Engaging in an auditory task suppresses responses in auditory cortex

Engaging in an auditory task suppresses responses in auditory cortex Otazu Tai Yang Zador

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Engaging in an auditory task suppresses responses in auditory cortex 2009 Nature Neuroscience 10.1038/nn.2306 Otazu2009-engaging-in-an-auditory-task-suppresses-resp Otazu2009-engaging-in-an-auditory-task-suppresses-resp.txt, the project's staged copy e2c7dc68297b7cdcd3015ba4e2b79d702adb784e not-redistributable neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them how engaging in a task, as distinct from selectively attending, changes sound-evoked responses in auditory cortex Quotation withheld because this record is not cleared for redistribution. what the neural signature of the non-selective component of attention is in auditory cortex Quotation withheld because this record is not cleared for redistribution. shows task engagement suppresses evoked responses in A1 - the opposite sign to selective attention - and proposes suppression as the wakeful baseline on which other modulations are superimposed Quotation withheld because this record is not cleared for redistribution. existence Quotation withheld because this record is not cleared for redistribution. task-engagement suppression of sound-evoked responses in auditory cortex Quotation withheld because this record is not cleared for redistribution. electrophysiology electrophysiology Quotation withheld because this record is not cleared for redistribution. mechanisms Raised thalamic spontaneous firing depresses thalamocortical synapses, which suppresses the cortical evoked response while leaving cortical spontaneous rate unchanged Quotation withheld because this record is not cleared for redistribution. mechanisms Preceding spontaneous activity leaves thalamocortical synapses in a depleted state, so identical thalamic evoked responses drive smaller cortical responses Quotation withheld because this record is not cleared for redistribution. mechanisms Release probability falls inversely with presynaptic rate, so a higher thalamic firing rate does not translate into a higher cortical spontaneous rate Quotation withheld because this record is not cleared for redistribution. mechanisms Suppression functions as an early stage of routing the sensory signal to motor centres by silencing neurons irrelevant to the current task Quotation withheld because this record is not cleared for redistribution. thalamic spontaneous rate rises during engagement while thalamic evoked responses do not change Quotation withheld because this record is not cleared for redistribution. synaptic depression at thalamocortical synapses could convert a raised thalamic spontaneous rate into a suppressed cortical evoked response without raising cortical spontaneous rate Quotation withheld because this record is not cleared for redistribution. suppression concentrates the same stimulus into fewer, harder-firing neurons - the representation becomes sparser by kurtosis Quotation withheld because this record is not cleared for redistribution. headphones deliver identical stimuli regardless of the animal's position, so any difference must come from the animal's state Quotation withheld because this record is not cleared for redistribution. suppression correlates with a cell's spontaneous rate, a property independent of the stimulus used Quotation withheld because this record is not cleared for redistribution. synaptic depression is argued to cover the steady-state effects, with other mechanisms left open for the first few stimuli Quotation withheld because this record is not cleared for redistribution. Simultaneous multi-neuron recording meant stimuli could not be matched to each neuron's receptive field. what this limits: every response-magnitude comparison: BECAUSE ... WE RECORDED FROM SEVERAL NEURONS SIMULTANEOUSLY, WE COULD NOT OPTIMIZE THE STIMULUS PROPERTIES TO MATCH THE RECEPTIVE FIELD PROPERTIES of the recorded neurons Quotation withheld because this record is not cleared for redistribution. The paradigm differs enough from barrel-cortex whisking studies that the two sets of results cannot be compared in detail. what this limits: any comparison with the barrel-cortex literature: DIFFERENCES IN THE BEHAVIORAL PARADIGMS USED IN THE PRESENT WORK ... AND THE PARADIGMS USED IN THE BARREL SYSTEM prevent it Quotation withheld because this record is not cleared for redistribution. The attentional load of the task was modest, and a harder task might have reduced or reversed the suppression. what this limits: the size and sign of the suppression: the attentional load was modest, and a harder task might have reduced or reversed it Quotation withheld because this record is not cleared for redistribution. The synaptic and circuit mechanism of the suppression is not established. what this limits: the mechanistic reading of the suppression: OUR RESULTS REPRESENT A FIRST STEP TOWARD UNDERSTANDING THE SYNAPTIC AND CIRCUIT MECHANISMS - the mechanism is not established here Quotation withheld because this record is not cleared for redistribution. the absence of target enhancement is attributed to a modest attentional load, so a harder task might have changed