Journal: Science Advances

Article Title: A spatial code for temporal information is necessary for efficient sensory learning

doi: 10.1126/sciadv.adr6214

Figure Lengend Snippet: ( A ) Sketch of experimental setup for simultaneous patterned optogenetic stimulation and single-unit recording in AC and for intrinsic imaging. ( B ) AC window showing the location of a stimulation spot along the tonotopic axis of the primary auditory field (A1) with 64-channel silicon probe inserted via a hole in the coverglass (top right) to record single-unit responses to light patterns and illustrative data from three channels. ( C ) Responses of four AC neurons to different optogenetic stimulation patterns illustrating how spatiotemporal and spatial codes are extracted. ( D ) Sketch of the temporal modulation patterns applied to a single spot on the AC. ( E and F ) Z -scored responses of 344 single units to the 15 Hz high rate versus and 4 Hz high rate (E) and 15 Hz high rate versus 4 Hz low rate stimulations (F) ordered by preference for 15-Hz versus 4-Hz stimulation. Right: Difference in each neuron’s average firing rate between stimulations. ( G ) Accuracy of a neural decoder trained to discriminate between the optogenetic patterns based only on spatial information or with spatiotemporal information ( n = 344 units, bootstrap over units). ( H ) Sketch of the relative timing patterns applied to two spots A and B and the purely spatial pattern applied to either A or B. ( I and J ) Z -scored responses of 344 single units to A, B stimulations (I) and AB, BA stimulations (J), ordered by preference for A versus B stimulation. Right: Difference in each neuron’s average firing rate between stimulations. ( K ) Accuracy of a neural decoder trained to discriminate between the optogenetic patterns based only on spatial information or with spatiotemporal information ( n = 344 units, bootstrap over units).

Article Snippet: For MFB stimulation, a bipolar stimulation electrode (60-μm-diameter twisted stainless steel, PlasticsOne) was implanted using stereotaxic coordinates (antero-posterior−1.4, medio-lateral +1.2, dorso-ventral +4.8).

Techniques: Single-unit Recording, Imaging

Journal: Science Advances

Article Title: A spatial code for temporal information is necessary for efficient sensory learning

doi: 10.1126/sciadv.adr6214

Figure Lengend Snippet: ( A ) Sketch of experimental setup for behavioral discrimination of patterned optogenetic stimulation in AC and cranial window from an example mouse showing the location of the stimulation spots in the tonotopic axis of the primary auditory field. ( B ) Sample lick traces (top) and mean lick signal (bottom) for Go and NoGo trials in the task with temporal modulation and firing rate cues that the mouse successfully learnt (left) and in the task with temporal modulation cues only in which the mouse failed to discriminate (right). ( C ) Learning curves for an example mouse performing the two tasks with temporal modulation. ( D ) Learning curves for all mice performing the tasks with temporal modulation ( n = 7, error bars are SEM). ( E ) Accuracy at 2500 trials for all mice (paired Wilcoxon test, P = 0.031, signed rank value = 21, n = 6). ( F ) Learning curves for an example mouse performing the relative temporal order task and the spatial pattern task. ( G ) Learning curves for all mice performing each task ( n = 7, error bars are SEM). ( H ) Accuracy at 2500 trials for all mice (paired Wilcoxon test, P = 0.032, signed rank value = 27, n = 7).

Article Snippet: For MFB stimulation, a bipolar stimulation electrode (60-μm-diameter twisted stainless steel, PlasticsOne) was implanted using stereotaxic coordinates (antero-posterior−1.4, medio-lateral +1.2, dorso-ventral +4.8).

Techniques:

Journal: Imaging Neuroscience

Article Title: Chemogenetic inhibition of dopaminergic neurons reduces stimulus-induced dopamine release, thereby altering the hemodynamic response function in the prefrontal cortex

doi: 10.1162/imag_a_00200

Figure Lengend Snippet: Experimental design. (A) VTA neurons were infected bilaterally with either AAV8-CamKIIa-hM4D (Gi)-mcherry (the DREADD virus) or AAV2-CamKIIa-mcherry (the control virus). (B) Three weeks after virus injection, a stimulation electrode was implanted in the right fimbria/fornix. The correct position of the electrode was adjusted by recording the electrophysiological response in the r-NAcc. The responding electrode was removed after adjusting the stimulation electrode (left box). One week after the second fMRI measurement, a carbon electrode was implanted again in the r-NAcc, and in vivo voltammetry was performed to measure stimulus-induced dopamine release in the r-NAcc. (C) The fMRI measurement was performed 1 week after electrode implantation. The same rat was measured two times, after either CNO or NaCl application. Stimulus-induced fMRI responses were simultaneously recorded in all individual VOIs. (D, E) In an additional group of rats, in vivo electrophysiology was performed to the measure stimulus-induced neuronal responses in the mPFC (D) and the CA1 region of the dHC (the recordings depict the response to an individual test pulse).

