banks of the posterior third of the principal sulcus of two rhesus monkeys trained to look at a fixation point and make saccades to stimuli in the visual periphery. Sixty-six percent (220/257) discharged or were suppressed in association with one or more aspects of the tasks we used. 2. Fifty-eight percent (151/257) of the neurons responded to the appearance of a spot of light in some part of the contralateral visual field. Cells did not seem to have absolute requirements for stimulus shape, size, or direction of motion. 3. Thirty-six percent (29/79) of visually responsive neurons tested quantitatively gave an enhanced response to the stimulus in the receptive field when the monkey had to make a saccade to the stimulus when its appearance was synchronous with the disappearance of the fixation point (synchron task). Twenty-nine percent (19/57) of the neurons gave an enhanced response to the stimulus when the monkey had to make a saccade to the stimulus some time after it appeared (delayed-saccade task). In general, enhancement in the synchron task correlated well with enhancement in the delayed-saccade task. 4. Enhancement was spatially specific. It did not occur when the monkey made a saccade to a stimulus outside the receptive field even though there was a stimulus within the receptive field. 5. Twenty-three percent (27/117) of neurons studied in the delayed-saccade task gave two bursts, one at the appearance of the stimulus and a second one around the saccade. This second burst generally did not occur when the monkey made the same saccade to a remembered target, but instead required the presence of the visual stimulus, and so we describe it as a reactivation of the visual response. Reactivation was also spatially specific. 6. The latency from reactivation to the beginning of the saccade ranged from 160 ms before the saccade to the beginning of the saccade. Reactivation usually continued for several hundred milliseconds after the saccade, sometimes for the duration of the trial. 7. Reactivation and enhancement are not the same mechanism. Although some cells showed both phenomena there was no correlation between enhancement and reactivation. 8. Cells that showed reactivation in the saccade task also showed reactivation at a weaker level in a suppressed-saccade task. In this task the monkeys had to hold fixation despite the disappearance of the fixation point and the continued presence of the peripheral stimulus.(ABSTRACT TRUNCATED AT 400 WORDS)


1999 ◽  
Vol 82 (1) ◽  
pp. 343-358 ◽  
Author(s):  
Jennifer F. Linden ◽  
Alexander Grunewald ◽  
Richard A. Andersen

The lateral intraparietal area (LIP), a region of posterior parietal cortex, was once thought to be unresponsive to auditory stimulation. However, recent reports have indicated that neurons in area LIP respond to auditory stimuli during an auditory-saccade task. To what extent are auditory responses in area LIP dependent on the performance of an auditory-saccade task? To address this question, recordings were made from 160 LIP neurons in two monkeys while the animals performed auditory and visual memory-saccade and fixation tasks. Responses to auditory stimuli were significantly stronger during the memory-saccade task than during the fixation task, whereas responses to visual stimuli were not. Moreover, neurons responsive to auditory stimuli tended also to be visually responsive and to exhibit delay or saccade activity in the memory-saccade task. These results indicate that, in general, auditory responses in area LIP are modulated by behavioral context, are associated with visual responses, and are predictive of delay or saccade activity. Responses to auditory stimuli in area LIP may therefore be best interpreted as supramodal responses, and similar in nature to the delay activity, rather than as modality-specific sensory responses. The apparent link between auditory activity and oculomotor behavior suggests that the behavioral modulation of responses to auditory stimuli in area LIP reflects the selection of auditory stimuli as targets for eye movements.


2012 ◽  
Vol 108 (5) ◽  
pp. 1392-1402 ◽  
Author(s):  
Elsie Premereur ◽  
Wim Vanduffel ◽  
Pieter R. Roelfsema ◽  
Peter Janssen

