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Biomedical subjects

P R Laming

Publications and source records attributed to P R Laming.

33 records · Page 2Linked to original sources
PubMed1988

Effects of telencephalic ablation on habituation of arousal responses, within and between daily training sessions in goldfish.

Goldfish Carassius auratus were presented with a moving shadow stimulus at 2-min intervals and their cardiac and ventilatory responses were monitored. Normal fish, fish with their telencephalon ablated, and those with sham operations were compared for responsiveness and habituation to repeatedly presented stimuli over the 3-day test period. While all groups showed increased habituation on successive days testing, fish with their telencephalon ablated showed significantly slower response habituation within the daily test sessions when compared with the control groups. Subjects with their telencephalon ablated also showed a tendency for increased responsiveness on initial stimulus presentation and poorer retention between days of information relating to the eliciting test stimulus.

Animals↗
PubMed1987

Epileptogenesis is associated with heightened arousal responses in fish.

Intramuscular injection of sodium penicillin in roach (Rutilus rutilus) caused delayed habituation of arousal responses to repeated presentation of the onset of illumination or of a 'tap' stimulus. Topical application of aluminum hydroxide to the telencephalon of roach had a similar effect but was shown, also, to induce electroencephalographic seizures, in which the EEG amplitude was elevated from 4-20 times its normal level. Both treatments caused intermittent, abnormal 'weaving' behaviour and sporadic, violent, uncoordinated motor activity. In goldfish, Carassius auratus, topical application of aluminum hydroxide also caused delayed habituation of quantitatively measured, cardiac arousal responses to a moving shadow stimulus, compared to controls. This delayed habituation was, however, largely a result of the elevated magnitude of these arousal responses. The results are discussed in relation to brain mechanisms normally operative during arousal which may be hyperactive in epilepsy.

Administration, Topical↗
PubMed1987

Developmental, sexual and reproductive differences in habituation shown by the guppy (Poecilia reticulata).

Behavioural arousal responses of guppies (Poecilia reticulata) were observed to repeated presentation of 2 seconds increased illumination at 30 second intervals. Habituation of responses occurred more rapidly in males than in females and habituation in females was related to their reproductive state. Exposure of gravid females for 8 days to a daily series of stimuli resulted in their young having enhanced habituation postnatally. The results are discussed in relation to developmental and possible hormonal influences on arousal and its habituation in fish.

Animals↗
PubMed1987

Behavioural arousal and its habituation in the squirrel fish, Holocentrus rufus: the role of the telecephalon.

Squirrel fish were captured, maintained for 2 days and then tested for their responses to stimuli in laboratory aquaria. A tap on the side of the aquarium or a shadow moving overhead elicited an arousal response involving a reduction in opercular movements, movement of the pectoral fins, and erection of the spiny dorsal fin. This latter response, when regularly provoked by a moving shadow at 15-s intervals, decreased in duration and habituated. When fish were restricted in a wire mesh trough and the stimulus was the onset of illumination to one eye at 15-s intervals, responses were quantitatively similar although shorter in duration. A series of stimuli delivered to one eye until habituation followed by a series to the other eye reduced the duration of initial responses and the number of trials for habituation of responses to stimuli delivered to the second eye. Responses were equivalent regardless of which eye (left or right) was first presented with stimuli. Section of the telencephalic anterior commissure considerably restricted the transfer of information about experience of stimuli presented to the first eye. Commissural section, combined with unilateral lesions in the posterior-medial telencephalon, severely impaired habituation of responses to the contralateral eye. Lateral lesions had no effect. The results are discussed in relation to the visual projection in Holocentrus and telecephalic involvement in arousal and its habituation in teleosts as a whole.

Animals↗
PubMed1986

Cardiac and ventilatory arousal responses and their habituation in goldfish: effects of the intensity of the eliciting stimulus.

Recordings were made of cardiac and ventilatory responses of goldfish to the onset of 10 sec illumination presented at 2 min intervals. These responses were measured by increases in cardiac interbeat interval, ventilatory interbreath interval and by reductions in ventilatory amplitude. Four groups of fish were subjected to intensities of 52, 78, 90 and 160 lux. Habituation of responses was considered to have occurred when its magnitude fell within the limits of normal variation of the physiological variable. It was found that the more intense the stimulus the greater was the magnitude of the initial physiological response and correlated with this the number of stimulus presentations required for habituation. The relationship between stimulus intensity, initial response magnitude and resistance to habituation was consistent for cardiac responses. The results are discussed with respect to current knowledge of arousal and its habituation.

Animals↗
PubMed1986

Localization of telencephalic regions concerned with habituation of cardiac and ventilatory responses associated with arousal in the goldfish (Carassius auratus).

Goldfish (Carassius auratus) were presented with a "light-on" stimulus at 2-min intervals, and their cardiac and ventilatory responses were monitored. Normal fish, fish with sham operations for telencephalic lesions, and fish with bilateral electrolytic lesions of the telencephalon (anterior commissural and posterior telencephalic groups) were compared for responsiveness and habituation to regularly presented stimuli. There was no evident difference in responsiveness between the four groups, though 3 fish with lesions in the regions ventralis pars dorsalis and ventralis pars ventralis gave fright responses to novel stimuli. Lesions in posterior telencephalic regions dorsalis pars centralis and ventralis pars intermedialis and at the telencephalic/diencephalic border close to the habenula caused significant impairment of habituation.

