Barn owl ITD maps depend on phase matching rather than absolute conduction latency

Evidence

We found the microsecond precision needed to construct maps of ITD is achieved through precisely regulated phase delays, rather than by regulation of absolute latency, consistent with the observation that nucleus laminaris neurons respond over a wide range of integer multiples of their preferred interaural phase difference (Christianson and Peña 2006 ). Thus latencies from the ear to the point of coincidence detection need only be adjusted within a stimulus period, creating a flexible yet precise system for detection of sound source sound location. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2843

Axons from NM form presynaptic maps of ITD in NL. These inputs generate a field potential that varies systematically with recording position and can be used to map ITDs. In the barn owl, the representation of best ITD shifts systematically in NL, forming multiple, largely overlapping maps of ITD (Fig. 1a ). We had previously found that conduction delays could account for the shift in maps of ITD (Carr et al. 2013 ). — Dijk, Pim van, Physiology, Psychoacoustics and…, 2849

Categorization

• XREF: The ‘coarse delay during development, fine tuning modulo 2π’ two-step mechanism parallels later discussion of Hebbian/STDP learning rules in the same chapter.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 2843; Dijk, Pim van, Physiology, Psychoacoustics and…, 2849