Limits...
Spectral and Temporal Acoustic Features Modulate Response Irregularities within Primary Auditory Cortex Columns.

Carrasco A, Brown TA, Lomber SG - PLoS ONE (2014)

Bottom Line: Hence, the purpose of the present investigation was to examine the effects of sensory information features on columnar response properties.Neuronal responses to simple (pure tones), complex (noise burst and frequency modulated sweeps), and ecologically relevant (con-specific vocalizations) acoustic signals were measured.Collectively, the present investigation demonstrates that despite consistencies in neuronal tuning (characteristic frequency), irregularities in discharge activity between neurons of individual A1 columns increase as a function of spectral (signal complexity) and temporal (duration) acoustic variations.

View Article: PubMed Central - PubMed

Affiliation: Cerebral Systems Laboratory, University of Western Ontario, London, Ontario, Canada; Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.

ABSTRACT
Assemblies of vertically connected neurons in the cerebral cortex form information processing units (columns) that participate in the distribution and segregation of sensory signals. Despite well-accepted models of columnar architecture, functional mechanisms of inter-laminar communication remain poorly understood. Hence, the purpose of the present investigation was to examine the effects of sensory information features on columnar response properties. Using acute recording techniques, extracellular response activity was collected from the right hemisphere of eight mature cats (felis catus). Recordings were conducted with multichannel electrodes that permitted the simultaneous acquisition of neuronal activity within primary auditory cortex columns. Neuronal responses to simple (pure tones), complex (noise burst and frequency modulated sweeps), and ecologically relevant (con-specific vocalizations) acoustic signals were measured. Collectively, the present investigation demonstrates that despite consistencies in neuronal tuning (characteristic frequency), irregularities in discharge activity between neurons of individual A1 columns increase as a function of spectral (signal complexity) and temporal (duration) acoustic variations.

No MeSH data available.


Distribution of neuronal response similarity levels within primary auditory cortex columns.(A) Distribution of PSTH peak response incidence during pure tone, white noise, FM sweep, and con-specific vocalization signals. (B) Distribution of response profile similarity (cross-correlation value at time-lag zero) during pure tone, white noise, FM sweep, and con-specific vocalization signals. Note the increase in response dissimilarities as a function of acoustic signal duration. Horizontal lines in boxplots illustrate lower quartile, median, and upper quartile values. Whisker length shows limits of data distribution.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4262427&req=5

pone-0114550-g005: Distribution of neuronal response similarity levels within primary auditory cortex columns.(A) Distribution of PSTH peak response incidence during pure tone, white noise, FM sweep, and con-specific vocalization signals. (B) Distribution of response profile similarity (cross-correlation value at time-lag zero) during pure tone, white noise, FM sweep, and con-specific vocalization signals. Note the increase in response dissimilarities as a function of acoustic signal duration. Horizontal lines in boxplots illustrate lower quartile, median, and upper quartile values. Whisker length shows limits of data distribution.

Mentions: Analyses of variations in PSTH peak incidence revealed similar findings. Specifically, despite lack of significant differences in the number of response peaks measured during tonal exposure (mean response peaks ± SE; 25 ms: 0.01±0.001; 50 ms: 0.01±0.003; Fig. 4A, B), discrepancies in peak incidence as a function of signal duration were detected during noise burst (mean response peaks ± SE. 25 ms: 0.11±0.01; 50 ms: 0.13±0.01; 100 ms: 0.22±0.01; 250 ms: 0.28±0.01; 500 ms: 0.36±0.02; Fig. 4C–G) and FM sweep exposure (mean response peaks ± SE; 25 ms: 0.43±0.02; 50 ms: 0.58±0.02; 100 ms: 0.65±0.02; 250 ms: 0.83±0.03; 500 ms: 1.15±0.04; Fig. 4H–L). In addition, irrespective of signal direction (forward or backward) substantial differences in PSTH peak occurrences were detected during con-specific vocalizations (mean response peaks ± SE; forward: 1.71±0.05; backward: 1.8; ±0.08; Fig. 4M–N). Statistical analyses corroborated the aforementioned qualitative observations (see distribution and significance tables in Figs. 5and6) by demonstrating a robust relationship between spectro-temporal composition of acoustic signals and amount of response irregularities within A1 columns.