Macaque frontal eye fields (FEF) and the lateral intraparietal area (LIP) are high-level oculomotor control centers that have been implicated in the allocation of spatial attention. Electrical microstimulation of macaque FEF elicits functional magnetic resonance imaging (fMRI) activations in area LIP, but no study has yet investigated the effect of FEF microstimulation on LIP at the single-cell or local field potential (LFP) level. We recorded spiking and LFP activity in area LIP during weak, subthreshold microstimulation of the FEF in a delayed-saccade task. FEF microstimulation caused a highly time- and frequency-specific, task-dependent increase in gamma power in retinotopically corresponding sites in LIP: FEF microstimulation produced a significant increase in LIP gamma power when a saccade target appeared and remained present in the LIP receptive field (RF), whereas less specific increases in alpha power were evoked by FEF microstimulation for saccades directed away from the RF. Stimulating FEF with weak currents had no effect on LIP spike rates or on the gamma power during memory saccades or passive fixation. These results provide the first evidence for task-dependent modulations of LFPs in LIP caused by top-down stimulation of FEF. Since the allocation and disengagement of spatial attention in visual cortex have been associated with increases in gamma and alpha power, respectively, the effects of FEF microstimulation on LIP are consistent with the known effects of spatial attention.


1998 ◽  
Vol 79 (5) ◽  
pp. 2814-2819 ◽  
Author(s):  
Lawrence H. Snyder ◽  
Aaron P. Batista ◽  
Richard A. Andersen

Snyder, Lawrence H., Aaron P. Batista, and Richard A. Andersen. Change in motor plan, without a change in the spatial locus of attention, modulates activity in posterior parietal cortex. J. Neurophysiol. 79: 2814–2819, 1998. The lateral intraparietal area (LIP) of macaque monkey, and a parietal reach region (PRR) medial and posterior to LIP, code the intention to make visually guided eye and arm movements, respectively. We studied the effect of changing the motor plan, without changing the locus of attention, on single neurons in these two areas. A central target was fixated while one or two sequential flashes occurred in the periphery. The first appeared either within the response field of the neuron being recorded or else on the opposite side of the fixation point. Animals planned a saccade (red flash) or reach (green flash) to the flash location. In some trials, a second flash 750 ms later could change the motor plan but never shifted attention: second flashes always occurred at the same location as the preceding first flash. Responses in LIP were larger when a saccade was instructed ( n = 20 cells), whereas responses in PRR were larger when a reach was instructed ( n = 17). This motor preference was observed for both first flashes and second flashes. In addition, the response to a second flash depended on whether it affirmed or countermanded the first flash; second flash responses were diminished only in the former case. Control experiments indicated that this differential effect was not due to stimulus novelty. These findings support a role for posterior parietal cortex in coding specific motor intention and are consistent with a possible role in the nonspatial shifting of motor intention.


1987 ◽  
Vol 10 (3) ◽  
pp. 407-436 ◽  
Author(s):  
Michael A. Arbib

AbstractIntermediate constructs are required as bridges between complex behaviors and realistic models of neural circuitry. For cognitive scientists in general, schemas are the appropriate functional units; brain theorists can work with neural layers as units intermediate between structures subserving schemas and small neural circuits.After an account of different levels of analysis, we describe visuomotor coordination in terms of perceptual schemas and motor schemas. The interest of schemas to cognitive science in general is illustrated with the example of perceptual schemas in high-level vision and motor schemas in the control of dextrous hands.Rana computatrix, the computational frog, is introduced to show how one constructs an evolving set of model families to mediate flexible cooperation between theory and experiment. Rana computatrix may be able to do for the study of the organizational principles of neural circuitry what Aplysia has done for the study of subcellular mechanisms of learning. Approach, avoidance, and detour behavior in frogs and toads are analyzed in terms of interacting schemas. Facilitation and prey recognition are implemented as tectal-pretectal interactions, with the tectum modeled by an array of tectal columns. We show how layered neural computation enters into models of stereopsis and how depth schemas may involve the interaction of accommodation and binocular cues in anurans.


1998 ◽  
Vol 15 (4) ◽  
pp. 755-764 ◽  
Author(s):  
M.L. FIRSOV ◽  
D.G. GREEN

Photoreceptors in the isolated turtle retina of two species of turtle, Chelydra serpentina and Pseudemus scripta elegans, were penetrated with double-barrel electrodes. Physiological responses were recorded through one barrel and Neurobiotin tracer was injected from the other. Intracellular injection of Neurobiotin revealed patterns of tracer-coupled photoreceptors. Both the patterns of tracer coupling and the electrophysiology suggest a high degree of specificity of connections. Rods seem to be coupled only to rods and green and red cones seem to be coupled to cones of the same spectral type. Receptive-field profiles, measured with a thin, sharply focused slit of light, often had well-defined peaks and troughs in sensitivity. We have taken advantage of this observation and used the position of a peak in sensitivity to locate the position on the retina of a coupled cell. In one rod, it was possible to correlate physiological and morphological data and to show that the peaks in the physiological receptive field occurred at positions on the retina where there were dye-coupled cells. This provides direct evidence that gap junctions produce the physiological coupling between rods.


