|Behavioral Models of Response Inhibition and Attention: Implications for Attention Deficit Hyperactivity Disorder (ADHD)|
|Sunday, May 27, 2012|
|10:30 AM–11:50 AM |
|609 (Convention Center)|
|Area: EAB/CBM; Domain: Basic Research|
|Chair: Suzanne H. Mitchell (Oregon Health & Science University)|
|Discussant: Joel Nigg (Oregon Health & Science University)|
An inability to inhibit responses and failure to sustain attention are key aspects of attention deficit hyperactivity disorder (ADHD). Symposium will include3 data-based presentations using mouse, rat, and human participants. Presentations will focus on different behavioral models that can be used to examine response inhibition (a Go/No-go task, differential reinforcement of low rate [DRL] schedules, fixed minimum interval [FMI] schedules) and attention (reaction time to Go signals, failures to maintain responding). For each task, its ability to assess the specific psychological construct (response inhibition or attention) will be evaluated and data from environmental, pharmacological and genetic manipulations that are expected to affect inhibition and attention will be presented. The discussant, Joel Nigg, who is an expert in ADHD research, will examine the data and models in the light of human research in ADHD as well as the utility of such behavioral models in treatment development and the identification of factors causally related to the etiology of the disorder.
|Keyword(s): ADHD, attention, preclinical research, response inhibition|
Effects of Methamphetamine on Response Inhibition in Mice
|Travis Moschak (Oregon Health & Science University), Katherine A. Stang (Oregon Health & Science University), SUZANNE H. MITCHELL (Oregon Health & Science University)|
The study examined whether administration of methamphetamine (MA) would result in different levels of inhibition in animals selected to consume or respond more to MA. A Go/No-go task was used to assess inhibition in male and female mice selected for low or high levels of MA consumption [MALDR and MAHDR] or selected for low or high levels of locomotor sensitization to repeated injections of MA [MAHSENS and MALSENS]. Mice selected for MA consumption did not differ in drug-nave levels of inhibition (responding during the No-go signal [false alarms]). However, mice selected for low levels of sensitization displayed lower levels of inhibition than mice selected for high levels, but also lower levels of responding in general. When MA was administered prior to the task, inhibition improved for both sets of mice. However, simultaneous reductions in responding during the Go signal [hits] suggest that these reductions in inhibition reflected reduced levels of operant responding or motivation, and highlight the complications associated with interpreting responding during a Go/No-go task. Together, the data suggest a shared genetic component between inhibition processes, general levels of operant responding and MA sensitization.
Assessing Response Inhibition With the Fixed Minimum Interval (FMI) Schedule of Reinforcement
|FEDERICO SANABRIA (Arizona State University), Elizabeth Watterson (Arizona State University)|
Attention Deficit Hyperactivity Disorder (ADHD) involves a chronic impairment in the ability to withhold reinforced responses. A straightforward method to assess such ability in animal models consists of reinforcing a response contingent on withholding it for a fixed time interval. This method is typically instantiated as a differential reinforcement of low rates (DRL) schedule of reinforcement. In DRL, a response is reinforced only after not emitting it for a minimum time. As a response-inhibition assessment method, DRL has two drawbacks: (1) it elicits response bursts that are not readily interpretable and are confounded with contingency-sensitive interresponse times (IRTs), and (2) it precludes the dissociation of the prepotency of the reinforced response from the capacity to withhold that response. Both drawbacks are corrected by the topographical separation of the responses that delimit each IRT. This correction is Mechner and Guevrekians (1962) fixed minimum interval (FMI) schedule of reinforcement. The utility of FMI as a response-inhibition assessment technique is demonstrated in a series of studies in rats and pigeons. These studies describe the sensitivity of various constituents of FMI performance to rate of reinforcement, reinforcer magnitude, chronic stress, housing conditions, rat strain (an animal model of ADHD vs. its normoactive control), and methylphenidate.
Lapses of Attention in Mice, Rats, and Humans
|JERRY B. RICHARDS (University at Buffalo), Larry W. Hawk Jr. (University at Buffalo), Michelle Bubnik (University at Buffalo)|
"Lapses in attention" are a fundamental symptom of Attention Deficit Hyperactivity Disorder (ADHD). We have developed a simple non parametric procedure which uses simple reaction time (RT) procedures to quantitatively characterize "lapses of attention." The mode of the distribution of reaction times (RTs) is used to estimate the speed at which the subject is capable of responding, and the mean deviation of the RTs from the mode is used to identify lapses of attention. A larger number of lapses of attention results in a greater rightward skew of the distribution, as well as a larger deviation of the RTs from the mode (DevMode). We have completed a series of studies in which we have used this procedure to characterize lapses of attention in mice, rats and children with ADHD.