Slow Modulation of Ongoing Discharge in the Auditory Cortex during an Interval-Discrimination Task

Abstract

In this study, we recorded single unit activity from rat auditory cortex while the animals performed an interval-discrimination task. The animals had to decide whether two auditory stimuli were separated by either 150 or 300 ms, and go to the left or right nose poke accordingly. Spontaneous firing in between auditory responses was compared in the attentive versus non-attentive brain states. We describe the firing rate modulation detected during intervals while there was no auditory stimulation. Nearly 18% of neurons (n = 14) showed a prominent neuronal discharge during the interstimulus interval, in the form of an upward or downward ramp towards the second auditory stimulus. These patterns of spontaneous activity were often modulated in the attentive versus passive trials. Modulation of the spontaneous firing rate during the task was observed not only between auditory stimuli, but also in the interval preceding the stimulus. These slow modulatory components could be locally generated or the result of a top-down influence originated in higher associative association areas. Such a neuronal discharge may be related to the computation of the interval time and contribute to the perception of the auditory stimulus.

Chemosensory Convergence on Primary Olfactory Cortex

“…To obtain single unit activity, waveforms were clustered automatically using the valley-seeking algorithm in Plexon Offline Sorter (Koontz and Fukunaga, 1972; Abolafia et al, 2011). After clustering, waveforms were visually inspected in order to remove clusters containing noise or artifacts.…”

Visually Cued Action Timing in the Primary Visual Cortex

“…The role of sensory areas—especially primary sensory areas—has long been regarded as providing a faithful representation of the external world (Felleman and Van Essen, 1991; Goldman-Rakic, 1988; Kandel et al, 2000; Miller and Cohen, 2001); several studies have shown that these areas convey sensory information (Ghazanfar and Schroeder, 2006; Hubel and Wiesel, 1962, 1968; Lemus et al, 2010; Liang et al, 2013), while others have shown causal roles in sensory perception (Glickfeld et al, 2013; Jaramillo and Zador, 2011; Sachidhanandam et al, 2013; Znamenskiy and Zador, 2013). However, this view has recently been challenged by observations that sensory cortices represent not only stimulus features but also non-sensory information (Abolafia et al, 2011; Ayaz et al, 2013; Brosch et al, 2011; Fontanini and Katz, 2008; Gavornik and Bear, 2014; Jaramillo and Zador, 2011; Keller et al, 2012; Niell and Stryker, 2010; Niwa et al, 2012; Pantoja et al, 2007; Samuelsen et al, 2012; Serences, 2008; Shuler and Bear, 2006; Stanisor et al, 2013; Zelano et al, 2011). In the visual modality, it has been shown that V1 can predict the learned typical interval between a stimulus and a reward (Chubykin et al, 2013; Shuler and Bear, 2006) and that the ability to learn such intervals depends on cholinergic input from the basal forebrain (Chubykin et al, 2013).…”

Neuronal activity in primate auditory cortex during the performance of audiovisual tasks

“…Slow firing changes can start after auditory stimuli, reinforcers and behavioral responses, end with reinforcers and possibly with auditory stimuli and behavioral responses, and depend on the expected reward (Komura et al, 2001;Brosch et al, 2011b). A few other studies have also described slow firing changes in auditory cortex for different tasks (Kitzes et al, 1978;Gottlieb et al, 1989;Shinba et al, 1995;Quirk et al, 1997;Armony et al, 1998;Abolafia et al, 2011). Slow firing changes have been proposed to be related to anticipating, memorising and associating task elements (Brosch et al, 2011a,b).…”