Despite the concern that has been expressed about potential method biases, and the pervasiveness of research settings with the potential to produce them, there is disagreement about whether they really are a problem for researchers in the behavioral sciences. Therefore, the purpose of this review is to explore the current state of knowledge about method biases. First, we explore the meaning of the terms “method” and “method bias” and then we examine whether method biases influence all measures equally. Next, we review the evidence of the effects that method biases have on individual measures and on the covariation between different constructs. Following this, we evaluate the procedural and statistical remedies that have been used to control method biases and provide recommendations for minimizing method bias.

Sources of Method Bias in Social Science Research and Recommendations on How to Control It

The field of neuroscience has, after a long period of looking the other way, again embraced emotion as an important research area. Much of the progress has come from studies of fear, and especially fear conditioning. This work has pin- pointed the amygdala as an important component of the system involved in the acqui- sition, storage, and expression of fear memory and has elucidated in detail how stimuli enter, travel through, and exit the amygdala. Some progress has also been made in understanding the cellular and molecular mechanisms that underlie fear conditioning, and recent studies have also shown that the findings from experimental animals apply to the human brain. It is important to remember why this work on emotion succeeded where past efforts failed. It focused on a psychologically well-defined aspect of emo- tion, avoided vague and poorly defined concepts such as "affect," "hedonic tone," or "emotional feelings," and used a simple and straightforward experimental approach. With so much research being done in this area today, it is important that the mistakes of the past not be made again. It is also time to expand from this foundation into broader aspects of mind and behavior

http://gruberpeplab.com/3131/LeDoux_2000_Emotioncircuitbrain.pdf

Emotion Circuits in the Brain

The contribution of the amygdala and hippocampus to the acquisition of conditioned fear responses to a cue (a tone paired with footshock) and to context (background stimuli continuously present in the apparatus in which tone-shock pairings occurred) was examined in rats. In unoperated controls, responses to the cue conditioned faster and were more resistant to extinction than were responses to contextual stimuli. Lesions of the amygdala interfered with the conditioning of fear responses to both the cue and the context, whereas lesions of the hippocampus interfered with conditioning to the context but not to the cue. The amygdala is thus involved in the conditioning of fear responses to simple, modality-specific conditioned stimuli as well as to complex, polymodal stimuli, whereas the hippocampus is only involved in fear conditioning situations involving complex, polymodal events. These findings suggest an associative role for the amygdala and a sensory relay role for the hippocampus in fear conditioning.

/pdf/differential-contribution-of-amygdala-and-hippocampus-to-4rauxwzsik.pdf

Differential Contribution of Amygdala and Hippocampus to Cued and Contextual Fear Conditioning

Here we provide a review of the animal and human literature concerning the role of the amygdala in fear conditioning, considering its potential influence over autonomic and hormonal changes, motor behavior and attentional processes. A stimulus that predicts an aversive outcome will change neural transmission in the amygdala to produce the somatic, autonomic and endocrine signs of fear, as well as increased attention to that stimulus. It is now clear that the amygdala is also involved in learning about positively valenced stimuli as well as spatial and motor learning and this review strives to integrate this additional information. A review of available studies examining the human amygdala covers both lesion and electrical stimulation studies as well as the most recent functional neuroimaging studies. Where appropriate, we attempt to integrate basic information on normal amygdala function with our current understanding of psychiatric disorders, including pathological anxiety.

The amygdala: vigilance and emotion

The field of neuroscience has, after a long period of looking the other way, again embraced emotion as an important research area. Much of the progress has come from studies of fear, and especially...

Amygdala central nucleus lesions effect on heart rate conditioning in the rabbit

Multiple unit activity recorded from amygdala central nucleus during Pavlovian heart rate conditioning in rabbit

The present study was conducted to assess the effects of beta-adrenergic manipulation within the central nucleus of the amygdala on Pavlovian heart rate conditioning in the rabbit. Administration of the beta-adrenergic antagonist dl-propranolol into the central nucleus impaired the acquisition of conditioned heart rate responding compared to a vehicle injected control group. No significant effects of dl-propranolol on either baseline heart rate or on the heart rate orienting response were observed. The effect of dl-propranolol on conditioning exhibited stereospecificity, and animals receiving combined intracerebral injections of dl-propranolol and the beta-adrenergic agonist 1-isoproterenol did not exhibit comparable conditioning impairments. In addition, dl-propranolol administration dorsal to the central nucleus or into amygdala sites anterior or posterior to the central nucleus was less effective. These results support the interpretation that beta-adrenergic activity within the central nucleus region of the amygdala complex contributes to the acquisition of classically conditioned heart rate responding.

β-adrenergic manipulation in amygdala central n. alters rabbit heart rate conditioning

The research described represents an attempt to determine the exact amygdala components which contribute to the acquisition of conditioned responding during aversive conditioning. Our initial analysis focuses on the amygdala central nucleus and its contribution to the acquisition of conditioned bradycardia during Pavlovian fear conditioning in the rabbit. The results demonstrate that (a) lesions of the central nucleus attenuate the magnitude of the conditioned bradycardia response, (b) the administration of s-adrenergic antagonists and opiate agonists into the region of the central nucleus also attenuate the magnitude of the conditioned bradycardia response, (c) the medial component of the central nucleus projects directly to cardioregulatory nuclei in the dorsal medulla including the site of origin of cardioinhibitory neurons in the rabbit, (d) electrical stimulation of the central nucleus in rabbit produces profound, short-latency bradycardia and depressor responses, with maximum bradycardia elicited from the site of origin of the central nucleus-dorsal medulla projection, and (e) during the course of the conditioning procedure increases in central nucleus neuronal activity develop to the conditioned stimulus (CS) at the time when the conditioned bradycardia response develops. In some cases the magnitude of the increase in neuronal activity to the CS was significantly correlated with the magnitude of the bradycardia response to the CS over the course of the conditioning session.

The Amygdala Central Nucleus: Contributions to Conditioned Cardiovascular Responding during Aversive Pavlovian Conditioning in the Rabbit

Six right- and six left-handed subjects were run in a repeated measures design to determine the influences of alcohol on hemiretina detection thresholds. Stimuli were presented tachistoscopically to the hemiretinae at blood alcohol concentrations (BACs) of 0, 50, and 100 mg%. The nasal hemiretinae had higher thresholds than the temporal hemiretinae and this difference was independent of alcohol. Alcohol interacted with visual field and handedness. The results showed that the highest alcohol dose (100 mg%) raised detection thresholds more for the hemifield contralateral to the subject's preferred hand than the ipsilateral hemifield. Results are discussed in terms of lateral dominance and attention.

Robert C. Frysinger

Papers

Amygdala central nucleus lesions effect on heart rate conditioning in the rabbit

Multiple unit activity recorded from amygdala central nucleus during Pavlovian heart rate conditioning in rabbit

β-adrenergic manipulation in amygdala central n. alters rabbit heart rate conditioning

The Amygdala Central Nucleus: Contributions to Conditioned Cardiovascular Responding during Aversive Pavlovian Conditioning in the Rabbit

Alcohol influence on hemisphere differences and signal detection thresholds.