Housing experience affects adult neurogenesis in turtles (Chrysemys picta).

Adult neurogenesis increases in mammals when they are exposed to an enriched environment or given the opportunity to exercise. In this experiment, we investigated whether turtles would show differences in the number of new neurons in the telencephalon when they were exposed to deep water, conspecifics, and plants and logs (EE group), compared to a group of animals housed in individual cages with shallow water (IN group). A control group (EX) was given deep water and conspecifics but no plants and logs.

The Role of Acetylcholine in Attention in Turtles (Chrysemys picta).

Research on mammals and turtles has suggested that acetylcholine is involved in attention in these groups. Two experiments investigated the ability of painted turtles (Chrysemys picta) to ignore irrelevant stimuli when the basal forebrain acetylcholine system was compromised. In experiment 1, turtles given lesions of the basal magnocellular cholinergic nucleus (NBM) or sham lesions were tested on a go/no go discrimination between horizontal and vertical stripes with or without irrelevant inserts in the box.

Plasticity and Adult Neurogenesis in Amphibians and Reptiles: More Questions than Answers.

Studies of the relationship between behavioral plasticity and new cells in the adult brain in amphibians and reptiles are sparse but demonstrate that environmental and hormonal variables do have an effect on the amount of cell proliferation and/or migration. The variables that are reviewed here are: enriched environment, social stimulation, spatial area use, season, photoperiod and temperature, and testosterone. Fewer data are available for amphibians than for reptiles, but for both groups many issues are still to be resolved.

Blinks slow memory-guided saccades.

Memory-guided saccades are slower than visually guided saccades. The usual explanation for this slowing is that the absence of a visual drive reduces the discharge of neurons in the superior colliculus. We tested a related hypothesis: that the slowing of memory-guided saccades was due also to the more frequent occurrence of gaze-evoked blinks with memory-guided saccades compared with visually guided saccades.

Characterizing the spontaneous blink generator: an animal model.

Although spontaneous blinking is one of the most frequent human movements, little is known about its neural basis. We developed a rat model of spontaneous blinking to identify and better characterize the spontaneous blink generator. We monitored spontaneous blinking for 55 min periods in normal conditions and after the induction of mild dry eye or dopaminergic drug challenges.

Emotional valence and arousal effects on memory and hemispheric asymmetries.

This study examined predictions based upon the right hemisphere (RH) model, the valence-arousal model, and a recently proposed integrated model (Killgore & Yurgelun-Todd, 2007) of emotion processing by testing immediate recall and recognition memory for positive, negative, and neutral verbal stimuli among 35 right-handed women. Building upon methodologies of previous studies, we found that words presented to the right visual field/left hemisphere (RVF/LH) were recalled and recognized more accurately than words presented to the left visual field/right hemisphere (LVF/RH), and we found significant valence by visual field interactions. Some findings were consistent with one of the models evaluated whereas others were consistent with none of the models evaluated.

Role of acetylcholine in negative patterning in turtles (Chrysemys picta).

Turtles were run on a negative patterning task involving 2 positive elements, a key with white stripes on a black background, and a solid red key, and a compound stimulus combining the 2 elements, white stripes on a red background. Injections of scopolamine, methylscopolamine, or saline were started at the same time that the compound stimulus was introduced, after the animals had been autoshaped to press the key for each of the elements. Scopolamine disrupted the learning of negative patterning, but methylscopolamine had no effect.

Affective ratings and startle modulation in people with nonclinical depression.

This study tested predictions based on the emotion context insensitivity (ECI) hypothesis of Rottenberg, Gross, and Gotlib (2005) that a nonclinical sample of people with depressive symptoms would show reduced responses to both positive and negative stimuli relative to people without depression and would show an enhanced response to novelty. Seventy individuals completed diagnostic questionnaires, made ratings of 21 affectively valenced pictures, and then viewed the same 21 pictures and 21 novel pictures while startle blink responses were recorded from electromyographic activity of the orbicularis oculi. People with scores on the Beck Depression Inventory (BDI; Beck, Ward, Mendelson, Mock, & Erbaugh, 1961) indicative of depression demonstrated a lack of affective startle modulation compared to the nondepression group.