2008 ◽  
Vol 100 (2) ◽  
pp. 646-656 ◽  
Author(s):  
Ben Scholl ◽  
Michael Wehr

Sensory deafferentation results in rapid shifts in the receptive fields of cortical neurons, but the synaptic mechanisms underlying these changes remain unknown. The rapidity of these shifts has led to the suggestion that subthreshold inputs may be unmasked by a selective loss of inhibition. To study this, we used in vivo whole cell recordings to directly measure tone-evoked excitatory and inhibitory synaptic inputs in auditory cortical neurons before and after acoustic trauma. Here we report that acute acoustic trauma disrupted the balance of excitation and inhibition by selectively increasing and reducing the strength of inhibition at different positions within the receptive field. Inhibition was abolished for frequencies far below the trauma-tone frequency but was markedly enhanced near the edges of the region of elevated peripheral threshold. These changes occurred for relatively high-level tones. These changes in inhibition led to an expansion of receptive fields but not by a simple unmasking process. Rather, membrane potential responses were delayed and prolonged throughout the receptive field by distinct interactions between synaptic excitation and inhibition. Far below the trauma-tone frequency, decreased inhibition combined with prolonged excitation led to increased responses. Near the edges of the region of elevated peripheral threshold, increased inhibition served to delay rather than abolish responses, which were driven by prolonged excitation. These results show that the rapid receptive field shifts caused by acoustic trauma are caused by distinct mechanisms at different positions within the receptive field, which depend on differential disruption of excitation and inhibition.


2003 ◽  
Vol 90 (3) ◽  
pp. 2029-2052 ◽  
Author(s):  
Melanie T. Wyder ◽  
Dino P. Massoglia ◽  
Terrence R. Stanford

This study investigates the visuomotor properties of several nuclei within primate central thalamus. These nuclei, which might be considered components of an oculomotor thalamus (OcTh), are found within and at the borders of the internal medullary lamina. These nuclei have extensive anatomical links to numerous cortical and subcortical visuomotor areas including the frontal eye fields, supplementary eye fields, prefrontal cortex, posterior parietal cortex, caudate, and substantia nigra pars reticulata. Previous single-unit recordings have shown that neurons in OcTh respond during self-paced spontaneous saccades and to visual stimuli in the absence of any specific behavioral requirement, but a thorough account of the activity of these areas in association with voluntary, goal-directed movement is lacking. We recorded activity from single neurons in primate central thalamus during performance of a visually guided delayed saccade task. The sample consisted primarily of neurons from the centrolateral and paracentral intralaminar nuclei and paralaminar regions of the ventral anterior and ventral lateral nuclei. Neurons responsive to sensory, delay, and motor phases of the task were observed in each region, with many neurons modulated during multiple task periods. Across the population, variation in the quality and timing of saccade-contingent activity suggested participation in functions ranging from generating a saccade (presaccadic) to registering its consequences (e.g., efference copy). Finally, many neurons were found to carry spatial information during the delay period, suggesting a role for central thalamus in higher-order aspects of visuomotor control.


2009 ◽  
Vol 364 (1521) ◽  
pp. 1203-1209 ◽  
Author(s):  
Jeff Hawkins ◽  
Dileep George ◽  
Jamie Niemasik

In this paper, we propose a mechanism which the neocortex may use to store sequences of patterns. Storing and recalling sequences are necessary for making predictions, recognizing time-based patterns and generating behaviour. Since these tasks are major functions of the neocortex, the ability to store and recall time-based sequences is probably a key attribute of many, if not all, cortical areas. Previously, we have proposed that the neocortex can be modelled as a hierarchy of memory regions, each of which learns and recalls sequences. This paper proposes how each region of neocortex might learn the sequences necessary for this theory. The basis of the proposal is that all the cells in a cortical column share bottom-up receptive field properties, but individual cells in a column learn to represent unique incidences of the bottom-up receptive field property within different sequences. We discuss the proposal, the biological constraints that led to it and some results modelling it.


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