Somatosensory discrimination based on cortical microstimulation

Romo, Ranulfo; Hernandez, Antonio; Zainos, Antonio; Salinas, Emilio

doi:10.1038/32891

Cited by 454 publications

(433 citation statements)

References 15 publications

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“…Moreover, rabbits acquiring an associative learning using a trace-conditioning paradigm are unable to differentiate between the peripheral or central presentation of the same CS, i.e., their subjective experience was similar for both stimuli (1). These results also suggest that a similar sensory percept is evoked when animals are stimulated in the S1 area for vibrissae as when stimulated directly on the whisker pad (4,5). In this regard, it has been convincingly shown that neural responses in the S1 encode the observed performance of behaving monkeys during vibrotactile discrimination tasks, and that the electrical microstimulation of the same S1 areas can substitute for the direct stimulation of the corresponding Meissner's corpuscles located at the finger tips and sensitive to frequencies (Ͻ50 Hz) subjectively perceived as a flutter (2).…”

Section: Discussionsupporting

confidence: 56%

“…Thus, the neural activities recorded at the different S1 areas seem to correlate with sensory events (3). Accepting that centrally evoked sensory percepts could be similar to those evoked by peripheral stimuli (4,5), it can be hypothesized that the electrical microstimulation of selected S1 sites can substitute for peripheral skin receptor activation during the acquisition of an associative task, such as the classical conditioning of eyelid responses.…”

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confidence: 99%

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Microstimulation of the somatosensory cortex can substitute for vibrissa stimulation during Pavlovian conditioning

Leal‐Campanario

Delgado‐García

Gruart

2006

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

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The primary somatosensory cortex (S1) contains a map representation of the body surface. We hypothesized that S1 stimulation can successfully substitute for (or be substituted by) direct stimulation of skin receptors. We prepared rabbits for evoking eyelid conditioned responses (CRs) using a trace ''shock-air puff'' paradigm. In a first series of experiments, animals received a conditioned stimulus (CS, a train of electrical pulses) in the whisker pad or in the S1 areas for vibrissae or for the hind limb. In the three cases, the CS was followed 250 ms from its end by an air puff presented to the cornea as an unconditioned stimulus (US). Learning curves from the three groups presented similar values, although animals stimulated with a central CS acquired their CRs faster. In a second series of experiments, animals were divided into four groups and were presented either centrally or peripherally with the same CS for six conditioning sessions. Then, the CS was switched from central to peripheral, or vice versa, for 5 additional days. Conditioned animals were not able to discriminate between peripheral (vibrissae) stimuli and stimuli presented to the corresponding S1 (vibrissae) area, but they were able to discriminate between CSs presented to S1 (hind limb) and body (vibrissae) regions. The kinetic properties of evoked CRs were not modified by CS switching. It is proposed that S1 allows the construction of somatosensory percepts of the body surface but does not allow distinguishing the central or peripheral location of the evoking stimuli.associative learning ͉ eyelid motor system ͉ rabbits ͉ sensory substitution ͉ trace-conditioning paradigm T he physiological role of the primary somatosensory cortex (S1) seems to be the generation of neural codes coherent with sensory stimuli impinging upon skin receptors (1). Indeed, it has been shown that neuronal responses in the S1 reproduced the actual discriminative behavior of monkeys during the performance of selective vibrotactile discrimination tasks (2). Thus, the neural activities recorded at the different S1 areas seem to correlate with sensory events (3). Accepting that centrally evoked sensory percepts could be similar to those evoked by peripheral stimuli (4, 5), it can be hypothesized that the electrical microstimulation of selected S1 sites can substitute for peripheral skin receptor activation during the acquisition of an associative task, such as the classical conditioning of eyelid responses.To check the proposed hypothesis, we decided to use here a trace-conditioning paradigm, using peripheral (whisker pad) or central (S1 area for vibrissae or hind limb) electrical stimulation as a conditioned stimulus (CS) and an air puff directed at the cornea (ipsilateral to the whisker pad and contralateral to the stimulated S1 areas) as an unconditioned stimulus (US). The rationale was the following. As opposed to delay conditioning, in which the CS precedes the US in its initiation and coterminates with it, in trace conditioning, there is a time gap between the end of ...

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Section: Discussionsupporting

confidence: 56%

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confidence: 99%

Microstimulation of the somatosensory cortex can substitute for vibrissa stimulation during Pavlovian conditioning

Leal‐Campanario

Delgado‐García

Gruart

2006

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

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“…medial premotor cortex ͉ monkeys ͉ sensory discrimination ͉ working memory S tudies in behaving monkeys that combine psychophysical and neurophysiological experiments have provided new insights into how a neural representation of a sensory stimulus relates to perception (1)(2)(3)(4)(5)(6)(7)(8), memory (9)(10)(11)(12), and decision making (13)(14)(15)(16)(17)(18)(19). In particular, there has been important progress regarding the neural codes associated with these cognitive functions in the visual and somatic modality (20,21).…”