Article Snippet: The bipolar stimulation electrode (114 μm diameter, Teflon-coated tungsten wire, insulated except at the tip; A-M Systems, Science Products GmbH, Hofheim, Germany) was placed unilaterally in the right hippocampal fornix/fimbria fiber tract (AP—1.5 mm, ML 2.6 mm, and DV 2.5–3.3 mm from the dural surface), according to the rat atlas of . A monopolar recording electrode was lowered into the right nucleus accumbens (r-NAcc) to adjust the correct placement of the stimulation electrode in the right fimbria/fornix (AP 1.7 mm, ML 1.6 mm, and DV 6.5–7.2 mm from the dural surface).

Techniques: Infection, Virus, Control, Injection, In Vivo

Journal: Imaging Neuroscience

Article Title: Chemogenetic inhibition of dopaminergic neurons reduces stimulus-induced dopamine release, thereby altering the hemodynamic response function in the prefrontal cortex

doi: 10.1162/imag_a_00200

Figure Lengend Snippet: Electrical stimulation of the right fimbria/fornix fibers generates two different BOLD activation patterns. (A) Performing a GLM analysis with the data from all measured rats (n = 11) revealed a widespread BOLD activation pattern (top panel). (B) VOI analysis of all voxels in the r-dHC revealed the presence of strong variability after the first stimulation period when all rats (n = 11) were included in the analysis. (C) Performing the same GLM analysis with two subgroups revealed the presence of two different BOLD activation patterns. The calculation of the contrast between the two groups indicated significantly different clusters of BOLD activation (red clusters: stronger activation for rats with nADs than for rats without nADs; blue clusters: weaker activation for rats with nADs than for rats without nADs; lower panel). (D) The variability after the first stimulation period resulted from the presence of two different BOLD time series: one where the BOLD signals remained elevated after the first stimulation period (solid line), and one where they did not (dashed line). Significant differences between these two BOLD time series are indicated by the black line at the top. (E) Electrophysiological recordings in the r-dHC indicated that the first stimulation period (indicated by the gray box) also caused two neuronal response patterns, one with nADs after cessation of the stimulation (top) and one without nADs (bottom). (F) Comparison of the BOLD responses to the first stimulation period and the averaged responses to the last six stimulation periods. When the first BOLD response did not return to baseline (solid line), the average of the last six BOLD responses was also significantly stronger.

Article Snippet: The bipolar stimulation electrode (114 μm diameter, Teflon-coated tungsten wire, insulated except at the tip; A-M Systems, Science Products GmbH, Hofheim, Germany) was placed unilaterally in the right hippocampal fornix/fimbria fiber tract (AP—1.5 mm, ML 2.6 mm, and DV 2.5–3.3 mm from the dural surface), according to the rat atlas of . A monopolar recording electrode was lowered into the right nucleus accumbens (r-NAcc) to adjust the correct placement of the stimulation electrode in the right fimbria/fornix (AP 1.7 mm, ML 1.6 mm, and DV 6.5–7.2 mm from the dural surface).

Techniques: Activation Assay, Comparison

Journal: Imaging Neuroscience

Article Title: Chemogenetic inhibition of dopaminergic neurons reduces stimulus-induced dopamine release, thereby altering the hemodynamic response function in the prefrontal cortex

doi: 10.1162/imag_a_00200

Figure Lengend Snippet: Comparison of the stimulus-related BOLD response and dopamine release in the r-NAcc in the control (A and B) and DREADD-expressing (C and D) rats. (A) In the control rats, the presence of CNO did not affect the magnitude of the BOLD response or dopamine release (NaCl blue line; CNO green line). (B) There was no difference in the average BOLD response (left top) or dopamine release during trains 5–10 (left bottom). Correlating the BOLD response and dopamine release during all 10 consecutive stimulation periods revealed a negative correlation between these two parameters (right side). (C) In the DREADD-expressing rats, the presence of CNO reduced the BOLD responses and dopamine release in the r-NAcc. (D) There was a significant difference in the average BOLD response (left top) and dopamine release during trains 5–10 (left bottom). Correlating the magnitude of BOLD response with the amount of dopamine released during consecutive stimulation (right side) revealed a similar negative correlation between the two parameters in the presence of NaCl and CNO (i.e., the regression line has a similar slope). Thus, the regression line only shifted to the left when CNO activated the inhibitory DREADDs.

Article Snippet: The bipolar stimulation electrode (114 μm diameter, Teflon-coated tungsten wire, insulated except at the tip; A-M Systems, Science Products GmbH, Hofheim, Germany) was placed unilaterally in the right hippocampal fornix/fimbria fiber tract (AP—1.5 mm, ML 2.6 mm, and DV 2.5–3.3 mm from the dural surface), according to the rat atlas of . A monopolar recording electrode was lowered into the right nucleus accumbens (r-NAcc) to adjust the correct placement of the stimulation electrode in the right fimbria/fornix (AP 1.7 mm, ML 1.6 mm, and DV 6.5–7.2 mm from the dural surface).

Techniques: Comparison, Control, Expressing