the result duplicate of: limitations[2] · what this limits: the same scope as limitations[2] - the absence of target enhancement is attributed to a modest attentional load, so a harder task might have changed the result Quotation withheld because this record is not cleared for redistribution. a minority of units, 8 of 32, showed the opposite effect what this limits: the word 'suppression' as a description of the population: A MINORITY SHOWED AN INCREASE (8/32 UNITS). THIS HAD THE EFFECT OF CONCENTRATING THE STIMULUS-EVOKED SPIKES INTO [a] SMALLER POPULATION OF NEURONS Quotation withheld because this record is not cleared for redistribution. suppression interacts with repetition rate and disappears at the highest rates what this limits: the stimulus range over which the effect holds: AT ALL BUT THE HIGHEST REPETITION RATES, THE RESPONSES IN THE ENGAGED CONDITION WERE RELATIVELY SUPPRESSED ... THUS SUPPRESSION INTERACTS WITH REPETITION RATE Quotation withheld because this record is not cleared for redistribution. the thalamocortical depression account is offered as an explanation that could work, not one that was tested here what this limits: the thalamocortical mechanism: SYNAPTIC DEPRESSION OF THE THALAMOCORTICAL INPUTS COULD EXPLAIN HOW THE RELATIVE ENHANCEMENT ... MIGHT LEAD TO SUPPRESSION - offered, not tested here Quotation withheld because this record is not cleared for redistribution. the two intermodal experiments used a harder task and longer training than the main experiment what this limits: any comparison between the intermodal experiments and the main one: WE USED A TONE DISCRIMINATION TASK WHICH WAS SUBSTANTIALLY MORE CHALLENGING (~3 WEEKS TRAINING, PERFORMANCE ~80%) Quotation withheld because this record is not cleared for redistribution. the whisking-versus-quiet suppression in barrel cortex, used as the cross-modal parallel for the same effect Quotation withheld because this record is not cleared for redistribution. short-term synaptic depression and the inverse relation between release probability and presynaptic rate, imported as the circuit explanation Quotation withheld because this record is not cleared for redistribution. the tetrodes advanced at least 40 micrometres EVERY DAY eliminates: the same cells being counted as independent observations across sessions - without moving the electrode, a strong effect in one neuron is re-measured daily and the sample size is a fiction · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. attention is split into a well-defined SELECTIVE component and a much less well-defined non-selective one covering arousal, vigilance and sustained attention - and the two have OPPOSITE signs in this cortex Quotation withheld because this record is not cleared for redistribution. engaged is coined here for the non-selective component: performing a task, as against being awake and not performing one Quotation withheld because this record is not cleared for redistribution. modulation index is defined twice in this paper with different contents - engaged versus passive in the main experiment, auditory versus olfactory block in the intermodal one Quotation withheld because this record is not cleared for redistribution. suppression is proposed not as an effect but as the BASELINE on which other attentional and non-attentional modulations are superimposed Quotation withheld because this record is not cleared for redistribution. method: tetrode recording in rat A1 and auditory thalamus across four task variants, comparing engaged and passive conditions with identical headphone-delivered stimuli a second reading DIFFERING from the recorded value. Recorded: electrophysiology — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. phenomenon: behavioural-state modulation of sensory cortex a second reading DIFFERING from the recorded value. Recorded: task-engagement suppression of sound-evoked responses in auditory cortex — note: a second reading, verbatim-verified, disagreeing with the value on the record. Not applied - a person decides. Quotation withheld because this record is not cleared for redistribution. contradicts → prior studies reporting increased spontaneous activity with task engagement (cited as reference 19) Quotation withheld because this record is not cleared for redistribution. builds-on → rat barrel cortex whisking-versus-quiet-wakefulness studies (cited as references 37–39) Quotation withheld because this record is not cleared for redistribution. contradicts → the expectation that engagement, like selective attention, enhances cortical responses Quotation withheld because this record is not cleared for redistribution. contradicts → the account of neural activity as a resource allocated in greater measure with increasing arousal Quotation withheld because this record is not cleared for redistribution. qualifies → studies reporting increased spontaneous activity with task engagement Quotation withheld because this record is not cleared for redistribution. supports → barrel cortex reports of suppression during whisking relative to quiet wakefulness Quotation withheld because this record is not cleared for redistribution. distinguishes-from → sleep and anaesthesia, which have their own distinct signatures differs in: THE AXIS IS THE SIGNATURE EACH STATE LEAVES. 