Animals↗
PubMed1984

Visual unit, EEG and sustained potential shift responses in the brains of toads (Bufo bufo) during alert and defensive behavior.

Cranially mounted differential preamplifiers allowed visual unit activity, EEGs and sustained potential shifts to be monitored from the tectum of freely moving toads (Bufo bufo). Alert behavior was elicited by a moving visual stimulus. Movement of the stimulus in the receptive field of a unit elicited its activity and increased the amplitude of the high frequency component of the local EEG, accompanied by a sustained potential shift. When an animal received a "prod" with a perspex rod, defensive behavior ensued accompanied by slight activity of the visual unit, a large increase in the amplitude of the lower frequency component of the EEG and a large, sustained, potential shift. The results are discussed in relation to the specific neuronal unit responses of the animal and to possible sensitising functions of the non-specific EEG and sustained potential shift responses.

Animals↗
PubMed1984

Effects of olfactory bulb ablation on cardiac and ventilatory arousal responses and their habituation in the goldfish Carassius auratus.

The effects of olfactory bulb ablation on the cardiac and ventilatory arousal responses to the onset of illumination and habituation of these responses were investigated in goldfish. Bulbectomy did not effect the magnitude of response on novel stimulus presentation. Normal, sham operated, and olfactory bulb-ablated animals showed similar rates of habituation. These results suggest that deficits in feeding and sexual behavior in goldfish are due to the loss of specific olfactory influences on lower brain centers and not due to a decrease in general responsiveness.

Animals↗
PubMed1984

Effects of telencephalic ablation on visual unit, sustained potential shift, and EEGs recorded from the toad tectum in response to a visual stimulus.

Extracellular recordings were made of visual unit activity, sustained potential shifts (SPSs), and electroencephalographic activity (EEGs) from the optic tectum and of EEGs from the telencephalon of immobilized toads (Bufo bufo). Moving visual stimuli were presented, and the bioelectric responses were monitored both before and after ligature of the telencephalon. The operation reduced the neuronal spike frequency and the amplitude of the tectal SPS and EEG responses. EEGs were still recorded from the tectum and even the isolated telencephalon. The results are discussed in relation to possible adaptive functions of SPS and EEG changes, the genesis of the EEG, and the role of the telencephalon in visually guided prey-catching behavior.

Animals↗
PubMed1982

Habituation of fright and arousal responses in the teleosts Carassius auratus and Rutilus rutilus.

The habituation of fright and arousal responses of goldfish (Carassius auratus) and roach (Rutilus rutilus) to the repeated operation of a plunger in the water was studied. The early response was of fright, which habituated, and the response characteristic of arousal appeared, which then habituated as well. Longer intervals between stimuli required more presentations of the stimulus for habituation to occur in goldfish. Roach required more presentations of the stimulus than goldfish for the responses to habituate, and telencephalic ablation severely impaired habituation of arousal, though not fright responses, in this species. The results are discussed in relation to recent work on arousal, habituation, and telencephalic function in fish.

Animals↗
PubMed1981

Deficits in habituation of cardiac arousal responses incurred by telencephalic ablation in goldfish, Carassius auratus, and their relation to other telencephalic functions.

The effects of telencephalic ablation on the habituation of cardiac arousal responses in goldfish was studied. The ablation was performed either by ligating the telencephalon of habituated fish between stimulus presentations or by aspiration prior to habituation. The former technique caused dishabituation; the latter, a slower rate of habituation than that of sham-operated controls. The habituation deficit incurred by surgical ablation was found to decline with time, being small after 2 wk. The results are discussed in relation to other telencephalic involvements in behavior and to the plasticity of other parts of the brain which enables them to assume telencephalic functions.

Animals↗
PubMed1980

Electroencephalographic studies on arousal in the goldfish (Carassius auratus).

Goldfish with implanted intracranial electroencephalographic (EEG) electrodes showed high-voltage slow activity of 6-9 Hz and a low-voltage fast activity of 16-24 Hz when resting in the dark. The former frequency was prevalent in the telencephalon, diencephalon, and midbrain but remained only in parts of the midbrain and cerebellum when the fish was left resting in an illuminated environment. In this latter condition the 16-24 Hz activity became predominant. Presentation of two stimuli, the onset of illumination and the passage of a moving edge across the source of illumination, caused bradycardia and a reduction in ventilatory rate, associated with behavioral arousal in this animal. An increase in the amplitude of 16-24 Hz activity in the EEG also occurred, most evident in the anterior and posterior tectum and dorsomedial and posterior telencephalon. Anterior tectal EEGs, on arousal, had the shortest latency and longest duration and were most resistant to habituation on repeated presentation of the moving-edge stimulus, the dorsomedial telencephalon showing similar characteristics to a lesser degree. It is suggested that these areas may be intimately concerned with the arousal response in teleosts.

Animals↗