Spectral and Temporal Acoustic Features Modulate Response Irregularities within Primary Auditory Cortex Columns.

Carrasco A, Brown TA, Lomber SG - PLoS ONE (2014)

Distribution of neuronal response similarity levels within primary auditory cortex columns.(A) Distribution of PSTH peak response incidence during pure tone, white noise, FM sweep, and con-specific vocalization signals. (B) Distribution of response profile similarity (cross-correlation value at time-lag zero) during pure tone, white noise, FM sweep, and con-specific vocalization signals. Note the increase in response dissimilarities as a function of acoustic signal duration. Horizontal lines in boxplots illustrate lower quartile, median, and upper quartile values. Whisker length shows limits of data distribution.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4262427&req=5

pone-0114550-g005: Distribution of neuronal response similarity levels within primary auditory cortex columns.(A) Distribution of PSTH peak response incidence during pure tone, white noise, FM sweep, and con-specific vocalization signals. (B) Distribution of response profile similarity (cross-correlation value at time-lag zero) during pure tone, white noise, FM sweep, and con-specific vocalization signals. Note the increase in response dissimilarities as a function of acoustic signal duration. Horizontal lines in boxplots illustrate lower quartile, median, and upper quartile values. Whisker length shows limits of data distribution.
Mentions: Analyses of variations in PSTH peak incidence revealed similar findings. Specifically, despite lack of significant differences in the number of response peaks measured during tonal exposure (mean response peaks ± SE; 25 ms: 0.01±0.001; 50 ms: 0.01±0.003; Fig. 4A, B), discrepancies in peak incidence as a function of signal duration were detected during noise burst (mean response peaks ± SE. 25 ms: 0.11±0.01; 50 ms: 0.13±0.01; 100 ms: 0.22±0.01; 250 ms: 0.28±0.01; 500 ms: 0.36±0.02; Fig. 4C–G) and FM sweep exposure (mean response peaks ± SE; 25 ms: 0.43±0.02; 50 ms: 0.58±0.02; 100 ms: 0.65±0.02; 250 ms: 0.83±0.03; 500 ms: 1.15±0.04; Fig. 4H–L). In addition, irrespective of signal direction (forward or backward) substantial differences in PSTH peak occurrences were detected during con-specific vocalizations (mean response peaks ± SE; forward: 1.71±0.05; backward: 1.8; ±0.08; Fig. 4M–N). Statistical analyses corroborated the aforementioned qualitative observations (see distribution and significance tables in Figs. 5and6) by demonstrating a robust relationship between spectro-temporal composition of acoustic signals and amount of response irregularities within A1 columns.

Bottom Line: Hence, the purpose of the present investigation was to examine the effects of sensory information features on columnar response properties.Neuronal responses to simple (pure tones), complex (noise burst and frequency modulated sweeps), and ecologically relevant (con-specific vocalizations) acoustic signals were measured.Collectively, the present investigation demonstrates that despite consistencies in neuronal tuning (characteristic frequency), irregularities in discharge activity between neurons of individual A1 columns increase as a function of spectral (signal complexity) and temporal (duration) acoustic variations.

View Article: PubMed Central - PubMed

Affiliation: Cerebral Systems Laboratory, University of Western Ontario, London, Ontario, Canada; Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada.

ABSTRACT
Assemblies of vertically connected neurons in the cerebral cortex form information processing units (columns) that participate in the distribution and segregation of sensory signals. Despite well-accepted models of columnar architecture, functional mechanisms of inter-laminar communication remain poorly understood. Hence, the purpose of the present investigation was to examine the effects of sensory information features on columnar response properties. Using acute recording techniques, extracellular response activity was collected from the right hemisphere of eight mature cats (felis catus). Recordings were conducted with multichannel electrodes that permitted the simultaneous acquisition of neuronal activity within primary auditory cortex columns. Neuronal responses to simple (pure tones), complex (noise burst and frequency modulated sweeps), and ecologically relevant (con-specific vocalizations) acoustic signals were measured. Collectively, the present investigation demonstrates that despite consistencies in neuronal tuning (characteristic frequency), irregularities in discharge activity between neurons of individual A1 columns increase as a function of spectral (signal complexity) and temporal (duration) acoustic variations.

No MeSH data available.