'Spontaneous and evoked cortical activity showed A CHARACTERISTIC NEURAL SIGNATURE UNDER EACH CONDITION: SPONTANEOUS CORTICAL ACTIVITY WAS REDUCED IN THE LESS AROUSED STATES (SLEEP AND ANESTHETIZED) compared with the awake but passive condition.' Task engagement is distinguished from sleep and anaesthesia not by the direction of the effect on evoked responses - which can look alike - but by what happens to SPONTANEOUS activity at the same time. Quotation withheld because this record is not cleared for redistribution. engaged —distinct-from→ selective attention engaged selective attention strength of the relation: 1 · note: OPPOSITE IN SIGN in the same cortex - the sharpest sign contrast in the corpus, and the reason the construct has to be split Quotation withheld because this record is not cleared for redistribution. synaptic depression —causes→ auditory cortex synaptic depression auditory cortex strength of the relation: 0.7 · note: could explain - proposed, not tested here Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but synaptic depression 'COULD EXPLAIN' suppression of the cortical evoked response; causes is hedged and 'auditory cortex' drops the response. Quotation withheld because this record is not cleared for redistribution. engaged —distinct-from→ arousal engaged arousal strength of the relation: 0.95 · note: argued from the SIGN: raised arousal would raise firing, and firing fell Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span argues arousal would not explain the suppression; distinct-from is loose. Quotation withheld because this record is not cleared for redistribution. paired t-test paired t-test Quotation withheld because this record is not cleared for redistribution. kurtosis kurtosis Quotation withheld because this record is not cleared for redistribution. standard error of the mean standard error of the mean Quotation withheld because this record is not cleared for redistribution. correlation correlation Quotation withheld because this record is not cleared for redistribution. p-value p-value Quotation withheld because this record is not cleared for redistribution. Mahalanobis distance (spike-cluster quality metric) Mahalanobis distance (spike-cluster quality metric) Quotation withheld because this record is not cleared for redistribution. modulation index modulation index Quotation withheld because this record is not cleared for redistribution. kurtosis of the firing rate distribution kurtosis of the firing rate distribution Quotation withheld because this record is not cleared for redistribution. paired t-test paired t-test Quotation withheld because this record is not cleared for redistribution. Engaging in an auditory task suppressed sound-evoked responses in auditory cortex, the opposite sign of the enhancement produced by selective attention. Quotation withheld because this record is not cleared for redistribution. The suppression of evoked responses occurred with no accompanying change in pre-stimulus spontaneous cortical activity. Quotation withheld because this record is not cleared for redistribution. Responses to the task-relevant target sound were suppressed as much as responses to the last non-target sound. Quotation withheld because this record is not cleared for redistribution. Sound-evoked responses during auditory-attention blocks were not suppressed relative to olfactory-attention blocks. Quotation withheld because this record is not cleared for redistribution. The amount of suppression was unrelated to a neuron's spatial selectivity, frequency selectivity, or the octave distance between its best frequency and the attended frequency. Quotation withheld because this record is not cleared for redistribution. The authors conclude that the suppression in the engaged condition does not depend on the animal triggering the stimulus. Quotation withheld because this record is not cleared for redistribution. Firing-rate kurtosis rose from 4.1 (passive) to 8.4 (engaged), indicating a sparser stimulus representation during engagement. Quotation withheld because this record is not cleared for redistribution. In the auditory thalamus engagement left evoked responses unchanged but raised spontaneous firing rates, the opposite pattern to cortex. Quotation withheld because this record is not cleared for redistribution. Thalamic evoked responses did not differ between engaged and passive conditions (p=0.80). Quotation withheld because this record is not cleared for redistribution. Sleep and ketamine anesthesia reduced spontaneous cortical activity relative to the awake passive state, giving those low-arousal states a neural signature distinct from passive wakefulness. Quotation withheld because this record is not cleared for redistribution. Neural activity did not differ between the passive blocks recorded before and after the task, excluding recording drift, satiety and reward expectation as explanations for the suppression. Quotation withheld because this record is not cleared for redistribution. task engagement suppressed evoked responses across single units, multiunit activity and LFP Quotation withheld because this record is not cleared for redistribution. cortical spontaneous activity did not