Effects of blocking nitric oxide on learning in turtles (Chrysemys picta).

Turtles (Chrysemys picta) were given the nitric oxide synthase inhibitor NW-nitro-L-arginine methyl ester (L-NAME) or its inactive isomer NW-nitro-D-arginine methyl ester (D-NAME) and were trained on a negative patterning task or a simple go/no-go discrimination task. L-NAME impaired the learning of negative patterning but did not affect retention of the task if it had already been learned. D-NAME had no effect.

Classical fear conditioning in the anxiety disorders: a meta-analysis.

Fear conditioning represents the process by which a neutral stimulus comes to evoke fear following its repeated pairing with an aversive stimulus. Although fear conditioning has long been considered a central pathogenic mechanism in anxiety disorders, studies employing lab-based conditioning paradigms provide inconsistent support for this idea. A quantitative review of 20 such studies, representing fear-learning scores for 453 anxiety patients and 455 healthy controls, was conducted to verify the aggregated result of this literature and to assess the moderating influences of study characteristics.

Avian brains and a new understanding of vertebrate brain evolution.

We believe that names have a powerful influence on the experiments we do and the way in which we think. For this reason, and in the light of new evidence about the function and evolution of the vertebrate brain, an international consortium of neuroscientists has reconsidered the traditional, 100-year-old terminology that is used to describe the avian cerebrum. Our current understanding of the avian brain - in particular the neocortex-like cognitive functions of the avian pallium - requires a new terminology that better reflects these functions and the homologies between avian and mammalian brains.

Revised nomenclature for avian telencephalon and some related brainstem nuclei.

The standard nomenclature that has been used for many telencephalic and related brainstem structures in birds is based on flawed assumptions of homology to mammals. In particular, the outdated terminology implies that most of the avian telencephalon is a hypertrophied basal ganglia, when it is now clear that most of the avian telencephalon is neurochemically, hodologically, and functionally comparable to the mammalian neocortex, claustrum, and pallial amygdala (all of which derive from the pallial sector of the developing telencephalon). Recognizing that this promotes misunderstanding of the functional organization of avian brains and their evolutionary relationship to mammalian brains, avian brain specialists began discussions to rectify this problem, culminating in the Avian Brain Nomenclature Forum held at Duke University in July 2002, which approved a new terminology for avian telencephalon and some allied brainstem cell groups.

The Avian Brain Nomenclature Forum: Terminology for a New Century in Comparative Neuroanatomy.

Many of the assumptions of homology on which the standard nomenclature for the cell groups and fiber tracts of avian brains have been based are in error, and as a result that terminology promotes misunderstanding of the functional organization of avian brains and their evolutionary relationship to mammalian brains. Recognizing this problem, a number of avian brain researchers began an effort to revise the terminology, which culminated in the Avian Brain Nomenclature Forum, held at Duke University from July 18 to 20, 2002. In the new terminology approved at this Forum, the flawed conception that the telencephalon of birds consists nearly entirely of a hypertrophied basal ganglia has been purged from the telencephalic terminology, and the actual parts of the basal ganglia and its brainstem afferent cell groups have been given names reflecting their now evident homologies.

Sensation seeking and startle modulation by physically threatening images.

The potential moderating effect of sensation seeking on anxious reactivity to threatening experiences was assessed using the affective modulation of startle-blink paradigm. Startle blinks, as measured by electromyographic (EMG) activity in response to loud (100 dB) white-noise stimuli, were elicited during the presentation of positive, neutral, and threatening visual images. Unlike participants low in sensation seeking who showed blink potentiation during threatening versus neutral images, participants high in sensation seeking showed equal magnitudes of startle to neutral and threatening images.