Steven J. Barnes

Kindling of basolateral amygdala but not ventral hippocampus or perirhinal cortex disrupts sensorimotor gating in rats

The neural mechanisms mediating prepulse inhibition (PPI) appear to have relevance to neurological and psychiatric disorders. Patients with temporal lobe epilepsy exhibit psychotic symptoms and disrupted PPI, therefore the present experiments examined the consequences of seizures induced by kindling on PPI. Rats were chronically implanted with an electrode into the basolateral amygdala, perirhinal cortex, or ventral hippocampus and stimulated twice daily until 3 fully generalized, class 5 seizures were elicited. Kindling of basolateral amygdala, but not perirhinal cortex or ventral hippocampus, disrupted PPI when testing began 2min, but not 48h, following the elicitation of the third class 5 seizure. Startle amplitudes were unaffected by kindling. These results suggest that the anatomical origin of seizures is an important factor in determining their potentially disruptive effects on PPI.

Reversible lesions of the rhinal cortex produce delayed non-matching-to-sample deficits in rats.

Rats with cannulae guides implanted in the rhinal cortex were tested on a delayed non-matching-to-sample task, following either lidocaine or sham microinfusions. Bilateral lidocaine microinfusions to the rhinal cortex produced significant delayed non-matching-to-sample deficits. These results are consistent with the putative role of the rhinal cortex in object recognition but because the deficits were not shown to be time dependent, non-mnemonic interpretations cannot be ruled out. These results also illustrate the utility of reversible lidocaine lesions in the study of the neuroanatomical basis of delayed non-matching-to-sample.

Conditioning of Ictal and Interictal Behaviors in Rats by Amygdala Kindling: Context as the Conditional Stimulus

The authors showed that conditional effects of the stimulation environment modulate both the ictal and interictal behaviors of rats subjected to amygdala kindling. Rats received 53 stimulations to the left basolateral amygdala in 1 conditional stimulus (CS) context (CS+) and 53 sham stimulations (the stimulation lead was attached but no current was delivered) in another context (CS-), quasirandomly over 54 days. Three kinds of conditional effects were observed. First, after several stimulations, less ambulatory activity, more freezing, and less rearing reliably occurred in the CS+ context than in the CS-context. Second, after 45 stimulations, all of the rats chose the CS- context over the CS+ context in a conditioned place preference test. Third, when the rats were finally stimulated in the CS- context, their motor seizures were less severe: Latencies were longer, motor seizures were shorter, convulsive patterns were of a lower class, and there were fewer falls.

Conditioning of a flavor aversion in rats by amygdala kindling.

Rats received 30 stimulations and 30 sham stimulations (the lead was attached to the subjects but no current was delivered) to the left basolateral amygdala in a quasirandom sequence. Stimulations were preceded by the presentation of 1 flavored solution conditional stimulus (CS+); sham stimulations were preceded by the presentation of another flavored solution, CS-. As kindled motor seizures developed, the rats began to consume significantly less of the CS+ than the CS-. Moreover, at the end of the experiment, the rats consumed significantly less of the CS+ than the CS- during a 20-min conditioned flavor preference test in which both solutions were available simultaneously. These findings confirm and extend the recent report that interictal changes in defensive behavior can be conditioned by amygdalar kindling.

Anticipating the attack: temporal conditioning during amygdala kindling in rats.

The present study showed that amygdala-kindled rats use short-interval timing superimposed on phase or ordinal timing to predict when a convulsion will occur. In 2 experiments, rats received 1 stimulation and 1 sham stimulation each day, always at the same times (conditioned stimulus [CS]+ and CS- times, respectively) and 150 s after rats had been placed in the testing chamber (the preadministration interval). As kindling progressed, the rats displayed more defensive behavior at the CS+ time than at the CS- time. Then, a stimulation-free peak-procedure test was conducted: At the CS+ time, but not at the CS- time, defensive behavior increased progressively as the 150-s preadministration interval elapsed, and then it gradually declined.

Online and mobile technologies for self-management in bipolar disorder: A systematic review.

