Formation of associations in auditory cortex by slow changes of tonic firing

Behavioral semantics of learning and crossmodal processing in auditory cortex: The semantic processor concept

“…We shall focus here on the animal domain because no specific data seems to be available to determine which additional local influences on task processing in AC are exerted by verbal instructions. However, the results of a few human studies specifically addressing task-related processes in AC are compatible with the animal studies Brechmann et al, 2007). Very few studies on auditory learning and processing in humans (e.g.…”

“…A second learning-related observation that has attracted attention more recently is that AC activity can be heavily influenced by various other sensory modalities (Cahill et al, 1996;Bangert et al, 2001;Schroeder et al, 2001;Schroeder and Foxe, 2002;Brosch et al, 2005;Ghazanfar and Schroeder, 2006;Bizley et al, 2007). This influence is even seen in primary AC and is not necessarily restricted to a modulation of acoustically evoked responses of neurons, but may also elicit firing of neurons to those non-auditory events that constitute the procedural framework of an auditory task (Brosch et al, 2005(Brosch et al, , 2010.…”

“…This influence is even seen in primary AC and is not necessarily restricted to a modulation of acoustically evoked responses of neurons, but may also elicit firing of neurons to those non-auditory events that constitute the procedural framework of an auditory task (Brosch et al, 2005(Brosch et al, , 2010.…”

Tonic effects of the dopaminergic ventral midbrain on the auditory cortex of awake macaque monkeys

“…The glutamate-mediated effects potentially convey temporally precise information of neurons in the dopaminergic ventral midbrain to auditory cortex, such as reward-related information. The dopamine-mediated effects may change the signal-to-noise ratio of the neuronal responses to auditory stimuli, may modify the relative processing weights of different sites in auditory cortex and may be involved in the generation of the slow firing changes in auditory cortex that have been observed between task elements when subjects are engaged in auditory discrimination and short-term-memory tasks (Brosch et al 2011;Huang et al 2012).…”

“…The change in dopamine tone imposed by electrically stimulating the dopaminergic ventral midbrain could contribute to the tonic firing changes in auditory cortex that have been observed between salient task elements when subjects are engaged in auditory categorization (Brosch et al 2011) and short-term-memory tasks (Gottlieb et al 1989;Huang et al 2012). With our protocol of applying brief electrical stimulation trains every 900 ms, we observed that the spontaneous firing in auditory cortex decreased within about 5 s (corresponding to five stimulations).…”