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confidence: 99%

Neural correlates of a postponed decision report

Lemus

Hernandez

Luna

et al. 2007

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

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Depending on environmental demands, a decision based on a sensory evaluation may be either immediately reported or postponed for later report. If postponed, the decision must be held in memory. But what exactly is stored by the underlying memory circuits, the final decision itself or the sensory information that led to it? Here, we report that, during a postponed decision report period, the activity of medial premotor cortex neurons encodes both the result of the sensory evaluation that corresponds to the monkey's possible choices and past sensory information on which the decision is based. These responses could switch back and forth with remarkable flexibility across the postponed decision report period. Moreover, these responses covaried with the animal's decision report. We propose that maintaining in working memory the original stimulus information on which the decision is based could serve to continuously update the postponed decision report in this task.medial premotor cortex ͉ monkeys ͉ sensory discrimination ͉ working memory S tudies in behaving monkeys that combine psychophysical and neurophysiological experiments have provided new insights into how a neural representation of a sensory stimulus relates to perception (1-8), memory (9-12), and decision making (13-19). In particular, there has been important progress regarding the neural codes associated with these cognitive functions in the visual and somatic modality (20,21). The basic philosophy of this approach has been to investigate these cognitive functions by using highly simplified stimuli, so that diverse subcortical and cortical areas can be studied during the same behavior.In the task we previously used, monkeys report whether the second stimulus frequency (f2) is higher or lower than the first stimulus frequency (f1) (22). This cognitive operation requires that subjects compare information of f1 temporally stored in working memory to the current information of f2 to form a decision of whether f2 Ͼ f1 or f2 Ͻ f1, and to immediately report the outcome by pressing one of two push buttons. We found that the activity of the recorded neurons of several cortical areas encodes f1 in a monotonic firing rate code beginning in the primary somatosensory cortex (5-7), continuing in the secondary somatosensory cortex (5), the ventral premotor cortex (19), the prefrontal cortex (10), and the medial premotor cortex (MPc) (18). Except for the primary somatosensory cortex, these cortical areas encode information of f1 during the delay period between f1 and f2 (5,10,11,(17)(18)(19). During presentation of f2, some neurons of all these cortical areas respond to f2, but some other neurons reflect past information of f1, or of the difference between f2 and f1, and generate a differential response consistent with the decision motor report (17)(18)(19). In this chain of neural processes, the primary motor cortex becomes engaged only during the motor report period (19,21). These results showed that the stimulus parameters of f1 and f2 and their interactions can be dec...

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“…Although artificial cortical microstimulation can be perceptually indistinguishable from natural stimulation 15 , this need not always be the case; our results do not reveal the conditions under which such fine temporal differences are important for the readout of acoustically-evoked (i.e. natural) stimuli.…”

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confidence: 53%

Millisecond-scale differences in neural activity in auditory cortex can drive decisions

et al. 2008

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Neurons in the auditory cortex can lock with millisecond precision to the fine timing of acoustic stimuli, but it is not known whether this precise spike timing can be used to guide decisions. We used chronically implanted microelectrode pairs to stimulate neurons in the rat auditory cortex directly. Here we demonstrate that rats can exploit differences in the timing of cortical activity as short as three milliseconds to guide decisions.Animals can detect the fine timing of some stimuli. For example, interaural time differences of less than one millisecond are used for the spatial localization of sound 1 . It is also clear that cortical neurons can lock with millisecond precision to the fine timing of some stimuli in the auditory cortex 2, 3 , the visual cortex 4 , somatosensory cortex 5,6 and in vitro 7 . Furthermore, spike generation in the auditory cortex is controlled by a stereotyped and precisely timed sequence of excitatory input followed approximately three milliseconds later by inhibitory input 8 . However, although it has recently been established that even a few cortical spikes are sufficient to drive decisions 9, 10 , it has been difficult to establish whether the fine timing of cortical activity can suffice.We therefore set out to probe the precision with which the fine timing of neural activity in the auditory cortex could guide behaviour in the rat. For the spatial localization of sound, the relevant sub-millisecond interaural time difference cues are extracted by specialized subcortical structures. To ensure that we were probing cortical rather than subcortical mechanisms, we bypassed subcortical auditory pathways and trained animals to respond to direct intracortical electrical stimulation. We used transient biphasic current trains delivered via two chronically implanted intracortical microelectrodes 11-13 to stimulate two populations of neurons in primary auditory cortex (area A1; Fig. 1a). We designed the stimulation patterns so that the only cue available to guide behaviour was the relative timing of the activity elicited in the two cortical populations.We first trained adult male Long Evans rats to perform a simple auditory two alternative choice task (2-AC) 14 . The animal initiated a trial by inserting its nose into the centre port of a three port operant chamber, triggering one of two acoustic stimuli. These stimuli indicated whether the left or right goal port would be rewarded with water ( Fig. 1A; for details, see Supplemental material). Chance performance was 50%. After animals reached criterion performance (> 90%), we implanted electrodes at two sites (A and B; Fig. 1A) about 1.1 mm apart along the rostro-caudal axis in the rat's left primary auditory cortex (Fig. S3). We then substituted electrical stimulation (< 30 µA) through these

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Somatosensory discrimination based on cortical microstimulation

Cited by 454 publications

References 15 publications

Microstimulation of the somatosensory cortex can substitute for vibrissa stimulation during Pavlovian conditioning

Microstimulation of the somatosensory cortex can substitute for vibrissa stimulation during Pavlovian conditioning

Neural correlates of a postponed decision report

Millisecond-scale differences in neural activity in auditory cortex can drive decisions

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