Objective: Internet (eHealth) and smartphone-based (mHealth) approaches to self-management for bipolar disorder are increasingly common. Evidence-based self-management strategies are available for bipolar disorder and provide a useful framework for reviewing existing eHealth/mHealth programs to determine whether these strategies are supported by current technologies. This review assesses which self-management strategies are most supported by technology. Method: Based on 3 previous studies, 7 categories of self-management strategies related to bipolar disorder were identified, followed by a systematic literature review to identify existing eHealth and mHealth programs for this disorder. Searches were conducted by using PubMed, CINAHL, PsycINFO, EMBASE, and the Cochrane Database of Systematic Reviews for relevant peer-reviewed articles published January 2005 to May 2015. eHealth and mHealth programs were summarized and reviewed to identify which of the 7 self-management strategy categories were supported by eHealth or mHealth programs. Results: From 1,654 publications, 15 papers were identified for inclusion. From these, 9 eHealth programs and 2 mHealth programs were identified. The most commonly supported self-management strategy categories were “ongoing monitoring,” “maintaining hope,” “education,” and “planning for and taking action”; the least commonly supported categories were “relaxation” and “maintaining a healthy lifestyle.” eHealth programs appear to provide more comprehensive coverage of self-management strategies compared with mHealth programs. Conclusions and Implications for Practice: Both eHealth and mHealth programs present a wide range of self-management strategies for bipolar disorder, although individuals seeking comprehensive interventions might be best served by eHealth programs, while those seeking more condensed and direct interventions might prefer mHealth programs.

Stimulation site determines the conditioned effects of kindling in rats: anterior neocortex versus amygdala

Rats received 53 stimulations to either the left basolateral amygdala (BA) or left anterior neocortex (AN) in one environment (CS+) and 53 sham stimulations (the stimulation lead was attached but no current was delivered) in another environment (CS–), quasirandomly over 54 days. Confirming a previous report [Barnes, S.J., Pinel, J.P., Francis, L.H. & Wig, G.S. (2001) Behav. Neurosci., 115, 1065–1072], as BA kindling progressed, the CS+ began to elicit more defensive behaviours (i.e. less activity, more freezing and avoidance of the CS+) than the CS–, and at the end of the experiment, convulsions elicited in the CS+ were more severe than those elicited in the CS–. Like BA kindling, AN kindling led to less activity in the CS+; but unlike BA kindling, AN kindling led to more wet‐dog‐shakes and less, rather than more, severe convulsions in the CS+. During AN kindling, the mean number of wet‐dog‐shakes in the CS+ was negatively correlated with the mean convulsion class, suggesting that wet‐dog‐shakes contribute to the inherent variability of AN kindling. These findings confirm that inherent conditioned effects influence kindled convulsions and interictal behaviour and establish for the first time that the pattern of these conditioned effects is a function of the kindling site.

Creativity and Bipolar Disorder Igniting a Dialogue

Bipolar disorder (BD) has been related to heightened creativity, yet core questions remain unaddressed about this association. We used qualitative methods to investigate how highly creative individuals with BD understand the role of symptoms and treatment in their creativity, and possible mechanisms underpinning this link. Twenty-two individuals self-identified as highly creative and living with BD took part in focus groups and completed quantitative measures of symptoms, quality of life (QoL), and creativity. Using thematic analysis, five themes emerged: the pros and cons of mania for creativity, benefits of altered thinking, the relationship between creativity and medication, creativity as central to one’s identity, and creativity’s importance in stigma reduction and treatment. Despite reliance on a small sample who self-identified as having BD, findings shed light on previously mixed results regarding the influence of mania and treatment and suggest new directions for the study of mechanisms driving the creative advantage in BD.

Conditioned effects of kindling three different sites in the hippocampal complex of the rat.

Rats received kindling stimulations to the perirhinal cortex (PRh), ventral hippocampus (VH), or dorsal hippocampus (DH) in 1 environment and an equivalent number of sham stimulations in a 2nd environment. The PRh-kindled rats displayed rapid kindling and a swift emergence of conditioned interictal defensiveness. In contrast, the VH- and DH-kindled rats displayed much slower kindling and slow or no conditioning, respectively. No effects of conditioning on the convulsions, comparable with those associated with amygdala kindling, were observed. These results establish the generality of some of the previously reported kindling-related conditioned effects, confirm the site specificity of some of these effects, and suggest that the convulsions, rather than the stimulations, function as the unconditioned stimuli for the conditioning of interictal behavior.

An integrative theory of visual mentation and spontaneous creativity

It has been suggested that creativity can be functionally segregated into two processes: spontaneous and deliberate. In this paper, we propose that the spontaneous aspect of creativity is enabled by the same neural simulation mechanisms that have been implicated in visual mentation (e.g. visual perception, mental imagery, mind-wandering and dreaming). This proposal is developed into an Integrative Theory that serves as the foundation for a computational model of dreaming and site-specific artwork: A Machine that Dreams.