A signal detection theory analysis of gap detection in the rat

Abstract

An innocuous sensory event (a prestimulus) briefly preceding a startle-eliciting stimulus (SES) reduces the amplitude of the elicited reflex. This study used signal detection theory (SDT) techniques to quantify the effects of gaps (pauses in otherwise continuous noise) on the rat's acoustic startle reflex. Sixteen rats were given four identical test sessions consisting of the randomized presentation of 150 trials of the SES alone and 150trials ofagap-and-SES combination. Gap duration (1, 2, 4, and 8 msec) varied between sessions. Data analyses based on amplitude, difference scores, percentage scores, and SDTtechniques identified similar patterns. The three longest gaps, but not the shortest, were reliably detected, and differences among these three were identified with percentage and SDTanalyses. Analyses of amplitude changes over test sessions yielded different patterns for each measure. The results demonstrate that an SDTanalysis is a sensitive index of prestirnulus effects.

The biological basis of audition

“…Humans' ability to detect a gap in a broadband noise is on the scale of a few milliseconds (Eddins et al 1992, Forrest & Green 1987, Snell et al 1994. Remarkably similar results across many animal studies report gap detection that is similar to humans in the 2-6 msec range for broadband noise (e.g., Ison et al 1991, Leitner et al 1997, Syka et al 2002, Wagner et al 2003, including macaques (personal observation). Although gap detection appears to be fairly simple, there is strong support for a role of the auditory cortex (Bowen et al 2003, Ison et al 1991, Kelly et al 1996, Syka et al 2002.…”

Rat psychomotor vigilance task with fast response times using a conditioned lick behavior

“…This data is useful in understanding which aspects of task performance are affected by vigilance decrements. Another tool, signal detection theory (SDT), is a useful method to analyze decision making in the presence of uncertainty or other distractions [16, 22, 32, 37, 52, 53]. The most common SDT measures are correct hits (signal present and response present), correct rejections (stimulus absent and no response), misses (stimulus present but no response) and false alarms (signal is absent but responds as if signal is present).…”

“…Other methods include The Walter Reed performance assessment battery [55], 5-choice reaction time task [7, 19, 46] and 2-choice reaction time task [50]. Signal detection theory (SDT) also provides tools to assess behavioral measures of performance [32, 52, 53]. …”

Encoding of temporal features of auditory stimuli in the medial nucleus of the trapezoid body and superior paraolivary nucleus of the rat

“…Since the MNTB/SPON circuit is located in the auditory brainstem, information about the temporal structure of stimuli extracted by MNTB and SPON neurons must be relayed to the auditory midbrain and forebrain in order to contribute to gap detection phenomena observed in rat behavioral (Leitner et al, 1993(Leitner et al, , 1997 and human psychophysical experiments (reviewed by Phillips, 1999). The main projection target of the SPON is the ipsilateral IC (Beyerl, 1978;Zook and Casseday, 1982;Adams, 1983;Nordeen et al, 1983;Willard and Ryugo, 1983;Saint Marie and Baker, 1990;Schofield, 1991;Gonzalez-Hernandez et al, 1996;Saldaña and Berrebi, 2000), and neuronal correlates of gap detection attributable to the inhibitory input from the SPON might be expected there.…”