change, unlike other reports Quotation withheld because this record is not cleared for redistribution. task-relevant target and irrelevant non-target stimuli were suppressed equally Quotation withheld because this record is not cleared for redistribution. the representation became sparser, kurtosis 8.4 engaged against 4.1 passive Quotation withheld because this record is not cleared for redistribution. no suppression of auditory responses in an auditory block relative to an olfactory block Quotation withheld because this record is not cleared for redistribution. suppression appeared in both blocks relative to passive, so it does not depend on the task's modality Quotation withheld because this record is not cleared for redistribution. suppression was unrelated to spatial selectivity, frequency selectivity or distance from the attended frequency Quotation withheld because this record is not cleared for redistribution. the same suppression appeared when the animal did not trigger the stimulus, with a nearly identical modulation index Quotation withheld because this record is not cleared for redistribution. sleep and anaesthesia have their own distinct signatures, with reduced spontaneous activity Quotation withheld because this record is not cleared for redistribution. in thalamus, spontaneous activity rose during engagement while evoked responses were unchanged Quotation withheld because this record is not cleared for redistribution. thalamic burstiness did not change, unlike in sleep or reduced arousal Quotation withheld because this record is not cleared for redistribution. modulation index modulation index Quotation withheld because this record is not cleared for redistribution. modulation index range modulation index range Quotation withheld because this record is not cleared for redistribution. kurtosis kurtosis Quotation withheld because this record is not cleared for redistribution. isolation distance isolation distance Quotation withheld because this record is not cleared for redistribution. selective component selective component Quotation withheld because this record is not cleared for redistribution. non-selective component non-selective component Quotation withheld because this record is not cleared for redistribution. evoked response evoked response Quotation withheld because this record is not cleared for redistribution. thalamic spontaneous firing rate thalamic spontaneous firing rate Quotation withheld because this record is not cleared for redistribution. intertrial interval intertrial interval Quotation withheld because this record is not cleared for redistribution. repetition rate repetition rate Quotation withheld because this record is not cleared for redistribution. spontaneous firing rate spontaneous firing rate Quotation withheld because this record is not cleared for redistribution. −0.20 ± 0.03 vs −0.19±0.02 — modulation index of the multiunit evoked response in the head-fixed task compared with the freely moving task Quotation withheld because this record is not cleared for redistribution. 8.4 ± 2.4 vs 4.1 ± 0.7 — kurtosis of the firing-rate distribution when engaged versus passive Quotation withheld because this record is not cleared for redistribution. 8/32 units — minority of single units whose evoked activity increased rather than decreased when the animal was engaged Quotation withheld because this record is not cleared for redistribution. p<1e–16 — significance of the engagement-related suppression for multiunit activity and evoked LFP Quotation withheld because this record is not cleared for redistribution. p=0.80 — test of the difference in thalamic evoked response between engaged and passive conditions (no difference) Quotation withheld because this record is not cleared for redistribution. p<0.001 — significance of the elevation of thalamic spontaneous activity during engagement Quotation withheld because this record is not cleared for redistribution. 81% / 91% — behavioural accuracy during auditory versus olfactory blocks of the intermodal attention task Quotation withheld because this record is not cleared for redistribution. > 95% correct; ~1 week — criterion performance and training time on the two-alternative choice task before electrode implantation Quotation withheld because this record is not cleared for redistribution. kurtosis 8.4 plus or minus 2.4 engaged versus 4.1 plus or minus 0.7 passive — sparseness of the representation Quotation withheld because this record is not cleared for redistribution. 8 of 32 units — the minority showing enhancement rather than suppression Quotation withheld because this record is not cleared for redistribution. -0.20 plus or minus 0.03 head-fixed versus -0.19 plus or minus 0.02 self-triggered — modulation indices, showing self-triggering does not explain the effect Quotation withheld because this record is not cleared for redistribution. p = 0.80 — the thalamic evoked-response null Quotation withheld because this record is not cleared for redistribution. about 80% correct after three weeks versus over 95% after one week — the harder intermodal task against the main task Quotation withheld because this record is not cleared for redistribution.

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