Blockade of GABAA Receptors in the Interpositus Nucleus Modulates Expression of Conditioned Excitation but not Conditioned Inhibition of the Eyeblink Response

The cerebellum and related brainstem structures are essential for excitatory eyeblink conditioning. Recent evidence indicates that the cerebellar interpositus and lateral pontine nuclei may also play critical roles in conditioned inhibition (CI) of the eyeblink response. The current study examined the role of GABAergic inhibition of the interpositus nucleus in retention of CI. Male Long-Evans rats were implanted with a cannula positioned just above or in the anterior interpositus nucleus before training. The rats were trained with two different tones and a light as conditioned stimuli, and a periorbital shock as the unconditioned stimulus. CI training consisted of four phases: 1) excitatory conditioning (8 kHz tone paired with shock); 2) feature-negative discrimination (2 kHz tone paired with shock or 2 kHz tone concurrent with light); 3) summation test (8 kHz tone or 8 kHz tone concurrent with light); and 4) retardation test (light paired with shock). After reaching a criterion level of performance on the feature-negative discrimination (40% discrimination), 0.5 microl picrotoxin (a GABAA receptor antagonist) was infused at one of four concentrations, each concentration infused during separate test sessions. Picrotoxin transiently impaired conditioned responses during trials with the excitatory stimulus (tone) in a dose-dependent manner, but did not significantly impact responding to the inhibitory compound stimulus (tone-light). The results suggest that expression of conditioned inhibition of the eyeblink conditioned response does not require GABAergic inhibition of neurons in the anterior interpositus nucleus.     

Orientation of the diamond and the square revisited

Below the age of 7 or 8, children find it very difficult to reproduce a diamond compared with a square. They are also highly sensitive to contextual alignment cues from the age of three years. It is shown here that over the brief age-span of 4-6 years (inclusive), children come to control the weight they give to contextual cues. It is argued that this is a more likely precursor of the older child's ability to cope with obliques, than is the converse process of learning to specify targets and thence to prevent themselves from responding inappropriately to the context. Of course, both target-specification and contextual-responsiveness are manifest at all the ages, but the latter seems to have the leading edge in early development.     

Simulation of neural sets

A program has been written for the PDP-8/I computer which simulates the behavior of 64 model neurons which may be connected together to form a functional neural net. The simulation includes provisions for studying the possible mechanisms of learning in real systems. Operation of the net requires inputs from either a robot or a robot simulator program and output from the net serves as input to such a robot, so that the entire system investigates the Behavior of an organism and its brain in interaction with an environment.     

Terrorism Outside the Proverbial Vacuum: Implications for the Moral Context

Prior research has found that terrorists are not susceptible to certain and severe countermeasures. One possibility is that, instead, deterrence is relative. Based on this premise and inspired by situational action theory’s conceptualization of the “moral context,” this research proposes that there are circumstances that influence both moral norms and their enforcement. We hypothesize that one set of circumstances is that of high profile terrorist attacks, which in turn should decrease the hazard of future incidents. We find mixed support for our hypotheses, but maintain that it has important implications for policy.     

Examination of Life Satisfaction,Child Maltreatment Potential and Substance Use in Mothers Referred for Treatment by Child Protective Services for Child Neglect and Substance Abuse: Implications for Intervention Planning

There is evidence to suggest mothers who are served by child protective service agencies are relatively dissatisfied in their lives, leading some investigators to conclude life dissatisfaction may be associated with child maltreatment. To assist in better understanding this relationship the Life Satisfaction Scale for Caregivers (LSSC) was psychometrically developed in a sample of 72 mothers who were referred for behavioral treatment for child neglect and substance abuse by caseworkers from a local child protective service agency. The LSSC was developed to assess mothers’ happiness in nine domains (family, friendships, employment/work, spirituality/religion, safety, sex life/dating, ability to avoid drugs, ability to avoid alcohol, control over one’s own life). Results indicated two factors that appeared to be relevant to Social Satisfaction and Safety and Control Satisfaction. Higher satisfaction scores on both of these scales were negatively associated with child maltreatment potential and substance use at baseline (i.e., positive urinalysis test). Mothers who exposed their children to substances in utero or in infancy (a distinct type of child neglect) were found to report higher satisfaction scores on the LSSC than other types of child neglect. Hispanic-American, African-American, and Caucasian women reported similar levels of life satisfaction. Application of the LSSC as a non-stigmatizing, wellness-focused instrument is discussed within the context of intervention planning.