Search results for "Eyeblink conditioning"
showing 10 items of 26 documents
Hippocampal theta phase-contingent memory retrieval in delay and trace eyeblink conditioning
2017
Hippocampal theta oscillations (3-12Hz) play a prominent role in learning. It has been suggested that encoding and retrieval of memories are supported by different phases of the theta cycle. Our previous study on trace eyeblink conditioning in rabbits suggests that the timing of the conditioned stimulus (CS) in relation to theta phase affects encoding but not retrieval of the memory trace. Here, we directly tested the effects of hippocampal theta phase on memory retrieval in two experiments conducted on adult female New Zealand White rabbits. In Experiment 1, animals were trained in trace eyeblink conditioning followed by extinction, and memory retrieval was tested by presenting the CS at t…
Affective modulation of conditioned eyeblinks
2009
Affective states are known to modulate reflexive actions. Aversive states potentiate defensive reflexes while appetitive states diminish them. The present study examined whether the same holds for associatively learned defensive eyeblinks to mild, initially neutral auditory stimuli. First, delay eyeblink conditioning was applied to human participants while they viewed emotionally neutral images. Next, the conditioned eyeblink responses (CRs) of the participants were tested during the viewing of unpleasant, neutral, or pleasant images. The most vigorous CRs were found during the unpleasant images, although they did not differ between neutral and pleasant images. The results add to the motiva…
Effect of transcranial direct current stimulation on semantic discrimination eyeblink conditioning
2015
Abstract Background Transcranial direct current stimulation (tDCS) is a neuromodulation method that has been used to modulate learning. We tested whether anodal tDCS targeted at the left DLPFC could enhance learning in a semantic variant of discrimination eyeblink conditioning, i.e., whether the stimulation would have a specific effect on the discrimination ability, rate of acquisition, amplitude of the conditioned response (CR), or all of these. Methods Immediately prior to the eyeblink conditioning, the participants received either active stimulation of 1 mA for 10 min or sham stimulation. The anode was placed over F3 and the cathode over the right supraorbital area. The conditioned stimu…
Breathe out and learn: Expiration-contingent stimulus presentation facilitates associative learning in trace eyeblink conditioning.
2019
Rhythmic variation in heart rate and respiratory pattern are coupled in a way that optimizes the level of oxygen in the blood stream of the lungs and the body as well as saves energy in pulmonary gas exchange. It has been suggested that the cardiac cycle and respiratory pattern are coupled to neural oscillations of the brain. Yet, studies on how this rhythmic coupling is related to behavior are scarce. There is some evidence that, for example, the phase of respiration affects memory retrieval and the electrophysiological oscillatory state of the limbic system. It is also known that the phase of the cardiac cycle and hippocampal electrophysiological oscillations alone affect learning. Here, …
Interpositus nucleus inactivation reduces unconditioned response amplitude after paired but not explicitly unpaired treatment in rabbit eyeblink cond…
2001
The amplitude of unconditioned responses (URs) in unconditioned stimulus (US) alone presentations were measured in six rabbits during explicitly unpaired and classical conditioning treatments. After both phases of the experiment, the interpositus nucleus (IPN) was reversibly inactivated by a cold probe. URs after unpaired treatment were unaffected by inactivation but after acquisition of a robust level of conditioned responses (CRs), URs in US-alone test trials were reduced in amplitude compared with URs immediately before and after inactivation. The results suggest that the IPN has a role in CR-related reflex modification.
Cooling of the cerebellar interpositus nucleus abolishes somatosensory cortical learning-related activity in eyeblink conditioned rabbits.
2005
Nictitating membrane movement and multiple-unit activity in the somatosensory cortex were recorded from rabbits during paired (N = 6) and unpaired (N = 5) presentations of a tone conditioned stimulus (CS) and an airpuff unconditioned stimulus (US). A behavioural conditioned response (CR) to the CS and an accompanying neural response in the somatosensory cortex developed only in the paired group. Inactivation of the cerebellar interpositus nucleus abolished both the acquired CR and the accompanying neural response. However, the CS facilitated both behavioural and neural responses to the US during the inactivation. Thus, the absence of the CR could not be accounted for by the general inabilit…
Activity in the rabbit somatosensory cortex reflects the active procedural memory trace of a classically conditioned eyeblink response.
2003
Behavioral responses and neural responses in the somatosensory cortex were recorded in nine rabbits during the unpaired and paired treatments of classical eyeblink conditioning with a tone conditioned stimulus (CS) and an airpuff unconditioned stimulus. During the unpaired treatment, neither the behavioral nor neural responses to the CS were observed. During the paired treatment, behavioral conditioned response (CR), accompanied by neural activity, was developed. In well-trained animals occasional failures to elicit the CR were accompanied by an absence of neural responses. Nevertheless, the CS modified the behavioral unconditioned response in paired trials, implying that the CR-failures co…
Phase matters: responding to and learning about peripheral stimuli depends on hippocampal θ phase at stimulus onset.
2015
Hippocampal θ (3–12 Hz) oscillations are implicated in learning and memory, but their functional role remains unclear. We studied the effect of the phase of local θ oscillation on hippocampal responses to a neutral conditioned stimulus (CS) and subsequent learning of classical trace eyeblink conditioning in adult rabbits. High-amplitude, regular hippocampal θ-band responses (that predict good learning) were elicited by the CS when it was timed to commence at the fissure θ trough (Trough group). Regardless, learning in this group was not enhanced compared with a yoked control group, possibly due to a ceiling effect. However, when the CS was consistently presented to the peak of θ (Peak group…
Effects of Hippocampal State-Contingent Trial Presentation on Hippocampus-Dependent Nonspatial Classical Conditioning and Extinction
2014
Hippocampal local field potentials are characterized by two mutually exclusive states: one characterized by regular θ oscillations (∼4–8 Hz) and the other by irregular sharp-wave ripples. Presenting stimuli during dominant θ oscillations leads to expedited learning, suggesting that θ indexes a state in which encoding is most effective. However, ripple-contingent training also expedites learning, suggesting that any discrete brain state, much like the external context, can affect learning. We trained adult rabbits in trace eyeblink conditioning, a hippocampus-dependent nonspatial task, followed by extinction. Trials were delivered either in the presence or absence of θ or regardless of hippo…
Hippocampo-cerebellar theta band phase synchrony in rabbits.
2009
Hippocampal functioning, in the form of theta band oscillation, has been shown to modulate and predict cerebellar learning of which rabbit eyeblink conditioning is perhaps the most well-known example. The contribution of hippocampal neural activity to cerebellar learning is only possible if there is a functional connection between the two structures. Here, in the context of trace eyeblink conditioning, we show (1) that, in addition to the hippocampus, prominent theta oscillation also occurs in the cerebellum, and (2) that cerebellar theta oscillation is synchronized with that in the hippocampus. Further, the degree of phase synchrony (PS) increased both as a response to the conditioning sti…